Implant Placement Surgical Protocol










644
27
Implant Placement Surgical
Protocol
RANDOLPH R. RESNIK
Pre-Implant Placement Protocols
e technique for dental implant surgery has evolved over the years
from the original protocol pioneered in the 1970s by Per-Ingvar
Brånemark, a Swedish physician and researcher. With Brånemarks
delayed approach, implant placement was completed, then after
a healing period, the implants were exposed and prosthetically
rehabilitated. Today, with the integration of computer and digi-
tized technology, dental implant clinicians now have a full array of
choices with the placement of dental implants.
Flap Design
Prior to the placement of implants, the underlying bone and oste-
otomy site must be exposed for implant osteotomy preparation
and insertion (Chapter 26).
Full-thickness ap: e most common technique includes a mu-
coperiosteal ap, which may involve the buccal, lingual, and
crestal areas.
Flapless: is technique does not reect the crestal soft tissue. Instead,
a core of keratinized tissue (the size of the implant crest module di-
ameter) is removed over the crestal bone. e implant osteotomy is
then performed in the center of the core of the exposed bone. is
protocol requires no sutures around the healing abutment after
implant placement. e advantages of this technique include less
discomfort, tenderness, and swelling, which are usually minimal.
e primary disadvantage of the apless approach is the in-
ability to assess the bone volume before or during the implant
osteotomy or insertion. erefore this technique should only be
used when the bone width is abundant (>7 mm). In addition,
bone grafting needs and procedures cannot be precisely evaluat-
ed. e soft tissue around the implant site should be ideal in the
amount of attached keratinized mucosa because the soft tissue
pouch is over the bone site, not in a region related to the soft tis-
sue. Often, the keratinized tissue is reduced on the buccal half of
the ridge and the tissue punch may inadvertently remove all the
keratinized tissue on the facial aspect of the implant. Because the
crest of the ridge is below the soft tissue, it is dicult to see lines
on the drill to access the depth of drilling. erefore stops on the
drill are particularly benecial. e clinician may have diculty
in assessing the location of the implant crest module in relation
to the crest of bone because it is also below the soft tissue. And
lastly, the interdental papillae may not be elevated with this tech-
nique. erefore the soft tissue drape should be ideal in volume
of keratinized tissue, both faciolingually and mesiodistally.
Surgical Approaches
Freehand surgery: is may include the ap or apless technique, with
the clinician placing the implant with the diagnostic information
available (i.e., position of adjacent teeth, radiographs). Freehand
surgery may include the use of nonlimiting surgical templates,
which allow the surgeon the dimensional variability in implant
location because the template will indicate the position of the
nal prosthesis; however, it will not specically guide the place-
ment of the implant (see Chapter 15 for surgical approaches).
Guided: is type of surgery, which may be performed ap or apless,
guides the osteotomy from a digitally designed and printed surgical
template. is type of surgery allows the highest level of precision
and control because the implant position is dictated via a compre-
hensive three-dimensional evaluation of the anatomy. Guided sur-
gery may be dierentiated by the type of support of the template:
Bone supported: e template rests on the alveolar bone and
this technique requires the reection of a full thickness ap.
Tissue (mucosa) supported: e template is supported by the soft
tissue. is type of template is most commonly used with a
apless technique.
Tooth-supported: is is the most accurate technique and in-
cludes placement of the template directly on the natural
teeth for support.
Guided surgery may also be classied according to the amount
of drill guidance:
Pilot template: Allows guidance for the position and angulation
for only the rst drill in the surgical protocol. After the rst
drill, the osteotomy is completed freehand.
Universal template: is type of template is compatible with all
implant systems and allows for depth, position, and angula-
tion. However, the nal osteotomy drill, along with implant
placement, is completed freehand.
Fully guided template: Template that allows for depth, position,
angulation, and implant placement via the guide.

645
CHAPTER 27 Implant Placement Surgical Protocol
Navigational directed surgery: Computerized navigation surgery has
evolved from neurosurgical procedures into the eld of dental
implantology. is technique allows the clinician to precisely
transfer a detailed presurgical implant plan to the patient. e
clinician uses computerized navigation to adjust the position
and angulation of the surgical drill according to the presurgical
digital implant plan. e real-time imaging of the surgical drill
allows for continuous updates on the positioning of the drill to
avoid critical anatomic structures.
Dental Implant Osteotomy Preparation
Decreasing Heat During Osteotomy Preparation
e heat generated during an implant osteotomy is related to the
presence and temperature of irrigation,
1-3
amount of bone being
prepared,
4,5
drill sharpness and design,
5,6
time of preparation,
7
depth of the osteotomy,
8,9
pressure on the drill,
5
drill speed,
10
and
variation in cortical thickness (bone density).
11
Bone cell survival is very susceptible to heat. Eriksson has dem-
onstrated that, in animal studies, bone temperature as low as 3°C
above normal (40°C) can result in bone cell necrosis.
12
erefore
a conscious eort is made to control temperature elevation every
time a rotary instrument is placed in contact with bone. Many
dental implant preparation variables need to be addressed in
understanding the reduction of heat during the osteotomy process.
Irrigation versus No Irrigation
Although some authors have advocated implant osteotomy
preparation without irrigation, the literature does not support
it.
13
Yacker and colleagues showed that, without irrigation,
drill temperatures greater than 100°C are reached within sec-
onds of the osteotomy, and consistent temperatures greater than
47°C are measured several millimeters away from the implant
osteotomy.
14
Benington and colleagues have reported that the
osteotomy temperature may rise up to 130.1°C without irriga-
tion after monitoring changes in bone temperature during the
sequence of drilling for implant site preparation.
15
To minimize heat generation, at least 50 mL/min of cooled
irrigation of sterile saline (0.9% NaCl) should be used as a pro-
fuse irrigant and is a critical factor in the osteotomy process. e
more dense the bone, the greater the need for copious irrigation.
Distilled water should not be used because rapid cell death may
occur in this medium.
4,9
e irrigant also may act as a lubricant
and removes bone particles from the implant osteotomy site. e
temperatures of the irrigant can also aect the bone temperature.
Barrak and colleagues reported that cooling the irrigation uid
to 10°C, no mean temperature change >1°C will occur. ere-
fore placing the irrigation uid into a refrigerator before implant
surgery will help to prevent heat generation during implant place-
ment
16,17
(Fig. 27.1).
Graduated versus One-Step Drilling
e amount of heat produced in the bone is directly related to the
amount of bone removed by each drill.
18
For example, a 2-mm
pilot drill generates greater heat than a 1.5-mm pilot drill.
4
As a
result, most manufacturers suggest that the rst drill (pilot) should
be approximately 1.5 mm in diameter. In a similar fashion, the
amount of heat generated by successive drills is also directly related
to the increase in drill diameter.
19
For example, a 3-mm drill after
a 2-mm drill removes 0.5 mm on each side of the drill. A 2.5-mm
drill after a 2-mm drill only cuts 0.25 mm of bone on each side of
the osteotomy. e smaller incremental drill size allows the clinician
to prepare the site faster, with less pressure and less heat genera-
tion.
6
In addition, when larger increases in drill diameter are used
to prepare bone, the clinician may inadvertently change the angula-
tion of the drill because the larger drill is removing a greater bone
volume and the tactile sense is decreased. As a result, an elliptical
osteotomy may be prepared that does not correspond accurately
to the round implant diameter. e gradual increase in osteotomy
size also reduces the drill shatter at the crestal opening, which can
inadvertently fragment the bony crest in which complete bony con-
tact is especially desired. e gradual increase in drill diameter also
maintains the sharpness of each drill for a longer period, which also
reduces the heat generation (Fig. 27.2).
Fig. . Irrigation should use 0.9% NaCl (sterile saline), which may be
cooled to reduce heat generation. The irrigation bags may be stored in a
refrigerator.
Fig. . Number of steps in the preparation of the osteotomy is related to
the bone density. Usually D1 will require all drills including the bone tap, the D2
protocol uses all drills except the bone tap, D3 requires the standard protocol
stopping at the second to last drill, and D4 uses only the first or second drills.

646
PART VI Implant Surgery
Drilling Speed
e subject of drilling speed has become very controversial in
implant dentistry today. Eriksson and colleagues originally rec-
ommended drilling speeds of 1500 to 2000 rotations per minute
(rpm) with irrigation.
20
Most recently in implant dentistry, the
rotational speed of the drill has been suggested to be less than
2000 rpm, and several manufacturers have recommended speeds
as low as 50 rpm. Kim and colleagues suggested drilling osteoto-
mies at 50 rpm without irrigation and stated that the bone tem-
perature may not signicantly increase.
13
However, Yeniyol and colleagues showed that excessively low drill-
ing speeds (less than 250 rpm) increased the degree of fragmentation
of the osteotomy edge. It has been shown that low speed drills will
wobble,” which leads to overpreparation of the osteotomy site.
21
A controversial subject in implant dentistry is whether higher
drilling speed is correlated with higher bone temperature dur-
ing preparation. Although some reports have shown this, the
majority of well-documented studies disprove this. For exam-
ple, if high-speed preparation was detrimental, then slow-speed
handpieces would be used to prepare natural teeth. A high-speed
handpiece (300,000 rpm) can remove bone over an impacted
tooth or during an apicoectomy and still allow bone regenera-
tion. Rafel prepared bone at 350,000 rpm in a human mandible
and found a temperature of only 23.5°C at a distance of 3 mm
from the drill periphery.
22
High-speed drills at 300,000 rpm
have been used to prepare blade implant osteotomies for years,
yet studies proved bone grew over the blade shoulder and was in
direct contact with the implant.
23
A study by Sharawy and colleagues compared four drill designs
(two internal irrigated and two external irrigated) at speeds of
1225, 1667, and 2500 rpm.
4
ermocouples connected to a com-
puter to record temperature and time were placed within 1 mm of
the osteotomy site in D2-type bone (Fig. 27.3). All drill designs
in the study recorded lower bone temperatures with the great-
est rotations per minute and, conversely, found the highest bone
temperatures with the lowest rotations per minute (Figs. 27.4 and
27.5). As important, the slowest rotations per minute resulted
in bone temperatures at or greater than 40°C, which may be a
threshold of bone cell death. e highest rotations per minute
(2500) increased the bone temperature by 2° to 3.5°C, whereas
the 1225 rpm recorded a bone temperature greater than 41°C.
erefore the higher speed of 2500 rpm may prepare bone at a
lower temperature than 1500 rpm, especially when in dense bone.
e rotational speed of the drill is one of the more critical criteria
to reduce bone temperatures.
Sharawy and colleagues demonstrated that, regardless of the
drill design or method of irrigation, 2500 rpm prepared bone at
a lower temperature than slower speeds.
4
e clinician should
allow the cutting surface of the drill to contact D1 and D2 bone
fewer than 5 of every 10 seconds. Ideally, a pumping up-and-
down motion (i.e., bone dancing) is used to prepare the osteot-
omy and provide constant irrigation to the drill cutting surface. It
also maintains a constant drill speed and reduces the friction time
against the bone, all of which reduce heat.
Drilling Time
Eriksson reported bone cell death when a temperature of 40°C
was applied for 7 minutes, or when a temperature of 47°C was
applied for 1 minute.
12
In other words, time and temperature are
interrelated critical factors in implant site preparation. As the tem-
perature increases, the time the bone temperature is elevated must
be reduced. In the study by Sharawy and colleagues, the time the
bone temperature remained elevated was recorded for each rota-
tion per minute evaluated.
4
When the drill prepared an 8-mm
depth osteotomy, the temperature remained elevated for 45 to 58
seconds (Fig. 27.6). e slower the rotations per minute (1225),
the longer the bone temperature remained above the baseline.
Because two to three drills are used to prepare an implant site, at
1225 rpm the rst drill may increase the temperature to 41°C, the
second drill to 45°C, and the third drill to 49°C, when the time
between each sequence is not extended more than 1 minute. In the
study by Sharawy and colleagues, the rst drill diameter recorded
the longest preparation time and the highest temperature, and the
longest recovery time. erefore to reduce the preparation time
within the bone to a minimum in D1 bone, the clinician should
not apply constant pressure to the drill, but “bone dance” with
8 mm
B
0.1 mm
Mean of four channels
Ch. B
Ch. D
Ch. A
Ch.
C
Fig. . Thermocouples were positioned within 1 mm of the drill site
and inserted into bone for a depth of 8 mm. The wires were connected to
a computer to measure the temperature, time of preparation, and time the
bone temperature was elevated.
4.5
*
*
*
*
*
4
3.5
3
2.5
2
1.5
1
0.5
0
2.3 mm
Mean rise in temperature
3.2 mm 4.2 mm
1225 rp
m
1667 rp
m
2500 rp
m
Fig. . Internally cooled drill of the Paragon implant system recorded
41°C with the first drill at 1225 rpm; 2500 rpm reduced the bone tempera-
ture preparation for all drill diameters.
3.5
3
2.5
2
1.5
1
0.5
0
2 mm 3 mm
Mean rise in temperature (°C)
3.85 mm 4.3 mm
1225 rp
m
1667 rp
m
2500 rp
m
Fig. . Externally cooled drills of the Brånemark implant system
recorded reduced temperatures at 2500 rpm, compared with slower
speeds.

647
CHAPTER 27 Implant Placement Surgical Protocol
intermittent pressure for 1 second in the D1 bone and 1 to 2
seconds out of the bone while the cooled irrigation is allowed to
perfuse the site.
In summary, in D1 and D2 bone, a higher speed (1500–2000
rpm) should be used in the preparation of bone. In poorer quality
bone (e.g., D3 and D4) drilling speed is not as crucial, therefore a
lower speed maybe use (1000 rpm).
Drilling Pressure
e pressure exerted when preparing the osteotomy should not
result in heat generation. Hobkirk and Rusiniak found that the
average force placed on a handpiece during preparation of an oste-
otomy is 1.2 kg.
11
Matthews and Hirsch concluded that the force
applied to the handpiece was more inuential than the drill speed
in temperature elevation.
24
When the pressure on the handpiece
was increased appropriately, drill speeds from 345 to 2900 rpm
did not aect the temperature. Matthews and Hirsch found that
increasing both speed and pressure allowed the drill to cut more
eciently and generated less heat. e eect of drill speed and
pressure related to bone temperature was also reported by Bris-
man.
10
In cortical bone, speeds of 1800 rpm with a load of 1.2
kg produced the same heat as when speed increased to 2400 rpm
with a pressure of 2.4 kg. e greater speed and greater pressure
was more ecient than low speeds. Increasing pressure alone
increased heat; increasing speed alone also increased heat. Dier-
ent amounts of pressure are therefore used in response to the den-
sity of the bone. Sucient pressure should be used on the drill to
proceed at least 2 mm every 5 seconds. If this is not achieved, then
new (sharper) or smaller diameter drills are indicated for each site
preparation. e pressure on the drills should not reduce the rota-
tions per minute, which makes the drill less ecient and increases
heat. Handpieces of sucient torque should be used to prevent
this complication.
Intermittent versus Continuous Drilling
When preparing an osteotomy site, continuous drilling (i.e., no
pumping motion) results in numerous possible negative conse-
quences. When constant pressure is applied, irrigation cannot
enter the osteotomy site; therefore this may result in heat-related
damage. In addition, by not removing the drill from the osteot-
omy site during preparation, bone debris is maintained within the
utes of the surgical burs, resulting in potential heat generation.
is also leads to less ecient drilling.
When intermittent drilling or bone dancing (i.e., continuously
bringing the surgical bur in and out of the osteotomy site), less
heat generation is seen. By bringing the bur in and out of the
osteotomy site, irrigation may enter the site along with allowing
any debris to be removed, thus making the cutting process more
ecient. e only disadvantage of the bone dancing technique is
the possibility of changing angulation or inadvertent widening of
the osteotomy site.
25
Care should be exercised in withdrawing and
inserting the implant drill at the same trajectory or angulation.
Insertion Torque
e insertion torque (IT) is the force used to insert a dental implant
into a prepared osteotomy. e amount of torque is expressed in
units of newton centimeters (N/cm), which ultimately determines
the loading protocol. IT is the primary most important factor in
determining primary stability, with higher torque values leading
to higher primary stability.
26
Lower values of IT have been shown to be associated with
implant failures.
27
Many studies have indicated IT near the range of 35-45 N/cm
to be ideal for implant integration.
28,29
To standardize the amount
of torque, calibrated torque wrenches, physiodispenser instru-
ments with integrated electronic torque control settings, and pre-
set torque settings on the implant electric motor systems should
be used (Box 27.1).
Bone Density Factors Related to Implant
Preparation
As discussed in Chapter 18, the density of the available bone
has a signicant eect on the predictability and success of dental
implants. In the past, clinical reports that did not alter the surgical
and prosthetic protocol had variable survival rates. In this chap-
ter, a generic surgical protocol will be discussed, which is directly
60
50
40
30
20
5.46
4.28
55
51.8
41.6
3.78
4.1
2.84
51.4
47.8
38.2
2.8
3.64
2.3
46.8
31.6
32
2.3
3.14
2.08
35
18.4
13.6
2.02
3.25 mm 3.8 mm2.7 mm
Drill diameters
Time (seconds)
Osteotomy preparation at 1225 rpm
Elevated bone temperature at 1225 rp
m
Osteotomy preparation at 1667 rpm
Elevate bone temperature at 1667 rpm
Osteotomy preparation at 2500 rpm
Elevated bone temperature at 2500 rp
m
2 mm
10
0
Fig. . Internally cooled drills of the Nobel Biocare, Steri-Oss implant system demonstrate the tem-
perature in the bone remains elevated for an extended period (up to 58 seconds) after site preparations in
D2 bone. The lower the rotations per minute are the longer the temperature remains elevated.

648
PART VI Implant Surgery
related to bone density that has been shown to increase success of
dental implants.
e density of available bone in an edentulous site has a pri-
mary inuence on treatment planning, implant design, surgical
approach, healing time, and initial progressive bone loading dur-
ing prosthetic reconstruction. e quality of the recipient bone
directly inuences the amount of trauma generated during oste-
otomy preparation. is in turn provokes a cascade of reactions at
the bone–implant interface that directly aect the quality of the
load-bearing surface.
Once the implant is initially integrated with the bone, the
bone-loading process from occlusal forces becomes a critical fac-
tor in long-term implant survival. e bone density under load
is directly related to the bone strength and is therefore a critical
parameter for long-term survival.
30,31
e occlusal stresses applied
through the implant to the bone must remain within the physi-
ologic to mild overload zone; otherwise, pathologic overload with
associated bone loss and microfracture leading to implant failure
may occur. e treatment planning and scientic rationale of
strength, modulus of elasticity, bone-implant contact (BIC) per-
centage, and stress transfer dierence related to bone density has
been addressed in Chapter 18. is chapter addresses the modi-
cations of the surgical and healing aspects related to each bone
density in the oral environment.
Literature Review
Lekholm and Zarb listed four bone qualities found in the anterior
regions of the jawbone: quality 1, comprises homogeneous com-
pact bone; quality 2, a thick layer of compact bone surrounding
a core of dense trabecular bone; quality 3, a thin layer of corti-
cal bone surrounding dense trabecular bone of favorable strength;
and quality 4, a thin layer of cortical bone surrounding a core of
low-density trabecular bone.
32
Irrespective of the dierent bone
qualities, all bone was treated with the same implant design and
standard surgical and prosthetic protocols.
After the proposed protocols of Brånemark and colleagues,
it was found that implant survival in initial surgical success was
related to the quality of bone.
33
A higher surgical failure was
observed in softer bone types, especially in the maxilla. For exam-
ple, Engquist reported the surgical loss of 38 of 191 implants in
the maxilla in D4 bone (20% loss) compared with 8 of 148 man-
dibular implants (5% loss) before stage II surgery.
34
Jan and Ber-
man reported an overall 8.3% surgical and initial healing loss in
444 maxillary implants with softer bone.
35
Friberg and colleagues
reported a 4.8% implant failure at stage II uncovery for 732 max-
illary posterior implants, which was greater than mandibular fail-
ure.
36
Quirynen etal. also reported a 4.1% implant loss at stage
II uncovery out of 269 implants in the maxilla.
37
Fugazzotto and
colleagues reported 22 failures out of 34 implants placed in qual-
ity 4 bone.
38
Hutton and colleagues identied poor bone quantity
and quality 4 as the highest risk of implant failure in a study of
510 implants, with an overall failure rate in the maxilla nine times
greater than in the mandible.
39
Sullivan and colleagues indicated a
6.4% stage II failure rate in the maxilla (12/188) and a 3.2% fail-
ure in the mandible (7/216).
40
Snauwaert and colleagues reported
more frequent early failures in poor density maxillae.
41
Herrmann
and colleagues correlated failure factors such as poor bone quality
and volume.
42
A number of reports in the literature demonstrated
that the greatest risk of surgical failure was observed in the softest
bone type (D4), especially when found in the maxilla.
On the other extreme, a large clinical study from 33 US
Department of Veterans Aairs (VA) hospitals by the Dental
Implant Clinical Research Group (DICRG) states quality 1 bone
had the highest surgical failure rate (4.3%), followed by quality 4
(3.9%), quality 2 (2.9%), and quality 3 with the fewest failures
at 2.6% (Fig. 27.7). e overall implant surgical failure was 3%;
the maxilla had better success at stage II surgery (98.1%) than
the mandible (96.4%).
43
It must be emphasized that these reports
only present implant failures up to stage II uncovery. e DICRG
also noted that the failure rate was twice as great for surgeons who
had placed fewer than 50 implants, compared with more experi-
enced surgeons. e literature contains many published reports
that indicated an implant surgical failure range from 3.2% to
5% in the mandible and 1.9% to 20% in the maxilla, with most
reports indicating the greatest failure rates in maxillary implants
with soft bone. It is clear from these reports that a wide range of
results may be achieved; therefore consideration should be given
to methods that improve surgical survival.
Misch developed a dierent surgical protocol for dierent bone
qualities in 1988. e Misch classication of bone density includes
four classications, D1, D2, D3, and D4, which are based on
the amount of cortical and cancellous bone. D1 bone is primarily
composed of dense cortical bone and found mainly in the anterior
mandible, with basal bone. D2 bone has dense-to-porous corti-
cal bone on the crest and, within the bone, has coarse trabecular
bone. D3 bone types have a thinner porous cortical crest and ne
trabecular bone in the region next to the implant. D4 bone has
almost no crestal cortical bone. e ne trabecular bone composes
almost all of the total volume of bone next to the implant.
After these specic methods, prospective and retrospective
multicenter clinical studies in a wide range of oce settings found
surgical survival to be greater 99%, regardless of the density type
of bone, the arch (mandible versus maxilla), and gender and age of
• Irrigation: copious amounts of 0.9% NaCl
• Irrigation solution temperature: refrigerate before use
• Drilling technique: graduated protocol (more drills)
• Intermittent(bonedancing)
• Drilling speed: D1, D2 bone is 1500–2000 rpm; D3, D4 bone is 1000 rpm
• Drilling time: greater drilling time, greater heat generation
• Drilling pressure: minimize pressure, never allow rotations per minute
to decrease from excess pressure
• Insertion torque: 35-45 N/cm
BOX
27.1
Generic Osteotomy Preparation Summary
Stage I
Stage II
Implant failure %
12
34
1
2
3
4
5
0
Decreasing bone quality
Fig. . A study by the Dental Implant Research Group represented 33
different hospitals that place dental implants. The highest surgical failure
rate was quality 1 bone, followed by quality 4 bone. The fewest surgical
failures were observed in quality 3 bone.

649
CHAPTER 27 Implant Placement Surgical Protocol
the patient.
44,45
erefore a dierent surgical protocol for dier-
ent bone densities appears warranted. e implant design, surgical
protocol, healing, treatment plans, and progressive loading time
spans are unique for each bone density type. More recently the
use of improved rotary instruments, implant designs, and surgi-
cal approaches for dierent bone qualities has been recognized
as a valid recommendation. A multicenter prospective clinical
study by Misch and colleagues of 364 consecutive implants in
104 consecutive patients found a surgical survival rate (up to
abutment connection) at stage II of 100% for D1, 98.4% for
D2, 99.8% for D3, and 100% for D4 implants
46
(Fig. 27.8).
Altering the surgical approach for each bone density can yield an
overall implant surgical survival of 99.8% and a 2-year survival
of 99.4%. In this chapter the surgical considerations and opti-
mal healing time are discussed relative to each bone category,
based on the literature, prospective clinical studies, and long-
term experience.
Bone Density Classifications
Misch dened four bone density groups in all regions of the
jaws that vary in both macroscopic cortical and trabecular bone
types.
47
e regions of the jaws are divided into (1) the ante-
rior maxilla (second premolar to second premolar), (2) posterior
maxilla (molar region), (3) anterior mandible (rst premolar to
rst premolar), and (4) posterior mandible (second premolar and
molars). e regions of the jaws often have similar bone densities
(Fig. 27.9).
In general, the anterior mandible is usually D2 bone, the poste-
rior mandible is D3 bone, the anterior maxilla is D3 bone, and the
posterior maxilla is often D4 bone. is generalization is used for
the initial treatment plan. However, resorbed anterior mandibles
may be D1 bone in approximately 25% of male patients and the
posterior maxilla may have D3 bone after 6 months in the majority
of sinus graft patients. e regional locations of the dierent densi-
ties of cortical bone are more consistent than the highly variable
trabecular bone. Bone density may be most precisely determined
before surgery by a computed tomography (CT) scan of the eden-
tulous site (accompanied by Hounseld values of the bone). Refor-
matted software allows “electronic surgery” of the CBCT images
and relates the Hounseld values at the implant–bone interface.
Conventional dental radiographs, such as periapical, panoramic,
or lateral cephalometric images, are usually not diagnostic (Boxes
27.2 and 27.3) in the assessment of bone density.
A common point at which to evaluate bone quality is dur-
ing surgery. e presence and thickness of a crestal cortical plate
and the density of trabecular bone are easily determined during
implant osteotomy preparation. e density of bone is deter-
mined by the initial bone drill, and evaluation continues until the
nal osteotomy preparation.
It should be emphasized that the bone density (D1–D4) clas-
sication of Misch is slightly dierent from Lekholm and Zarbs
bone quality types (Q1–Q4). According to Misch and colleagues,
D3 bone has ne trabeculae that is 47% to 68% weaker than D2
trabeculae, and 20% stronger than D4 trabeculae, whereas Lek-
holm and Zarb stated that Q3 bone has favorable-strength tra-
beculae similar to Q2.
34,36
In other words, the actual strength of
the trabecular bone is dierent for each bone density, regardless of
the presence or absence of cortical bone adjacent to the implant.
In addition, the Lekholm and Zarb bone quality only evaluated
bone in the anterior maxilla and mandible. e Misch bone den-
sity scale also evaluated the posterior molar regions of the jaws.
As a result, a primary dierence between D3 and D4 bone is also
the presence of cortical bone in D3, which increases its overall
strength and modulus of elasticity.
32
e quality 4 bone of Lek-
holm and Zarb is similar to Mischs D3, whereas D4 bone is even
weaker because little to no cortical bone is present to improve the
strength or the elastic modulus of the ne trabecular bone.
Osseodensification
A new method of implant preparation, termed osseodensica-
tion (OD), has recently been introduced to implant dentistry.
Cumulative % survival
100.0
99.8
99.6
99.4
99.2
99.0
0612 18 24
Months
Fig. . Multicenter study reported a surgical success of 99.6%,
regardless of bone quality. (Data from Misch CE, Hoar JB, Beck G, etal.
A bone quality based implant system: a preliminary report of stage I and
stage II. Implant Dent. 1998;7:35–42.)
D1 D2 D3 D4
Fig. . Misch Classification for Bone Density. D1, dense cortical bone;
D2, dense-to-porous cortical bone with coarse trabecular bone; D3, thin-
ner porous cortical crest and fine trabecular bone; and D4, minimal crestal
cortical bone with fine trabecular bone.
1. CBCT Radiographic (Hounsfield units)
2. Location
3. Past history of surgery in area
4. Tactile sensation
BOX
27. 2
Determination of Bone Density
D1: >1250
D2: 850 – 1250
D3: 350 – 850
D4: 0 – 350
BOX
27. 3
Hounseld Unit Numbers Related to
Bone Density

650
PART VI Implant Surgery
Huwais and colleagues, in 2013, introduced a surgical protocol
that includes the use of special densifying burs, which results with
low plastic deformation of the bone. e specially designed burs
(Densah burs) result in bone densication as the osteotomy is pre-
pared, thereby increasing bone at the implant interface.
48
e Densah burs utilize the concept of osteotomes, along with
drilling speed to laterally compact bone during preparation. Bone
is preserved and condensed through compaction autografting,
increasing the bone density and improving the mechanical stability
of the implant.
49
Conventional surgical drills excavate bone dur-
ing implant osteotomies, which requires approximately 12 weeks
of bone remodeling to repair. Because the OD protocol preserves
bone while increasing density, the healing time may be shorter.
46
Other methods of OD by use of undersizing the drills has been
established. Degidi and colleagues showed a signicant increase
in primary stability by decreasing the preparation size by 10%.
50
Alghamdi and colleagues used an adapted bone site preparation
technique by undersizing the osteotomy sites in poor bone den-
sity and showed favorable implant survival rates.
51
erefore in the
Misch implant placement protocol, the implant placement surgical
protocol is specic for each bone density and varies with the amount
of overpreparation and underpreparation of the osteotomy sites.
Generic Drilling Sequence
Before discussing the surgical implant protocol specic to bone
density, the clinician must understand the generic protocol for
dental implant osteotomy preparation and placement.
Step 1: Pilot Drill
With most surgical systems, a 1.5-mm or 2.0-mm surgical pilot drill
is used to initiate the osteotomy. Pilot drills are end-cutting starter
drills used to most commonly initiate an osteotomy in the center
of the ridge in a mesiodistal and buccolingual dimension. e oste-
otomy should be completed with a reduction handpiece (e.g., 16:1
or 20:1 high-torque handpiece) and an electric motor at a preferred
speed of 2000 rpm (i.e., for D1 and D2 bone) and >1000 rpm (i.e.,
for D3 and D4) under copious amounts of chilled saline irrigant.
e osteotomy is made no greater than 7 to 9 mm deep in the bone
(Fig. 27.10). e rationale for preparation of only 7 to 9 mm is if the
angulation is determined to be nonideal, then it is easier to modify.
Step 2: Position Verification
Once the initial osteotomy is prepared, it is assessed for ideal posi-
tion (see Chapter 28). If incorrect, the osteotomy location may be
stretched” to the proper location by a side-cutting Lindemann bur.
is bur makes the hole oblong toward the corrected center position.
After the new position is obtained, it should be deepened 1 to 2 mm
beyond the depth of the initial osteotomy. is will prevent the sec-
ond surgical bur from entering the rst nonideal implant osteotomy.
Usually a direction indicator (depth gauge), which corresponds to
the initial bur diameter, is then inserted into the osteotomy and the
angulation and position assessed (Fig. 27.11). If direction indicators
are not available, then older surgical burs may be used after slight
modication (i.e., shortened 2–4 mm to allow for radiographic ease).
A periapical radiograph should be obtained to determine proximity
to any vital structures. e clinician should be well aware of the “Y”
factor of their surgical drill system. e Y factor corresponds to the
additional length of the bur that is inherent with surgical drills (i.e.,
a 10-mm depth drill may drill to a length that exceeds 11.0 mm).
Ideal nal implant positioning should be a minimum of 1.5
mm from an adjacent tooth, 3.0 mm from another implant, and
2.0 mm from a vital structure such as the inferior alveolar canal
or mental foramen.
Tw ist Drill
Ø1.5 × 8 mm
Ø1.5
Fig. . Pilot drill. (A and B) With most surgical systems, the first drill includes a pilot drill with an
approximate diameter of 1.5 mm. This initial drill is usually not prepared to final depth to allow for direction
modification if needed.

You're Reading a Preview

Become a DentistryKey membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Was this article helpful?

64427Implant Placement Surgical ProtocolRANDOLPH R. RESNIKPre-Implant Placement Protocolse technique for dental implant surgery has evolved over the years from the original protocol pioneered in the 1970s by Per-Ingvar Brånemark, a Swedish physician and researcher. With Brånemark’s delayed approach, implant placement was completed, then after a healing period, the implants were exposed and prosthetically rehabilitated. Today, with the integration of computer and digi-tized technology, dental implant clinicians now have a full array of choices with the placement of dental implants.Flap DesignPrior to the placement of implants, the underlying bone and oste-otomy site must be exposed for implant osteotomy preparation and insertion (Chapter 26). Full-thickness ap: e most common technique includes a mu-coperiosteal ap, which may involve the buccal, lingual, and crestal areas.Flapless: is technique does not reect the crestal soft tissue. Instead, a core of keratinized tissue (the size of the implant crest module di-ameter) is removed over the crestal bone. e implant osteotomy is then performed in the center of the core of the exposed bone. is protocol requires no sutures around the healing abutment after implant placement. e advantages of this technique include less discomfort, tenderness, and swelling, which are usually minimal.e primary disadvantage of the apless approach is the in-ability to assess the bone volume before or during the implant osteotomy or insertion. erefore this technique should only be used when the bone width is abundant (>7 mm). In addition, bone grafting needs and procedures cannot be precisely evaluat-ed. e soft tissue around the implant site should be ideal in the amount of attached keratinized mucosa because the soft tissue pouch is over the bone site, not in a region related to the soft tis-sue. Often, the keratinized tissue is reduced on the buccal half of the ridge and the tissue punch may inadvertently remove all the keratinized tissue on the facial aspect of the implant. Because the crest of the ridge is below the soft tissue, it is dicult to see lines on the drill to access the depth of drilling. erefore stops on the drill are particularly benecial. e clinician may have diculty in assessing the location of the implant crest module in relation to the crest of bone because it is also below the soft tissue. And lastly, the interdental papillae may not be elevated with this tech-nique. erefore the soft tissue drape should be ideal in volume of keratinized tissue, both faciolingually and mesiodistally.  Surgical ApproachesFreehand surgery: is may include the ap or apless technique, with the clinician placing the implant with the diagnostic information available (i.e., position of adjacent teeth, radiographs). Freehand surgery may include the use of nonlimiting surgical templates, which allow the surgeon the dimensional variability in implant location because the template will indicate the position of the nal prosthesis; however, it will not specically guide the place-ment of the implant (see Chapter 15 for surgical approaches).Guided: is type of surgery, which may be performed ap or apless, guides the osteotomy from a digitally designed and printed surgical template. is type of surgery allows the highest level of precision and control because the implant position is dictated via a compre-hensive three-dimensional evaluation of the anatomy. Guided sur-gery may be dierentiated by the type of support of the template:Bone supported: e template rests on the alveolar bone and this technique requires the reection of a full thickness ap.Tissue (mucosa) supported: e template is supported by the soft tissue. is type of template is most commonly used with a apless technique.Tooth-supported: is is the most accurate technique and in-cludes placement of the template directly on the natural teeth for support. Guided surgery may also be classied according to the amount of drill guidance: Pilot template: Allows guidance for the position and angulation for only the rst drill in the surgical protocol. After the rst drill, the osteotomy is completed freehand.Universal template: is type of template is compatible with all implant systems and allows for depth, position, and angula-tion. However, the nal osteotomy drill, along with implant placement, is completed freehand.Fully guided template: Template that allows for depth, position, angulation, and implant placement via the guide. 645CHAPTER 27 Implant Placement Surgical ProtocolNavigational directed surgery: Computerized navigation surgery has evolved from neurosurgical procedures into the eld of dental implantology. is technique allows the clinician to precisely transfer a detailed presurgical implant plan to the patient. e clinician uses computerized navigation to adjust the position and angulation of the surgical drill according to the presurgical digital implant plan. e real-time imaging of the surgical drill allows for continuous updates on the positioning of the drill to avoid critical anatomic structures. Dental Implant Osteotomy PreparationDecreasing Heat During Osteotomy Preparatione heat generated during an implant osteotomy is related to the presence and temperature of irrigation,1-3 amount of bone being prepared,4,5 drill sharpness and design,5,6 time of preparation,7 depth of the osteotomy,8,9 pressure on the drill,5 drill speed,10 and variation in cortical thickness (bone density).11Bone cell survival is very susceptible to heat. Eriksson has dem-onstrated that, in animal studies, bone temperature as low as 3°C above normal (40°C) can result in bone cell necrosis.12 erefore a conscious eort is made to control temperature elevation every time a rotary instrument is placed in contact with bone. Many dental implant preparation variables need to be addressed in understanding the reduction of heat during the osteotomy process.Irrigation versus No IrrigationAlthough some authors have advocated implant osteotomy preparation without irrigation, the literature does not support it.13 Yacker and colleagues showed that, without irrigation, drill temperatures greater than 100°C are reached within sec-onds of the osteotomy, and consistent temperatures greater than 47°C are measured several millimeters away from the implant osteotomy.14 Benington and colleagues have reported that the osteotomy temperature may rise up to 130.1°C without irriga-tion after monitoring changes in bone temperature during the sequence of drilling for implant site preparation.15To minimize heat generation, at least 50 mL/min of cooled irrigation of sterile saline (0.9% NaCl) should be used as a pro-fuse irrigant and is a critical factor in the osteotomy process. e more dense the bone, the greater the need for copious irrigation. Distilled water should not be used because rapid cell death may occur in this medium.4,9 e irrigant also may act as a lubricant and removes bone particles from the implant osteotomy site. e temperatures of the irrigant can also aect the bone temperature. Barrak and colleagues reported that cooling the irrigation uid to 10°C, no mean temperature change >1°C will occur. ere-fore placing the irrigation uid into a refrigerator before implant surgery will help to prevent heat generation during implant place-ment16,17 (Fig. 27.1). Graduated versus One-Step Drillinge amount of heat produced in the bone is directly related to the amount of bone removed by each drill.18 For example, a 2-mm pilot drill generates greater heat than a 1.5-mm pilot drill.4 As a result, most manufacturers suggest that the rst drill (pilot) should be approximately 1.5 mm in diameter. In a similar fashion, the amount of heat generated by successive drills is also directly related to the increase in drill diameter.19 For example, a 3-mm drill after a 2-mm drill removes 0.5 mm on each side of the drill. A 2.5-mm drill after a 2-mm drill only cuts 0.25 mm of bone on each side of the osteotomy. e smaller incremental drill size allows the clinician to prepare the site faster, with less pressure and less heat genera-tion.6 In addition, when larger increases in drill diameter are used to prepare bone, the clinician may inadvertently change the angula-tion of the drill because the larger drill is removing a greater bone volume and the tactile sense is decreased. As a result, an elliptical osteotomy may be prepared that does not correspond accurately to the round implant diameter. e gradual increase in osteotomy size also reduces the drill shatter at the crestal opening, which can inadvertently fragment the bony crest in which complete bony con-tact is especially desired. e gradual increase in drill diameter also maintains the sharpness of each drill for a longer period, which also reduces the heat generation (Fig. 27.2). • Fig. . Irrigation should use 0.9% NaCl (sterile saline), which may be cooled to reduce heat generation. The irrigation bags may be stored in a refrigerator.• Fig. . Number of steps in the preparation of the osteotomy is related to the bone density. Usually D1 will require all drills including the bone tap, the D2 protocol uses all drills except the bone tap, D3 requires the standard protocol stopping at the second to last drill, and D4 uses only the first or second drills. 646PART VI Implant SurgeryDrilling Speede subject of drilling speed has become very controversial in implant dentistry today. Eriksson and colleagues originally rec-ommended drilling speeds of 1500 to 2000 rotations per minute (rpm) with irrigation.20 Most recently in implant dentistry, the rotational speed of the drill has been suggested to be less than 2000 rpm, and several manufacturers have recommended speeds as low as 50 rpm. Kim and colleagues suggested drilling osteoto-mies at 50 rpm without irrigation and stated that the bone tem-perature may not signicantly increase.13However, Yeniyol and colleagues showed that excessively low drill-ing speeds (less than 250 rpm) increased the degree of fragmentation of the osteotomy edge. It has been shown that low speed drills will “wobble,” which leads to overpreparation of the osteotomy site.21A controversial subject in implant dentistry is whether higher drilling speed is correlated with higher bone temperature dur-ing preparation. Although some reports have shown this, the majority of well-documented studies disprove this. For exam-ple, if high-speed preparation was detrimental, then slow-speed handpieces would be used to prepare natural teeth. A high-speed handpiece (∼300,000 rpm) can remove bone over an impacted tooth or during an apicoectomy and still allow bone regenera-tion. Rafel prepared bone at 350,000 rpm in a human mandible and found a temperature of only 23.5°C at a distance of 3 mm from the drill periphery.22 High-speed drills at 300,000 rpm have been used to prepare blade implant osteotomies for years, yet studies proved bone grew over the blade shoulder and was in direct contact with the implant.23A study by Sharawy and colleagues compared four drill designs (two internal irrigated and two external irrigated) at speeds of 1225, 1667, and 2500 rpm.4 ermocouples connected to a com-puter to record temperature and time were placed within 1 mm of the osteotomy site in D2-type bone (Fig. 27.3). All drill designs in the study recorded lower bone temperatures with the great-est rotations per minute and, conversely, found the highest bone temperatures with the lowest rotations per minute (Figs. 27.4 and 27.5). As important, the slowest rotations per minute resulted in bone temperatures at or greater than 40°C, which may be a threshold of bone cell death. e highest rotations per minute (2500) increased the bone temperature by 2° to 3.5°C, whereas the 1225 rpm recorded a bone temperature greater than 41°C. erefore the higher speed of 2500 rpm may prepare bone at a lower temperature than 1500 rpm, especially when in dense bone. e rotational speed of the drill is one of the more critical criteria to reduce bone temperatures.Sharawy and colleagues demonstrated that, regardless of the drill design or method of irrigation, 2500 rpm prepared bone at a lower temperature than slower speeds.4 e clinician should allow the cutting surface of the drill to contact D1 and D2 bone fewer than 5 of every 10 seconds. Ideally, a pumping up-and-down motion (i.e., bone dancing) is used to prepare the osteot-omy and provide constant irrigation to the drill cutting surface. It also maintains a constant drill speed and reduces the friction time against the bone, all of which reduce heat. Drilling TimeEriksson reported bone cell death when a temperature of 40°C was applied for 7 minutes, or when a temperature of 47°C was applied for 1 minute.12 In other words, time and temperature are interrelated critical factors in implant site preparation. As the tem-perature increases, the time the bone temperature is elevated must be reduced. In the study by Sharawy and colleagues, the time the bone temperature remained elevated was recorded for each rota-tion per minute evaluated.4 When the drill prepared an 8-mm depth osteotomy, the temperature remained elevated for 45 to 58 seconds (Fig. 27.6). e slower the rotations per minute (1225), the longer the bone temperature remained above the baseline. Because two to three drills are used to prepare an implant site, at 1225 rpm the rst drill may increase the temperature to 41°C, the second drill to 45°C, and the third drill to 49°C, when the time between each sequence is not extended more than 1 minute. In the study by Sharawy and colleagues, the rst drill diameter recorded the longest preparation time and the highest temperature, and the longest recovery time. erefore to reduce the preparation time within the bone to a minimum in D1 bone, the clinician should not apply constant pressure to the drill, but “bone dance” with 8 mmB0.1 mmMean of four channelsCh. BCh. DCh. ACh. C• Fig. . Thermocouples were positioned within 1 mm of the drill site and inserted into bone for a depth of 8 mm. The wires were connected to a computer to measure the temperature, time of preparation, and time the bone temperature was elevated.4.5*****43.532.521.510.502.3 mmMean rise in temperature3.2 mm 4.2 mm1225 rpm1667 rpm2500 rpm• Fig. . Internally cooled drill of the Paragon implant system recorded 41°C with the first drill at 1225 rpm; 2500 rpm reduced the bone tempera-ture preparation for all drill diameters.3.532.521.510.502 mm 3 mmMean rise in temperature (°C)3.85 mm 4.3 mm1225 rpm1667 rpm2500 rpm• Fig. . Externally cooled drills of the Brånemark implant system recorded reduced temperatures at 2500 rpm, compared with slower speeds. 647CHAPTER 27 Implant Placement Surgical Protocolintermittent pressure for 1 second in the D1 bone and 1 to 2 seconds out of the bone while the cooled irrigation is allowed to perfuse the site.In summary, in D1 and D2 bone, a higher speed (1500–2000 rpm) should be used in the preparation of bone. In poorer quality bone (e.g., D3 and D4) drilling speed is not as crucial, therefore a lower speed maybe use (∼1000 rpm). Drilling Pressuree pressure exerted when preparing the osteotomy should not result in heat generation. Hobkirk and Rusiniak found that the average force placed on a handpiece during preparation of an oste-otomy is 1.2 kg.11 Matthews and Hirsch concluded that the force applied to the handpiece was more inuential than the drill speed in temperature elevation.24 When the pressure on the handpiece was increased appropriately, drill speeds from 345 to 2900 rpm did not aect the temperature. Matthews and Hirsch found that increasing both speed and pressure allowed the drill to cut more eciently and generated less heat. e eect of drill speed and pressure related to bone temperature was also reported by Bris-man.10 In cortical bone, speeds of 1800 rpm with a load of 1.2 kg produced the same heat as when speed increased to 2400 rpm with a pressure of 2.4 kg. e greater speed and greater pressure was more ecient than low speeds. Increasing pressure alone increased heat; increasing speed alone also increased heat. Dier-ent amounts of pressure are therefore used in response to the den-sity of the bone. Sucient pressure should be used on the drill to proceed at least 2 mm every 5 seconds. If this is not achieved, then new (sharper) or smaller diameter drills are indicated for each site preparation. e pressure on the drills should not reduce the rota-tions per minute, which makes the drill less ecient and increases heat. Handpieces of sucient torque should be used to prevent this complication. Intermittent versus Continuous DrillingWhen preparing an osteotomy site, continuous drilling (i.e., no pumping motion) results in numerous possible negative conse-quences. When constant pressure is applied, irrigation cannot enter the osteotomy site; therefore this may result in heat-related damage. In addition, by not removing the drill from the osteot-omy site during preparation, bone debris is maintained within the utes of the surgical burs, resulting in potential heat generation. is also leads to less ecient drilling.When intermittent drilling or bone dancing (i.e., continuously bringing the surgical bur in and out of the osteotomy site), less heat generation is seen. By bringing the bur in and out of the osteotomy site, irrigation may enter the site along with allowing any debris to be removed, thus making the cutting process more ecient. e only disadvantage of the bone dancing technique is the possibility of changing angulation or inadvertent widening of the osteotomy site.25 Care should be exercised in withdrawing and inserting the implant drill at the same trajectory or angulation. Insertion Torquee insertion torque (IT) is the force used to insert a dental implant into a prepared osteotomy. e amount of torque is expressed in units of newton centimeters (N/cm), which ultimately determines the loading protocol. IT is the primary most important factor in determining primary stability, with higher torque values leading to higher primary stability.26Lower values of IT have been shown to be associated with implant failures.27Many studies have indicated IT near the range of 35-45 N/cm to be ideal for implant integration.28,29 To standardize the amount of torque, calibrated torque wrenches, physiodispenser instru-ments with integrated electronic torque control settings, and pre-set torque settings on the implant electric motor systems should be used (Box 27.1). Bone Density Factors Related to Implant PreparationAs discussed in Chapter 18, the density of the available bone has a signicant eect on the predictability and success of dental implants. In the past, clinical reports that did not alter the surgical and prosthetic protocol had variable survival rates. In this chap-ter, a generic surgical protocol will be discussed, which is directly 60504030205.464.285551.841.63.784.12.8451.447.838.22.83.642.346.831.6322.33.142.083518.413.62.023.25 mm 3.8 mm2.7 mmDrill diametersTime (seconds)Osteotomy preparation at 1225 rpmElevated bone temperature at 1225 rpmOsteotomy preparation at 1667 rpmElevate bone temperature at 1667 rpmOsteotomy preparation at 2500 rpmElevated bone temperature at 2500 rpm2 mm100• Fig. . Internally cooled drills of the Nobel Biocare, Steri-Oss implant system demonstrate the tem-perature in the bone remains elevated for an extended period (up to 58 seconds) after site preparations in D2 bone. The lower the rotations per minute are the longer the temperature remains elevated. 648PART VI Implant Surgeryrelated to bone density that has been shown to increase success of dental implants.e density of available bone in an edentulous site has a pri-mary inuence on treatment planning, implant design, surgical approach, healing time, and initial progressive bone loading dur-ing prosthetic reconstruction. e quality of the recipient bone directly inuences the amount of trauma generated during oste-otomy preparation. is in turn provokes a cascade of reactions at the bone–implant interface that directly aect the quality of the load-bearing surface.Once the implant is initially integrated with the bone, the bone-loading process from occlusal forces becomes a critical fac-tor in long-term implant survival. e bone density under load is directly related to the bone strength and is therefore a critical parameter for long-term survival.30,31 e occlusal stresses applied through the implant to the bone must remain within the physi-ologic to mild overload zone; otherwise, pathologic overload with associated bone loss and microfracture leading to implant failure may occur. e treatment planning and scientic rationale of strength, modulus of elasticity, bone-implant contact (BIC) per-centage, and stress transfer dierence related to bone density has been addressed in Chapter 18. is chapter addresses the modi-cations of the surgical and healing aspects related to each bone density in the oral environment.Literature ReviewLekholm and Zarb listed four bone qualities found in the anterior regions of the jawbone: quality 1, comprises homogeneous com-pact bone; quality 2, a thick layer of compact bone surrounding a core of dense trabecular bone; quality 3, a thin layer of corti-cal bone surrounding dense trabecular bone of favorable strength; and quality 4, a thin layer of cortical bone surrounding a core of low-density trabecular bone.32 Irrespective of the dierent bone qualities, all bone was treated with the same implant design and standard surgical and prosthetic protocols.After the proposed protocols of Brånemark and colleagues, it was found that implant survival in initial surgical success was related to the quality of bone.33 A higher surgical failure was observed in softer bone types, especially in the maxilla. For exam-ple, Engquist reported the surgical loss of 38 of 191 implants in the maxilla in D4 bone (20% loss) compared with 8 of 148 man-dibular implants (5% loss) before stage II surgery.34 Jan and Ber-man reported an overall 8.3% surgical and initial healing loss in 444 maxillary implants with softer bone.35 Friberg and colleagues reported a 4.8% implant failure at stage II uncovery for 732 max-illary posterior implants, which was greater than mandibular fail-ure.36 Quirynen etal. also reported a 4.1% implant loss at stage II uncovery out of 269 implants in the maxilla.37 Fugazzotto and colleagues reported 22 failures out of 34 implants placed in qual-ity 4 bone.38 Hutton and colleagues identied poor bone quantity and quality 4 as the highest risk of implant failure in a study of 510 implants, with an overall failure rate in the maxilla nine times greater than in the mandible.39 Sullivan and colleagues indicated a 6.4% stage II failure rate in the maxilla (12/188) and a 3.2% fail-ure in the mandible (7/216).40 Snauwaert and colleagues reported more frequent early failures in poor density maxillae.41 Herrmann and colleagues correlated failure factors such as poor bone quality and volume. 42 A number of reports in the literature demonstrated that the greatest risk of surgical failure was observed in the softest bone type (D4), especially when found in the maxilla.On the other extreme, a large clinical study from 33 US Department of Veterans Aairs (VA) hospitals by the Dental Implant Clinical Research Group (DICRG) states quality 1 bone had the highest surgical failure rate (4.3%), followed by quality 4 (3.9%), quality 2 (2.9%), and quality 3 with the fewest failures at 2.6% (Fig. 27.7). e overall implant surgical failure was 3%; the maxilla had better success at stage II surgery (98.1%) than the mandible (96.4%).43 It must be emphasized that these reports only present implant failures up to stage II uncovery. e DICRG also noted that the failure rate was twice as great for surgeons who had placed fewer than 50 implants, compared with more experi-enced surgeons. e literature contains many published reports that indicated an implant surgical failure range from 3.2% to 5% in the mandible and 1.9% to 20% in the maxilla, with most reports indicating the greatest failure rates in maxillary implants with soft bone. It is clear from these reports that a wide range of results may be achieved; therefore consideration should be given to methods that improve surgical survival.Misch developed a dierent surgical protocol for dierent bone qualities in 1988. e Misch classication of bone density includes four classications, D1, D2, D3, and D4, which are based on the amount of cortical and cancellous bone. D1 bone is primarily composed of dense cortical bone and found mainly in the anterior mandible, with basal bone. D2 bone has dense-to-porous corti-cal bone on the crest and, within the bone, has coarse trabecular bone. D3 bone types have a thinner porous cortical crest and ne trabecular bone in the region next to the implant. D4 bone has almost no crestal cortical bone. e ne trabecular bone composes almost all of the total volume of bone next to the implant.After these specic methods, prospective and retrospective multicenter clinical studies in a wide range of oce settings found surgical survival to be greater 99%, regardless of the density type of bone, the arch (mandible versus maxilla), and gender and age of •  Irrigation: copious amounts of 0.9% NaCl•  Irrigation solution temperature: refrigerate before use•  Drilling technique: graduated protocol (more drills)• Intermittent(bonedancing)•  Drilling speed: D1, D2 bone is 1500–2000 rpm; D3, D4 bone is ∼1000 rpm•  Drilling time: greater drilling time, greater heat generation•  Drilling pressure: minimize pressure, never allow rotations per minute to decrease from excess pressure•  Insertion torque: 35-45 N/cm • BOX 27.1 Generic Osteotomy Preparation SummaryStage IStage IIImplant failure %1234123450Decreasing bone quality• Fig. . A study by the Dental Implant Research Group represented 33 different hospitals that place dental implants. The highest surgical failure rate was quality 1 bone, followed by quality 4 bone. The fewest surgical failures were observed in quality 3 bone. 649CHAPTER 27 Implant Placement Surgical Protocolthe patient.44,45 erefore a dierent surgical protocol for dier-ent bone densities appears warranted. e implant design, surgical protocol, healing, treatment plans, and progressive loading time spans are unique for each bone density type. More recently the use of improved rotary instruments, implant designs, and surgi-cal approaches for dierent bone qualities has been recognized as a valid recommendation. A multicenter prospective clinical study by Misch and colleagues of 364 consecutive implants in 104 consecutive patients found a surgical survival rate (up to abutment connection) at stage II of 100% for D1, 98.4% for D2, 99.8% for D3, and 100% for D4 implants46 (Fig. 27.8). Altering the surgical approach for each bone density can yield an overall implant surgical survival of 99.8% and a 2-year survival of 99.4%. In this chapter the surgical considerations and opti-mal healing time are discussed relative to each bone category, based on the literature, prospective clinical studies, and long-term experience.Bone Density ClassificationsMisch dened four bone density groups in all regions of the jaws that vary in both macroscopic cortical and trabecular bone types.47 e regions of the jaws are divided into (1) the ante-rior maxilla (second premolar to second premolar), (2) posterior maxilla (molar region), (3) anterior mandible (rst premolar to rst premolar), and (4) posterior mandible (second premolar and molars). e regions of the jaws often have similar bone densities (Fig. 27.9).In general, the anterior mandible is usually D2 bone, the poste-rior mandible is D3 bone, the anterior maxilla is D3 bone, and the posterior maxilla is often D4 bone. is generalization is used for the initial treatment plan. However, resorbed anterior mandibles may be D1 bone in approximately 25% of male patients and the posterior maxilla may have D3 bone after 6 months in the majority of sinus graft patients. e regional locations of the dierent densi-ties of cortical bone are more consistent than the highly variable trabecular bone. Bone density may be most precisely determined before surgery by a computed tomography (CT) scan of the eden-tulous site (accompanied by Hounseld values of the bone). Refor-matted software allows “electronic surgery” of the CBCT images and relates the Hounseld values at the implant–bone interface. Conventional dental radiographs, such as periapical, panoramic, or lateral cephalometric images, are usually not diagnostic (Boxes 27.2 and 27.3) in the assessment of bone density.A common point at which to evaluate bone quality is dur-ing surgery. e presence and thickness of a crestal cortical plate and the density of trabecular bone are easily determined during implant osteotomy preparation. e density of bone is deter-mined by the initial bone drill, and evaluation continues until the nal osteotomy preparation.It should be emphasized that the bone density (D1–D4) clas-sication of Misch is slightly dierent from Lekholm and Zarb’s bone quality types (Q1–Q4). According to Misch and colleagues, D3 bone has ne trabeculae that is 47% to 68% weaker than D2 trabeculae, and 20% stronger than D4 trabeculae, whereas Lek-holm and Zarb stated that Q3 bone has favorable-strength tra-beculae similar to Q2.34,36 In other words, the actual strength of the trabecular bone is dierent for each bone density, regardless of the presence or absence of cortical bone adjacent to the implant. In addition, the Lekholm and Zarb bone quality only evaluated bone in the anterior maxilla and mandible. e Misch bone den-sity scale also evaluated the posterior molar regions of the jaws. As a result, a primary dierence between D3 and D4 bone is also the presence of cortical bone in D3, which increases its overall strength and modulus of elasticity.32 e quality 4 bone of Lek-holm and Zarb is similar to Misch’s D3, whereas D4 bone is even weaker because little to no cortical bone is present to improve the strength or the elastic modulus of the ne trabecular bone. OsseodensificationA new method of implant preparation, termed osseodensica-tion (OD), has recently been introduced to implant dentistry. Cumulative % survival100.099.899.699.499.299.00612 18 24Months• Fig. . Multicenter study reported a surgical success of 99.6%, regardless of bone quality. (Data from Misch CE, Hoar JB, Beck G, etal. A bone quality based implant system: a preliminary report of stage I and stage II. Implant Dent. 1998;7:35–42.)D1 D2 D3 D4• Fig. . Misch Classification for Bone Density. D1, dense cortical bone; D2, dense-to-porous cortical bone with coarse trabecular bone; D3, thin-ner porous cortical crest and fine trabecular bone; and D4, minimal crestal cortical bone with fine trabecular bone. 1. CBCT Radiographic (Hounsfield units) 2. Location 3. Past history of surgery in area 4. Tactile sensation • BOX 27. 2 Determination of Bone DensityD1: >1250D2: 850 – 1250D3: 350 – 850D4: 0 – 350 • BOX 27. 3 Hounseld Unit Numbers Related to Bone Density 650PART VI Implant SurgeryHuwais and colleagues, in 2013, introduced a surgical protocol that includes the use of special densifying burs, which results with low plastic deformation of the bone. e specially designed burs (Densah burs) result in bone densication as the osteotomy is pre-pared, thereby increasing bone at the implant interface.48e Densah burs utilize the concept of osteotomes, along with drilling speed to laterally compact bone during preparation. Bone is preserved and condensed through compaction autografting, increasing the bone density and improving the mechanical stability of the implant.49 Conventional surgical drills excavate bone dur-ing implant osteotomies, which requires approximately 12 weeks of bone remodeling to repair. Because the OD protocol preserves bone while increasing density, the healing time may be shorter.46Other methods of OD by use of undersizing the drills has been established. Degidi and colleagues showed a signicant increase in primary stability by decreasing the preparation size by 10%.50 Alghamdi and colleagues used an adapted bone site preparation technique by undersizing the osteotomy sites in poor bone den-sity and showed favorable implant survival rates.51 erefore in the Misch implant placement protocol, the implant placement surgical protocol is specic for each bone density and varies with the amount of overpreparation and underpreparation of the osteotomy sites. Generic Drilling SequenceBefore discussing the surgical implant protocol specic to bone density, the clinician must understand the generic protocol for dental implant osteotomy preparation and placement.Step 1: Pilot DrillWith most surgical systems, a 1.5-mm or 2.0-mm surgical pilot drill is used to initiate the osteotomy. Pilot drills are end-cutting starter drills used to most commonly initiate an osteotomy in the center of the ridge in a mesiodistal and buccolingual dimension. e oste-otomy should be completed with a reduction handpiece (e.g., 16:1 or 20:1 high-torque handpiece) and an electric motor at a preferred speed of 2000 rpm (i.e., for D1 and D2 bone) and >1000 rpm (i.e., for D3 and D4) under copious amounts of chilled saline irrigant. e osteotomy is made no greater than 7 to 9 mm deep in the bone (Fig. 27.10). e rationale for preparation of only 7 to 9 mm is if the angulation is determined to be nonideal, then it is easier to modify. Step 2: Position VerificationOnce the initial osteotomy is prepared, it is assessed for ideal posi-tion (see Chapter 28). If incorrect, the osteotomy location may be “stretched” to the proper location by a side-cutting Lindemann bur. is bur makes the hole oblong toward the corrected center position. After the new position is obtained, it should be deepened 1 to 2 mm beyond the depth of the initial osteotomy. is will prevent the sec-ond surgical bur from entering the rst nonideal implant osteotomy.Usually a direction indicator (depth gauge), which corresponds to the initial bur diameter, is then inserted into the osteotomy and the angulation and position assessed (Fig. 27.11). If direction indicators are not available, then older surgical burs may be used after slight modication (i.e., shortened 2–4 mm to allow for radiographic ease). A periapical radiograph should be obtained to determine proximity to any vital structures. e clinician should be well aware of the “Y” factor of their surgical drill system. e Y factor corresponds to the additional length of the bur that is inherent with surgical drills (i.e., a 10-mm depth drill may drill to a length that exceeds 11.0 mm).Ideal nal implant positioning should be a minimum of 1.5 mm from an adjacent tooth, 3.0 mm from another implant, and 2.0 mm from a vital structure such as the inferior alveolar canal or mental foramen.  Tw ist DrillØ1.5 × 8 mmABØ1.5• Fig. . Pilot drill. (A and B) With most surgical systems, the first drill includes a pilot drill with an approximate diameter of 1.5 mm. This initial drill is usually not prepared to final depth to allow for direction modification if needed. 651CHAPTER 27 Implant Placement Surgical ProtocolStep 3: Second Twist DrillThe second drill used is approximately 2.5 mm in diameter, and is an end-cutting twist drill required for the initial oste-otomy to the required depth. The osteotomy location and angulation are reassessed at this point. A slight correction of position or angulation with a Lindemann drill may be com-pleted; however, it should ideally be accomplished after the first drill (Fig. 27.12). Step 4: Final Shaping DrillsDepending on the surgical system used, most shaping drills are used to sequentially widen the osteotomy to the match-ing diameter of the implant being placed. Depending on the diameter, multiple twist drills maybe used. e desired depth, along with the ideal location and angulation of the osteotomy, should be veried. Most implant drill kits will clearly identify the drill sequence and nal osteotomy diameter related to each diameter implant (Fig. 27.13). Usually, the nal drill will be within 1.0 mm of the nal diameter of the implant diameter (i.e., a 4.0-mm implant will have a nal drill size of approxi-mately 3.2 mm). Step 5: Crest Module and Bone Tap DrillsMost implant crest modules (implant neck) are larger in diam-eter than the implant body. e larger diameter often requires a side-cutting crest module drill in D1 (and some D2) crestal bone situations to prepare the crestal aspect of the implant osteotomy. is drill is not recommended when the bone density is poor (D3 and D4) (Fig. 27.14). is drill is used to open up the crestal area of the ridge to accommodate the wider crest module. When used, copious amounts of saline should be used.In addition, usually in D1 bone, some implant systems will require the use of a bone tap or threadformer to prepare the threads in the bone before implant insertion. Most often for single-tooth implants, the threadformers or taps should use a high-torque, slow-speed handpiece and be rotated at less than 30 rpm into the bone. Irrigation also helps to lubricate and clean the bone tap and osteotomy site of debris during this process. ABParallel Pin Ø4.3 mm• Fig. . (A) Parallel pin placed into pilot drill osteotomy to verify position-ing clinically and radiographically.. (B) If modification of osteotomy is indi-cated, use of a Lindemann bur should be used to reposition osteotomy. Tw ist Drill Ø2.4/1.5 × 8 mmBAØ2.4/1.5• Fig. . (A and B) Second twist drill is used to widen the osteotomy to allow for larger diameter drills. 652PART VI Implant SurgeryStep 6: Implant Insertione implant site may then be prepared for implant insertion. e osteotomy is lavaged with sterile saline and aspirated to remove bone debris and stagnant blood. is reduces the risk of these materials being forced into the bone marrow spaces or neurovas-cular channels during implant insertion, causing hydrostatic pres-sure. is pressure may increase the devital zone of bone around the implant or even cause short-term neurosensory impairments when the implant site is in the vicinity of the mandibular canal.e implant may be inserted with a hand ratchet or handpiece. e advantage of inserting an implant with a handpiece is that the placement will be more ideal and deviation is less likely, especially in poorer quality of bone (e.g., D3 and D4 bone). However, in better quality of bone, especially D1, diculty in insertion may Tw ist DrillØ3.0 × 11.5 mm Shaping DrillØ3.5 × 11.5 mm Shaping DrillØ4.3 × 11.5 mm4.3×11.53.5×11.5Ø2.8/2.4Final DrillBA• Fig. . Final shaping drills. (A and B) Final drills used to widen the osteotomy to accommodate the diameter of the intended implant.ABScrew Tap Ø4.3 mmØ4.3Ø5.0• Fig. . Tap drill. (A and B) Used mainly in D1 bone at approximately 30 rpm. 653CHAPTER 27 Implant Placement Surgical Protocolsometimes occur. When placing an implant with a hand ratchet, good apical pressure should be used to decrease the possibility of deviating the path of the implant. If the implant is tightened into the osteotomy and signicant stress occurs at the crestal area, pres-sure necrosis may occur and an increase in the devital zone of bone around the implant during healing will occur. If this should occur, the implant may be unthreaded 1 to 2 mm and then reinserted back into the osteotomy. When the implant is placed into the nal position, a post-insertion periapical radiograph is taken to verify ideal positioning (Fig. 27.15). Dental Implant Surgical Protocol 1 (D1 Bone)Dense Cortical (D1) Bonee dense D1 bone (i.e., similar to the hardness of oak or maple wood) is composed of almost all dense cortical bone. e maxilla almost never presents with D1 bone. In division A bone, approx-imately 4% of the anterior mandibles and 2% of the posterior mandibles have this dense bone category. In division C–h bone of an anterior mandible, these numbers increase and may reach 25% in males, whereas weaker bone density D3 and D4 bone are less commonly encountered.e Hounseld unit numbers are usually greater than 1250 HU.Advantages of D1 Bonee homogeneous, dense D1 bone type presents several advantages for implant dentistry. Composed histologically of dense lamellar bone with complete haversian systems, it is highly mineralized and able to withstand higher occlusal loads. e cortical lamellar bone may heal with little interim woven bone formation, ensur-ing excellent bone strength while healing next to the implant.52,53D1 bone is more often found in anterior mandibles with moderate to severe resorption and greater crown/implant ratios. Implants placed into this bone density improve the dissipation of stresses in the crestal cortical region despite higher moments of force from the greater crown height to sustain long-term func-tional stress.e percentage of light microscopic contact of bone at the implant interface is greatest in D1 bone type and greater than 80% (Fig. 27.16). In addition, this bone density exhibits greater strength than any other bone type. e strongest bone also ben-ets from the greatest BIC. Because of the density of this bone, less stress is transmitted to the apical third of the implants than in other bone types. As a result, shorter implants can better with-stand greater loads than in any other bone densities. In fact, the placement of longer implants may decrease surgical survival rates because overheating during osteotomy preparation is a primary concern in this bone type. Greater heat is often generated at the apical portion of the osteotomy, especially when preparing dense cortical bone.54 Disadvantages of D1 BoneIncreased Crown-Implant Ratio. Dense cortical bone also presents several disadvantages. Because these cases are usually seen with mandibles with limited height (i.e., usually less than 12 mm), the crown height space is often greater than 15 mm. As a result, additional force-multiplying factors (i.e., such as cantile-vers or lateral forces) are further magnied on the implant-pros-thetic system. It is imperative that stress-reducing factors may be incorporated in the prosthesis design to reduce these eects, not only on the bone, but also on the prosthetic components (Fig. 27.17). Poorer Blood Supply. D1 bone has fewer blood vessels than the other three types; therefore it is more dependent on the peri-osteum for its nutrition. e cortical bone receives the outer one-third of all its arterial and venous supply from the periosteum.55 is bone density is almost all cortical, and the capacity of regen-eration is impaired because of the poor blood circulation. ere-fore delicate and minimal periosteal reection is indicated. When D1 density is present, the bone width is usually abundant and the mandible widens apically. Fortunately, there are few occur-rences when facial or lingual undercuts are observed with D1 bone densities, and ap reection can be safely kept to a minimum. e precise closure of the periosteum and the overlaying tissue has been shown to help recover the blood supply and is encouraged.56 Because of the compromised blood supply, this type of bone will actually take longer time to heal compared with D2 bone. Overheating the Bone. e primary surgical problem of D1 bone is the dense cortical bone is more dicult to prepare for endosteal implants than any other bone density. e most common cause of implant failure in this bone quality is surgical trauma resulting from overheating the bone during the implant osteotomy procedures because surgical drills progress with more diculty.AB• Fig. . Implant insertion. (A) Placement of implant with a hand ratchet, which is usually used only in D1 and D2 bone. (B) Placement of implant with handpiece, which is usually indicated in D2, D3, and D4 bone. 654PART VI Implant Surgerye zone of devitalized bone that forms around the implant is larger in this bone density and must be remodeled and replaced by vital bone for the interface to be load bearing (Fig. 27.18). As a result, implant surgical failure may be greater in D1 bone than any other bone density. erefore it is imperative the clinician strive to minimize the thermal trauma. Pressure Necrosis. Because of the thick, dense cortical bone, placement of an implant may lead to an increase in internal stresses at the crestal area. erefore after implant placement to the height of the bone level, the implant may be unthreaded 1 to 2 mm, the bone allowed to relieve the stresses, and then it is reinserted to the nal placement level. By allowing the bone to expand from creep, it is less likely that pressure necrosis, which leads to bone loss or die-back, will occur (Box 27.4). Implant Osteotomy Drilling SequenceIn D1 bone, all the drills of the surgical system should be utilized. Because of the density of this bone type, more graduated drills will result in less heat generation. A secondary cause of lack of osseous integration may be related to mechanical trauma of the bone. ere are several methods to reduce mechanical trauma in D1 bone, and one of these is related to nal drill size selection. In D1 bone, the nal bone preparation may be sized slightly larger in both width and height, especially for a threaded implant, than the manufacturer-recommended surgical protocol. is reduces the risk of microfracture trauma between the implant threads during insertion, which may lead to brous tissue formation at the bone–implant interface. In addition, a nal drill dimension only used in D1 bone remains sharper for this critical step.If a surgical drill of slightly greater diameter is not available with the implant system, the clinician can use the nal drill size available and pass it within the osteotomy several times. By enter-ing the osteotomy site multiple times, the osteotomy diameter will become slightly oversized. In fact, all drills for the D1 drilling sequence may use this method, therefore, less bone is removed with future drills, resulting in less heat generation.A bone tap should be used in D1 bone before insertion of a threaded implant. ere are several reasons for the use of a bone tap. Because the nal drill osteotomy is almost 1 mm smaller than the outer diameter of the implant, the bone tap creates the space for the thread of the implant. is drill has open utes, which permit the shaving of the bone to accumulate and be removed before placing the implant. A self-tapping implant insertion compresses the bone in the region of the threads. is is an advantage in softer bone types, but not in cortical bone. e tap reduces the mechanical trauma to the bone while the implant is inserted. e bone is also able to slightly recover from the trauma of the tap once it is removed and permits a more passive implant placement. Watzek and colleagues found a higher woven bone interface (i.e., a sign of bone trauma) when a self-threading implant design was used, compared with a pretapped implant site.57 Satomi and colleagues found a higher BIC after initial healing with pretapped implant osteotomies compared with a self-tapping site, which is also indicative of less bone trauma. e use of a self-tapping implant insertion technique in dense bone • Fig. . D1 bone has the highest bone-implant contact (BIC), which is usually greater than 80% after initial bone healing. Thus the strongest bone is also the bone with the greatest BIC. Both these conditions make D1 bone the most suitable for occlusal loading.VDI• Fig. . Devital zone (D) of bone next to the implant (I) is primarily created by heat generated during surgery, which radiates from the site, especially in cortical bone. Other contributing factors include lack of blood supply, pressure necrosis from implant placement, microfracture from bone tapping, and implant insertion. V, Vital bone.• Fig. . Division D mandible, which will usually be composed of D1 bone. Because of the extensive atrophy, the crown-implant ratio is increased. 655CHAPTER 27 Implant Placement Surgical Protocolqualities has demonstrated a signicantly higher degree of hard tis-sue trauma; therefore it is not recommended in D1 bone.58e bone tap should be used with a hand ratchet and irriga-tion. e slow-speed, high-torque handpiece is very ecient and has several advantages in D2 bone. However, D1 bone is so strong that the handpiece gears may strip, and the handpiece is more likely to require repeated repair.e hand position of the surgeon is important in maintain-ing constant force and direction on the hand ratchet during the bone-tapping process. When using a ratchet, the horizontal rota-tion on the tap causes it to tip back and forth around the vertical axis. erefore, when using a ratchet the ratchet is held while the thumb of the other hand is placed directly over the bone tap, the index nger of the same hand retracts the lip for improved access and vision. e ratchet rotates the tap with one hand while the thumb and middle nger of the other hand apply constant pres-sure and direction to the tap so it does not tip back and forth or strip the osteotomy site (which may happen if the tap does not continue to advance within the osteotomy each turn of the tap).A bone tap in D1 bone prevents the antirotational compo-nent of the implant body from being damaged during implant insertion in this dense bone type. A minor advantage to tap-ping may be the fact that drill remnants are more likely to be left in the implant osteotomy during preparation in dense bone or with a new drill and cutting edge. The bone tap may remove these remnants and decrease the risk of long-term corrosion from dissimilar metals contacting within the bone, although no reports in the literature have indicated this to be a problem.Once the tapping process is complete, the osteotomy is irri-gated and suctioned. e implant should be inserted with a hand ratchet, minimizing damage to the handpiece and allow-ing the clinician to gauge the IT of the implant. e implant should not be tightened with a high-torque pressure (>75 N/cm) to the full depth of the osteotomy; this causes it to “bottom out” and may set up microfractures along the implant inter-face. Instead, once the threaded implant is introduced into the osteotomy and in nal position, it is often unthreaded 1 to 2 mm to ensure that there is no residual pressure along the bone interface. en, after 20 to 30 seconds, the implant may be reinserted to its nal position. is step is primarily used in D1 bone because excessive initial strain may form at the inter-face of the cortical bone with even one extra rotation of the implant.59 e rotational stress is usually highest at the crestal region, which may even cause mechanical bone microfracture and marginal bone loss.Use of Copious Amounts of Irrigation. As the depth of the osteotomy increases, the risk of the inadequate irrigation increases.60 erefore the bone dancing method of prepara-tion is paramount, especially when reaching the apical area of the osteotomy. Copious amounts of either external irrigating drilling techniques should be used; however, many other fac-tors should be understood. Irrigation, drill design, rotations per minute, and drill sizing are paramount to reduce heat. In addition, the chilling of the saline bags (i.e., placed in refrig-erator before use) allow for the decrease in heat generation (Fig. 27.19). Bone Debris Removal. During osteotomy preparation of D1 bone, fragments of bone often adhere to the utes of the surgi-cal burs. is bone is a great source for grafting around com-promised sites after implant placement. Also, bone chips in the osteotomy may cause an increase in frictional heat and should be removed by irrigation in D1 bone to maintain optimal cutting action (Fig. 27.20). e bone debris should be frequently wiped o the cutting utes of the drill with a surgical sponge. ese bone shavings prevent coolant from reaching the bone and result in the drill being less ecient. e color of these bone shavings is important to evaluate. Any beige coloration to the bone debris indicates excessive heat is being generated and the bone debris is nonvital (Fig. 27.21). A brownish color indicates the bone cell death extends several millimeters away from the implant oste-otomy. e color of the bone debris should be reddish or white, which indicates vital bone (Fig. 27.22). Use of New Drills. e use of new drills with a sharp cutting ute is most critical for D1 bone surgery. Bone drills become dull after repeated use, especially if autoclaved frequently. Chacon and col-leagues evaluated three dierent drill systems after repeated drilling and sterilization. e bone temperature 0.5 mm from the osteot-omy preparation increased every 25 uses of the system, even though light microscopic evaluation showed little wear.6 When the drills become dull, the clinician may not appreciate it in softer bone, but when D1 bone is prepared, the drill sharpness can become critical. Larger Crest Module. Most implant designs have a larger crest module compared with the body of the implant. is design fea-ture ensures a bone “seal” around the top portion of the implant after it is threaded into position. For example, a crest module is usually 4.1 mm for a 3.75-mm-diameter implant. Because the nal osteotomy drill of many systems is in the 3.2-mm-diameter range, the 0.9-mm dierence is substantial, especially in crestal cortical bone. As a result, a crestal bone drill is used in D1 bone, which prepares the larger diameter at the top of the osteotomy (Fig. 27.23). In a study by Novaes and colleagues, the dierence in crestal bone loss after an initial healing period of 3 months was 1.5 mm between using a crestal drill compared with no crestal drill.61 e additional bone trauma from compressing a larger crest mod-ule into the osteotomy is signicant and may increase surgical Bone NecrosisPrevention:• Finalimplantplacementatorabovebonelevel• Unthread½turntorelieveinternalstresses Decreased Blood SupplyPrevention• Primarilyfromperiosteum• Increasedhealingtime• Minimalreection Should Use Bone TapPrevention:• Decreasespressurenecrosis• Allowspassiveimplantt• Preventsinternalimplant–body/implant–boneinterfacemicrofracture• Removesdrillremnants Overheating during OsteotomyPrevention:• Newdrilldesigns,utes,geometry• Abundantexternalirrigation• Intermittentpressureondrill(bonedancing)• Pauseevery3–5seconds;keepirrigating• Incrementaldrillsequence(more drills; pass same drill more than once to widen osteotomy in preparation of next drill) • BOX 27. 4 D1 Bone Disadvantages 656PART VI Implant Surgerybone loss around the implant (i.e., pressure necrosis). erefore a crestal bone drill should be used in D1 bone as the last drilling step in the preparation of the osteotomy. Final Implant Positioning. e ideal implant length for D1 bone is 10 mm for a 4-mm-diameter implant. ere is little, if any, benet to increased implant length beyond 10 mm in D1 bone for a threaded implant body because most all the stresses after healing are limited to the crestal half of the implant, with occlusal loading (Fig. 27.24). e longer implant makes bone preparation more dicult and generates more heat in this bone type. e nal placement of the implant in relation to the crest of the ridge is related to its design and the bone density. A one-stage surgical approach is often used in D1 bone. A healing abutment may be added to permit the implant to heal above the soft tissue, thus eliminating a second-stage surgery.e D1 dense compact bone is often of decreased height. ere-fore the actual support system of the implant may be increased in division C–h limited-height bone type by not countersinking the smooth portion of the implant crest module below the crest of the ridge. e smooth portion of the implant body may be placed above the ridge if no load is applied to the implant during initial healing, and the risk of micromovement during this period is minimal. Bone HealingMany of the cutting cones that develop from monocytes in the circu-lating blood and are responsible for bone remodeling at the implant interface. ese blood cells originate from the blood vessels found in well-vascularized trabecular bone, which has a greater capacity for AB• Fig. . (A) Pretapped bone site has less woven (newly generated) bone and illustrated less trauma on implant insertion. (B) A self-tapping implant insertion causes greater bone trauma and exhibits massive woven regenerative bone formation as a consequence. (From Watzek G, Dan-hel-Mayhauser M, Matejka M, etal. Experimental comparison of Bråne-mark and TPS dental implants in sheep [abstract]. In: UCLA Symposium: Implants in the Partially Edentulous Patient; 1990.)• Fig. . Bone chip debris should be frequently removed by irrigation in D1 bone to improve efficiency of the drill and before implant insertion after bone tapping.• Fig. . Bone debris in the drill should be evaluated. A brown or beige color indicates the temperature is too high and the bone is devitalized.• Fig. . Bone debris in the drill should be white or reddish, which indicates vital bone and ideal preparation conditions.• Fig. . Crestal bone tap should be used in D1 bone to prepare mar-ginal bone to receive the crest module of the implant body, which is larger in diameter than the implant body. 657CHAPTER 27 Implant Placement Surgical Protocolregeneration than compact bone. erefore in some aspects cortical bone requires greater healing time compared with trabecular bone.On the other hand, because of the load-bearing capability of D1 bone and the excellent Bone-Implant Contact (BIC), prosthetic loading of D1 bone may start before the completion of the initial healing phase. Conditions that contribute to a lack of movement during healing are primordial to achieve a direct bone–implant interface. D1 bone is strong and often able to resist micromovement, regardless of whether an implant is loaded. As a result, immediate implant loading is often possible when multiple implants are splinted together, without compromise to the overall survival rate of the implant. However, most often, a blend of treat-ment conditions result in a minimum 3-month unloaded healing period in this bone type.Once the bone–implant interface is established, it exhibits the strongest load-bearing properties of any bone type. As a result, progressive bone loading is not necessary to develop a stable condition. e restoring clinician may proceed without delay as desired to the nal prosthesis (Box 27.5; Fig. 27.25). Dental Implant Surgical Protocol 2 (D2 Bone)Dense-to-Thick Porous Cortical and Coarse Trabecular Bone (D2)e second density of bone found in the edentulous jaws (D2) is a combination of dense-to-porous cortical bone on the crest and coarse trabecular bone within the cortical plates (Fig. 27.26). e Hounseld values on reformatted CBCT images are 750 to 1250 units for this bone quality. e tactile feeling when prepar-ing this bone density is similar to preparations in spruce or white pine wood (i.e. soft wood). e D2 bone trabeculae are 40% to 60% stronger than D3 trabeculae. is bone type occurs most fre-quently in the anterior mandible, followed by the posterior man-dible. On occasion it is observed in the anterior maxilla, especially for a single missing tooth, although the dense-to-porous cortical bone is then found primarily on the lingual surface of the implant site.62• Fig. . D1 Bone: Mandibular cross-sectional image depicting mainly dense D1 bone.D1 Bone Surgical Protocol• Drillingspeed:∼2000 to 2500 rpm• Bonetap:25rpm• Irrigation:copiousamountsofsaline• Bonedance:verycriticaltoreduceheat• Drillosteotomymultipletimeswitheachdrilltooversize osteotomy• Ideallyusenewdrills• Alwaysinsertimplant with hand wrench, not a handpiece • BOX 27. 5 implant Placement Surgical Protocols Twist DrillØ1.5 × 8 mmØ1.5Ø2.4/1.5Ø2.8/2.43.5×11.54.3×11.5Ø4.3 Twist DrillØ2.4/1.5 × 8 mm Twist DrillØ3.0 × 11.5 mm Shaping DrillØ3.5 × 11.5 mm Screw Ta p Ø4.3 mm Shaping DrillØ4.3 × 11.5 mmFinal Drill Parallel Pin Ø4.3 mm• Fig. . D1 implant placement surgical protocol. In this protocol, all surgical burs, including a bone tap are used. 658PART VI Implant SurgeryAdvantages of D2 BoneD2 bone provides excellent implant interface healing, and osteo-integration is very predictable; therefore it is the ideal type of bone. ere exist no disadvantages in D2 bone.Most implant systems refer to this density of bone for their generalized surgical protocol. e dense-to-porous cortical bone on the crest or lateral portions of the implant site provide a secure initial rigid interface. e implant may even be placed slightly above the crest of the ridge, with decreased compromise or risk of movement at the interface during healing compared with softer bone types. e intrabony blood supply allows bleeding during the osteotomy, which helps control overheating during preparation and is most benecial for bone–implant interface healing.63 Implant Osteotomy Surgical SequenceThe drill sequence for D2 bone is similar to D1 bone, with a few exceptions. Therefore all drills in the surgical sequence are used except the bone tap. The use of a bone tap for D2 bone is dependent on the final osteotomy size, the implant body size, the depth of the thread, and the shape of the thread. A bone tap most often will lead to a decreased primary stability in D2 bone. A crestal bone drill should be used for most implant designs in D2 bone.64 The osteotomy preparation should proceed at a higher speed (e.g., ∼2000 rpm). Sharawy and colleagues showed that D2 bone with an osteotomy depth of 8 mm could be prepared in 4 to 8 seconds, dependent on drill design and rpm.39 There-fore the osteotomy depth should not proceed slowly, creat-ing additional heat. Enough pressure should be placed on the handpiece to proceed approximately at least 5 mm every 5 seconds.e implant may be threaded into position with a low-speed (less than 30 rpm), high-torque (75 N/cm) handpiece, rather than using a hand ratchet. e handpiece allows a more precise implant rotation, and a constant pressure ensures the implant will progress into the site without risk of stripping the bone within the threads. During this process, the irrigation may be stopped so the patient does not attempt to close the mouth and swallow, which may contaminate the implant and cause it to be pushed o the axis of the implant osteotomy. However, if minimal bleeding is present, then a small amount of irrigation may be used.A threaded implant placed in the anterior mandible engages the cortical bone at the edentulous crest, and often the lingual lat-eral side. In division C–h bone, the implant may also engage the apical cortical region; however, in the mandible, care should be exercised to not perforate the inferior border. is provides imme-diate stability and proven long-term survival.When the anterior maxilla presents this bone density, it is treated similarly to the D2 mandible. A threaded implant should engage the palatal cortical plate rather than the labial corti-cal bone, which is thinner and porous. However, care should be exercised because the implant may be pushed more labial, even stripping the facial plate. e anterior maxilla usually has less available bone height than does the anterior mandible. As a result, the apex of the implant may engage the thin cortical plate of the oor of the nose when a solid, traditional screw-type system is used. Because the greatest stresses after healing are primarily transmitted around the crest, the primary advantage of the apical end of the implant engaging cortical bone is initial stability during healing. HealingThe excellent blood supply and rigid initial fixation of D2 bone permits adequate bone healing within 4 months. The lamellar bone–implant interface is more than 60% established at the 4-month healing interval. BIC is approximately 70% at this point in time, especially when cortical bone engages the lateral and lingual portions of the implant (Fig. 27.27). Abut-ment placement and prosthodontic therapy may then com-mence. It should be noted that the time frame for initial bone healing is based on the density of the bone and not on the location in the jaws. Therefore a 4-month rigid healing phase is adequate for porous cortical and coarse trabecular (D2) bone, even when found in the maxilla. Progressive bone load-ing is usually not required for D2 bone, although an increase in BIC takes place during the initial loading period (Box 27.6; Fig. 27.28). Dental Implant Surgical Protocol 3 (D3 Bone)Thin Porous Cortical and Fine Trabecular Bone (D3)e third density of bone (D3) is composed of thinner porous cor-tical bone on the crest and ne trabecular bone within the ridge (Fig. 27.29). e CBCT-reformatted images may have a range of 375 to 750 HU. is bone quality provides the clinician with a tactile sense similar to drilling in compressed balsa wood. e trabeculae are approximately 50% weaker than those in D2 bone. D3 bone is found most often in the anterior maxilla and posterior regions of the mouth in either arch. It may also be found in the division B edentulous ridge, modied by osteoplasty to provide adequate width for a root-form implant placement. Sinus aug-mentation grafts are often D3 bone in the posterior maxilla after a healing period of 6 months or more.65 D3 bone is least prevalent • Fig. . D2 bone has a dense to porous cortical crest, and inner tra-becular bone is coarse. It is found most often in the anterior mandible. 659CHAPTER 27 Implant Placement Surgical Protocolin division C–h or division D anterior mandibles. Larger diam-eter implants (5 mm or 6 mm) are more essential in D3 bone in the molar regions than in the previous categories. A rough-ened implant body (i.e., such as acid-etched media or resorbable blast media) presents advantages in this bone density, regardless of design, to compensate for the limited initial bone contact and decreased bone strength inherent in the trabecular architecture.e porous cortical layer is thinner on the crest and labial aspect of the maxilla, and the ne trabecular pattern is more discrete in wide edentulous sites. e D3 anterior maxilla is usually of less width than its mandibular D3 counterpart. e D3 bone is not only 50% weaker than D2 bone, but the BIC is also less favorable in D3 bone. ese additive factors can increase the risk of implant failure. erefore small-diameter implants are not suggested in most situations. Instead, bone spreading in this bone density is mechanically easier to perform (i.e. less cortical thickness) and allows the placement of greater diameter implants. e increased-diameter implants lead to improved prognosis, especially when lateral forces or greater force magnitudes are expected. In addi-tion, bone spreading compacts the trabecular bone and increases its density after initial healing (e.g., OD).Advantages of D3 Bonee main advantage of D3 porous compact and ne trabecular bone is that the implant osteotomy preparation time and diculty is minimal for each drill size and is usually less than 10 seconds. e crest module drill and bone tap may be eliminated in the surgical protocol. Blood supply is excellent for initial healing, and intraosseous bleeding helps cool the osteotomy during prepara-tion. As a result, this bone density is usually associated with a high surgical survival rate. Disadvantages of D3 BoneD3 bone also presents several disadvantages. It is more delicate to surgically manage than the previous two bone density types as its preparation takes minimal eort.• Drillingspeed:∼2000 to 2500 rpm• Bonetap:usuallynotneeded• Irrigation:copiousamountsofsaline• Bonedance:verycriticaltoreduceheat• Implantplacement:withinsertionwrenchorhandpiece • BOX 27. 6 D2 Bone Surgical Protocol Tw ist Drill Ø1.5 × 8 mmParallel Pin Ø4.3 mm Twist Drill Ø2.4/1.5 × 8 mm Twist Drill Ø3.0 × 11.5 mm Shaping Drill Ø3.5 × 11.5 mm Shaping Drill Ø4.3 × 11.5 mmFinal DrillØ1.5Ø2.4/1.5Ø2.8/2.43.5×11.54.3×11.5• Fig. . D2 surgical protocol. Note the use of all surgical burs except the bone tap.• Fig. . Bone-implant contact is approximately 70% in D2 bone after initial healing and is excellent for load-bearing capability. 660PART VI Implant Surgerye motor speed in drilling the osteotomy is not as important as in D1 or D2 bone. erefore bone preparation in D3 bone can range from 1000 to 2000 rpm and must be made with constant care of direction to avoid enlargement or elliptical preparation of the site.A common mistake that causes an elliptical site (i.e., over-sized osteotomy) to form is the pronation of the wrist, which redirects the handpiece direction. In dense bone, the side of the drill encroaches on the dense cortical crest, which opposes the movement and stops the rotation before the crestal osteotomy is enlarged. In D3 bone the arc pathway is not stopped and the osteotomy at the level of the crestal bone is of greater diameter than the drill. If the implant design does not increase at the crestal region, then the surgical defect created around the crestal area of the implant may heal with brous tissue rather than bone and cause an initial bony pocket.erefore the osteotomy should be drilled with the arm in a “drill press” type of motion (i.e., in one plane). To improve rigid xation of traditional root-form designs during healing, the opposing thin cortical bone of the nasal or antral oor is often engaged in the maxilla or the apicolingual plate in the mandible, when immediate loading (IL) is considered. If the original implant height determined before surgery does not engage the opposing cortical bone, then the osteotomy is increased in depth until it is engaged. Slightly longer implants may be placed in this approach to further increase surface area of support. However, it should be remembered that this tech-nique improves stability during healing but does not decrease the crestal loads to bone after healing. Instead, implant crest module design and the crestal one-third of the implant body design are necessary to decrease stress when the implant pros-thesis is loaded.e clinician must be careful to avoid undesired lateral per-forations of the cortical bone during osteotomy procedures, especially on the thin, labial porous cortical plate of the max-illa. A common mistake is the stripping of the thin facial plates during the osteotomy. e initial and intermediate drills proceed through the ne trabecular bone without incident. However, the lingual aspect of the end-cutting drill contacts the thick palatal cortical bone within the osteotomy, which resists preparation, and pushes the drill facially, which may strip the facial plate. A very rm hand, which prevents lateral displacement of the drill and handpiece during the implant osteotomy and does not permit the drill to move facially, is mandatory to prevent this unwanted complication. Implant Osteotomy Surgical SequenceIn D3 bone, the nal drill (i.e., in some systems the nal two drills) is not used because the placement of the implant allows for the lateral displacement of the bone, increasing bone density. A crestal bone drill should not be used in D3 bone. e thin, porous cortical bone on the crest provides improved initial stabil-ity of the implant when it is compressed against the crest module of the implant. Unlike D1 and D2 bone, the nal drill diameter (3.0–3.4 mm for a standard-diameter implant) is of benet for the 4.1-mm to 4.2-mm crest module dimension to compress the weaker bone. e compressed soft bone not only provides greater stability, but it heals with a higher BIC, which is a benet during the initial bone-loading process.A bone tap is never indicated in D3 bone because the ne trabeculae are 50% weaker than D2 trabeculae, and when the implant is threaded into position, it compresses the bone. is provides improved initial stability and increases the BIC dur-ing initial healing. Bone compaction is a benet when the bone density is poor. Because crest module drills and a bone tap are usually not used in D3 bone, the number of steps and time of preparation are reduced. With any drill in D3 bone, it should only be passed once in the osteotomy to avoid oversizing the preparation. On the other hand, a complication often occurs when inserting the threaded implant into the prepared bone site of the anterior maxilla. e threaded implant does not com-pletely thread into the more dense palatal plate of bone in this region, and the implant may be pushed facially, often stripping the facial bone because the implant is threaded into position. is often occurs when a ratchet is used instead of a handpiece when placing the implant. A hand ratchet often will distort and widen the top of the osteotomy and impair proper bone con-tact with the crest module of the implant. In addition, the hand ratchet will often push the implant toward the facial bone, into the softer bone. is causes the implant to be positioned more facially than originally prepared and may even strip the thin cor-tical plate on the facial aspect of the osteotomy.In abundant bone volume, the implant may self-tap the soft, thin, trabecular bone to enhance initial stability. An implant with a wider crest module can compress the crestal bone when inserted without using a countersink drill. The implant should not be removed and reinserted because initial rigid fixation may be compromised. If the only cortical bone is on the crest of the ridge, as in a posterior mandible, the implants are not countersunk below the crest in this density of bone. The thin, porous cortical plate provides greater ini-tial stability than the fine trabecular bone underneath. This is especially important in the posterior mandible of a clench-ing parafunctional patient because bone torsion occurs during heavy biting pressures.erefore for placement of an implant in D3 bone, a low-speed (30 rpm), high-torque handpiece should be used rather than a hand wrench for self-tapping implant insertion. is D3• Fig. . D3 bone exhibits minimal cortical bone and thin trabecular bone. 661CHAPTER 27 Implant Placement Surgical Protocoldecreases the risk of oversizing the osteotomy with an ellipti-cal implant insertion, which usually results from hand wrench placement in softer bone. A rm hand during handpiece inser-tion also can prevent the implant from being pushed facially and away from the thicker lingual cortical plate. Tightening a threaded implant to increase xation once completely inserted is not recommended because stripping of the threads and decreased xation may occur.A roughened surface condition or coating on a threaded implant body is advantageous in this soft bone condition to enhance initial stability and the amount of initial trabecular bone at the bone–implant interface. e amount of bone initially at the bone–implant interface is reduced compared with bone types D1 and D2. If the lingual and apical cortical bone are not engaged at the time of implant placement, then less than 50% of the implant surface may actually contact bone. An additional implant may be used to improve load distribution and prosthodontic support dur-ing the early loading period. Often a two-stage technique is rec-ommended to minimize premature loading of the implant (Fig. 27.30; Box 27.7). Healinge time frame for atraumatic healing is usually 5 months or more. e actual implant interface develops more rapidly than D2 bone; however, the extended time permits the regional accel-eratory phenomenon (RAP) from implant surgery to stimulate the formation of more trabecular bone patterns. In addition, the more advanced bone mineralization within the extra months also increases its strength before loading. An extended gradual loading period (e.g., progressive bone loading) is also recommended to further improve this bone density during the initial bone loading (Box 27.8). Dental Implant Surgical Protocol 4 (D4 Bone)Fine Trabecular Bone (D4)Fine trabecular (D4) bone has very little density and little or no cortical crestal bone. It is the opposite spectrum of dense cor-tical (D1) bone. e most common locations for this type of bone are the posterior molar region of a maxilla in the long-term Tw ist Drill Ø1.5 × 8 mmParallel Pin Ø4.3 mm Twist Drill Ø2.4/1.5 × 8 mm Twist Drill Ø3.0 × 11.5 mm Shaping Drill Ø3.5 × 11.5 mmØ1.5Ø2.4/1.5Ø2.8/2.43.5×11.5• Fig. . D3 surgical protocol. Note the use of all surgical burs except the last shaping drill.Bone-Implant Contact• Approximately50%• Longerhealingperiod• Additionalimplantsrecommended Implant Placement• Onechance,widenosteotomy• Thincrestalcorticalbonewhichdecreasesprimarystability• Greaterriskofoverload during healing • BOX 27.7 Disadvantages of D3 Bone• Underprep:nolastbur(osseodensication)• Drillingspeed:∼1000 to 2500 rpm (speed not as important in poorer qualitybone)• Finaldrillandbonetap:notused• Irrigation:copiousamountsofsaline• Bonedance:notascriticalincomparisontobetterqualitybone• Implantplacement:handpiece • BOX 27. 8 D3 Bone Surgical Protocol 662PART VI Implant Surgeryedentulous patient, or in an augmented ridge in height and width with particulate bone or substitutes, or in a sinus graft. It is rarely observed in the mandible but on occasion does exist. ese edentulous ridges are often very wide but have reduced vertical height. is bone type is also present after osteoplasty in wide D3 ridges because the crestal cortical bone is removed dur-ing this procedure.e tactile sense during osteotomy preparation of this bone is similar to sti, dense Styrofoam. e bone trabeculae may be up to 10 times weaker than the cortical bone of D1. e BIC after initial loading is often less than 25% (Fig. 27.31). A CBCT scan with reformatted images of D4 bone has a Hounseld number of 0 - 350 HU. units.Division B implants are not suggested in this bone type. Bone spreading is easiest in this bone density, and larger diameter implants are suggested whenever possible. A roughened implant surface coating is almost mandatory to improve the amount of BIC in this bone quality after initial healing.Disadvantages of D4 BoneFine trabecular bone presents the most arduous endeavor to obtain rigid xation. Bone trabeculae are sparse and, as a result, initial xation of any implant design presents a surgical challenge (Fig. 27.32).Additional implants are placed to improve implant-bone loading distribution and prosthodontic rehabilitation, espe-cially during the rst critical year of function. For xed resto-rations, no cantilever on the prosthesis is used with this bone density. An additional implant may be placed at the time of surgery in the second molar region to further improve sup-port. e implant of choice in the wide posterior maxilla with D4 bone is a greater diameter and roughened surface. or HA-coated threaded implant. When properly inserted, the-threaded implant can be more stable and provides greater surface area. e larger diameter implant oers greater surface area for sup-port, further compresses the ne trabecular bone for greater ini-tial rigidity, has a greater chance to engage the lateral regions of cortical bone for support, and improves stress transfer during loading (Box 27.9). Implant Osteotomy Drilling Sequencee initial drill and possibly the second drill are used to determine site depth and angulation is the only one that should be used in this bone type, after which osteotomes may be used with a surgical mallet or handpiece to compress the bone site, rather than remove bone, as the osteotomy increases in size (Figs. 27.33 and 27.34).e compaction technique of the site is prepared with great care. e bone site may be easily distorted, resulting in reduced initial stability of the implant. e nal osteotomy diameter is similar to the D3 preparation. e residual ridge is easily expanded in this bone type. e osteotomy may both compress the bone tra-beculae and expand the osteotomy site.e implant should self-tap the bone or shape the implant receptor site while being seated with a slow-speed, high-torque handpiece. A hand wrench is contraindicated because it may devi-ate the positioning of the implant. e pressure on the implant during insertion corresponds to the speed of rotation, and the implant proceeds to self-tap the soft bone. It is dicult to thread an implant in soft bone in dicult access regions. If there is any cortical bone in the opposing landmark, it is engaged to enhance stability and simultaneously ensure the maximum length of implant. An implant with a greater crestal diameter presents the added benet to further compress the crestal bone for stability.Once inserted, the implant should not be removed and reinserted; instead, one-time placement is mandatory. e implant is counter-sunk in this bone if any risk of loading is expected during healing (e.g., • Fig. . Posterior maxillary region may be D4 bone, with bone-implant contact after initial loading no greater than 25%.• Fig. . Conventional drilling procedure uses an extraction technique that removes bone from the site. Note fragmentation of the osteotomy margin.Bone AnatomyLocation:• Minimalcorticalcrest,decreasedprimarystabilitycorticalcrest• Decreasedboneheight(i.e.maxillaryposterior) • Requiresmoreimplants Osteotomy• Mustundersizeosteotomyforosseodensication• SurgicalAccess(i.e.posteriormaxilla) • BOX 27. 9 Disadvantages of D4 Bone 663CHAPTER 27 Implant Placement Surgical Protocolunder a soft tissue–borne prosthesis). Countersinking the implant below the crest reduces the risk of micromovement during healing in this very soft bone No countersink drill is used before countersinking. A two-stage technique is recommended because this will minimize premature loading of the implant (Fig. 27.35; Box 27.10). Healinge healing and progressive bone-loading sequence for D4 bone require more time than the other three types of bone. Time is needed to allow bone to remodel at the surface and to intensify its trabecular pattern. e additional time also allows a more advanced bone mineralization and increased strength. Six or more months of undisturbed healing is suggested. e compression technique for surgery, the extended healing time, and progres-sive bone-loading protocol allow the remodeling of this bone into a more organized and load-bearing quality similar to D3 bone before the nal prosthetic loading of the implants (Fig. 27.36). Primary StabilityAccurate assessment of primary stability is crucial in the implant placement protocol. Methods of measuring implant stability include percussion testing, IT, reverse torque testing, resonance frequency analysis (RFA), and surgical experience.PeriotestIn the early days of implantology, instrumented percussion testing used the Periotest system. Periotest evaluations have been used to gauge primary stability. e system is composed of a metallic tap-ping rod in a handpiece, which is electromagnetically driven and electronically controlled. Signals produced by tapping are con-verted to unique values called Periotest values. ese results are expressed in arbitrary units with acceptable Periotest values in the ranges of −4 to −2 and −4 to +2. However, today this device has been supplanted by RFA because of the lack of reproducibility of results derived from Periotest measurements (Fig. 27.37). Resonance Frequency AnalysisIn implantology today, the more common method of determining primary stability is resonance frequency analysis (RFA). RFA is a test-ing method that provides objective and reliable measurements of lat-eral micromobility at various stages of the implant treatment process. e method analyzes the rst resonance frequency of a small trans-ducer attached to an implant or abutment. It can be used to monitor the changes in stiness and stability at the implant–tissue interface and to discriminate between successful implants and clinical failures. e Implant Stability Quotient (ISQ) is the scale of measurement for use with the RFA method.is more objective assessment of stability may help improve a clinician’s learning curve and is useful for future comparison. Multiple studies66,67 have determined that an acceptable stabil-ity range lies between 55 and 85 ISQ, with an average ISQ level of 70.68• Fig. . Bone compaction instruments (osteotomes) are used after the initial pilot drill to prepare the osteotomy.D4D2• Fig. . In D4 bone, the implant is often countersunk below the crest of the ridge, wherever a soft tissue–borne restoration is worn during the initial healing phase. In D2 bone, the implant is usually placed at the crest of the bone.• Underprep(osseodensication)• Drillingspeed:∼1000 to 2500 rpm (speed not as important in poorer qualitybone)• Irrigation:copiousamountsofsaline• Bonedance:notrecommendedaswillenlargeosteotomy• Implantplacement:handpiece(donotdeviatefromoriginalosteotomy) • BOX 27.10 D4 Bone Surgical Protocol• Fig. . Bone compaction technique to prepare the implant site, which results in osseodensification. 664PART VI Implant SurgeryVarious studies have shown that the RFA protocol can provide the clinician with important information about the current status of the bone-implant interface via ISQ values. In combination with clinical and radiographic ndings, the use of RFA can be used as a valuable diagnostic adjunct with regards to the bone density, heal-ing protocols, and loading protocols for dental implants, as well as recognizing the potential failure of implants.Sennerby reported on a classication of ISQ values in rela-tion to the health of dental implants. e ISQ values were placed into three zones based on RFA measurements at the time of implant placement. Recommendations include the “safe zone” which includes ISQ values of 70 or above. ese high ISQ values are usually suitable for immediate load pro-tocols. e second classication includes “questionable” implants, which represent values from 55 – 70 ISQ. Values in this range require continuous monitoring to determine if ISQ numbers increase after longer healing. It is recommended that implants with ISQ’s in this range should undergo progressive bone loading techniques. e last zone includes implants with an ISQ value of less than 55. ese implants are compromised and may be associated with an increased failure rate. ere-fore, increased healing times are recommended along with pro-gressive bone loading protocols. If subsequent readings still remain low after healing and progressive bone loading proto-cols, further healing may be warranted.69Numerous studies have shown the successful use of RFA in the evaluation of implant health. Sjöström et al.70 evaluated the primary stability of maxillary implants of successful vs. failed implants. e average ISQ for the successful implants were 62 ISQ and the failed implants were 54 ISQ. Turkyilmaz and McGlumphy in a retrospective study of 300 implants over three years showed failed implants with an average ISQ of 46 and suc-cessful implants an average of 67 ISQ. In the evaluation of Hounseld units and insertion torque, similar signicant dier-ences were found.71 (Fig. 27.38; Box 27.11).In general, the RFA technique via ISQ values provide valuable information on the current status of the implant–bone interface. e ISQ values correlate to the micromobility of the implant, which is directly related to the biomechanical properties of the surrounding bone tissue and the quality of the bone-implant interface. rough various studies, it has been shown that lower ISQ values are directly associated with eventual implant failure. erefore, the RFA technique is a valuable modality in evalu-ating dental implant health during any phase of the implant process.72 Tw ist Drill Ø1.5 × 8 mmParallel Pin Ø4.3 mm Twist Drill Ø2.4/1.5 × 8 mmOsteotome Ø3.0 mmOsteotome Ø3.5 mmØ2.4/1.5Ø1.5• Fig. . D4 surgical protocol. Only one to two burs are used, then osteotomes osseodensify the oste-otomy, which results in an increased bone density.• Fig. . Periotest, which uses a tapping rod to evaluate implant stability. 665CHAPTER 27 Implant Placement Surgical ProtocolOne-Stage versus Two-Stagee clinician is often confronted with the choice of completing the dental implant procedure with a one-stage or a two-stage pro-tocol. Numerous studies have shown no dierence in success rates between the two techniques.73,74Two-Stage Surgerye two-stage surgery technique involves the placement of the implant and a low-prole cover screw, which is inserted into the implant body. When the cover screw is in nal position, it may be slightly tightened, loosened, and tightened again. No tissue, blood coagulants, or bone particles should prevent the complete seating of the cover screw. In addition, the cover screw should not be tightened with signicant force because this may result in the implant rotating, which increases the possibility of nonintegration.e two-stage surgical approach oers several advantages. By submerging the implant below the tissue, no pressure is placed on the surgery site, allowing the implant to heal undisturbed. In addition, there exists less chance of infection, and overloading the implant prematurely is less likely. However, with a two-stage approach, a second-stage surgery is required, which usually will lead to longer healing times. Studies have shown that less keratin-ized tissue is present compared with a one-stage protocol.e indications for a two-stage surgery include anytime pri-mary stability is in question, such as compromised bone density. If excessive parafunctional habits are present, then submerging the implant is an ideal treatment to minimize the possibility of biome-chanical overloading. Last, if bone grafting procedures are used in conjunction with the implant placement, then undisturbed heal-ing via a two-stage technique is ideal (Fig. 27.39; Box 27.12). One-Stage SurgeryA one-stage surgical protocol involves the placement of a healing abutment that extends slightly above the crest of the tissue. e soft tissue is then sutured around the healing abutment to form a soft tissue drape during the healing period. ere are numerous advantages to the one-stage surgery technique.One advantage is that the soft tissue matures while the bone interface is healing. is permits the restoration to be fabricated with complete assessment of the soft tissue prole. In the two-step AACBD• Fig. . Penguin RFA. (A) Penguin RFA measures implant stability and osseointegration. (B) Reus-able MulTipeg is inserted into the implant body. (C) Penguin is placed in approximation to the reusable MulTipeg. (D) Final reading of the RFA, ideally the Implant Stability Quotient reading will be greater than 55.• Autoclavable• CalibratedtransducersusedareSmartPegs• Magneticpegisxedtotheimplantxtureorabutment• Pegisexcitedthroughmagneticpulsesandstartstovibrate,inducinganelectricvoltthatispickedupbythemagneticRFA• Establishmentofanewunittodescribethefrequencies=ISQ• Readingsaretakenintwodirections(MD)andBLand the average is recordedastheISQBL, buccal-lingual; ISQ,ImplantStabilityQuotient;MD, mesial-distal; RFA, radiofrequencyanalysis. • BOX 27.11 Resonance Frequency Analysis 666PART VI Implant Surgeryprocedure, the soft tissue is less mature when the prosthesis is fabricated because a stage II surgery is required to uncover the implant and place a healing abutment.Because a healing abutment has been placed on the implant, a second surgical procedure and suture removal appointment are not necessary. is saves the patient discomfort and results in two less appointments (stage II uncovery and suture removal).e abutment to implant connection may be placed above the crest of bone in the one-stage surgery. is higher location of the implant–abutment connection may reduce some of the early crestal bone loss in a developing implant interface. In addi-tion, Weber observed an improved hemidesmosome soft tis-sue–implant connection when the components above the bone were not removed and reinserted, such as when the healing gap connection is below the bone.75 Depending on the crest mod-ule design, the one-stage surgical approach may have less early crestal bone loss.e one-stage technique also has numerous disadvantages. e higher prole permucosal extension (PME) is more at risk of load-ing during healing, especially when an overlying soft tissue–borne transitional restoration is worn. erefore a disadvantage may be a higher healing failure rate. However, clinical studies of one-stage surgery indicate similar implant survival rates in good bone vol-umes and quality.Because the healing abutment is placed with nger pressure, patients may tend to place unnecessary force on the abutment via their tongue. is may result in the loosening of the abutment and possible aspiration. If the healing abutment becomes partially loose, then soft tissue will often grow in between the abutment and implant, preventing complete seating of the prostheses. When a bone graft is placed at the time of implant insertion, primary closure of the soft tissues improves the environment to grow bone. erefore the one-stage approach is indicated less often under these conditions.A one-stage surgical protocol is indicated when implant place-ment involves excellent primary stability. e patient should not exhibit any parafunctional or force-related habits and there should be no bone grafting procedures completed in conjunction with the implant placement (Fig. 27.40; Box 27.13; Table 27.1). SummaryBone remodels in relation to the forces exerted on it. Depending on the location of the edentulous ridge and the amount of time the area has been edentulous, the density of bone is variable. Clini-cally, the surgeon can correlate the hardness of the trabecular bone and the presence of a cortical plate with four dierent densities of bone. e typical locations of these dierent densities, the altera-tion in surgical technique with each type, and the advantages and • Fig. . After implant placement, a cover screw is inserted into the implant. A second-stage surgery is indicated to expose the implant for prosthetic rehabilitation.Advantages:• Submergedimplant• Nopressureonsurgerysite• LesschanceofinfectionDisadvantages:• Second-stagesurgeryneeded• Longerhealingtimes• Lesskeratinizedtissueversusone-stageIndications:• ?Primarystability• Bonegrafting/membranes• Parafunction/forceissues • BOX 27.12 Two-Stage Surgical Protocol• Fig. . After implant placement, a healing abutment is inserted into the implant to allow for ideal soft tissue healing.Advantages:• Nosecondsurgery• Shortenstreatmenttime• BettertissuehealthDisadvantages:• Healingabutmentscanbeloose• Force-relatedissues• LessspaceforinterimprosthesisIndications:• Favorableprimarystability• Nobonegrafting/membranes• Noparafunction/forceIssues • BOX 27.13 One-Stage Surgical Protocol 667CHAPTER 27 Implant Placement Surgical Protocoldisadvantages of each have been related to each density classica-tion. e dense cortical bone of D1 is the strongest bone, approxi-mately 10 times greater than D4 bone, and is the most dicult to prepare. e thick, porous cortical and coarse trabecular D2 bone is twice as strong as D3 bone and is ideal for implant support. e thin, porous cortical and ne trabecular D3 bone is similar to prep-arations in compressed balsa wood. e ne trabecular bone of D4 is similar to osteotomies in dense Styrofoam. e initial drills may be used to distinguish among the four bone density types.A surgical preparation and implant insertion protocol has been discussed which relates specically to the bone density. D1 bone heals with a lamellar bone interface and has the greatest percent-age of bone at the implant body contact regions. D2 bone heals with woven and lamellar bone, is adequately mineralized at 4 months, and often has approximately 70% bone in initial contact after healing with the implant body. D3 bone has about 50% bone at the initial implant interface after healing and benets from a roughened surface on the screw-shaped implant body to increase initial xation and bone contact. An additional 1 month (total of 5 months) is used for initial bone healing, compared with D2 bone, to permit a greater percentage of bone trabeculae to min-eralize and form around the implant. D4 bone density has the least amount of trabeculae at implant placement. Additional time for bone healing and incremental bone loading will improve the density and result in implant survival similar to that of other bone densities.References 1. Eriksson AR, Albrektsson T, Albrektsson B. Heat caused by drill-ing in cortical bone. Temperature measured invivo in patients and animals. Acta Orthop Scand. 1984;55:629–631. 2. Schroeder A. Preparation of the implant bed. In: Schroeder A, Sutter F, eds. Oral Implantology. New York: ieme; 1996. 3. Ercoli C, Funkenbusch PD, Lee HJ, etal. e inuence of drill wear on cutting eciency and heat production during osteotomy preparation for dental implants: a study of drill durability. Int J Oral Maxillofac Implants. 2004;19:335–349. 4. Sharawy M, Misch CE, Weller N, et al. Heat generation during implant drilling: the signicance of motor speed. Oral Maxillofac Surg. 2002;60:1160–1169. 5. Matthews J, Hirsch C. Temperatures measured in human cortical bone when drilling. J Bone Joint Surg. 1972;45A:297–308. 6. Chacon GE, Bower DL, Larsen PE, etal. Heat production by 3 implant drill systems after repeated drilling and sterilization. J Oral Maxillofac Surg. 2006;64:265–269. 7. Adell R, Lekholm U, Brånemark PI. Surgical procedures. In: Bråne-mark PI, Zarb GA, Albrektsson T, eds. Tissue-integrated Prosthe-ses Osseointegration in Clinical Dentistry. Chicago: Quintessence; 1985. 8. Wiggins KL, Malkin S. Drilling of bone. J Biomech. 1976;9:553–559. 9. Rafel SS. Temperature changes during high-speed drilling on bone. J Oral Surg Anesth Hosp Dent Serv. 1962;20:475–477. 10. Brisman DL. e eect of speed, pressure, and time on bone tem-perature during the drilling of implant sites. Int J Oral Maxillofac Implants. 1996;11:35–37. 11. Hobkirk J, Rusiniak K. Investigation of variable factors in drilling bone. J Oral Surg. 1977;35:968–973. 12. Eriksson RA, Albrektsson T. Temperature threshold levels for heat-induced bone tissue injury: a vital-microscopic study in the rabbit. J Prosthet Dent. 1983;50:101–107. 13. Kim SJ, Yoo J, Kim YS, Shin SW. Temperature change in pig rib bone during implant site preparation by low-speed drilling. J Appl Oral Science. 2010;18(5):522–527. 14. Yacker M, Klein M. e eect of irrigation on osteotomy depth and bur diameter. Int J Oral Maxillofac Implants. 1996;11: 635–638. 15. Benington IC, Biagioni PA, Briggs J, Sheridan S, Lamey PJ. ermal changes observed at implant sites during internal and external irriga-tion. Clin Oral Implants Res. 2002;13(3):293–297. 16. Barrak I, et al. Eect of the combination of low-speed drilling and cooled irrigation uid on intraosseous heat generation during guided surgical implant site preparation: an invitro study. Implant Dentistry. 2017;26(4):541–546. 17. Boa K, etal. Intraosseous generation of heat during guided surgical drilling: an exvivo study of the eect of the temperature of the irri-gating uid. Br J Oral Maxillofac Surg. 2016;54(8):904–908. 18. Davidson SR, James DF. Drilling in bone: modeling heat generation and temperature distribution. J Biomech Eng. 2003;125:305–314. 19. Yacker M, Klein M. e eect of irrigation on osteotomy depth and bur diameter. Int J Oral Maxillofac Implants. 1996;11: 635–638. 20. Eriksson RA, Adell R. Temperatures during drilling for the place-ment of implants using the osseointegration technique. J Oral Max-illofac Surg. 1986;44:4–7. 21. Yeniyol S, Jimbo R, Marin C, etal. e eect of drilling speed on early bone healing to oral impl Oral. Surg Oral Med Oral Pathol Oral Radiol. 2013;116:550–555. Surgical Preparation and Implant Insertion ProtocolBone Density Location Similar Density Drilling Protocol Drilling Speed Insertion LevelInsertion TechniqueIdeal HealingD1 Anteriormandible Maple/oakwood Alldrills+bonetap 2000 rpm (bone dancing)Atorslightlyabove crestHand ratchet 3–4 monthsD2 AnteriormandiblePosterior mandible, AnteriormaxillaWhite pine wood Alldrills(possiblebonetap)2000 rpm (bone dancing)Level with crest Hand ratchet or handpiece4 monthsD3 AnteriormaxillaPosterior mandibleBalsa wood Alldrillsexceptlastshaping drill∼1000 rpm Atorslightlybelow crestHandpiece (30 rpm)4–5 monthsD4 Posterior maxilla Styrofoam Onlyonetotwobegin-ning burs, then osteotomes∼1000 rpm SlightlybelowcrestHandpiece (30 rpm)5–6 months TABLE 27.1 668PART VI Implant Surgery 22. Rafel SS. Temperature changes during high-speed drilling on bone. J Oral Surg Anesth Hosp Dent Serv. 1962;20:475–477. 23. Babbush CA. e endosteal blade vent implant—the histology of animal studies and scanning electron microscope observations. In: Babbush CA, ed. Surgical Atlas of Dental Implant Techniques. Phila-delphia: WB Saunders; 1980. 24. Matthews J, Hirsch C. Temperatures measured in human cortical bone when drilling. J Bone Joint Surg. 1972;45A:297–308. 25. Watcher R, Stoll P. Increase of temperature during osteotomy. In vitro and in vivo investigations. Int J Oral Maxillofac Surg. 1991;20:245–249. 26. Meredith N. A review of implant design, geometry and placement. Appl Osseointegr Res. 2008;6:6e12. 27. Ottoni JM, Oliveira ZF, Mansini R, Cabral AM. Correlation between placement torque and survival of single-tooth implants. Int J Oral Maxillofac Implants. 2005;20(5):769–776. 28. da Cunha HA, Francischone CE, Filho HN, de Oleviera RC. A comparison between cutting torque and resonance frequency in the assessment of primary stability and nal torque capacity of standard and TiUnite single-tooth implants under immediate loading. Int J Oral Maxillofac Implants. 2004;19(4):578–585. 29. Horwitz J, Zuabi O, Peled M, Machtei EE. Immediate and delayed restoration of dental implants in periodontally sus-ceptible patients: 1 year results. Int J Oral Maxillofac Implants. 2007;22(3):423–429. 30. Qu Z. Mechanical Properties of Trabecular Bone in Human Mandible [doctoral esis]. Birmingham, Ala: University of Alabama at Bir-mingham.; 1994. 31. Misch CE, Qu Z, Bidez MW. Mechanical properties of trabecu-lar bone in the human mandible: implications for dental implant treatment planning and surgical placement. J Oral Maxillofac Surg. 1999;57:700–706. 32. Lekholm U, Zarb GA. Patient selection and preparation. In: Bråne-mark PI, Zarb GA, Albrektsson T, eds. Tissue-integrated Prostheses. Chicago: Quintessence; 1985. 33. Adell R, Lekholm U, Rockler B. A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. Int J Oral Surg. 1981;10:387–416. 34. Engquist B, Bergendal T, Kallus T, etal. A retrospective multicenter evaluation of osseointegrated implants supporting overdentures. Int J Oral Maxillofac Implants. 1988;3:129–134. 35. Jan RA, Berman CL. e excessive loss of Brånemark xtures in type IV bone: a 5-year analysis. J Periodontol. 1991;62:2–4. 36. Friberg B, Jemt T, Lekholm U. Early failures in 4,641 consecutively placed Brånemark dental implants: a study from stage I surgery to the connection of completed prostheses. Int J Oral Maxillofac Implants. 1991;6:142–146. 37. Quirynen M, Naert I, van Steenberghe D, etal. A study of 589 con-secutive implants supporting complete xed prostheses: dental and periodontal aspects. J Prosthet Dent. 1992;68:655–663. 38. Fugazzotto PA, Wheeler SL, Lindsay JA. Success and failure rates of cylinder implants in type IV bone. J Periodontol. 1993;64:1085–1087. 39. Hutton JE, Heath MR, Chai JY, etal. Factors related to success and failure rates at 3 year follow up in a multicenter study of over-dentures supported by Branemark implants. Int J Oral Maxillofac Implants. 1995;10:33–42. 40. Sullivan DY, Sherwood RL, Collins TA, etal. e reverse-torque test: a clinical report. Int J Oral Maxillofac Implants. 1996;11:179–185. 41. Snauwaert K, Duyck D, van Steenberghe D, etal. Time dependent failure rate and marginal bone loss of implant supported prostheses: a 15-year follow-up. Study Clin Oral Invest. 2000;4:13–20. 42. Herrmann I, Lekholm U, Holm S, et al. Evaluation of patient and implant characteristics as potential prognostic factors for oral implant failures. Int J Oral Maxillofac Implants. 2005;20:220–230. 43. Truhlar RS, Morris HF, Ochi S, etal. Second stage failures related to bone quality in patients receiving endosseous dental implants: DICRG Interim Report No. 7. Dental Implant Clinical Research Group. Implant Dent. 1994;3:252–255. 44. Misch CE, Hoar JB, Beck G, etal. A bone quality based implant system: a preliminary report of stage I and stage II. Implant Dent. 1998;7:35–42. 45. Misch CE, Poitras Y, Dietsh-Misch F. Endosteal implants in the edentulous posterior maxilla—rationale and clinical results. Oral Health. 2000:7–16. 46. Frost HM. A brief review for orthopedic surgeons: Fatigue damage (microdamage) in bone (its determinants and clinical implications). J Orthop Sci. 1998;3:272–281. 47. Misch CE. Density of bone: eect on treatment plans, surgical approach, healing, and progressive bone loading. Int J Oral Implan-tol. 1990;6:23–31. 48. Huwais S. Inventor; Fluted osteotome and surgical method for use. US Patent Application US2013/0004918. 2013. 49. Huwais S, Meyer E. Osseodensication: a novel approach in implant osteotomy preparation to increase primary stability, bone mineral density and bone to implant contact. Int J Oral Maxillofac Implants. 2016;32:27–36. 50. Degidi M, Giuseppe Daprile, Piattelli A. Inuence of underprepara-tion on primary stability of implants inserted in poor quality bone sites: an invitro study. J Oral Maxillofac Surg. 2015;73(6):1084–1088. 51. Alghamdi H, Anand PS, Anil S. Undersized implant site preparation to enhance primary implant stability in poor bone density: a prospec-tive clinical study. J Oral Maxillofac Surg. 2011;69(12):e506–e512. 52. Roberts EW, Turley PK, Brezniak N, etal. Bone physiology and metabolism. J Calif Dent Assoc. 1987;15:54–61. 53. Roberts WE. Fundamental principles of bone physiology, metabo-lism and loading. In: Naert I, van Steenberghe D, Worthington P, eds. Osseointegration in Oral Rehabilitation. Carol Stream: Ill: Quin-tessence; 1993. 54. Haider R, Watzek G, Plenk Jr H. Inuences of drill cooling and bone structure on primary implant xation. Int J Oral Maxillofac Implants. 1993;8:83–91. 55. Chanavaz M. Anatomy and histophysiology of the periosteum: clas-sication of the periosteal blood supply to the adjacent bone with 855r and gamma spectrometry. J Oral Implantol. 1995;21:214–219. 56. Crock JG, Morrisson WA. A vascularized periosteal ap: anatomical study. Br J Plast Surg. 1992;45:474–478. 57. Watzek G, Danhel-Mayhauser M, Matejka M, et al. Experimen-tal Comparison of Brånemark and TPS Dental Implants in Sheep [Abstract]Presented at Ucla Symposium: Implants in the Partially Eden-tulous. Patient Palm Springs, CA; 1990. 58. Satomi K, Akagawa Y, Nikai H, etal. Bone implant interface struc-tures after nontapping and tapping insertion of screw type titanium alloy endosseous implants. J Prosthet Dent. 1988;59:339–342. 59. Beer A, Gahleitner A, Holm A, etal. Adapted preparation technique for screw-type implants: explorative invitro pilot study in a porcine bone model. Clin Oral Implants Res. 2007;18:103–107. 60. Watzek G, Haider R, Gitsch M, etal. Inuence of Drill Cooling and Bone Structure on Primary Implant Fixation. Boston: American Acad-emy of Osseo-integration; 1991. [abstract]. 61. Novaes Jr AB, de Oliveira RR, Taba Jr M, etal. Crestal bone loss minimized when following the crestal preparation protocol: a histo-morphometric study in dogs. J Oral Implantol. 2005;31:276–282. 62. Orenstein IH, Synan WJ, Truhlar RS, etal. Bone quality in patients receiving endosseous dental implants: DICRG Interim Report No. 1. Implant Dent. 1994;3:90–94. 63. Rhinelander FW. e normal circulation of bone and its response to surgical intervention. J Biomed Mater Res. 1974;8:87–90. 64. Degidi M, Daprile G, Piattelli A. Determination of primary stabil-ity: a comparison of the surgeon’s perception and objective measure-ments. Int J Oral Maxillofac Implants. 2010;25(3):558–561. 65. Misch CE. Maxillary sinus augmentation for edentulous arches for implant dentistry: organized alternative treatment plans. Int J Oral Implantol. 1987;4:7–12. 66. Bischof M, et al. Implant stability measurement of delayed and immediately loaded implants during healing. Clin Oral Implants Res. 2004;15(5):529–539. 669CHAPTER 27 Implant Placement Surgical Protocol 67. Sennerby L, Meredith N. Resonance frequency analysis: measuring implant stability and osseointegration. Compend Contin Educ Dent. 1998;19(5):493–498, 500, 502; quiz 504. 68. Konstantinović VS, Ivanjac F, Lazić V, etal. Assessment of implant stability by resonant frequency analysis. Military Med Pharm J Ser-bia. 2015;72(2):169. 69. Lars S. Resonance frequency analysis for implant stability measure-ments. A review. Integration Diagn Update. 2015;1:11. 70. Sjöström M, Lundgren S, Nilson H, Sennerby L. Monitoring of implant stability in grafted bone using resonance frequency analysis. A clinical study from implant placement to 6 months of loading. Int J Oral Maxillofac Surg. 2005;34:45–51. 71. Turkyilmaz I, McGlumphy EA. Inuence of bone density on implant stability parameters and implant success: a retrospective clinical study. BMC Oral Health. 2008;8:32. 72. Östman PO, Hellman M, Wendelhag I, Sennerby L. Resonance frequency analysis measurements of implants at placement surgery. Int J Prosthodont. 2006;19(1). 73. Cardelli P, etal. Clinical assessment of submerged vs non-submerged implants placed in pristine bone. Oral Implantol. 2013;6(4):89. 74. Byrne G. Outcomes of one-stage versus two-stage implant place-ment. J Am Dent Assoc. 2010;141(10):1257–1258. 75. Weber HP, Fiorellini JP. e biology and morphology of the implant-tissue interface. Alpha Omegan. 1992;85:61–64.

Related Articles

Leave A Comment?