Immediate Load/Restoration in Implant Dentistry










860
33
Immediate Load/Restoration in
Implant Dentistry
RANDOLPH R. RESNIK AND CARL E. MISCH
F
or years the two-stage surgical protocol established by
Brånemark etal.
1
to accomplish osseointegration was con-
sidered a prerequisite for achieving osseointegration and
long-term success. is traditional surgical protocol consisted of
placing dental implants slightly below the crestal bone, obtain-
ing and maintaining a soft tissue covering over the implant, and
allowing for a nonloaded implant environment for 3 to 6 months.
e success of the two-stage technique was highly documented;
however, many in the eld still strived for shorter treatment times
and fewer surgical interventions. With advances in implant tech-
nology, the traditional protocol in implant dentistry has been
reevaluated, which has led to a growing interest in the immediate-
loading protocol. An abundance of clinical studies have shown
positive outcomes and success with loading implants immediately
or within a short period after implant placement.
2,3
e immediate-loaded implant concept has become popular in
the dental profession because it allows patients to have the ability
to combine the surgical and prosthetic procedures into a single
appointment. As a result of the immediate-loading technology,
advances have led to an array of new implant designs and treat-
ment protocols. In this chapter the concept of immediate-loading
protocol will be discussed in detail, together with various imme-
diate-loading protocols for single-tooth replacement, multiteeth
replacement, and full-arch rehabilitation.
Immediate-Loading Terminology
e concept of immediate-loading implants involves a nonsub-
merged first-stage surgery, with the immediate loading of the
implants with an interim or nal prosthesis. e terminology and
nomenclature for these techniques are poorly understood, with
little consistency. erefore in an attempt to standardize the lan-
guage in which immediate loading is discussed, Misch etal.
4
sug-
gested a terminology for immediate restoration and/or occlusal
loading (Box 33.1).
Advantages of Immediate Load Protocol
Less Discomfort for Patients
When the immediate loaded principle is used, patient dis-
comfort and morbidity are reduced. No second-stage surgery
(i.e., uncover) is required, therefore fewer appointments will
be necessary for the patient. In many delayed loading situa-
tions, it is necessary for the patient to wear a removable pros-
thesis throughout the healing period. Not only does this lead
to increased discomfort and inconvenience for the patient, but
also the possibility of overloading the tissue and/or implant is
greater. With the immediate load technique, a removable pros-
thesis is not worn, therefore decreasing the morbidity to the
patient.
Faster Treatment
e immediate-loading protocol reduces the need for second-
stage surgery and subsequent healing of the tissue. erefore a
more simplied surgical workow is indicated that leads to shorter
treatment time. In addition, in most cases, surgical intervention
and complex bone augmentation procedures are not required to
restore resorbed ridges that result from the postextraction bone
remodeling process. is results in far fewer appointments and
shorter treatment time.
More Ideal Soft Tissue Drape
In some clinical situations, placing a prosthesis at the time of sur-
gery will allow for better soft tissue healing. e surrounding tis-
sue is given the opportunity to mature and heal to the existing
prosthesis. is is most important in esthetic areas, where soft tis-
sue shrinkage after second-stage surgery may compromise the soft
tissue margins and papilla contours.
Immediate Satisfaction and Patient Acceptance
Placing a prosthesis immediately after implant placement has
been associated with increased psychological acceptance and
patient satisfaction. In cases of full arch extractions, inserting
a prosthesis immediately not only improves esthetics, but also
will maintain masticatory function and muscle mass. Blomberg
and Lindquist
5
evaluated patients undergoing extractions and
immediate placement of an implant-supported bridge and their
overall satisfaction to the procedure. Overwhelmingly, patients
stated a signicant improvement in their quality of life and
increased self-condence.
5

861
CHAPTER 33 Immediate Load/Restoration in Implant Dentistry
Greater Bone-Implant Contact
Numerous studies are available that report positive success rates
with immediate-loaded implants that are exposed to the oral cav-
ity during the healing phase.
6,7
Histologic studies have shown an
improved bone-implant contact (BIC) with immediate-loaded
implants compared with conventional protocol implants.
8,9
Piat-
telli etal.
10
evaluated the histology of nonsubmerged, unloaded,
and early-loaded titanium implants in monkeys. ey deter-
mined that early-loaded implants exhibited lamellar cortical
bone that was thicker in comparison with unloaded implants.
10
Testori etal.
11
reported a BIC of 64.2% for a single immedi-
ate-loaded implant and a BIC of 38.9% for a single submerged
implant.
Disadvantages of Immediate Load Implants
Increased Skill Level Required
Especially when extracting teeth and placing implants at the
same time, an increased skill level is required. ese types of cases
require signicant preplanning, most commonly with advanced
cone beam computed tomography (CBCT) interactive treatment
planning. In addition, CBCT bone reduction and placement
guides may be indicated, which increases the complexity of the
surgery and prosthetic protocols.
Initial Surgical/Prosthetic Appointment Longer
In some cases the surgical placement of implants and the prosthetic
procedures may require a longer appointment duration than nor-
mal. is may lead to increases exceeding the patients tolerance
for appointment length. With some patients, this may predispose
them to an increased possibility of medical complications.
Possible Increased Implant Morbidity
An often talked about disadvantage for the immediate load con-
cept is the risk for implant bone loss or implant failure. In general
this is not supported by clinical studies and research. Chen et.
al. in a systemic review and meta-analysis compared immediate
loaded implants vs. conventional loading and found no dierence
in marginal bone loss between the two techniques. However, if
failure does occur, this will often lead to the patient’s loss of con-
dence in the doctor, increased costs and treatment time, together
with a longer treatment period.
Prerequisites for Immediate-Loading
Protocol
For the immediate-loading protocol to be successful, various treat-
ment planning and patient factors need to be taken into consider-
ation implemented in the patients treatment.
Adequate Bone Density
Ideally the bone density should be favorable for an immediate-
loaded prosthesis (D1, D2, D3). However, in some cases of poor
bone quality, even with modied surgical protocols, achieving an
insertion torque greater than 35 N-cm is unachievable. In these
clinical situations the immediate-loading protocol is not recom-
mended, and a healing period of 4 to 6 months is suggested before
loading the dental implants. In addition, the prosthetic rehabilita-
tion should include a progressive bone-loading protocol, which
increases bone density around the implants.
12
Sufficient Bone Dimensions
For immediate load cases, it is imperative that sucient height
and width of bone are available for the placement of implants.
Lazzara etal.
13
stated that 12 mm of available bone height is rec-
ommended (i.e., for a 10-mm implant) and 6 mm of available
bone width is required for adequate support. In clinical cases of
compromised bone quantity, immediate-loaded implants may be
at higher risk for bone loss or failure, therefore more implants or
implants with a greater surface area are recommended.
Ideal Insertion Torque
In the literature it is generally accepted that the immediate-load-
ing concept is based on obtaining an insertion torque of greater
than 35 N-cm to provide sucient implant stability when the
prosthesis is placed under loading situations.
14-16
However, stud-
ies have shown successful implant integration at insertion torques
of 30 N-cm or less.
17
Maló etal.
18
stated that implants inserted
with <30 N-cm of torque in an All-on-4 protocol have similar
short-term success outcomes and marginal bone loss compared
with implants inserted with 30 N-cm of torque.
In most clinical situations with favorable bone quality (i.e.,
D1, D2, D3), insertion torque of greater than 35 N-cm is usually
attainable. In clinical situations of less dense bone (i.e., D3, D4),
this is often dicult, if not impossible, to obtain without surgical
placement protocol revision. erefore modied surgical drilling
protocols should be used in less dense bone, which may include
underpreparation of the osteotomy sites, use of osteotomes, or
osseodensication protocols.
Immediate occlusal loading: Insertion of an implant-supported interim
prosthesis (e.g., polymethylmethacrylate [PMMA] temporary) or final
restoration in occlusal contact within 2 weeks of the implant insertion.
Early occlusal loading: Refers to an implant-supported prosthesis in
occlusion between 2 weeks and 3 months after implant placement (i.e.,
occlusal loading implants after a short healing period, 5 weeks).
Delayed or staged occlusal loading: An implant prosthesis with an
occlusal load after more than 3 months after implant insertion. The
delayed occlusal loading approach may use either a two-stage surgical
procedure that covers the implants with soft tissue or a one-stage
approach that exposes the implant with a healing abutment.
Nonfunctional immediate prosthesis: This describes an implant
prosthesis with no direct occlusal load within 2 weeks of implant
insertion and is primarily considered in partially edentulous patients (i.e.,
congenitally missing maxillary lateral incisor).
Nonfunctional early prosthesis: Describes a prosthesis delivered between
2 weeks and 3 months after the implant insertion.
114
Occlusal loading: The prosthesis is in contact with the opposing dentition
in centric occlusion.
Nonocclusal loading: The prosthesis is not in contact in centric occlusion
with the opposing dentition in the natural jaw position.
Provisional prosthesis: A fixed or removable dental prosthesis designed
to enhance esthetics, stabilization, and/or function for a limited period,
after which it is to be replaced by a definitive dental prosthesis. This
type of prosthesis assists in the determination of the therapeutic
effectiveness of a specific treatment plan or the form and function.
115
BOX
33.1
Immediate Load/Function Denitions

862
PART VI Implant Surgery
Ideal Resonance Frequency Analysis Readings
e primary stability of an inserted dental implant can be mea-
sured via resonance frequency analysis (RFA). e RFA values
will give a numerical assessment on the lateral movement (i.e.,
micromotion) of the implant during the healing phase. e
micromotion diers for each implant system, mainly dictated
on the implant design. For example, for implants with rough-
ened surfaces, tolerance is in the range of 50 to 150 μm,
19,20
and
with machined surfaces is approximately 100 μm of micromove-
ment.
21
Studies have conrmed an implant stability quotient
(ISQ) of 70 or greater is needed for an immediate-loaded pros-
thesis, 65 to 70 for early loading, and 60 to 65 for traditional
healing (Fig. 33.1).
22,23
Ability to Achieve an Adequate Anteroposterior
Spread
e anteroposterior (A-P) spread (i.e., distance between the mid-
dle of the most anterior implant and the distal of the posterior
implants) is important in increasing the mechanical advantage
and force distribution of the prosthesis. In general the A-P spread
is related to the ability to cantilever the prosthesis. e larger the
A-P spread distance, the greater the force distribution for forces
applied to the immediate-loaded prosthesis. However, force fac-
tors play a signicant role in determining if a prosthesis may be
cantilevered.
24
Rational for Implant Immediate-Loading
Protocol
Effect of Surgical Trauma on Healing
e immediate implant-loading concept challenges the conven-
tional healing period of 3 to 6 months of no loading before the
restoration of the implant. Often the risks of this procedure are
perceived to be during the first week after the implant insertion
surgery. In reality the bone interface is stronger on the day of
implant placement compared with 3 months later
23
(Fig. 33.2).
e surgical process of the implant osteotomy preparation and
implant insertion result in a regional acceleratory phenomenon of
bone repair around the implant interface.
24
As a result of the sur-
gical placement, organized, mineralized lamellar bone next to the
implant site becomes unorganized, less mineralized, and mainly
made up of woven bone.
25
e implant-bone interface is weak-
est and most at risk for overload at 3 to 6 weeks after surgical
insertion because the surgical trauma causes bone remodeling at
the interface that is least mineralized and unorganized during this
AB
C
Fig. . Resonance Frequency Analysis with Penguin RFA. (A) MultiPeg placed into Implant Body,
(B) Penguin RFA reading, (C) The Penguin RFA measures the resonance frequency of the reusable Multi-
peg. The frequency is displayed as an ISQ-value (Implant Stability Quotient).

863
CHAPTER 33 Immediate Load/Restoration in Implant Dentistry
time frame. A clinical report by Buchs etal.
27,28
found imme-
diate-loaded implant failure occurred primarily between 3 and 5
weeks after implant insertion from mobility without infection. At
4 months the bone is still only 60% mineralized, organized lamel-
lar bone.
28
However, this has proved to be sufficient in most bone
types and clinical situations for two-stage healing and delayed
implant loading.
One method to decrease the risk for immediate occlusal over-
load is to decrease the surgical trauma and amount of initial bone
remodeling at implant placement. Roberts etal.
29,30
reported a
devital zone of bone for 1 mm or more around the implant as a
result of the surgical trauma (Fig. 33.3). Causes of trauma include
thermal injury and microfracture of bone during implant place-
ment. Excessive surgical trauma and thermal injury may lead
to osteonecrosis and result in fibrous encapsulation around the
implant.
31
Eriksson and Albrektsson
32,33
have reported bone cell
death at temperatures as low as 40°C, which relate to surgical fac-
tors of the amount of bone prepared, drill sharpness, depth of the
osteotomy, and variation in cortical thickness.
Studies have shown a self-tapping implant causes greater bone
remodeling (woven bone) around the implant during initial heal-
ing compared with a bone tap and implant placement technique.
34
e implant should be nonmobile on insertion; however, pressure
necrosis from increased torque may increase the risk for micro-
damage at the interface and result in bone loss. Pressure necrosis
may occur from placing excessive torque on the implant, which
results in an increased amount of strain at the interface. When
this occurs, an increase in the amount of bone remodeling will
take place, which decreases the strength of the bone-implant inter-
face. erefore it is prudent to minimize factors related to thermal
injury and surgical trauma when considering the immediate-load-
ing protocol.
Bone-Loading Trauma
Cortical and trabecular bone have been shown to be modified by
modeling or remodeling.
25
Remodeling, or bone turnover, permits
the repair of bone after trauma or allows the bone to respond to
its local mechanical environment. e bone most often is lamel-
lar in nature; however, it may become woven bone during the
repair or remodeling process. Lamellar bone and woven bone are
the primary bone tissue types found around a dental implant.
Lamellar bone is organized, highly mineralized, is the strongest
bone type, has the highest modulus of elasticity, and is called load-
bearing bone. By comparison, woven bone is unorganized, less
mineralized, weaker, and more exible (lower modulus of elas-
ticity). Woven bone may form at a rate of 60 μm/day, whereas
lamellar bone forms at a rate of 1 to 5 μm/day.
28
e classic two-
stage surgical approach to implant dentistry permitted the surgi-
cal repair of the implant to be separated from the early loading
response by 3 to 6 months. erefore the majority of the woven
bone that formed to repair the initial surgical trauma was replaced
with lamellar bone. Lamellar bone is stronger and able to respond
to the mechanical environment of occlusal loading. e rationale
for immediate loading is not only to reduce the risk for fibrous
tissue formation (i.e., which results in clinical failure), but also
to minimize woven bone formation and promote lamellar bone
maturation to sustain occlusal load.
e woven bone of surgical trauma has been called repair bone,
and the woven bone formed from the mechanical response may
be called reactive woven bone.
35
Remodeling also is called bone
turnover, and not only repairs damaged bone but also allows the
implant interface to adapt to its biomechanical situation (Fig.
33.4). e interface-remodeling rate is the period of time for bone
at the implant interface to be replaced with new bone. Once the
bone is loaded by the implant prosthesis, the interface begins to
remodel again. However, this time the trigger for this process is
strain, rather than the trauma of implant placement. Strain is
defined as the change in length of a material divided by the origi-
nal length, and it is measured as the percentage of change. When
the surgical trauma is too great or the mechanical stress is too
severe, fibrous tissue may form rather than bone. Fibrous tissue at
an implant interface will usually result in clinical mobility rather
than rigid fixation.
AB
Fig. . (A) A densitometry profile of an implant 10 days after insertion. The two parallel lines at the
interface represent the bone-implant contact. (B) After 3 months the densitometry profile was repeated.
The implant interface is weaker at this time than the initial radiograph showed. (Data are from Strid KG:
Radiographic results. In Brånemark PI, Zarb GA, Albrektsson T, eds. Tissue Integrated Prostheses. Chi-
cago: Quintessence; 1985.)

864
PART VI Implant Surgery
Histologic Evaluation of Immediate-Loaded
Implants
Short-Term Evaluation
General agreement is that excess stresses to an implant interface
may cause overload and implant failure. However, immediate load-
ing of an implant does not necessarily result in excessive stresses.
e initial histologic response of bone at the implant interface has
been evaluated on immediate-loaded implants. A direct BIC with
favorable bone quality around the implants has been reported.
Romanos etal.
25
demonstrated no statistical dierence between
immediate- and delayed-loaded implants. Sharawy
27
evaluated the
immediate- versus delayed-healing interface of 20 dental implants
in five adult beagle dogs (Fig. 33.5). All implants were inserted
into premolar grafted bone defect sites. e implants were paired,
so half of the implants were submerged, and the adjacent implants
received an abutment and were subjected to immediate function
for 4 weeks. e implants then were evaluated with histometric
analyses of plastic embedded calcified sections. No statistically
significant dierence (P > 0.05) was found in the BIC ratios
between the submerged and loaded implants (Fig. 33.6). Similarly,
the volume fractions of the interface bone were not significantly
dierent. e bone next to the implants appeared mature and
showed evidence of remodeling.
27
Suzuki etal.
28
performed a clinical and histologic evaluation
of immediate-loaded posterior implants in nonhuman primates.
After loading 10 implants for 90 days, they were compared with
5 control implants with no loading. e BIC percentage ranged
from 50.3% to 64.1%, with an average of 56.3% for the con-
trols. e immediate-loaded group had one implant failure, seven
implants with an average of 67.6% BIC, and two implants with
43.2% and 45.6% BIC, respectively. erefore the study demon-
strated immediate-loaded implants may have a higher BIC than
nonloaded implants, most likely a response to the strain condi-
tions in the bone. However, three implants had less BIC or failure
compared with controls. Although benefits exist related to imme-
diate loading, it appears some risks are involved in the procedure.
28
Testori et al.
30
reported on the histologic interface of two
implants in humans that were immediately loaded after 4 months.
T
O
O
Fig. . Bone remodeling around an implant after surgery replaces a
1-mm or more devital zone of bone. Arrows indicate the devital zone of
bone replacement. O, Original bone; T, implant.
Fig. . Bone remodeling replaces the existing bone with new bone
and is controlled primarily by the amount of microstrain within the bone.
The rate of the bone remodeling also is related directly to the amount of
microstrain.
A
B
Fig. . (A,B) Paired implants inserted into a canine model, with one
implant not loaded and the other immediately placed into function for 4 weeks.

865
CHAPTER 33 Immediate Load/Restoration in Implant Dentistry
e bone contact ranged from 78% to 85%, with no epithelial
migration. erefore immediately loading an implant interface
apparently does not necessarily place the interface at increased risk
for fibrous tissue formation.
30
Long-Term Evaluation
Piatelli etal.
31
evaluated bone reactions and the bone and tita-
nium interface in early loaded implants in monkeys, compared
with unloaded implants in the same arch several months after
immediate loading. No statistically significant dierences were
detected in the BIC after 8 months.
31
However, loaded implants
had less marrow spaces and more compact bone. A later study by
the same group demonstrated greater bone contact in immedi-
ately loaded implants at 9 months.
33
No fibrous tissue was found
at the interface. After 15 months, unloaded and immediately
loaded implants were compared, and loaded implants exhibited
greater (almost twice) direct bone contact at the interface. In
particular, early loaded screws demonstrated thicker lamellar and
cortical bone than unloaded implants. is finding suggests that
early occlusal loading may enhance bone remodeling and further
increase bone density.
36
Randow etal.
39
evaluated the bone interface in a human patient
after 18 months in an immediate-loading situation. ey noted a
direct bone-implant interface. Ledermann
37,38
confirmed these
results in a 95-year-old patient who had an immediate-loaded,
bar-connected overdenture in function for 12 years. us a long-
lasting direct BIC relationship appears to be possible.
39
Immediate Occlusal Loading: Factors That
Decrease Risks
Bone Microstrain
When bone is loaded, its shape may change. is change may be
measured as strain. Microstrain conditions 100 times less than the
ultimate strength of bone may trigger a cellular response. Frost
40
has developed a microstrain language for bone based on its bio-
logical response at dierent microstrain levels (Fig. 33.7). Bone
fractures at 10,000 to 20,000 microstrain (me) units (1%–2%
strain). However, at levels of 20% to 40% of this value, bone
already starts to disappear or form fibrous tissue and is called the
pathologic overload zone. e ideal microstrain for bone is called
the physiologic or adapted zone. e remodeling rate of the bone
in the jaws of a dentate canine or human that is in the physiologic
zone is about 40% each year.
42
At these levels of strain, the bone is
allowed to remodel and remain an organized, mineralized lamel-
lar bone. is is called the ideal load-bearing zone for an implant
interface. e mild overload zone corresponds to an intermedi-
ate level of microstrain between the ideal load-bearing zone and
pathologic overload. In this strain region, bone begins a healing
process to repair microfractures, which are often caused by fatigue.
Histologically the bone in this range is called reactive woven bone.
Rather than the surgical trauma causing this accelerated bone
repair, the microstrain causes the trauma from overload. In either
condition the bone is less mineralized, less organized, weaker, and
has a lower modulus of elasticity.
One goal for an immediate-loaded implant-prosthesis sys-
tem is to decrease the risk for occlusal overload and its resultant
increase in the remodeling rate of bone. Under these conditions
the surgical regional acceleratory phenomenon may replace
the bone interface without the additional risk for biomechani-
cal overload. When strain is placed on the horizontal axis and
stress is positioned on the vertical axis, the relationship between
these two mechanical indexes results in the exibility or modulus
of elasticity of a material. erefore the modulus conveys the
amount of deformation in a material (strain) for a given load
(stress) level. e lower the stress applied to the bone (force
divided by the functional surface area that receives the load),
the lower the microstrain in the bone (Fig. 33.8). erefore one
method to decrease microstrain and the remodeling rate in bone
is to provide conditions that increase functional surface area to
the implant-bone interface.
43
e surface area of load may be
increased in a number of ways: implant number, implant size,
implant design, and implant body surface conditions. e force
to the prosthesis also is related to the strain and may be altered in
magnitude, duration, direction, or type. Methods that aect the
amount of force include patient conditions, implant position,
and direction of occlusal load.
Increased Surface Area
Implant Number
e clinician may increase the functional surface area of occlu-
sal load at an implant interface by increasing implant number.
erefore rather than three to five implants to support a fixed
prosthesis, use of additional implants when immediate loading is
planned is more prudent. Immediate-loading reports in the lit-
erature with the lowest percentage survival correspond to fewer
implants loaded.
34,44
In numerous studies, 10 to 13 implants were inserted and
splinted together per arch, and implant survival rate may be greater
than 97%.
35,40-42
e increased number of implants also increases
the retention of the restoration and reduces the number of pon-
tics. e increased retention minimizes the occurrence of partially
unretained restorations during healing, which can overload the
implants still supporting the restoration. e decrease in pontics
may decrease the risk for fracture of the transitional prosthesis,
which also may be a source of overload to the remaining implants
supporting the prosthesis. In general the maxilla typically requires
more implants in comparison with the mandible. is approach
helps compensate for the less dense bone and increased directions
of force often found in the maxillary arch.
I
I
Fig. . No statistical difference in bone-implant contact percent and
the volume fractions of the interface were found between the implants
immediately loaded and those with no load for 1 month.

866
PART VI Implant Surgery
Implant Size
e surface area may also be increased by the size of the implant.
Each 3-mm increase in length can improve surface area support
by more than 20%.
48
e benefit of increased length is not found
at the crestal-bone interface but rather in initial stability of the
bone-implant interface. Most of the stresses to an implant-bone
interface are concentrated at the crestal bone, so the increased
implant length does little to decrease the stress that occurs at the
transosteal region around the implant.
49
erefore length is not
an eective method to decrease stress because it does not address
the problem in the functional surface area region of the bone-
implant interface. However, because the implant is loaded before
the establishment of a histologic interface, implant length is more
relevant for immediate-load applications, especially in softer bone
types. e additional implant length also may permit the implant
to engage the opposing cortical plate, which further increases the
initial stability of the implant.
e functional surface area of each implant support system
is related primarily to the width and the design of the implant.
Wider root form implants provide a greater area of bone con-
tact than narrow implants (of similar design). e crest of the
ridge is where the occlusal stresses are greatest. As a result, width
is more important than length of implant (once a minimum
length has been obtained for initial fixation). Bone augmen-
tation in width may be indicated to increase implant diame-
ter when forces are greater, as in cases of moderate-to-severe
parafunction. e major increase in tooth size occurs in the
molar regions for natural teeth, where root surface area doubles
compared with the rest of the dentition (Fig. 33.9). erefore
implant diameter often is increased in the molar region. When
a larger-diameter implant is not possible without additional
augmentation surgery, more implants may be inserted (i.e., two
for each molar), which also is a method to double the overall
surface area in the posterior region.
Implant Body Design
e implant body design should be more specific for immedi-
ate loading because the bone has not had time to mature and
grow into recesses or undercuts in the design or attach to a
surface condition before the application of occlusal load. For a
threaded implant, bone is present in the depth of the threads
from the day of insertion. erefore the functional surface area
is greater during the immediate-load format. e number of
Mild
overload
window
Pathologic
overload
window
Adapted
window
Acute
disuse
windo
w
Strain
Spontaneous
fracture
Fig. . Frost has reported on four distinct microstrain patterns within the bone. The acute disuse
window results in atrophy, the adapted window is the physiologic response of organized bone, the mild
overload zone corresponds to fatigue fractures with reactive woven bone formation, and the pathologic
overload zone causes bone resorption. (Data are from Frost HM. Mechanical adaption of Frost’s mecha-
nostat theory. In: Martin DB, Burr DB, eds. Structure, Function and Adaption of Compact Bone. New York:
Raven Press; 1989.)
Disuse Ideal Mild
overload
Pathologic
overload
Strain
Ti
Bone
Stress (F/A)
Fig. . When stress is applied to a material, a change in shape occurs
(strain). The modulus of elasticity of a material represents the interaction
of stress and strain. Titanium (Ti) has a higher modulus of elasticity than
bone. When stress is applied to both of these materials, the microstrain
difference between the two in the Frost microstrain zone at the interface
at 50 units or less is disuse atrophy. When the microstrain difference is 50
to 2500 units, the ideal loading zone is present; between 2500 and 4000
units, the zone is in mild overload; and at more than 4000 units, the zone
is in pathologic overload.

867
CHAPTER 33 Immediate Load/Restoration in Implant Dentistry
the threads also aects the amount of area available to resist
the forces during immediate loading. e greater the number
of threads, the greater the functional surface area at the time of
immediate load.
Another variable in implant design is the thread depth, which
varies in implant design. e greater the thread depth, the greater
the functional surface area for immediate-load application. In
general the thread depth of most threaded implants is approxi-
mately 0.2 mm, whereas the thread depth of other implant designs
may reach 0.42 mm.
49
erefore one threaded implant may have
more than two times the overall functional surface area compared
with other implants of similar length and width.
e functional surface area of an implant body may aect the
remodeling rate of bone during loading. A macrosphere implant
with reduced surface area may have twice the remodeling rate of
a typical threaded implant design. A square-threaded implant
design, with deeper threads in greater number, is reported to have
a 10-fold reduction in remodeling rate under similar loading con-
ditions and approximates 50% per year. e higher the remodel-
ing rate, the weaker is the bone interface. e teeth have a bone
remodeling rate of 40% per year, which maintains lamellar bone
at the interface.
50
e thread geometry also may aect the strength of early osseo-
integration and the bone-implant interface. Steigenga
51
placed 72
implants into 12 rabbits and reverse-torque tested the unloaded
implants after 12 weeks. One-third of the implants had a V-thread,
one-third had a reverse buttress shape, and one-third had a square
thread. e number and depth of threads were the same, as were
the width and length of each implant. e V-thread and reverse
buttress thread geometry yielded similar values for reverse-torque
and BIC values. e square thread demonstrated statistically
significantly higher values for both of these evaluations.
Implant thread design may aect the bone turnover rate
(remodeling rate) during occlusal load conditions. For a V-shaped
thread design, a 10-fold greater shear force is applied to bone com-
pared with a square thread shape.
49
Bone is strongest to compres-
sion and weakest to shear loading.
52
Compressive forces decrease
the microstrain to bone compared with shear forces. erefore the
thread shape and implant design may decrease the early risks of
immediate loading while the bone is repairing the surgical trauma.
A few clinical trials have compared immediate loading with
dierent implant thread designs and tapered-implant bodies in
the completely edentulous patient. e short-term clinical reports
indicate a high success rate, regardless of implant design. As a
result, overall shape and thread geometry apparently may not be
the most important aspects for immediate occlusal load survival.
Implant number, implant position, and patient factors most likely
are more relevant components of success. Future studies in this
area certainly are needed.
Decreased Force Conditions
e clinician may evaluate forces by magnitude, duration, direc-
tion and type. Ideally these conditions should be reduced to mini-
mize the magnication of noxious eects of these forces.
Patient Factors. e greater the occlusal force applied to the
prosthesis, the greater is the stress at the implant-bone interface
and the greater the strain to the bone. erefore force conditions
that increase occlusal load increase the risks of immediate loading.
Parafunction such as bruxism and clenching represents significant
force factors because magnitude of the force is increased, the dura-
tion of the force is increased, and the direction of the force is
more horizontal than axial to the implants with a greater shear
component.
38
Balshi and Wolfinger
41
reported that 75% of all
failure in immediate occlusal loading occurred in patients with
bruxism. In their report, 130 implants were placed in 10 patients,
with 40 implants immediately loaded and 90 implants following
the traditional two-stage approach. e authors reported an 80%
survival rate for immediately loaded implants compared with 96%
for the traditional protocol. Grunder
42
appraised immediate load-
ing in eight edentulous patients, four of whom exhibited bruxism.
Overall success rates were 87% in the maxilla and 97% in the
mandible, with five of the seven implant failures in the bruxism
group. Parafunctional loads also increase the risk for abutment
screw loosening, unretained prostheses, or fracture of the tran-
sitional restoration used for immediate loading. If any of these
complications occur, then the remaining implants that are loaded
are more likely to fail.
Occlusal Load Direction. e occlusal load direction may aect
the remodeling rate. An axial load to an implant body maintains
more lamellar bone and has a lower remodeling rate compared
with an implant with an oset load. In an animal study, Barbier
and Schepers
43
observed osteoclasts and inammatory cells at the
interface of oset-loaded implants and noted lamellar bone and a
lower remodeling rate around axially loaded implants in the same
animal. erefore the clinician should eliminate posterior canti-
levers in the immediate-load transitional restoration because they
magnify the detrimental eects of force direction.
Implant Position. Dental implants have been used widely
to retain and support cross-arch fixed partial dentures (FPDs).
Implant position is often as important as implant number. For
example, elimination of cantilevers on two implants supporting
three teeth is recommended, rather than positioning the implants
next to each other with a cantilever.
53
e cross-arch splint form-
ing an arch is an eective design to reduce stress to the entire
implant support system. erefore the splinted-arch position con-
cept is advantageous for the immediate-load transitional prosthe-
sis in completely edentulous patients.
Implant position is one of the more important factors in imme-
diate loading for completely edentulous patients. e mandible
may be divided into three sections around the arch: the canine-
to-canine area and the bilateral posterior sections. Several clini-
cal reports discuss immediate load in a mandible with only three
0
50
100
150
200
250
300
350
400
450
Root surface areas of maxillary teeth
204
(1.1)
179
(1.0)
273
(1.5)
234
(1.3)
220
(1.2)
433
(2.4)
432
(2.4)
Fig. . The natural dentition root surface area is two times greater in
the molar region compared with any other tooth position. Treatment plans
for immediate loading should consider implant size or number to increase
surface area in this region, especially in the maxilla.

868
PART VI Implant Surgery
implants, as long as the implants are positioned in the midline and
each posterior region.
54,55
e maxilla requires more implant support than the mandible
because the bone is less dense and the direction of force is outside of
the arch in all eccentric movements. e maxilla is usually divided
into five sections, depending on the intensity of the force conditions
and the shape of the arch. e minimum five sections include the
incisor region, the bilateral canine areas, and the bilateral posterior
regions. At least one implant should be inserted into each maxillary
section and splinted together during the immediate-loading process.
Concerns have been raised regarding cross-arch splinting in
the mandible because of mandibular exure and torsion distal to
the mental foramens. Clinical reports indicate the acrylic used in
the transitional prosthesis is exible enough to alleviate these con-
cerns. However, the final restoration should be fabricated in at
least two independent sections when implants are placed in both
posterior molar positions.
56
Mechanical Properties of Bone
e modulus of elasticity is related to bone quality (Fig. 33.10).
e less dense the bone, the lower is the modulus. e amount of
BIC is also less for less dense bone. e strength of the bone also is
related directly to the density of the bone. e softer the bone, the
weaker are the bone trabeculae.
56,57
In addition, the remodeling
rate of cortical bone is slower than that of trabecular bone. As such,
the cortical bone is more likely to remain lamellar in structure dur-
ing the immediate-loading process, compared with trabecular bone.
e bone in the anterior regions of the jaw may have cortical
bone at the crestal and apical region of the root form implant,
whenever the implant is long enough to engage both cortexes. e
anterior root form implants should attempt to engage the oppos-
ing cortical plate when immediate load is contemplated. e
improved biomechanical condition of the cortical bone and the
additional implant surface area are advantageous. e maxillary
cortical bone is thin compared with the mandibular counterpart
at the crestal region and the opposing landmark. In the posterior
regions the maxillary sinus and mandibular canal usually negate
the apical engagement of the opposing cortex of bone, which is
also thin in the maxilla.
Cortical bone is also present on the lateral aspects of the resid-
ual ridge. Root form implants do not typically engage these plates
unless the edentulous ridge is narrow. Bone grafting must depend
on several factors to be predictable. Adequate blood supply and a
lack of micromovement are two important conditions. e devel-
oping bone is woven bone and more at risk for overload. e bone
graft in the region of the implant body may lead to less fixation and
lower initial BIC. Bone augmentation is more predictable when
soft tissue completely covers the graft (and membranes when pres-
ent). All of these conditions make bone grafting, implant insertion,
and immediate loading more at risk. erefore the suggestion is
that implants that are immediately loaded be placed in an exist-
ing bone volume adequate for early loading and the overall proper
prosthetic design. Bone grafting, before implant placement and
immediate loading, is suggested when inadequate bone volume is
present for proper reconstructive procedures (Fig. 33.11).
Immediate-Loading Protocol: Partially
Edentulous Patients
Single Implants
Immediate dental implants for single implants is well documented
in the literature, with numerous clinical trials showing satisfactory
survival and success rates. However, a major dierence with the
longevity of single immediate implants is the loading protocol. In
a meta-analysis study there was a ve times higher failure rate with
immediate-load single implants in comparison with delayed heal-
ing. No evaluated studies showed superior soft tissue and esthetic
advantages in comparison with delayed surgical protocols. In 1998
Misch
58,59
published the first article during the “reinvention” of
immediate “load” for partially edentulous patients. Because most
patients have adequate remaining teeth in contact to function, his
protocol included a provisional prosthesis primarily for esthetics,
and the implant prosthesis is completely void of any occlusal con-
tacts. is concept was termed N-FIT, or nonfunctional immedi-
ate teeth (Boxes 33.2 to 33.4).
Literature Review for Single Implants
Early Loading With Single Implants
Andersen etal.
60
evaluated early loading of eight implants in the
maxilla. After implant placement, impressions were completed
and interim acrylic resin restorations were fabricated approxi-
mately 1 week after surgery. At 6 months the interim crowns
were removed and a nal single tooth prosthesis was inserted.
After 5 years a 100% success rate was reported, along with a
0.53-mm bone gain between the implant placement and nal
evaluation. Cooper etal.
61
reported on the 3-year implant suc-
cess rate of immediate placed maxillary anterior implants after
surgery. Peri-implant bone levels, along with papilla growth,
were evaluated. e authors concluded that the gingival zenith
increased from year 1 to 3, and marginal bone loss was minimal
at an average of 0.42 mm.
Immediate Loading With Single Implants
Gomes etal.
62
published an initial report of immediate load-
ing on a single implant. is report included the fabrication
of a screw-retained provisional crown on an immediate-placed
implant. Ericsson etal.
63
reported on a prospective study with
single tooth implants with an immediate loading protocol com-
pared with a two-stage implant procedure. In the immediate-
loaded group, an interim single crown prosthesis was inserted
within 24 hours of placement. Within 6 months the implants
were restored with a nal prosthesis. Two implants (14%) in the
Ti
D1
D2,D3
D4
F/A
Elastic modulus
Fig. . The modulus of elasticity is related to the bone density. There-
fore the microstrain mismatch between titanium (Ti) and Division 4 (D4)
bone is greater than that between titanium and D1 bone, even when the
stress amount is the same. Force/Area (F/A)

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86033Immediate Load/Restoration in Implant DentistryRANDOLPH R. RESNIK AND CARL E. MISCHFor years the two-stage surgical protocol established by Brånemark etal.1 to accomplish osseointegration was con-sidered a prerequisite for achieving osseointegration and long-term success. is traditional surgical protocol consisted of placing dental implants slightly below the crestal bone, obtain-ing and maintaining a soft tissue covering over the implant, and allowing for a nonloaded implant environment for 3 to 6 months. e success of the two-stage technique was highly documented; however, many in the eld still strived for shorter treatment times and fewer surgical interventions. With advances in implant tech-nology, the traditional protocol in implant dentistry has been reevaluated, which has led to a growing interest in the immediate-loading protocol. An abundance of clinical studies have shown positive outcomes and success with loading implants immediately or within a short period after implant placement.2,3e immediate-loaded implant concept has become popular in the dental profession because it allows patients to have the ability to combine the surgical and prosthetic procedures into a single appointment. As a result of the immediate-loading technology, advances have led to an array of new implant designs and treat-ment protocols. In this chapter the concept of immediate-loading protocol will be discussed in detail, together with various imme-diate-loading protocols for single-tooth replacement, multiteeth replacement, and full-arch rehabilitation.Immediate-Loading Terminologye concept of immediate-loading implants involves a nonsub-merged first-stage surgery, with the immediate loading of the implants with an interim or nal prosthesis. e terminology and nomenclature for these techniques are poorly understood, with little consistency. erefore in an attempt to standardize the lan-guage in which immediate loading is discussed, Misch etal.4 sug-gested a terminology for immediate restoration and/or occlusal loading (Box 33.1). Advantages of Immediate Load ProtocolLess Discomfort for PatientsWhen the immediate loaded principle is used, patient dis-comfort and morbidity are reduced. No second-stage surgery (i.e., uncover) is required, therefore fewer appointments will be necessary for the patient. In many delayed loading situa-tions, it is necessary for the patient to wear a removable pros-thesis throughout the healing period. Not only does this lead to increased discomfort and inconvenience for the patient, but also the possibility of overloading the tissue and/or implant is greater. With the immediate load technique, a removable pros-thesis is not worn, therefore decreasing the morbidity to the patient. Faster Treatmente immediate-loading protocol reduces the need for second-stage surgery and subsequent healing of the tissue. erefore a more simplied surgical workow is indicated that leads to shorter treatment time. In addition, in most cases, surgical intervention and complex bone augmentation procedures are not required to restore resorbed ridges that result from the postextraction bone remodeling process. is results in far fewer appointments and shorter treatment time. More Ideal Soft Tissue DrapeIn some clinical situations, placing a prosthesis at the time of sur-gery will allow for better soft tissue healing. e surrounding tis-sue is given the opportunity to mature and heal to the existing prosthesis. is is most important in esthetic areas, where soft tis-sue shrinkage after second-stage surgery may compromise the soft tissue margins and papilla contours. Immediate Satisfaction and Patient AcceptancePlacing a prosthesis immediately after implant placement has been associated with increased psychological acceptance and patient satisfaction. In cases of full arch extractions, inserting a prosthesis immediately not only improves esthetics, but also will maintain masticatory function and muscle mass. Blomberg and Lindquist5 evaluated patients undergoing extractions and immediate placement of an implant-supported bridge and their overall satisfaction to the procedure. Overwhelmingly, patients stated a signicant improvement in their quality of life and increased self-condence.5  861CHAPTER 33 Immediate Load/Restoration in Implant DentistryGreater Bone-Implant ContactNumerous studies are available that report positive success rates with immediate-loaded implants that are exposed to the oral cav-ity during the healing phase.6,7 Histologic studies have shown an improved bone-implant contact (BIC) with immediate-loaded implants compared with conventional protocol implants.8,9 Piat-telli etal.10 evaluated the histology of nonsubmerged, unloaded, and early-loaded titanium implants in monkeys. ey deter-mined that early-loaded implants exhibited lamellar cortical bone that was thicker in comparison with unloaded implants.10 Testori etal.11 reported a BIC of 64.2% for a single immedi-ate-loaded implant and a BIC of 38.9% for a single submerged implant. Disadvantages of Immediate Load ImplantsIncreased Skill Level RequiredEspecially when extracting teeth and placing implants at the same time, an increased skill level is required. ese types of cases require signicant preplanning, most commonly with advanced cone beam computed tomography (CBCT) interactive treatment planning. In addition, CBCT bone reduction and placement guides may be indicated, which increases the complexity of the surgery and prosthetic protocols. Initial Surgical/Prosthetic Appointment LongerIn some cases the surgical placement of implants and the prosthetic procedures may require a longer appointment duration than nor-mal. is may lead to increases exceeding the patient’s tolerance for appointment length. With some patients, this may predispose them to an increased possibility of medical complications. Possible Increased Implant MorbidityAn often talked about disadvantage for the immediate load con-cept is the risk for implant bone loss or implant failure. In general this is not supported by clinical studies and research. Chen et. al. in a systemic review and meta-analysis compared immediate loaded implants vs. conventional loading and found no dierence in marginal bone loss between the two techniques. However, if failure does occur, this will often lead to the patient’s loss of con-dence in the doctor, increased costs and treatment time, together with a longer treatment period. Prerequisites for Immediate-Loading ProtocolFor the immediate-loading protocol to be successful, various treat-ment planning and patient factors need to be taken into consider-ation implemented in the patients treatment.Adequate Bone DensityIdeally the bone density should be favorable for an immediate-loaded prosthesis (∼D1, D2, D3). However, in some cases of poor bone quality, even with modied surgical protocols, achieving an insertion torque greater than 35 N-cm is unachievable. In these clinical situations the immediate-loading protocol is not recom-mended, and a healing period of 4 to 6 months is suggested before loading the dental implants. In addition, the prosthetic rehabilita-tion should include a progressive bone-loading protocol, which increases bone density around the implants.12 Sufficient Bone DimensionsFor immediate load cases, it is imperative that sucient height and width of bone are available for the placement of implants. Lazzara etal.13 stated that 12 mm of available bone height is rec-ommended (i.e., for a 10-mm implant) and 6 mm of available bone width is required for adequate support. In clinical cases of compromised bone quantity, immediate-loaded implants may be at higher risk for bone loss or failure, therefore more implants or implants with a greater surface area are recommended. Ideal Insertion TorqueIn the literature it is generally accepted that the immediate-load-ing concept is based on obtaining an insertion torque of greater than 35 N-cm to provide sucient implant stability when the prosthesis is placed under loading situations.14-16 However, stud-ies have shown successful implant integration at insertion torques of 30 N-cm or less.17 Maló etal.18 stated that implants inserted with <30 N-cm of torque in an All-on-4 protocol have similar short-term success outcomes and marginal bone loss compared with implants inserted with ≥30 N-cm of torque.In most clinical situations with favorable bone quality (i.e., D1, D2, D3), insertion torque of greater than 35 N-cm is usually attainable. In clinical situations of less dense bone (i.e., D3, D4), this is often dicult, if not impossible, to obtain without surgical placement protocol revision. erefore modied surgical drilling protocols should be used in less dense bone, which may include underpreparation of the osteotomy sites, use of osteotomes, or osseodensication protocols. Immediate occlusal loading: Insertion of an implant-supported interim prosthesis (e.g., polymethylmethacrylate [PMMA] temporary) or final restoration in occlusal contact within 2 weeks of the implant insertion.Early occlusal loading: Refers to an implant-supported prosthesis in occlusion between 2 weeks and 3 months after implant placement (i.e., occlusal loading implants after a short healing period, ∼5 weeks).Delayed or staged occlusal loading: An implant prosthesis with an occlusal load after more than 3 months after implant insertion. The delayed occlusal loading approach may use either a two-stage surgical procedure that covers the implants with soft tissue or a one-stage approach that exposes the implant with a healing abutment.Nonfunctional immediate prosthesis: This describes an implant prosthesis with no direct occlusal load within 2 weeks of implant insertion and is primarily considered in partially edentulous patients (i.e., congenitally missing maxillary lateral incisor).Nonfunctional early prosthesis: Describes a prosthesis delivered between 2 weeks and 3 months after the implant insertion.114Occlusal loading: The prosthesis is in contact with the opposing dentition in centric occlusion.Nonocclusal loading: The prosthesis is not in contact in centric occlusion with the opposing dentition in the natural jaw position.Provisional prosthesis: A fixed or removable dental prosthesis designed to enhance esthetics, stabilization, and/or function for a limited period, after which it is to be replaced by a definitive dental prosthesis. This type of prosthesis assists in the determination of the therapeutic effectiveness of a specific treatment plan or the form and function.115 • BOX 33.1 Immediate Load/Function Denitions 862PART VI Implant SurgeryIdeal Resonance Frequency Analysis Readingse primary stability of an inserted dental implant can be mea-sured via resonance frequency analysis (RFA). e RFA values will give a numerical assessment on the lateral movement (i.e., micromotion) of the implant during the healing phase. e micromotion diers for each implant system, mainly dictated on the implant design. For example, for implants with rough-ened surfaces, tolerance is in the range of 50 to 150 μm,19,20 and with machined surfaces is approximately 100 μm of micromove-ment.21 Studies have conrmed an implant stability quotient (ISQ) of 70 or greater is needed for an immediate-loaded pros-thesis, 65 to 70 for early loading, and 60 to 65 for traditional healing (Fig. 33.1).22,23 Ability to Achieve an Adequate Anteroposterior Spreade anteroposterior (A-P) spread (i.e., distance between the mid-dle of the most anterior implant and the distal of the posterior implants) is important in increasing the mechanical advantage and force distribution of the prosthesis. In general the A-P spread is related to the ability to cantilever the prosthesis. e larger the A-P spread distance, the greater the force distribution for forces applied to the immediate-loaded prosthesis. However, force fac-tors play a signicant role in determining if a prosthesis may be cantilevered.24 Rational for Implant Immediate-Loading ProtocolEffect of Surgical Trauma on Healinge immediate implant-loading concept challenges the conven-tional healing period of 3 to 6 months of no loading before the restoration of the implant. Often the risks of this procedure are perceived to be during the first week after the implant insertion surgery. In reality the bone interface is stronger on the day of implant placement compared with 3 months later23 (Fig. 33.2).e surgical process of the implant osteotomy preparation and implant insertion result in a regional acceleratory phenomenon of bone repair around the implant interface.24 As a result of the sur-gical placement, organized, mineralized lamellar bone next to the implant site becomes unorganized, less mineralized, and mainly made up of woven bone.25 e implant-bone interface is weak-est and most at risk for overload at 3 to 6 weeks after surgical insertion because the surgical trauma causes bone remodeling at the interface that is least mineralized and unorganized during this ABC• Fig. . Resonance Frequency Analysis with Penguin RFA. (A) MultiPeg placed into Implant Body, (B) Penguin RFA reading, (C) The Penguin RFA measures the resonance frequency of the reusable Multi-peg. The frequency is displayed as an ISQ-value (Implant Stability Quotient). 863CHAPTER 33 Immediate Load/Restoration in Implant Dentistrytime frame. A clinical report by Buchs etal.27,28 found imme-diate-loaded implant failure occurred primarily between 3 and 5 weeks after implant insertion from mobility without infection. At 4 months the bone is still only 60% mineralized, organized lamel-lar bone.28 However, this has proved to be sufficient in most bone types and clinical situations for two-stage healing and delayed implant loading.One method to decrease the risk for immediate occlusal over-load is to decrease the surgical trauma and amount of initial bone remodeling at implant placement. Roberts etal.29,30 reported a devital zone of bone for 1 mm or more around the implant as a result of the surgical trauma (Fig. 33.3). Causes of trauma include thermal injury and microfracture of bone during implant place-ment. Excessive surgical trauma and thermal injury may lead to osteonecrosis and result in fibrous encapsulation around the implant.31 Eriksson and Albrektsson32,33 have reported bone cell death at temperatures as low as 40°C, which relate to surgical fac-tors of the amount of bone prepared, drill sharpness, depth of the osteotomy, and variation in cortical thickness.Studies have shown a self-tapping implant causes greater bone remodeling (woven bone) around the implant during initial heal-ing compared with a bone tap and implant placement technique.34 e implant should be nonmobile on insertion; however, pressure necrosis from increased torque may increase the risk for micro-damage at the interface and result in bone loss. Pressure necrosis may occur from placing excessive torque on the implant, which results in an increased amount of strain at the interface. When this occurs, an increase in the amount of bone remodeling will take place, which decreases the strength of the bone-implant inter-face. erefore it is prudent to minimize factors related to thermal injury and surgical trauma when considering the immediate-load-ing protocol. Bone-Loading TraumaCortical and trabecular bone have been shown to be modified by modeling or remodeling.25 Remodeling, or bone turnover, permits the repair of bone after trauma or allows the bone to respond to its local mechanical environment. e bone most often is lamel-lar in nature; however, it may become woven bone during the repair or remodeling process. Lamellar bone and woven bone are the primary bone tissue types found around a dental implant. Lamellar bone is organized, highly mineralized, is the strongest bone type, has the highest modulus of elasticity, and is called load-bearing bone. By comparison, woven bone is unorganized, less mineralized, weaker, and more exible (lower modulus of elas-ticity). Woven bone may form at a rate of 60 μm/day, whereas lamellar bone forms at a rate of 1 to 5 μm/day.28 e classic two-stage surgical approach to implant dentistry permitted the surgi-cal repair of the implant to be separated from the early loading response by 3 to 6 months. erefore the majority of the woven bone that formed to repair the initial surgical trauma was replaced with lamellar bone. Lamellar bone is stronger and able to respond to the mechanical environment of occlusal loading. e rationale for immediate loading is not only to reduce the risk for fibrous tissue formation (i.e., which results in clinical failure), but also to minimize woven bone formation and promote lamellar bone maturation to sustain occlusal load.e woven bone of surgical trauma has been called repair bone, and the woven bone formed from the mechanical response may be called reactive woven bone.35 Remodeling also is called bone turnover, and not only repairs damaged bone but also allows the implant interface to adapt to its biomechanical situation (Fig. 33.4). e interface-remodeling rate is the period of time for bone at the implant interface to be replaced with new bone. Once the bone is loaded by the implant prosthesis, the interface begins to remodel again. However, this time the trigger for this process is strain, rather than the trauma of implant placement. Strain is defined as the change in length of a material divided by the origi-nal length, and it is measured as the percentage of change. When the surgical trauma is too great or the mechanical stress is too severe, fibrous tissue may form rather than bone. Fibrous tissue at an implant interface will usually result in clinical mobility rather than rigid fixation. AB• Fig. . (A) A densitometry profile of an implant 10 days after insertion. The two parallel lines at the interface represent the bone-implant contact. (B) After 3 months the densitometry profile was repeated. The implant interface is weaker at this time than the initial radiograph showed. (Data are from Strid KG: Radiographic results. In Brånemark PI, Zarb GA, Albrektsson T, eds. Tissue Integrated Prostheses. Chi-cago: Quintessence; 1985.) 864PART VI Implant SurgeryHistologic Evaluation of Immediate-Loaded ImplantsShort-Term EvaluationGeneral agreement is that excess stresses to an implant interface may cause overload and implant failure. However, immediate load-ing of an implant does not necessarily result in excessive stresses. e initial histologic response of bone at the implant interface has been evaluated on immediate-loaded implants. A direct BIC with favorable bone quality around the implants has been reported. Romanos etal.25 demonstrated no statistical dierence between immediate- and delayed-loaded implants. Sharawy27 evaluated the immediate- versus delayed-healing interface of 20 dental implants in five adult beagle dogs (Fig. 33.5). All implants were inserted into premolar grafted bone defect sites. e implants were paired, so half of the implants were submerged, and the adjacent implants received an abutment and were subjected to immediate function for 4 weeks. e implants then were evaluated with histometric analyses of plastic embedded calcified sections. No statistically significant dierence (P > 0.05) was found in the BIC ratios between the submerged and loaded implants (Fig. 33.6). Similarly, the volume fractions of the interface bone were not significantly dierent. e bone next to the implants appeared mature and showed evidence of remodeling.27Suzuki etal.28 performed a clinical and histologic evaluation of immediate-loaded posterior implants in nonhuman primates. After loading 10 implants for 90 days, they were compared with 5 control implants with no loading. e BIC percentage ranged from 50.3% to 64.1%, with an average of 56.3% for the con-trols. e immediate-loaded group had one implant failure, seven implants with an average of 67.6% BIC, and two implants with 43.2% and 45.6% BIC, respectively. erefore the study demon-strated immediate-loaded implants may have a higher BIC than nonloaded implants, most likely a response to the strain condi-tions in the bone. However, three implants had less BIC or failure compared with controls. Although benefits exist related to imme-diate loading, it appears some risks are involved in the procedure.28Testori et al.30 reported on the histologic interface of two implants in humans that were immediately loaded after 4 months. TOO• Fig. . Bone remodeling around an implant after surgery replaces a 1-mm or more devital zone of bone. Arrows indicate the devital zone of bone replacement. O, Original bone; T, implant.• Fig. . Bone remodeling replaces the existing bone with new bone and is controlled primarily by the amount of microstrain within the bone. The rate of the bone remodeling also is related directly to the amount of microstrain.AB• Fig. . (A,B) Paired implants inserted into a canine model, with one implant not loaded and the other immediately placed into function for 4 weeks. 865CHAPTER 33 Immediate Load/Restoration in Implant Dentistrye bone contact ranged from 78% to 85%, with no epithelial migration. erefore immediately loading an implant interface apparently does not necessarily place the interface at increased risk for fibrous tissue formation.30 Long-Term EvaluationPiatelli etal.31 evaluated bone reactions and the bone and tita-nium interface in early loaded implants in monkeys, compared with unloaded implants in the same arch several months after immediate loading. No statistically significant dierences were detected in the BIC after 8 months.31 However, loaded implants had less marrow spaces and more compact bone. A later study by the same group demonstrated greater bone contact in immedi-ately loaded implants at 9 months.33 No fibrous tissue was found at the interface. After 15 months, unloaded and immediately loaded implants were compared, and loaded implants exhibited greater (almost twice) direct bone contact at the interface. In particular, early loaded screws demonstrated thicker lamellar and cortical bone than unloaded implants. is finding suggests that early occlusal loading may enhance bone remodeling and further increase bone density.36Randow etal.39 evaluated the bone interface in a human patient after 18 months in an immediate-loading situation. ey noted a direct bone-implant interface. Ledermann37,38 confirmed these results in a 95-year-old patient who had an immediate-loaded, bar-connected overdenture in function for 12 years. us a long-lasting direct BIC relationship appears to be possible.39 Immediate Occlusal Loading: Factors That Decrease RisksBone MicrostrainWhen bone is loaded, its shape may change. is change may be measured as strain. Microstrain conditions 100 times less than the ultimate strength of bone may trigger a cellular response. Frost40 has developed a microstrain language for bone based on its bio-logical response at dierent microstrain levels (Fig. 33.7). Bone fractures at 10,000 to 20,000 microstrain (me) units (1%–2% strain). However, at levels of 20% to 40% of this value, bone already starts to disappear or form fibrous tissue and is called the pathologic overload zone. e ideal microstrain for bone is called the physiologic or adapted zone. e remodeling rate of the bone in the jaws of a dentate canine or human that is in the physiologic zone is about 40% each year.42 At these levels of strain, the bone is allowed to remodel and remain an organized, mineralized lamel-lar bone. is is called the ideal load-bearing zone for an implant interface. e mild overload zone corresponds to an intermedi-ate level of microstrain between the ideal load-bearing zone and pathologic overload. In this strain region, bone begins a healing process to repair microfractures, which are often caused by fatigue. Histologically the bone in this range is called reactive woven bone. Rather than the surgical trauma causing this accelerated bone repair, the microstrain causes the trauma from overload. In either condition the bone is less mineralized, less organized, weaker, and has a lower modulus of elasticity.One goal for an immediate-loaded implant-prosthesis sys-tem is to decrease the risk for occlusal overload and its resultant increase in the remodeling rate of bone. Under these conditions the surgical regional acceleratory phenomenon may replace the bone interface without the additional risk for biomechani-cal overload. When strain is placed on the horizontal axis and stress is positioned on the vertical axis, the relationship between these two mechanical indexes results in the exibility or modulus of elasticity of a material. erefore the modulus conveys the amount of deformation in a material (strain) for a given load (stress) level. e lower the stress applied to the bone (force divided by the functional surface area that receives the load), the lower the microstrain in the bone (Fig. 33.8). erefore one method to decrease microstrain and the remodeling rate in bone is to provide conditions that increase functional surface area to the implant-bone interface.43 e surface area of load may be increased in a number of ways: implant number, implant size, implant design, and implant body surface conditions. e force to the prosthesis also is related to the strain and may be altered in magnitude, duration, direction, or type. Methods that aect the amount of force include patient conditions, implant position, and direction of occlusal load. Increased Surface AreaImplant Numbere clinician may increase the functional surface area of occlu-sal load at an implant interface by increasing implant number. erefore rather than three to five implants to support a fixed prosthesis, use of additional implants when immediate loading is planned is more prudent. Immediate-loading reports in the lit-erature with the lowest percentage survival correspond to fewer implants loaded.34,44In numerous studies, 10 to 13 implants were inserted and splinted together per arch, and implant survival rate may be greater than 97%.35,40-42 e increased number of implants also increases the retention of the restoration and reduces the number of pon-tics. e increased retention minimizes the occurrence of partially unretained restorations during healing, which can overload the implants still supporting the restoration. e decrease in pontics may decrease the risk for fracture of the transitional prosthesis, which also may be a source of overload to the remaining implants supporting the prosthesis. In general the maxilla typically requires more implants in comparison with the mandible. is approach helps compensate for the less dense bone and increased directions of force often found in the maxillary arch. II• Fig. . No statistical difference in bone-implant contact percent and the volume fractions of the interface were found between the implants immediately loaded and those with no load for 1 month. 866PART VI Implant SurgeryImplant Sizee surface area may also be increased by the size of the implant. Each 3-mm increase in length can improve surface area support by more than 20%.48 e benefit of increased length is not found at the crestal-bone interface but rather in initial stability of the bone-implant interface. Most of the stresses to an implant-bone interface are concentrated at the crestal bone, so the increased implant length does little to decrease the stress that occurs at the transosteal region around the implant.49 erefore length is not an eective method to decrease stress because it does not address the problem in the functional surface area region of the bone-implant interface. However, because the implant is loaded before the establishment of a histologic interface, implant length is more relevant for immediate-load applications, especially in softer bone types. e additional implant length also may permit the implant to engage the opposing cortical plate, which further increases the initial stability of the implant.e functional surface area of each implant support system is related primarily to the width and the design of the implant. Wider root form implants provide a greater area of bone con-tact than narrow implants (of similar design). e crest of the ridge is where the occlusal stresses are greatest. As a result, width is more important than length of implant (once a minimum length has been obtained for initial fixation). Bone augmen-tation in width may be indicated to increase implant diame-ter when forces are greater, as in cases of moderate-to-severe parafunction. e major increase in tooth size occurs in the molar regions for natural teeth, where root surface area doubles compared with the rest of the dentition (Fig. 33.9). erefore implant diameter often is increased in the molar region. When a larger-diameter implant is not possible without additional augmentation surgery, more implants may be inserted (i.e., two for each molar), which also is a method to double the overall surface area in the posterior region. Implant Body Designe implant body design should be more specific for immedi-ate loading because the bone has not had time to mature and grow into recesses or undercuts in the design or attach to a surface condition before the application of occlusal load. For a threaded implant, bone is present in the depth of the threads from the day of insertion. erefore the functional surface area is greater during the immediate-load format. e number of MildoverloadwindowPathologicoverloadwindowAdaptedwindowAcutedisusewindowStrainSpontaneousfracture• Fig. . Frost has reported on four distinct microstrain patterns within the bone. The acute disuse window results in atrophy, the adapted window is the physiologic response of organized bone, the mild overload zone corresponds to fatigue fractures with reactive woven bone formation, and the pathologic overload zone causes bone resorption. (Data are from Frost HM. Mechanical adaption of Frost’s mecha-nostat theory. In: Martin DB, Burr DB, eds. Structure, Function and Adaption of Compact Bone. New York: Raven Press; 1989.)Disuse Ideal MildoverloadPathologicoverloadStrainTiBoneStress (F/A) • Fig. . When stress is applied to a material, a change in shape occurs (strain). The modulus of elasticity of a material represents the interaction of stress and strain. Titanium (Ti) has a higher modulus of elasticity than bone. When stress is applied to both of these materials, the microstrain difference between the two in the Frost microstrain zone at the interface at 50 units or less is disuse atrophy. When the microstrain difference is 50 to 2500 units, the ideal loading zone is present; between 2500 and 4000 units, the zone is in mild overload; and at more than 4000 units, the zone is in pathologic overload. 867CHAPTER 33 Immediate Load/Restoration in Implant Dentistrythe threads also aects the amount of area available to resist the forces during immediate loading. e greater the number of threads, the greater the functional surface area at the time of immediate load.Another variable in implant design is the thread depth, which varies in implant design. e greater the thread depth, the greater the functional surface area for immediate-load application. In general the thread depth of most threaded implants is approxi-mately 0.2 mm, whereas the thread depth of other implant designs may reach 0.42 mm.49 erefore one threaded implant may have more than two times the overall functional surface area compared with other implants of similar length and width.e functional surface area of an implant body may aect the remodeling rate of bone during loading. A macrosphere implant with reduced surface area may have twice the remodeling rate of a typical threaded implant design. A square-threaded implant design, with deeper threads in greater number, is reported to have a 10-fold reduction in remodeling rate under similar loading con-ditions and approximates 50% per year. e higher the remodel-ing rate, the weaker is the bone interface. e teeth have a bone remodeling rate of 40% per year, which maintains lamellar bone at the interface.50e thread geometry also may aect the strength of early osseo-integration and the bone-implant interface. Steigenga51 placed 72 implants into 12 rabbits and reverse-torque tested the unloaded implants after 12 weeks. One-third of the implants had a V-thread, one-third had a reverse buttress shape, and one-third had a square thread. e number and depth of threads were the same, as were the width and length of each implant. e V-thread and reverse buttress thread geometry yielded similar values for reverse-torque and BIC values. e square thread demonstrated statistically significantly higher values for both of these evaluations.Implant thread design may aect the bone turnover rate (remodeling rate) during occlusal load conditions. For a V-shaped thread design, a 10-fold greater shear force is applied to bone com-pared with a square thread shape.49 Bone is strongest to compres-sion and weakest to shear loading.52 Compressive forces decrease the microstrain to bone compared with shear forces. erefore the thread shape and implant design may decrease the early risks of immediate loading while the bone is repairing the surgical trauma.A few clinical trials have compared immediate loading with dierent implant thread designs and tapered-implant bodies in the completely edentulous patient. e short-term clinical reports indicate a high success rate, regardless of implant design. As a result, overall shape and thread geometry apparently may not be the most important aspects for immediate occlusal load survival. Implant number, implant position, and patient factors most likely are more relevant components of success. Future studies in this area certainly are needed. Decreased Force Conditionse clinician may evaluate forces by magnitude, duration, direc-tion and type. Ideally these conditions should be reduced to mini-mize the magnication of noxious eects of these forces.Patient Factors. e greater the occlusal force applied to the prosthesis, the greater is the stress at the implant-bone interface and the greater the strain to the bone. erefore force conditions that increase occlusal load increase the risks of immediate loading. Parafunction such as bruxism and clenching represents significant force factors because magnitude of the force is increased, the dura-tion of the force is increased, and the direction of the force is more horizontal than axial to the implants with a greater shear component.38 Balshi and Wolfinger41 reported that 75% of all failure in immediate occlusal loading occurred in patients with bruxism. In their report, 130 implants were placed in 10 patients, with 40 implants immediately loaded and 90 implants following the traditional two-stage approach. e authors reported an 80% survival rate for immediately loaded implants compared with 96% for the traditional protocol. Grunder42 appraised immediate load-ing in eight edentulous patients, four of whom exhibited bruxism. Overall success rates were 87% in the maxilla and 97% in the mandible, with five of the seven implant failures in the bruxism group. Parafunctional loads also increase the risk for abutment screw loosening, unretained prostheses, or fracture of the tran-sitional restoration used for immediate loading. If any of these complications occur, then the remaining implants that are loaded are more likely to fail. Occlusal Load Direction. e occlusal load direction may aect the remodeling rate. An axial load to an implant body maintains more lamellar bone and has a lower remodeling rate compared with an implant with an oset load. In an animal study, Barbier and Schepers43 observed osteoclasts and inammatory cells at the interface of oset-loaded implants and noted lamellar bone and a lower remodeling rate around axially loaded implants in the same animal. erefore the clinician should eliminate posterior canti-levers in the immediate-load transitional restoration because they magnify the detrimental eects of force direction. Implant Position. Dental implants have been used widely to retain and support cross-arch fixed partial dentures (FPDs). Implant position is often as important as implant number. For example, elimination of cantilevers on two implants supporting three teeth is recommended, rather than positioning the implants next to each other with a cantilever.53 e cross-arch splint form-ing an arch is an eective design to reduce stress to the entire implant support system. erefore the splinted-arch position con-cept is advantageous for the immediate-load transitional prosthe-sis in completely edentulous patients.Implant position is one of the more important factors in imme-diate loading for completely edentulous patients. e mandible may be divided into three sections around the arch: the canine-to-canine area and the bilateral posterior sections. Several clini-cal reports discuss immediate load in a mandible with only three 050100150200250300350400450Root surface areas of maxillary teeth204(1.1)179(1.0)273(1.5)234(1.3)220(1.2)433(2.4)432(2.4)• Fig. . The natural dentition root surface area is two times greater in the molar region compared with any other tooth position. Treatment plans for immediate loading should consider implant size or number to increase surface area in this region, especially in the maxilla. 868PART VI Implant Surgeryimplants, as long as the implants are positioned in the midline and each posterior region.54,55e maxilla requires more implant support than the mandible because the bone is less dense and the direction of force is outside of the arch in all eccentric movements. e maxilla is usually divided into five sections, depending on the intensity of the force conditions and the shape of the arch. e minimum five sections include the incisor region, the bilateral canine areas, and the bilateral posterior regions. At least one implant should be inserted into each maxillary section and splinted together during the immediate-loading process.Concerns have been raised regarding cross-arch splinting in the mandible because of mandibular exure and torsion distal to the mental foramens. Clinical reports indicate the acrylic used in the transitional prosthesis is exible enough to alleviate these con-cerns. However, the final restoration should be fabricated in at least two independent sections when implants are placed in both posterior molar positions.56 Mechanical Properties of Bonee modulus of elasticity is related to bone quality (Fig. 33.10). e less dense the bone, the lower is the modulus. e amount of BIC is also less for less dense bone. e strength of the bone also is related directly to the density of the bone. e softer the bone, the weaker are the bone trabeculae.56,57 In addition, the remodeling rate of cortical bone is slower than that of trabecular bone. As such, the cortical bone is more likely to remain lamellar in structure dur-ing the immediate-loading process, compared with trabecular bone.e bone in the anterior regions of the jaw may have cortical bone at the crestal and apical region of the root form implant, whenever the implant is long enough to engage both cortexes. e anterior root form implants should attempt to engage the oppos-ing cortical plate when immediate load is contemplated. e improved biomechanical condition of the cortical bone and the additional implant surface area are advantageous. e maxillary cortical bone is thin compared with the mandibular counterpart at the crestal region and the opposing landmark. In the posterior regions the maxillary sinus and mandibular canal usually negate the apical engagement of the opposing cortex of bone, which is also thin in the maxilla.Cortical bone is also present on the lateral aspects of the resid-ual ridge. Root form implants do not typically engage these plates unless the edentulous ridge is narrow. Bone grafting must depend on several factors to be predictable. Adequate blood supply and a lack of micromovement are two important conditions. e devel-oping bone is woven bone and more at risk for overload. e bone graft in the region of the implant body may lead to less fixation and lower initial BIC. Bone augmentation is more predictable when soft tissue completely covers the graft (and membranes when pres-ent). All of these conditions make bone grafting, implant insertion, and immediate loading more at risk. erefore the suggestion is that implants that are immediately loaded be placed in an exist-ing bone volume adequate for early loading and the overall proper prosthetic design. Bone grafting, before implant placement and immediate loading, is suggested when inadequate bone volume is present for proper reconstructive procedures (Fig. 33.11). Immediate-Loading Protocol: Partially Edentulous PatientsSingle ImplantsImmediate dental implants for single implants is well documented in the literature, with numerous clinical trials showing satisfactory survival and success rates. However, a major dierence with the longevity of single immediate implants is the loading protocol. In a meta-analysis study there was a ve times higher failure rate with immediate-load single implants in comparison with delayed heal-ing. No evaluated studies showed superior soft tissue and esthetic advantages in comparison with delayed surgical protocols. In 1998 Misch58,59 published the first article during the “reinvention” of immediate “load” for partially edentulous patients. Because most patients have adequate remaining teeth in contact to function, his protocol included a provisional prosthesis primarily for esthetics, and the implant prosthesis is completely void of any occlusal con-tacts. is concept was termed N-FIT, or nonfunctional immedi-ate teeth (Boxes 33.2 to 33.4). Literature Review for Single ImplantsEarly Loading With Single ImplantsAndersen etal.60 evaluated early loading of eight implants in the maxilla. After implant placement, impressions were completed and interim acrylic resin restorations were fabricated approxi-mately 1 week after surgery. At 6 months the interim crowns were removed and a nal single tooth prosthesis was inserted. After 5 years a 100% success rate was reported, along with a 0.53-mm bone gain between the implant placement and nal evaluation. Cooper etal.61 reported on the 3-year implant suc-cess rate of immediate placed maxillary anterior implants after surgery. Peri-implant bone levels, along with papilla growth, were evaluated. e authors concluded that the gingival zenith increased from year 1 to 3, and marginal bone loss was minimal at an average of 0.42 mm. Immediate Loading With Single ImplantsGomes etal.62 published an initial report of immediate load-ing on a single implant. is report included the fabrication of a screw-retained provisional crown on an immediate-placed implant. Ericsson etal.63 reported on a prospective study with single tooth implants with an immediate loading protocol com-pared with a two-stage implant procedure. In the immediate-loaded group, an interim single crown prosthesis was inserted within 24 hours of placement. Within 6 months the implants were restored with a nal prosthesis. Two implants (14%) in the TiD1D2,D3D4F/AElastic modulus• Fig. . The modulus of elasticity is related to the bone density. There-fore the microstrain mismatch between titanium (Ti) and Division 4 (D4) bone is greater than that between titanium and D1 bone, even when the stress amount is the same. Force/Area (F/A) 869CHAPTER 33 Immediate Load/Restoration in Implant Dentistryimmediate-loaded group failed, and no implant loss was seen in the two-stage protocol. Average bone loss was approximately 0.1 mm for both implant groups. Hui65 evaluated 24 patients who received implant restorations on single teeth after tooth extrac-tion in the esthetic zone. After a 1.5-year follow-up, all implants remained integrated.63Degidi etal.65 evaluated single implants that were nonfunc-tionally immediately loaded. All implants were placed with a min-imum insertion torque of 25 N-cm, and after 5 years of follow-up a 95.5% survival rate was reported. When comparing healed ver-sus immediate extraction sites, 100% and 92.5% success rates, • PatienthasafixedesthetictoothreplacementafterstageIsurgery.• NostageIIsurgeryisnecessary(eliminatesdiscomfortforthepatientand decreases overhead for the doctor).• Thesofttissueemergencemaybedevelopedwiththetransitionalprosthesis and the tissue allowed to mature during the bone-healing process.• Thesofttissuehemidesmosomeattachmentontheimplantbodybelowthe microgap connection may heal with an improved interface.• Thepatientisabletoevaluatetheestheticsoftheprovisionalprosthesisduring the healing phase. • BOX 33.3 Advantages of Nonfunctional Immediate Teeth• Ifforceisappliedtotheprovisionalprosthesis,micromovementoftheimplant may cause crestal bone loss or implant failure.• Parafunctionfromtongueorforeignhabits(i.e.,penbiting)maycausetrauma and crestal bone loss or implant failure.• Impressionmaterialoracrylicmaybecometrappedundertissueorbetween the implant and crestal bone.• Bonethatistoosoft,smallimplantdiameters,orimplantdesignswithless surface area may cause too great crestal stress contours and cause bone loss or implant failures.• Thedurationofthesurgeryand/orpostoperativeappointmentislonger. • BOX 33.4 Disadvantages of Nonfunctional Immediate TeethA BCC D• Fig. . (A) An iliac crest bone graft to the maxilla restores the bone volume of this type 2 DIVISION C-height (C−h), D maxilla. (B) Eleven implants were inserted, and an impression was made for the delivery of the temporary restoration at the suture removal appointment. (C) The final restoration is fabricated after at least 6 months. This intraoral photograph illustrates the definitive maxillary porcelain-metal restoration. (D) A panoramic radiograph of the final maxillary restoration and the corrected mandibular occlusal plane.Indications• Edentulousareawithfavorableavailableboneandbonedensity• Partiallyedentulouspatientswithcentricocclusalcontactsandexcursions on natural teeth (or healed implants) • Noparafunctionalhabits • Idealimplantpositionandimplantdimensions(i.e.,diameterandlength) Contraindications• Patientswithparafunctionaloralhabits(i.e.,anteriorandlateraltonguethrust, or biting on a pipe while smoking)• Occlusalcontactsthatwouldresultinfunctionalcontactsonimplantprosthesis • BOX 33.2 Nonfunctional Immediate Teeth 870PART VI Implant Surgeryrespectively, were reported. A 100% success rate was reported in favorable bone quality (type 1), whereas a 95.5% rate was found in poor bone quality (type 4).65Chaushu et al.66 compared the success of immediate-loaded implants in fresh extraction sites compared with sites that were healed. Provisional restorations were placed immediately the day of surgery. e authors concluded that immediate loading in an extraction site did increase the failure rate (i.e., approxi-mately 20%) in comparison with immediate-loaded healed sites. Mankoo67 described the immediate implant placement and provi-sionalization in the anterior region of the oral cavity. He reported this technique was advantageous, not only because of the lack of a stage 2 surgery required, but also the esthetic benets provided from a provisional restoration.In addition, a removable prosthesis is not required, which is usually dicult for the patient to adapt to and has associated esthetic issues.A meta-analysis identifying more than 5000 studies was com-pleted by Pigozzo etal.68 and concluded no signicant dierences between immediate- and early-loading protocols with single-implant crowns. e success and survival rate together with mar-ginal bone loss was evaluated up to 3 years. Surgical/Prosthetic Protocol for Single ImplantsAfter placement of a single tooth implant the clinician has three options at his or her disposal: 1. Two-stage technique: involves delayed healing and a second sur-gery to expose the implant before prosthetic rehabilitation 2. One-stage technique: a healing abutment is placed after implant placement, healing is completed, and prosthetic rehabilitation is delayed 3. Immediate restoration with a provisional prosthesis: may be loaded or nonfunctional; rarely will a single-tooth immediate implant be placed directly into function because of increased biomechanical forces that may result in poor healing or failure of the implant Single-Tooth Nonfunctional Immediate-Restoration Proceduree N-FIT concept presents a similar approach to the immedi-ate-loading technique, except the implant-supported transitional prosthesis is placed out of all direct opposing occlusal contacts during the bone healing period. As a result the implant clinician may fabricate an esthetic tooth replacement immediately for the patient, but with no occlusal contact. By placing an immediate prosthesis, the soft tissue contours, as well as the esthetics, may be developed via the provisional prosthesis and bone-healing process (Fig. 33.12).After implant placement, there exist multiple treatment options for the clinician to provisionalize the implant restoration. 1. Implant crown fabricated by the dental laboratory where the clinician relines the provisional prosthesis to a stock type abut-ment placement; this may be a cement or screw-retained pros-thesis. 2. Prefabricated crown that is relined by the clinician; usually a stock or prefabricate abutment is inserted and prepared, after which the provisional restoration is fabricated to the esthetics and functional demands of the area 3. Composite that is bonded to a stock or prefabricated abutment and the adjacent teeth 4. e clinician takes an impression of the implant after insertion, together with jaw records and opposing impressions; a healing abutment is placed; at the suture removal, which is usually 2 weeks after placement, the healing abutment is removed and replaced with a laboratory-modied abutment and provisional prosthesis; this is an example of early loadingNo matter what technique is used to fabricate a provisional prosthesis, it is imperative that the occlusion is strictly monitored. After placement of the interim crown the prosthesis should be evaluated in all centric and eccentric excursions to verify no con-tact. Of special concern is in the maxillary anterior region, because horizontal movement of the anterior teeth is far greater than the posterior teeth. erefore the excursive movements should be evaluated with all degrees of force (i.e., clenching and bruxing movements) (Fig. 33.13 and Box 33.5). Partially Edentulous (Greater Than One Edentulous Space)With partially edentulous spaces, immediate-loaded implants is a controversial topic. Most studies consist of patient treatment in load-based areas such as the posterior part of the oral cavity. Few studies have been completed in the esthetic zone. Until more detailed studies are available, clinicians should be conscious of placing immediate implants, especially in the esthetic in partially edentulous patients.Literature Review of Partially Edentulous ArchesEarly Loading in the Partially Edentulous ArchTestori etal.69 reported on a 3-year 97.7% success rate in a longitu-dinal, prospective, multicenter study of early implant loading. All implants were placed in the posterior region of the oral cavity and were loaded within 8 weeks. Cochran etal.,70 in a longitudinal, prospective, multicenter study, reported a 99.1% success rate after 1 year. Implants were placed in the posterior regions of the jaws, with various healing times based on the density of bone. Luongo etal.71 evaluated the immediate and early loading (11 days) of implants in the posterior maxilla and mandible. A 98.8% success rate was reported, and the results were similar to those with delayed-loaded implants. Vanden Bogaerde etal.,72 in a multicenter study, placed interim prostheses between 9 and 16 days after implant placement in the maxilla. An implant survival rate of 99.1% after 18 months was reported, with bone loss less than 0.8 mm. Immediate Loading in the Partially Edentulous ArchDrago and Lazzara73 related a study involving restored xed provi-sional implant crowns without occlusion immediately after implant placement. e implants were immediately restored with prefabri-cated stock abutments and cement retained. No occlusal contacts or interferences were present. Final prostheses were inserted 8 to 12 weeks after implant placement. After 18 months the implant survival rate was 97.4%, and an average bone loss of 0.76 mm was reported.73 Interestingly, Machtei etal.74 evaluated implants placed in the mandible in patients with chronic periodontitis. ey con-cluded that immediate-loading protocols are a predictable treat-ment; however, caution should be exercised in the molar regions. Schincaglia etal.75 reported a split-mouth study with bilateral, par-tially edentulous posterior mandibles. e overall success rate was 95%; an insertion torque of 20 N-cm or greater and an ISQ value more than 60 N-cm was recommended (Fig. 33.14).  871CHAPTER 33 Immediate Load/Restoration in Implant DentistryAB CD E• Fig. . Nonfunctional Immediate Prosthesis. (A) Maxillary right lateral incisor implant placement. (B) A acrylic temporary prosthesis is fabricated chairside and relined to fit the inserted abutment. (C) The adjacent teeth are acid-etched. (D) The provisional prosthesis is bonded to the adjacent teeth, and the occlusion is confirmed to include no contacts. (E) After 4 months of healing the provisional prosthesis is removed and the final prosthesis completed. 872PART VI Implant SurgeryA BCD• Fig. . Single-Tooth Provisional Prostheses. (A) Prosthesis may be bonded to adjacent teeth, however only when no horizontal mobility of the adjacent abutment teeth is present. (B) Provisional with no contact with adjacent teeth because of heavy excursive contacts on the canine. (C) Provisional placed on an immedi-ate mandibular premolar; note the slight contact in light occlusion, all contacts should be removed to remain nonfunctional, (D) Lateral incisor immediate load showing no occlusal contacts and ideal contacts on cuspid.Appointment #1: Surgery 1. Make impression of opposing arch and obtain tooth shade and centric bite registration. 2. Perform stage I implant surgery (use wider implants when possible). 3. Make an impression with additional silicone material or polyether. Verify that no impression material is entrapped underneath the flap. 4. Place a healing abutment approximately 2 mm above the tissue. 5. Suture (tissue thickness should be less than 4 mm). Laboratory Procedure 1. Impressions are mounted on an articulator with correct jaw records. 2. An abutment is selected and prepared for either a cement or screw-retained prosthesis. 3. Provisional prosthesis is fabricated with narrow occlusal table, minimal cusp height, and no occlusal or excursive contacts. Appointment #2: Suture Removal/Prosthesis Insertion 1. Sutures are removed atraumatically. 2. The healing abutment is removed and the internal opening of the implant is irrigated with chlorhexidine. 3. The laboratory-fabricated abutment is inserted (if cement retained). 4. Use countertorque (hemostat) and tighten to abutment screw 20 to 30 N-cm(whichislessthanfinalpreload). 5. Insert provisional prosthesis and evaluate contour and occlusion (no occlusal contacts).6. Instructpatienttoeatsoftfoods(e.g.,pasta,fish,cookedmeat).Norawvegetablesorhardbreadarealloweduntilfinalprosthesisdelivery.Nooral habits, such as gum chewing, are permitted. When possible the patient should avoid chewing food in implant regions. • BOX 33.5 Protocol for Stage I Nonfunctional Early Loading Immediate Teeth 873CHAPTER 33 Immediate Load/Restoration in Implant DentistryAC DBEGF• Fig. . (A) A panoramic radiograph of a patient with partial anodontia missing the bilateral permanent canines, first premolar, and second premolars. (B) The deciduous teeth have been extracted. (C) Two implants are used to support the prosthesis on each side. The mesiodistal space is inadequate for three implants. (D) The four implants are prepared for a cemented transitional prosthesis. (E) The transitional N-FIT restorations are primarily for esthetics and are completely out of occlusion in centric relation and all excursions. (F) The final restoration is made after 4 to 6 months. At this point the soft and hard tissues are mature. (G) The final restoration of the three-unit fixed partial denture supported by two immediate-loaded implants. 874PART VI Implant SurgeryCompletely Edentulous Archese immediate placement and loading of implants in the eden-tulous arches has become popular in implant dentistry today. In comparison with conventional implant procedures, the success of immediate placement and loading in the maxilla and man-dible is dependent on patient selection, the preoperative treat-ment planning, and the skill set of the clinician in completing the surgical and prosthetic phases of treatment. ese types of procedures tend to be more complex and can be associated with a higher degree of complications. e concept of immediate placement/load rst originated with the mandibular arch and has been well studied. However, even though studies are limited in the maxilla, the maxillary arch is becoming more popular in implant dentistry today.Literature Review of Edentulous ArchesEarly Loading in the Mandibular Edentulous ArchNumerous studies have shown favorable results with the early loading of the mandibular edentulous arch. Engquist etal.76,77 reported on more than 100 edentulous mandible patients. Each patient was treated with four Nobel Biocare implants in the anterior mandible for a xed implant prosthesis. ey evaluated four groups: one-stage surgery, two-stage surgery, one-piece abutments, and early loading. e permanent prosthesis was loaded between 10 days and 3 weeks. With the early load-ing group, approximately 7% of the implants failed; however, this group exhibited less marginal bone loss than the control group.76,77 Friberg etal.78 evaluated more than 750 implants in the edentulous mandible, with the xed prosthesis being placed approximately 13 days after implant placement. A 97.5% suc-cess rate was reported, with mean marginal bone resorption of approximately 0.4 mm. Immediate Loading in the Mandibular Edentulous ArchIn 1990 Schnitman etal.79 reported for the rst time the imme-diate loading of dental implants in the anterior mandible. Five to six implants were placed in the interforaminal region, with additional implants placed posterior. ree of the implants were used for an interim prosthesis, which was converted from the patient’s denture. e authors concluded the immediate loading of implants was a viable treatment option for patients because the long-term success was not impacted by the early loading of the implants. In a follow-up study, Schnitman etal.80 treated 10 patients with an immediate-loaded xed prosthesis. About 15.3% of the immediate implants failed, and all conventional loaded implants were successful. Schnitman etal.80 concluded that immediate-loaded implants in the short term are successful; however, in the long term, they may have a questionable progno-sis. Tarnow etal.81 evaluated patients treated with a minimum of 10 implants, with 5 of the implants submerged, with no loading. A xed interim prosthesis was inserted and later replaced with a xed provisional prosthesis. Although three of the implants failed (two immediate loaded and one submerged), Tarnow etal. concluded that immediate implants splinted together are a via-ble treatment option.More recently, studies have shown four to six implants placed in the mandible have favorable success rates. Chow etal.82 placed four implants in patients with a screw-retained interim prosthesis. After 1 year the implants had a 100% success rate. In a prospective four-center study, Testori etal.83 evaluated 62 patients in which an interim prosthesis was inserted within 4 hours of implant surgery. A success rate of 99.4% was reported, with crestal bone loss simi-lar to the traditional delayed technique. Aalam etal.84 evaluated 16 patients who received mandibular implants for screw-retained hybrid prostheses. After 3 years the implant success rate was 96.6%, and the prosthetic success rate was 100% (Fig. 33.15). Early Loading in the Maxillary Edentulous ArchFischer and Stenberg85 reported on early implant loading of 24 maxillary edentulous patients. After 3 years the implant success rate was 100%, and a 3-year study showed less radiographic bone loss in the early loaded than the control group.Olsson etal.86 studied for 1 year 10 patients who had received a xed full-arch provisional prosthesis 1 to 9 days after implant placement. A permanent prosthesis was placed 2 to 7 months after implant placement. About 6.6% of the implants failed, all from infection, and an associated 1.3-mm marginal bone loss was reported. Immediate Loading in the Maxillary Edentulous ArchBergkvist et al.87 reported on a provisional prosthesis placed on immediate-loaded maxillary implants. After a mean heal-ing period of 15 weeks, a nal screw-retained prosthesis was fabricated. Approximately 2% of the implants failed during the healing period, and the mean marginal bone loss was 1.6 mm after 8 months.87 Ibanez etal.88 evaluated 26 patients who had fully edentulous maxillae, with implants that were loaded within 2 days of placement with either a provisional or nal prosthesis. e success rate was 100% after a healing period of 1 to 6 years. e radiographic bone level change was a loss of 0.56 mm at 12 months and 0.94 mm at 72 months. Degidi etal.89 reported on a 5-year follow-up of implants immediately loaded with an interim prosthesis followed by a nal prosthesis. A 98% success rate was shown, with most failures occurring in the rst 6 months of healing. In addition, they concluded that wider implants were associated with an increased failure rate. Balshi etal.,90 in evaluation of 55 patients who received imme-diate implants, along with immediate-loaded implants, found a 99.0% survival rate of the implants and a 100% survival rate of the prosthesis. e interim prostheses consisted of an all-acrylic screw-retained prosthesis that was replaced approximately 4 to 6 months later (Fig. 33.16). Provisional Implantse use of provisional implants, which are dened as implants placed to retain an interim prosthesis, are not necessarily indi-cated for a permanent prosthesis. Originally these implants were thought not to achieve osseointegration. However, Balkin etal.91 evaluated miniimplants for light microscopy evaluation after 4 to 5 months of immediate function. ey reported that osseoin-tegration did occur with mature and healthy bone. Iezzi etal.92 reported on three provisional implants that were placed to retain a provisional prosthesis for 4 months. ey concluded the existence of bone trabeculae around the implants, as well as the occurrence of the bone remodeling process. Heberer etal.93 followed 254 pro-visional implants that were placed in 64 patients and remained functional up to 462 days. e total success rate reported was 82%, and patient factors such as gender, opposing occlusion, and implant position did not appear to be signicant. Simon and Caputo94 completed removal torque tests on provisional implants in 31 patients. ey concluded that osseointegration may pose 875CHAPTER 33 Immediate Load/Restoration in Implant DentistryFBAC DEGH• Fig. . Mandibular Immediate Loading (Chrome Guides). (A) Preoperative panoramic radiograph. (B) Reduction guide fixated into position. (C) Bone removed from anterior mandible to gain sufficient height for implant placement. (D) Post-osteotomy. (E) Implant guide on bone model. (F) Polymethylmethacrylate provisional prosthesis. (G) Fully guided implant placement. (H) Final hybrid prosthesis. an increased possibility of fracture in the mandible because they reported that implants left in after 10 months showed a higher possibility of fracture on removal (Fig. 33.17).All-on-4 Surgical/Prosthetic ProtocolMalo etal.95,96 originally introduced the concept of the All-on-4 protocol, which involves the immediate loading of a xed prosthe-sis on four implants placed in the maxilla or mandible. Although numerous options are available, in general two parallel implants are placed anteriorly and two angled implants are placed posteriorly. e posterior implants are accurately positioned to avoid key vital structures (e.g., maxillary sinus, inferior alveolar canal), increase A-P spread, and minimize cantilever length. Because of these posi-tioning protocols, a signicant treatment time savings is seen as sinus augmentation and bone-grafting procedures in the mandible are avoided. Usually in the maxilla, two posterior implants are posi-tioned at up to 45 degrees of angulation to avoid the maxillary sinus. In the mandible the position of the implants is dictated by the mental foramen position (i.e., possible anterior loop); however, they are usually angulated anteriorly 30 to 45 degrees. Multiunit abutments are placed into the implants with varying degrees of angulation, usually consisting of 0, 17, or 30 degrees.95,96Requirements of the All-on-4 Technique 1. Minimum of 35 N-cm insertion torque: If this cannot be achieved, then a conventional healing phase is recommended. 2. No signicant parafunction habits 3. Available bone dimensions:Maxilla: >5 mm of width and >10 mm of heightMandible: >5 mm of width and >8 mm of height 4. Favorable bone density of D1, D2, or D3 Advanced Fully Guided Immediate Placement/Loading Protocols (Box 33.6, Box 33.7, Fig. 33.18)ere exist various surgical/prosthetic protocols (e.g., 3D Diag-nostix, nSequence) that allow a fully guided surgical and prosthetic protocol, which combines three-dimensional CBCT-guided sur-gery with a denitive xed immediate prosthesis. ese protocols allow the clinician to maximize the precision of CBCT technology, together with having the capability of delivering a provisional xed prosthesis with precision and accuracy. ese techniques, compared with a freehand two-dimensional approach, have increased preci-sion, predictability, and time-saving consistency. e fully guided, immediate placement/loading protocols allow for three-dimensional (3D) precision digital implant planning with virtual surgical and prosthetic protocols, 3D modication of bony anatomy to optimize implant placement and positioning, implant placement with a fully guided technique, and same-day delivery of a screw-retained imme-diate xed prosthesis. In addition, this protocol allows for deni-tive control for surgical treatment planning, especially in immediate extraction cases where the bony anatomy requires alteration97 Fig. 33.19 (Box 33.8; Figs. 33.20 through 33.22).A B• Fig. . Zirconia Final Prosthesis. (A and B) The monolithic zirconia prosthesis has the advantages of greater flexural strength and higher fracture resistance.A B• Fig. . Provisional Implants. (A and B) Implants placed into “B,” “C,” and “D” implants with two miniimplants between the implants to retain an interim prosthesis (O-Ring Attachments).876PART VI Implant Surgery 1. Preoperative RecordsInitially, maxillary and mandibular impressions are obtained conventionally or digitally (i.e., intraoral scanner), along with an accurate bite registration. A tooth shade is selected. Intraoral and extraoral photographs may be taken to assist in the diagnosis and treatment planning. Maxillary and mandibular cone beam computedtomography(CBCT)scansareobtained,withthepatientwearingthebite registration in maximum intercuspation. The impressions, along with the CBCTscansareuploadedtoathird-partymanufacturerforprocessing. 2. Three-Dimensional Data ConversionThe digital three-dimensional (3D) data are merged with the 3D bony anatomy, which results in the formation of a 3D-specific dataset of tooth position, bony anatomy, occlusal considerations, prosthesis fabrication, and ideal biomechanical implant positioning. This is usually accomplished with a specialized software and third-party manufacturer (e.g., 3D Diagnostix). 3. Prosthetic and Surgical Treatment PlanWith an interdisciplinary team approach, the 3D data is used in formulating a prosthetic and surgical treatment plan. The prosthesis type should always be identified first and then the surgical plan formulated to fulfill the requirements of the prosthesis. The treatment planning factors should include: (1) type of prosthesis; (2) available bone; (3) bone density; (4) parafunctional forces; (5) anteroposterior spread; (6) occlusion; (7) implant dimensions and positions; (8) osteoplasty, if indicated; (9) path of prosthesis insertion; and (10) multiunit abutments and access holes. 4. Fabrication of Surgical Guides and Provisional ProsthesisAfter treatment planning is complete, the finalized data set is sent for milling and rapid prototyping by the third-party manufacturer. A bone reduction guide (if indicated), implant surgical guide, and abutment guide are usually fabricated via stereolithography. The provisional prosthesis is most commonly milled in a monolithic polymethylmethacrylate (PMMA) block material. The manufacturer will provide a detailed surgery report on the guide sequence, along with implant size and position protocols. 5. SurgeryAfter anesthesia a bone reduction guide or bone foundation is positioned, usually with the aid of a registration and existing teeth. In some cases this guide will be fixated to the bone. The teeth are then extracted. After extraction a surgical implant guide will be positioned, which will assist in implant placement. This may include a universal or a fully guided template. After implant placement, multiunitabutments,whichhavebeenpredeterminedfromtheCBCTplan,areplaced into the implant bodies. 6. Provisional Prosthesis InsertionTemporary, stock abutments are placed into each multiunit abutment. The PMMA provisional prosthesis is then inserted and evaluated for fit. The PMMA prosthesis is then luted to the temporary abutment via light-cured acrylic. The PMMA can then be removed and polished for final insertion. Soft tissue closure is accomplished with a resorbable suture material with high tensile strength (e.g., Vicryl). 7. Final Prosthesis FabricationAfter sufficient healing a final prosthesis (i.e., monolithic zirconia) is fabricated. The function, phonetics, and design of the PMMA provisional can be used as a guide for any future modifications of the permanent prosthesis. • BOX 33.6 Generic All-on-4 ProtocolThe All-on-4 treatment may be performed with two approaches: 1. Conventional surgery: full-thickness flap and freehand implant placement a. After flap elevation a midline osteotomy is completed in which the All-on-4 guide is placed. b. Posterior surgical osteotomy: The posterior sites are prepared at approximately 45 degrees, using the guide as an angulation tool. Implantsareinsertedatafinaltorqueof35to45N-cm.Thirty-degree multiunit abutments are placed into both posterior sites. The abutments are tightened to the manufacturer’s recommendations. c. Anterior surgical osteotomy: Prepare and place two anterior implantsintheapproximate“B”and“D”positions.Implantsareinsertedatafinaltorqueof35to45N-cm.Multiunitabutmentsareplaced into both anterior sites. The abutments are tightened to the manufacturer’s recommendations. 2. Guided: tissue- or bone-supported guide a. Implant placement: Four implants are placed according to the type of guide (tissue supported—flapless) or bone supported (flap is raised to expose residual ridge). The four implants are placed according totheinteractiveCBCTtreatmentplan.NOTE:theangulationoftheposterior implants is dictated by anatomic landmarks evaluated on the3DCBCT.Prosthetic Procedure 1. Temporary multiunit abutment copings are placed on each implant and hand tightened. 2. The fabricated prosthesis is tried in to verify proper seating and occlusion. Light-cured composite/acrylic is used fixate the interim prosthesis to the temporary abutments. The prosthesis is removed, and any voids present between the abutments and prosthesis are filled with composite/acrylic. 3. The prosthesis is polished and reinserted for final insertion. The abutment screws are placed with a final torque as per the manufacturer’srecommendations.Polytetrauoroethylene(PTFE)tapeisplaced in the access holes and light-cured composite/acrylic is used to cover the holes (Fig. 33.18). • BOX 33.7 All-on-4 Surgical/Prosthetic ApproachesAB• Fig. . (A and B) All-on-4 protocol, which includes two anterior implants and two posterior angled implants. 878PART VI Implant SurgeryABC DEFGHIJKLContinued 879CHAPTER 33 Immediate Load/Restoration in Implant DentistryA. Bone-Supported Surgical GuideClinician (Preoperative Appointment #1) 1. Conventional impressions + bite registration or digital impressions2. Obtainconebeamcomputedtomographic(CBCT)scan • Makesurebiteregistrationisinplaceandpatientclosesintocentricocclusion. 3. Tooth shade is selected Preplanning1. Thecaseisreviewedviathree-dimensionalinteractiveCBCTsoftwareand preplanned according to ideal implant position, biomechanical force factors, and prosthesis type (Fig.33.19A,B,C,D). 2. The treatment planned case, along with impressions (or digital impressions), is sent to a laboratory or manufacturer for fabrication of the following: • Theworkingstudycastsarefabricatedandmountedonanarticulator, using the surgical template as a reference. • ThesurgicaltemplateisfabricatedfromtheCBCTplanviaCAD/CAMor a 3D printer. • Multiunitabutmentsandprefabricatedtemporaryabutmentsareattached to the implant analogs on the working cast. • Apolymethylmethacrylate(PMMA)isfabricatedandhollowedout,which correspond to the abutment positions.The laboratory furnishes the implant clinician with: a. Bone foundation guide—Fixated guide that is bone supported and is used as the primary guide that holds all additional stackable guides that are used. In addition, if ridge reduction is indicated, this guide may be used as a stackable bone reduction guide (Fig.33.19E). b. Stackable surgical guide—This stackable (i.e., attaches into the bone foundationguide)templateisfabricatedfromtheCBCTtreatmentand corresponds to the position of the implants. Usually this is a fully guided template, which allows for all osteotomy preparation and implant placement through the guide (Fig. 33.19H, I, J). c. Multiunit abutments—Prefabricated abutments are specific to the implant system being used, which allows for the ideal angulation correction between the implants. Usually multiunits can be standard (no angulation) or angled with various angles (Fig. 33.19K, 33.20A). d. Temporary abutments—These are nonengaging screw-retained abutments placed into the multiunit abutments that are used to allow for fixation of the prosthesis to the multiunit abutments (Fig.33.19L,33.20B). e. Stackable abutment guide—A stackable abutment guide fits into the foundation guide and allows for the final positioning of the abutments, which are inserted into the implants and used to fixate the prosthesis. f. Silicone gasket—This is a flexible gasket that is placed over the temporary abutments to prevent flow of acrylic/composite into the tissue space when fixating the provisional prosthesis into the abutments (Fig.33.19M,N). g. Bite registration—Used to verify proper positioning and seating of the provisional prosthesis (Fig. 33.19P, Q). h. Provisional prosthesis—This prosthesis (usually a PMMA prosthesis) is inserted at the time of implant placement. It is used during the healing period to verify esthetic, vertical dimension, occlusion, and patient acceptance (Fig.33.19O,R). • BOX 33.8 Immediate Placement/Immediate-Loading ProtocolMN OPQR• Fig. . Stackable Guide (3ddx): (A) Interactive treatment plan including five mandibular implants, (B) Computerized Surgical Guide Design, (C) Computerized PMMA Prosthesis Design, (D) CADS/CAM model depicting osteoplasty requirement, (E) Foundation Guide which is also is used as the osteoplasty or bone reduction guide, (F) Fixation Pin Drill, (G) Fixation Pin Insertion, (H) Stackable Surgical Guide, (I) Stackable Surgical Guide placed on foundation guide, (J) Implant Placement, (K) Multi-Unit Abutment Placement into implants, (L) Temporary Abutment Placement into multi-unit abutments, (M) Gasket and PMMA Interim Prosthesis, (N) Gasket Placement over Abutments, (O) Interim Prosthesis Placement, (P) Bite Registration, (Q) Patient Bites into Occlusion with Bite Registration, (R) Flowable composite / acrylic inserted through holes to fixate PMMA prosthesis to Temporary Abutments. 880PART VI Implant SurgeryComplications of Fixed Provisional ProsthesesIf basic prosthodontic principles are not adhered to when placing a provisional prosthesis, complications may become more prevalent. Ideally the prosthesis should not interfere with soft tissue heal-ing, cantilevers should be limited and avoided if possible, occlu-sal tables narrowed buccal-lingually, and even and ideal occlusal contacts. Suarez-Feito etal.98 evaluated the complications in 242 consecutively treated patients, with more than 1000 implants sup-porting a provisional prosthesis. During the rst 60 to 90 days, 8.3% of patients had at least one fracture, with 7.4% occurring within the rst 4 weeks. In total, 8.3% of the patients had at least one fracture and 7.4% of the restorations fractured, of which more than half occurred during the rst 4 weeks. When the opposing occlusion was an implant-supported prosthesis, the fracture risk was 4.7 times higher. e maxillary arch had a 3.5 times greater fracture risk.98 Nikellis et al.99 reported similar results, which included a 16.6% fracture rate with provisional prostheses when the opposing dentition was an implant-supported prosthesis. To combat the higher complication rate in the maxilla, Collaert and De Bruyn100 suggested a metal framework to reinforce the pro-visional reconstruction, as their study showed seven out of nine provisional prostheses resulted with early fractures. After changing their protocol to include a cast metal bar, no additional fractures were seen.100 In addition, speech-related issues have been shown to be problematic. In the maxilla, usually because of implant posi-tion and increased structural reinforcement, compromised space for the tongue has been shown. erefore because of the bulkiness, patients often reported this problem. Molly etal.101 reported that i. Fixation Pins—usually 3 -4 fixation pins are used to fixate the foundation guide to the bone. The pins prevent any movement of the guide during the osteotomy process. (Fig. 33.19F, G). Clinician (Surgery: Appointment #2) 1. Remaining teeth are extracted if indicated, along with debridement of the extraction sockets (Fig. 33.21A–C). 2. The tissue is reflected to expose the residual ridge. The flap design is dictated on the size of the guide.NOTE:Theguideshouldbeevaluatedsothatitisfullyseated,withnorockingor movement. Caution should be exercised to verify no tissue impingement underneath the guide. The bone foundation guide is fixated with fixation pins to prevent movement of the guide during osteotomy preparation. Usually three to four fixation pins are used, which are based on the implant positions (Fig. 33.21D). 3. If bone reduction is indicated, the bone is reduced to the level of the guide with bone reduction burs. Therefore the bone foundation guide acts as a bone reduction guide. 4. The stackable surgical guide is placed over the bone foundation guide. The osteotomies are prepared according to the fully guided surgical protocol that is specific to the implant system being used. All implants are placed into the final position and the stackable surgical guide is removed (Fig.33.21E–G). 5. The stackable multi-unit guide is then positioned onto the bone foundation guide. This guide allows for the ideal positioning and placementofthemultiunitabutments.Notethatmultiunitabutmentsmay be straight or angled depending on the implant system being used. The multiunit abutments are torqued according to the manufacturer’s instructions and the stackable guide is removed.NOTE:Aperiapicalradiographmaybetakentoverifycompleteseatingofthe abutments. 6. The temporary screw-retained abutments are placed into the multiunit abutments. The abutment screws should not be finally torqued into place and only tightened with finger pressure (Fig. 33.21H). 7. The soft silicone jig is positioned over the temporary abutments. Complete seating of the jig should be verified because this may prevent complete seating of the interim prosthesis (Fig. 33.21I). 8. The interim prosthesis (e.g., PMMA, acrylic) is positioned over the temporary abutments and gasket. Complete seating of the prosthesis is verified, along with ideal occlusion. The bite registration index is inserted to confirm ideal vertical dimension and centric occlusion. Adjustments are made accordingly to the PMMA prosthesis or occlusal anatomy (Fig. 33.21J). • Alternativetechnique:Aduplicateprosthesismaybeusedtoobtaina bite registration or esthetic modification to be used in the final prosthesis. 9. Fixating Interim Prosthesis to Temporary Abutments: The interim prosthesis is then luted to the temporary abutments via light-cure composite (i.e., also may use self- or dual-cure acrylic) through injection vents present in the interim prosthesis. Patient closes in centric occlusion; light-cured composite is flowed through predrilled holes. The flowable acrylic is cured via a curing light. The silicone jig will prevent composite/acrylic from flowing into the abutment/sulcus area (Fig. 33.21K and 33.21L). 10. The screws holding the interim prosthesis to the abutments are loosened and removed. The prosthesis is inspected for voids between the temporary abutments and the interim prosthesis. Composite/acrylic is added accordingly. The prosthesis is then polished and reseated, with screws torqued to the manufacturer’s recommendations. Access holes are filled with sterilized polytetrafluoroethylene tape (plumber’s tape) and light-cured composite. • NOTE:Alternativetreatment:Beforethefinalseatingoftheinterimprosthesis, a clear duplicate prosthesis can be used to obtain jaw records and final impression for the final prosthesis fabrication. Clinician (Prosthetic: Appointment #3)• Aftersufficienthealing,theclinicianconfirmsthecorrectverticaldimension, occlusion, shade, and contours of the prosthesis. The interim prosthesis is removed and a final impression completed. A verification jig maybe used for the obtaining an accurate impression. Sectioned acrylic blocks which contain titanium cylinder are secured onto each implant.Eachcylinderislutedtogetherandthefinalimpressionistaken.If no changes are indicated, the laboratory is instructed to complete the final prosthesis, which most commonly is a monolithic zirconia full-arch prosthesis. Clinician (Prosthetic: Appointment #4)• Theclinicianinsertsthefinalprosthesisafterremovaloftheinterimprosthesis.• Theinterimprosthesisissavedasabackupprosthesisormaybeusedas a possible future provisional if the need should arise (Fig. 33.21M). B. Tissue-Supported Surgical GuideSame procedure as described in part A with the following exceptions:1. DualScanCBCTisutilizedforthefabricationofthetissuesupportedguide. 2. A tissue foundation guide is used instead of the bone foundation guide (Fig. 33.2L). 3. The tissue is not reflected and the procedure is completed flapless.4. Nobonereductionguideisused. • BOX 33.8 Immediate Placement/Immediate-Loading Protocol—cont’d 881CHAPTER 33 Immediate Load/Restoration in Implant Dentistry10% of maxillary immediate-loaded implant prostheses resulted in patients exhibiting nonadaptable speech deterioration. Van Lierde etal.102 showed similar results with immediate-loaded All-on-4 prostheses, where 53% of patients had related speech issues. e most common reason was the palatal positioning of implants with angulated abutments (Fig. 33.23). Immediate Load Implant Overdenturese immediate-load concept for mandibular overdentures has been discussed in the literature for more than 50 years. e sub-periosteal implant and the mandibular staple implant were loaded immediately after insertion and fullled the immediate-load de-nition. Babbush etal.103 reported on immediate-loaded overden-tures in the early 1980s, with threaded root form implants. More recently, Chiapasco etal.104 documented implant success rates of 88% to 97% over 5 to 13 years. In theory the risk of joining implants together with a bar for an implant overdenture is less than for a fixed prosthesis, because the patient may remove the res-toration at night to eliminate the risk for nocturnal parafunction. In addition, the overdenture may have some inherent movement and load to the soft tissue, which adds a stress relief system for the rigid implants.e treatment plan for implant number and position for implant overdentures that are completely implant supported (i.e., RP-4 prosthesis) should be similar to a fixed restoration. If the prosthesis has no movement while in place, then it cannot gain support from the soft tissue. Although the prosthesis may be removed, it is completely implant supported during function or parafunction.In contrast, a RP-5 prosthesis primarily loads the soft tissue with secondary support from the implants. Implant overden-tures with hard and soft tissue support may be at increased risk for immediate loading because the biomechanical torque to the implants may be increased compared with completely implant-supported restorations. One should exercise care relative to the amount and direction of prosthesis movement during the initial loading period.e use of a single immediate implant has been documented by numerous authors in the literature. Cordioli etal.105 and Kren-nmair and Ulm106 both concluded that one implant placed in the mandibular midline was a credible treatment, in particular for elderly patients with dentures who are experiencing masticatory complications. In addition, positive outcomes such as satisfaction and improved health-related quality of life, along with good func-tional outcomes, were reported to be greater.AB• Fig. . (A) Multiunit abutments with varying angulations that depend on implant trajectory. Most commonly, the multi-unit abutments are available in 0°, 17°, and 30° (B) Temporary abutments that insert into the multiunit abutments that secure the prosthesis to the implants. Usually, non-engaging abutments (arrow) are used for full arch cases. 882PART VI Implant SurgeryCEGBDFHAContinued 883CHAPTER 33 Immediate Load/Restoration in Implant DentistryIKJLM• Fig. . (A) Preoperative panoramic displaying nonrestorable maxillary and mandibular teeth. (B) Intra-oral view of nonrestorable teeth. (C) Extraction of maxillary teeth. (D) Bone foundation guide fixated on the residual ridge. This guide is also used as a bone reduction guide. (E) Stackable surgical guide: guide that inserts into the bone foundation guide, which is used to prepare osteotomies and placement of implants. (F) Implant placement via fully guided template. (G) Implant placement in maxilla. (H) Temporary screw-retained abutments inserted into the multiunit abutments. (I) Soft silicone jig is placed over the abutments to prevent composite/acrylic from flowing into the tissue spaces. (J) Polymethylmethacrylate (PMMA) pro-visional prosthesis: try-in of the PMMA prosthesis to verify complete seating. (K) Final insert of maxillary and mandibular PMMA interim prostheses. (L) Final insert of maxillary and mandibular zirconia prostheses. (M) Final postoperative prosthesis panoramic radiograph. 884PART VI Implant SurgeryABC• Fig. . Fractured Polymethylmethacrylate (PMMA) Prosthesis. (A to C) The most common compli-cation for a PMMA interim prosthesis is a fractured substructure. The enclosed images depict a fracture, mainly because of the large cantilever that is present.Liddelow and Henry107 reported on a 36-month prospective study evaluating a single-implant overdenture that is restored immediately into function. ey concluded that a single implant with an oxidized surface may provide benecial outcomes with minimal nancial outlay for the patient (Fig. 33.24).Ormianer etal.108 reported on a modied loading protocol with two implants that were immediately loaded in the mandible. A suc-cess rate of 96.4% was achieved with a modied xation technique. Impregum (3M ESPE) was used to provide retention for the pros-thesis during the early phases of treatment, as the impression mate-rial was changed every 2 weeks for the rst 3 months (Fig. 33.25). Immediate Load Overdenture Treatment ProtocolImmediate Load Implant Overdentures a. Immediate loading: After implant placement, abutments are placed into the implant bodies. e patient’s current prosthesis is modied to seat completely, without interferences from the denture. e appropriate female attachment is directly secured to the denture base with light-cured attachment acrylic/com-posite. After adequate healing, conventional prosthetic proto-cols may be used to fabricate a new prosthesis with either single or splinted implant attachments. b. Early loading: At the time of implant placement a nal impres-sion is made of the existing implants. At the postoperative appointment, jaw records are completed, with the correct ver-tical dimension and bite registration. Conventional prosthetic protocol is then adhered to complete the nal prosthesis with either single or splinted attachments. Immediate Loading: Postoperative InstructionsDietIf the immediately loaded prosthesis becomes partially unce-mented or fractures, the remaining implants attached to the res-toration are at increased risk for overload failure. erefore the diet of the patient should be limited to only soft foods during the immediate-loading process. Pasta and fish are acceptable, whereas hard crusts of bread, meat, and raw vegetables or fruits are contraindicated. Final ProsthesisAfter sucient healing is completed (~ 4 - 8 months), e interim prosthesis is removed and a nal impression is obtained to fabri-cate the nal prosthesis. • Fig. . A Tissue-supported immediate implant placement is a flap-less procedure which has a high incidence of complications and does not allow for ideal bone grafting of defects around placed implants. 885CHAPTER 33 Immediate Load/Restoration in Implant DentistryImmediate Loading: Postoperative ComplicationsFull-Arch Immediate Prosthesis (Multiunit Abutments)Göthberg etal.109 compared two types of multiunit abutments (one oxidized and the other machined) versus implant prostheses without abutments supporting xed prosthesis (i.e., FP-3) with either an immediate- or delayed-loading protocol. ere was no signicant dierence in marginal bone loss between the distinct loading protocols. However, implants with machined multiunit abutments presented signicantly less marginal bone loss after 3 years in comparison with oxidized abutments or no abutments. Full-Arch Immediate Prosthesis (Connection/Disconnection of Healing Abutments)Numerous researchers have evaluated the eect of placing the den-itive (nal) abutment at the time of the implant placement versus at a later stage on the soft and hard tissues. Molina etal.113 evalu-ated the connection and disconnection of healing abutments versus the nal abutment being placed at the time of insertion with early-loaded implants. ey determined that the continued connection/disconnection of the abutment led to bone loss during the healing phase. is study supported other immediate-placed implant stud-ies with similar outcomes.110-112 erefore throughout the full-arch immediate prosthesis protocol, the fewer the number of times heal-ing abutments are connected/disconnected, the less bone loss will result. e connection of the abutment at the time of implant place-ment seems to reduce bone level changes during the 6- month heal-ing period, compared with the use of standard healing abutments (which are continuously removed during the prosthetic process). ABC• Fig. . Immediate Single-Implant Overdenture. (A) One implant placed in the midline that results in varying results of patient satisfaction. (B) O-ring attachment placed. (C) Prosthesis with O-ring attachment.ABC• Fig. . Immediate-Loading Overdenture. (A) Mandibular Two-Implant O-Ring Attachment Overdenture, (B) Maxillary Two Implant Over-denture which is usually inadeqaute support for a Maxillary Overdenture, (C) Four Implant Overdenture will allows for greater support. 886PART VI Implant SurgerySummarye delivery of care for patients missing one or all of their teeth often requires implants to restore function, esthetics, bone and soft tissue contours, speech, and intraoral health. e delayed occlusal-loading protocol, either the one- or two-stage approach, has been evaluated for more than 30 years by a number of clini-cal settings and situations. However, in some patient conditions the delayed healing process can cause psychological, social, speech, and/or function problems. A full range of treatment options rela-tive to the initial hard and soft tissue healing is available. Immedi-ate restoration of a patient after implant surgery is one of these alternatives.A benefit/risk ratio may be assessed for each patient condition to ascertain whether immediate occlusal loading is a worthwhile alternative. e greater the benefit and/or the lower the risk, the more likely that immediate loading is considered. A complete edentulous mandible restored with an overdenture supported by four or more implants is a very low-risk condition. If the patient cannot tolerate a mandibular denture and does not wear the device, then an immediate-load protocol would be a high benefit. e highest risk for immediate loading would be a posterior single-tooth implant. Implant number cannot be increased, and implant length cannot engage cortical bone. When the single-tooth replacement is out of the esthetic zone, very low benefit is obtained with the immediate-restoration approach.Additional clinical studies to evaluate the associated risks, especially in the maxillary arch, are expected over the next several years. Until the profession has longer-term evidence and more multicenter studies, immediate occlusal loading will be a secondary treatment option, restricted on a case-by-case basis.A biomechanical rational for immediate loading may decrease the risk for occlusal overload during initial healing. e stresses applied to the implant support system result in strain to the bone interface. e greater the stress, the higher is the strain. Increasing implant area and/or reducing the forces applied to the prosthesis may reduce stress. e implant size, design, and surface condition all aect the area over which the occlusal forces are dissipated. e forces may be reduced by patient factors, implant position, reducing force magnifiers such as crown height or cantilever length, reducing the occlusal contacts, decreasing angled forces to the prostheses, and alter-ing the diet. e mechanical properties of bone also aect the risk for overload, because the bone density is directly related to the strength of bone, its elastic modulus, and the amount of BIC. All of these factors are important in the traditional two-stage approach. ey are especially noteworthy for immediate loading, because the surgical trauma of placing the implant also modifies the mechanical properties of bone during initial healing.e majority of clinical reports reveal similar survival rates between immediate-loaded and two-stage unloaded healing approaches in the completely edentulous patient. Nonetheless, these findings do not imply that a submerged surgical approach is no longer necessary or prudent in many cases. Future stud-ies may find indications based on surgical, host, implant, and occlusal conditions more beneficial for one versus the other. For example, the strength of bone and the modulus of elasticity are related directly to bone density. e softest bone type may be 10 times weaker than for the densest types. e microstrain mis-match of titanium and the softest bone is much greater than the densest bone. 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