Pulp Therapy for the Young Permanent Dentition










436 Part 4 The Transitional Years: Six to Twelve Years
An appropriate impression tray must be chosen. Properly tted
trays seat comfortably in the mouth and extend far enough pos-
teriorly to cover the most distal tooth and either the maxillary
tuberosity or the mandibular retromolar pad. e trays should be
of a nonperforated variety that holds the impression material in
problems are detected during the examination and denitive
analysis or if treatment is required. ese study casts can be
conventional stone casts (Fig. 31.33) or digital representations of
stone casts. In the former case, impressions are obtained using the
following method.
Figure 31.31 Digital images of pretreatment and posttreatment extraoral and intraoral views of orth-
odontic patients can be stored electronically in the patient record or printed as a hard copy. This method
circumvents the problems of losing images to either poor photographic technique or ling methods.
Figure 31.32 These three additional views are often obtained to evaluate facial esthetics and relation-
ships. (A) The three-quarter view with lips relaxed. (B) The three-quarter view with a posed smile. (C) The
lateral view with a posed smile.

CHAPTER 31 Examination, Diagnosis, and Treatment Planning 437
problems. ey can also be manipulated to view all relationships
for analysis and imported to the patient’s record as static images
for electronic archiving or printing (Fig. 31.34). e digital casts
also can be analyzed and measured like conventional casts (Fig.
31.35). Findings recorded during the clinical examination are
reviewed and conrmed using the casts. Alignment and tooth
position characteristics should receive special attention because
appliance design must be appropriate for each rotation and
displacement.
Advances in technology continue to change diagnostic records
in dentistry. Intraoral scanners have been developed to construct
a model of the teeth without making an impression. e scanner
creates a three-dimensional (3D) reconstruction of the teeth and
is as accurate as the traditional alginate impression. As this technol-
ogy continues to improve, its use may surpass the traditional
impression because patients do not like traditional impressions,
mostly because of gagging issues. In addition to intraoral scanning
of teeth, some are using the information gathered from a 3D cone
beam scan to construct a model of the teeth. ere is some question
if the reconstructions from cone beam computerized tomography
are as accurate as intraoral scanning and traditional impressions.
39
In general, they are probably accurate enough for diagnostic purposes
but not appliance construction.
After the diagnostic casts are obtained, analyses should be
performed to determine tooth size relationships and arch length
adequacy. e tooth size analysis compares the size of the teeth
in one arch with the size of the teeth in the other. Tooth size must
be compatible to ensure that teeth t together correctly after
treatment. e arch length analysis is done to predict whether
there is sucient space available in the dental arch for the unerupted
permanent teeth.
Tooth Size Analysis
e tooth size is calculated using Boltons method.
40
Bolton selected
55 cases of excellent occlusion and measured the mesiodistal
diameter of all teeth on the casts except for the permanent second
and third molars. From the measurements obtained, Bolton
determined that a certain ratio existed between the size of the
upper and lower permanent teeth. A ratio could be determined
for either the 6 anterior teeth or all 12 of the measured teeth in
each arch by measuring the teeth manually (Fig. 31.36). Little
constructed a table based on the Bolton ratios to simplify tooth
size determinations (Fig. 31.37).
14
is analysis can be performed
using the digital casts and the associated software (Fig. 31.38).
the tray and expresses the excess material into the vestibule. Some
semiperforated trays are now in use, but they must generate enough
tissue pressure to reect the tissue. When the soft tissue is displaced,
it allows the dentoalveolar morphology to be clearly viewed on
the cast. e trays also can be lined with wax that aids in tissue
displacement and makes seating the tray into position more
comfortable.
After the appropriate tray has been selected, the alginate is
mixed and placed in one tray. For either arch, the tray should be
rotated laterally into the mouth and rmly seated, rst posteriorly
against the palate or the retromolar pad. is technique limits the
posterior ow of alginate and forces excess alginate anteriorly and
laterally. e tray is then rotated and seated over the anterior teeth.
Finally, the tray is held in place until the alginate has set. After
the upper and lower impressions are obtained, a wax bite is made
by placing a softened piece of base plate or other wax bite material
between the teeth, having the patient close in centric occlusion.
e wax is cooled with air and serves to orient the casts properly
during trimming.
Impressions should be disinfected, wrapped in moist paper
towels, and stored in sealed plastic bags or poured soon in white
plaster because the alginate will dehydrate and distort if it is left
exposed for more than a few minutes. e plaster is thoroughly
mixed, usually using a vacuum spatulator to reduce bubbles, and
then vibrated into the impression and owed from one tooth to
another to prevent air entrapment, which results in holes in the
models. Separate plaster bases are poured, and the impressions are
inverted on the bases when the plaster is partially set. After the
plaster has set, the trays are separated carefully from the casts to
prevent breaking the teeth.
e maxillary cast is trimmed so that the top of the base is
parallel to the occlusal plane. e back of the upper cast is trimmed
perpendicular to its top and the midpalatal raphe. e maxillary
and mandibular casts are occluded, and the back of the mandibular
base is trimmed parallel to the top of the maxillary cast. Finally,
the sides of the casts are trimmed symmetrically, which allows the
clinician to judge arch symmetry.
Alternatively for digital casts, impressions are obtained in a
similar manner, but with a long-term stable alginate. e impressions
are disinfected, wrapped in moist towels, bagged in plastic, and
shipped to a commercial laboratory for pouring, and the resulting
models are scanned. A digital representation of the casts is transmit-
ted to the practitioner via the Internet. ese digital images are
less likely to be misplaced or broken and present no storage
Figure 31.33 Views of plaster casts that have been trimmed so that the backs are ush in centric
occlusion and the bases are trimmed symmetrically from the occlusal view so the intra-arch asymmetries
are obvious.

438 Part 4 The Transitional Years: Six to Twelve Years
Figure 31.35 The digital casts can also be manipulated to examine
relationships and measured electronically like conventional plaster casts
so that arch dimensions can be evaluated. (Courtesy OrthoCAD by
Cadent, Inc, San Yosa, CA.)
Figure 31.36 To complete the tooth size analysis developed by Bolton,
the mesiodistal width of each permanent tooth (except for second and
third molars) is measured with a Boley gauge or a needle-pointed divider.
The measurements are added together to provide totals for the six anterior
teeth and for the overall arch.
Figure 31.34 Digital casts can be displayed from the web or stored in image management software.
The digital casts can be manipulated so that the casts can be separated or occluded and rotated or
tipped to reveal all relationships. This prevents problems with loss and breakage of the casts and reduces
the store space problems. (From Proft WR, Fields HW, Sarver DM. Contemporary Orthodontics. 5th ed.
St Louis: Elsevier; 2013.)

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436 Part 4 The Transitional Years: Six to Twelve YearsAn appropriate impression tray must be chosen. Properly tted trays seat comfortably in the mouth and extend far enough pos-teriorly to cover the most distal tooth and either the maxillary tuberosity or the mandibular retromolar pad. e trays should be of a nonperforated variety that holds the impression material in problems are detected during the examination and denitive analysis or if treatment is required. ese study casts can be conventional stone casts (Fig. 31.33) or digital representations of stone casts. In the former case, impressions are obtained using the following method.• Figure 31.31 Digital images of pretreatment and posttreatment extraoral and intraoral views of orth-odontic patients can be stored electronically in the patient record or printed as a hard copy. This method circumvents the problems of losing images to either poor photographic technique or ling methods. • Figure 31.32 These three additional views are often obtained to evaluate facial esthetics and relation-ships. (A) The three-quarter view with lips relaxed. (B) The three-quarter view with a posed smile. (C) The lateral view with a posed smile. CHAPTER 31 Examination, Diagnosis, and Treatment Planning 437 problems. ey can also be manipulated to view all relationships for analysis and imported to the patient’s record as static images for electronic archiving or printing (Fig. 31.34). e digital casts also can be analyzed and measured like conventional casts (Fig. 31.35). Findings recorded during the clinical examination are reviewed and conrmed using the casts. Alignment and tooth position characteristics should receive special attention because appliance design must be appropriate for each rotation and displacement.Advances in technology continue to change diagnostic records in dentistry. Intraoral scanners have been developed to construct a model of the teeth without making an impression. e scanner creates a three-dimensional (3D) reconstruction of the teeth and is as accurate as the traditional alginate impression. As this technol-ogy continues to improve, its use may surpass the traditional impression because patients do not like traditional impressions, mostly because of gagging issues. In addition to intraoral scanning of teeth, some are using the information gathered from a 3D cone beam scan to construct a model of the teeth. ere is some question if the reconstructions from cone beam computerized tomography are as accurate as intraoral scanning and traditional impressions.39 In general, they are probably accurate enough for diagnostic purposes but not appliance construction.After the diagnostic casts are obtained, analyses should be performed to determine tooth size relationships and arch length adequacy. e tooth size analysis compares the size of the teeth in one arch with the size of the teeth in the other. Tooth size must be compatible to ensure that teeth t together correctly after treatment. e arch length analysis is done to predict whether there is sucient space available in the dental arch for the unerupted permanent teeth.Tooth Size Analysise tooth size is calculated using Bolton’s method.40 Bolton selected 55 cases of excellent occlusion and measured the mesiodistal diameter of all teeth on the casts except for the permanent second and third molars. From the measurements obtained, Bolton determined that a certain ratio existed between the size of the upper and lower permanent teeth. A ratio could be determined for either the 6 anterior teeth or all 12 of the measured teeth in each arch by measuring the teeth manually (Fig. 31.36). Little constructed a table based on the Bolton ratios to simplify tooth size determinations (Fig. 31.37).14 is analysis can be performed using the digital casts and the associated software (Fig. 31.38). the tray and expresses the excess material into the vestibule. Some semiperforated trays are now in use, but they must generate enough tissue pressure to reect the tissue. When the soft tissue is displaced, it allows the dentoalveolar morphology to be clearly viewed on the cast. e trays also can be lined with wax that aids in tissue displacement and makes seating the tray into position more comfortable.After the appropriate tray has been selected, the alginate is mixed and placed in one tray. For either arch, the tray should be rotated laterally into the mouth and rmly seated, rst posteriorly against the palate or the retromolar pad. is technique limits the posterior ow of alginate and forces excess alginate anteriorly and laterally. e tray is then rotated and seated over the anterior teeth. Finally, the tray is held in place until the alginate has set. After the upper and lower impressions are obtained, a wax bite is made by placing a softened piece of base plate or other wax bite material between the teeth, having the patient close in centric occlusion. e wax is cooled with air and serves to orient the casts properly during trimming.Impressions should be disinfected, wrapped in moist paper towels, and stored in sealed plastic bags or poured soon in white plaster because the alginate will dehydrate and distort if it is left exposed for more than a few minutes. e plaster is thoroughly mixed, usually using a vacuum spatulator to reduce bubbles, and then vibrated into the impression and owed from one tooth to another to prevent air entrapment, which results in holes in the models. Separate plaster bases are poured, and the impressions are inverted on the bases when the plaster is partially set. After the plaster has set, the trays are separated carefully from the casts to prevent breaking the teeth.e maxillary cast is trimmed so that the top of the base is parallel to the occlusal plane. e back of the upper cast is trimmed perpendicular to its top and the midpalatal raphe. e maxillary and mandibular casts are occluded, and the back of the mandibular base is trimmed parallel to the top of the maxillary cast. Finally, the sides of the casts are trimmed symmetrically, which allows the clinician to judge arch symmetry.Alternatively for digital casts, impressions are obtained in a similar manner, but with a long-term stable alginate. e impressions are disinfected, wrapped in moist towels, bagged in plastic, and shipped to a commercial laboratory for pouring, and the resulting models are scanned. A digital representation of the casts is transmit-ted to the practitioner via the Internet. ese digital images are less likely to be misplaced or broken and present no storage • Figure 31.33 Views of plaster casts that have been trimmed so that the backs are ush in centric occlusion and the bases are trimmed symmetrically from the occlusal view so the intra-arch asymmetries are obvious. 438 Part 4 The Transitional Years: Six to Twelve Years• Figure 31.35 The digital casts can also be manipulated to examine relationships and measured electronically like conventional plaster casts so that arch dimensions can be evaluated. (Courtesy OrthoCAD by Cadent, Inc, San Yosa, CA.)• Figure 31.36 To complete the tooth size analysis developed by Bolton, the mesiodistal width of each permanent tooth (except for second and third molars) is measured with a Boley gauge or a needle-pointed divider. The measurements are added together to provide totals for the six anterior teeth and for the overall arch. • Figure 31.34 Digital casts can be displayed from the web or stored in image management software. The digital casts can be manipulated so that the casts can be separated or occluded and rotated or tipped to reveal all relationships. This prevents problems with loss and breakage of the casts and reduces the store space problems. (From Proft WR, Fields HW, Sarver DM. Contemporary Orthodontics. 5th ed. St Louis: Elsevier; 2013.) CHAPTER 31 Examination, Diagnosis, and Treatment Planning 439 maxillary arch; see Fig. 31.14A). e size of the second premolar also varies highly. When signicant tooth size discrepancies are discovered, the child is best referred to a specialist because simple tooth movement does not produce an esthetically satisfactory result or good occlusion. Management of tooth size discrepancies often requires a combination of tooth movement and restorative dentistry.Ultimately, when tooth size problems are complex, diagnostic setups are required to determine which teeth should be positioned in specic orientations so that nal diagnostic decisions can be made. Several clinical situations contribute to tooth size discrepancy. Maxillary lateral incisors are commonly smaller than normal, result-ing in a mandibular anterior tooth size excess (relatively speaking, the lower teeth are too large even though the problem is in the Continued040.030.931.331.732.032.432.833.233.634.034.434.735.135.535.936.336.737.137.437.838.238.639.039.439.840.140.540.9Mandibular Anterior ExcessMaxillary Anterior Excess41.341.742.142.540.541.041.542.543.544.5BOLTON ANALYSIS45.546.547.548.549.550.551.552.553.554.542.043.044.045.046.047.048.049.050.051.052.053.054.055.00.40.81.11.51.51.5 0.8 0 1.0 2.0 3.0 4.0 5.0 6.0 7.01.91.9 1.1 0.4 0.5 1.5 2.5 3.5 4.5 5.5 6.52.32.5 3.52.72.74.65.0 4.2 3.5 2.7 1.9 1.1 0.4 0.5 1.5 2.5 3.51.5 2.5 3.54.5 5.5 6.53.8 3.1 2.3 1.5 0.801.0 2.0 3.0 4.0 5.0 6.0 7.03.13.53.64.24.65.05.45.86.26.56.96.96.5 5.8 5.0 4.2 3.5 2.7 1.9 1.1 0.46.5 5.8 5.0 4.2 3.5 2.7 1.9 1.1 0.40.56.2 5.4 4.6 3.6 3.1 2.3 1.5 0.8 06.9 6.2 5.4 4.6 3.6 3.1 2.3 1.5 0.8 01.01.02.0 3.0 4.01.00.52.0 3.0 4.04.5 5.5 6.55.0 6.0 7.0• Figure 31.37 To use the table, the mesiodistal width of each permanent tooth (permanent rst molar to permanent rst molar) is measured with a needle-pointed divider or sharp Boley gauge. The widths of the teeth are summed. To determine whether there is an anterior (canine to canine) or overall (molar to molar) tooth size discrepancy, the intersection of the maxillary and mandibular totals is located on the appropriate table. (A) The width of the mandibular anterior teeth is indicated on the vertical axis, and the width of the maxillary anterior teeth is found on the horizontal axis. The intersection indicates whether a tooth size discrepancy exists and whether it is a maxillary or mandibular excess, and it indicates the size of the discrepancy in millimeters. Because there is some error in measuring the casts and some error in the analysis itself, tooth size discrepancies of 1.5 mm or less are not considered signicant. 440 Part 4 The Transitional Years: Six to Twelve Yearsstudies is northwestern European. If the patient is not of northwestern European descent, the analysis should be inter-preted with some caution.4. Arch dimensions remain stable throughout growth. is assumption is made to simplify the procedure, although it is recognized that the intercanine width, intermolar width, and arch length dimensions do change with age and eruption of teeth. Skeletal growth patterns may also aect arch dimension stability. Patients with class II mandibular deciency tend to have proclined mandibular incisors to compensate for the deciency, whereas those with class III deciency tend to have more upright or retroclined mandibular incisors.Although several methods of space analysis exist, the Tanaka-Johnston analysis is most clinically useful because it requires no additional radiographs or tables to predict tooth size.41 e rst step in the Tanaka-Johnston analysis is to determine the available arch length. e distance from the mesial of the permanent rst molar to the mesial of the contralateral permanent rst molar is measured by dividing the arch into several segments (Fig. 31.39A). Each segment is measured over the contact points and incisal edges of Space Analysise space analysis is normally completed in the mixed dentition and is used to predict the amount of space available for the unerupted permanent teeth. A number of dierent methods of space analysis exist; however, all space analyses have two features in common. First, the permanent rst molars and the mandibular incisors must be erupted to allow one to perform the analysis. Second, the mandibular incisors (sometimes in addition to other measurements) are used to predict the size of the unerupted canines and premolars. e following four assumptions are made in calculat-ing a space analysis:1. All permanent teeth are developing normally. Although this seems obvious, the analysis is meaningless if teeth are congenitally missing.2. ere is a correlation between the size of the erupted mandibular incisors and the remaining permanent teeth. e prediction of unerupted tooth size is more accurate if the correlation is strong.3. e prediction tables are most valid for a specic population. e ethnic background of the patients used in most space analysis BOLTON ANALYSISMaxillary Overall ExcessMandibular Overall Excess8577.6 0 2.01.03.66.4 4.6 2.7 0.91.8 0 2.0 4.0 6.0 8.0 10.03.65.47.39.110.11.8 0 2.0 4.0 6.0 8.0 10.03.65.47.39.1 1.8 0 2.0 4.03.0 5.0 7.0 9.01.0 3.0 5.0 7.0 9.04.0 6.0 8.0 10.00.91.82.73.64.65.46.47.38.26.4 4.6 2.7 0.9 1.0 3.0 5.0 7.0 9.08.210.1 6.4 4.6 2.7 0.9 1.08.29.110.178.579.480.381.382.183.184.084.985.886.787.688.689.590.491.392.293.194.095.095.996.897.898.699.6100.4868788899091929394959697989985101102103104105106107108109110(B) This table provides the same information for overall tooth size relationships. (Courtesy Dr. Robert Little. From Proft WR, Fields HW Jr, eds. Contemporary Orthodontics. St Louis: Mosby; 1992.)• Figure 31.37, cont’d CHAPTER 31 Examination, Diagnosis, and Treatment Planning 441 • Figure 31.38 The tooth size analysis can be completed on conventional casts or electronically using digital casts. This screen capture shows that the teeth have been measured electronically using the cursor and mouse and then the analysis calculations performed by the software. (From Proft WR, Fields HW, Sarver DM. Contemporary Orthodontics. 5th ed. St Louis: Elsevier; 2013.)ABCDSum of incisors210.5 mmPredicted width of canineand two premolar in onemandibular quadrantTotal archlenghtSum ofincisors2 (predictedwidth)Availablearch length=––=+• Figure 31.39 (A) The rst step in the Tanaka-Johnston space analysis is to determine available arch length. This is accomplished by dividing the arch into several segments and measuring each segment over the contact points and incisal edges of the teeth. (B) The second step is to measure the width of the four mandibular incisors and add them together. (C) The mesiodistal width of the unerupted canine and premolars in one quadrant is calculated by using the previous formula. In the mandibular arch, 10.5 mm is used to determine the canine-premolar widths. In the maxillary arch, half the sum of the mandibular incisors is still used, but 11.0 mm is substituted for 10.5 mm because the unerupted perma-nent maxillary teeth are slightly larger. (D) The nal step in the analysis is to subtract the width of the four incisors and the predicted canine-premolar width from the total arch length. The remainder is the available arch length. If the remainder is positive, there is adequate space in the arch. If the remainder is negative, the permanent teeth require more room to erupt than is available in the arch. 442 Part 4 The Transitional Years: Six to Twelve Years• Figure 31.40 The software packages that support the digital casts provide for several methods of space analysis. Again, using the tooth dimensions measured from the casts, the analyses are calculated. The accuracy of the result is contingent on careful management of the cursor for tooth measurement and how the arch dimensions are dened by the arch form, which is shown here as the overlying arc on each arch. (From Proft WR, Fields HW, Sarver DM. Contemporary Orthodontics. 5th ed. St Louis: Elsevier; 2013.)the teeth. e segments are added together to provide an approxi-mation of total arch length. e second step in the analysis is measurement of the width of the four mandibular incisors (see Fig. 31.39B). e widths of the four incisors are added together to determine the amount of room necessary for ideal alignment. e mesiodistal width of the unerupted mandibular canine and premolars in one quadrant is predicted by adding 10.5 mm to half the width of the four lower incisors (see Fig. 31.39C). e nal step in the space analysis is to subtract the width of the lower incisors and two times the calculated premolar and canine width (both sides) from the total arch length approximation (see Fig. 31.39D). If the result is positive, there is more space available in the arch than is needed for the unerupted teeth. If the result is negative, the unerupted teeth require more space than is available to erupt in ideal alignment.e maxillary space analysis is conducted in the same way. Maxillary arch length is measured, the width of the maxillary incisors is determined, and 11.0 mm is added to half the width of the four lower incisors to predict the size of the unerupted maxillary canine and premolars in one quadrant. e incisor width and the predicted canine-premolar width are subtracted from the total arch length to determine the amount of space available in the maxillary arch. is analysis also can be performed using the digital casts and the associated software (Fig. 31.40).After the arch length predictions are made, the clinician should return to the cast and decide whether the results make sense. For example, if the arch appears to be crowded and the analysis predicts 5 mm of excess space, the analysis should be repeated or scrutinized for mistakes. Furthermore, the results should be considered in the context of the patient’s soft tissue profile. e space analysis may indicate that the patient is moderately short of space, yet because he or she has very retrusive lips and incisors, the treatment of choice would be to expand the arch by moving the incisors facially to provide better lip support (Fig. 31.41). Conversely, an analysis may predict that there is no crowding, yet extractions are considered necessary because the patient has very protrusive teeth and lips (Fig. 31.42). Dental protrusion and dental crowding are actu-ally manifestations of the same problem. Whether the arch is crowded or the incisors are protrusive depends on the interaction between the pressure of the resting tongue and the circumoral musculature.Two factors must be considered when using the Tanaka-Johnston analysis. It tends to overpredict slightly the width of the unerupted teeth. is makes the extent of crowding appear more severe than it actually is. In addition, if the patient is not of northwestern European background, it is dicult to know whether the prediction is overstated or understated. An alternative method for determining available space is to measure arch length and incisor width as noted previously and then obtain periapical radiographs of the canines and premolars. e mesiodistal widths of the unerupted teeth are measured on the periapical films and then corrected for CHAPTER 31 Examination, Diagnosis, and Treatment Planning 443 BA• Figure 31.41 The results of the space analysis (A) are considered in the context of the patient’s soft tissue prole. In this example, the space analysis indicates that the arch length is short. The prole analysis (B), however, indicates that the patient cannot tolerate further loss of lip support. It is more prudent in this case to expand the arch than to extract teeth to provide additional space. A B• Figure 31.42 In this example, the space analysis (A) indicates that there is no shortage of arch length. The prole analysis (B), however, indicates that the patient has extremely protrusive lips and incisors. It is more prudent to extract teeth and retract the incisors and lips in this case. This gure illustrates the fact that dental crowding and dental protrusion are actually manifestations of the same problem. magnication by comparing the width of erupted teeth on the lms with the actual width of these teeth on the cast. With this technique, an individual space analysis can be performed for every patient. e disadvantages of this technique are that the patient is exposed to more radiation, and undistorted radiographs of the canines are dicult to obtain.Analysis of Cephalometric Head Filmse facial prole analysis should be used by the clinician to gather basic information about the spatial relationships of the teeth and jaws. If the clinician identies signicant anteroposterior or vertical discrepancies, the patient should be evaluated by a specialist. At 444 Part 4 The Transitional Years: Six to Twelve Yearswords, the patient’s head should not be tipped up or down or to one side or the other. Incorrect positioning alters the perceived relationship of the skeletal structures and makes interpretation of the landmarks more dicult, even to the point of suspecting skeletal asymmetry. A mandibular deciency may not be apparent if the patient’s head is tipped upward. Natural head position is produced by having the patient look at the distant horizon and gradually assume a comfortable position by tipping the head up and down in smaller and smaller increments until he or she is comfortable. e teeth should be together in centric occlusion and the lips relaxed when the lm is exposed.After the head lm is made, the radiograph should be screened for pathologic ndings. Although cephalometric head lms can have points identied and measurements made by hand, currently, landmarks are located on a computer screen using a mouse and dedicated cephalometric software that can construct the tracing (Fig. 31.43). The software generates linear and angular that time, a lateral cephalometric radiograph may be used to obtain a more precise assessment of the problem. Analysis of lateral cephalometric head lms is an additional diagnostic aid used to determine the relationship between the skeletal and dental structures. e cephalometric head lm is normally ordered when signicant skeletal discrepancies exist and comprehensive orthodontic treatment is being considered. e cephalometric analysis is an adjunct to the facial prole analysis. It provides conrmation of the clinical examination and possibly more specic information about the contribution of each skeletal and dental component to the maloc-clusion. erefore it must be viewed carefully.42A large number of cephalometric analyses exist; however, the common goal of all analyses is to determine the size and position of the skeletal structures and the position of the teeth. e rst step in the cephalometric analysis is to obtain a diagnostic head film. For the radiograph to be diagnostic, the head must be positioned in a cephalostat in a natural, relaxed posture. In other • Figure 31.43 Current technology allows the clinician to digitize the critical points and have the mea-surements performed electronically by the software package (Dolphin Imaging and Management Solu-tions, Chatsworth, CA). This procedure can be performed with a personal computer and mouse using a digital radiographic image. The computer will provide various representations of traced landmarks and anatomy as well as lines and planes. CHAPTER 31 Examination, Diagnosis, and Treatment Planning 445 meatus (porion) with the inferior border of the orbital rim (orbitale; Fig. 31.45). Although the Frankfort horizontal plane is not always parallel to the true horizontal plane, it is still the most widely used horizontal reference line. e vertical reference line can be either a true perpendicular (to the horizon) through the nasion (the bony bridge of the nose) or a line perpendicular to the Frankfort plane through the nasion. e position and size of the maxilla and mandible are evaluated by comparing A point (maxilla) and pogonion (mandible), anterior points on these structures, to the vertical reference line. Normal maxillary position and size should place A point near the vertical line (Fig. 31.46).e pogonion is normally 5 mm behind the vertical plane with a well-positioned mandible in a preadolescent patient.43Angular and linear measurements can be used to compare the position of the maxilla with that of the mandible. e angle formed by connecting A and B points with nasion has traditionally been used to describe the position of the two jaws (Fig. 31.47). In normally related jaws, the angle is between 2 and 5 degrees. Larger positive values suggest a class II relationship, whereas negative values indicate class III tendencies. e dierence between the size of the lower and upper jaws, as determined from the Harvold measurements, can also be used to relate the jaws.44measurements, and a graphic image of the face constructed from the digitized landmarks provides the basis for the cephalometric analysis (Fig. 31.44). Depending on the sophistication of the program, the program can be used to simulate growth for the patient in yearly intervals or project treatment goals. In cases where there are multiple options for treatment, the software can dem-onstrate to patients how their face may change or look with each individual treatment.e analysis should evaluate the position of the maxilla and mandible in relation to that of the cranial base and the relationship of the maxilla and mandible to each other. Analysis also should evaluate the position of the teeth in each jaw and the relationship of the upper teeth to the lower teeth. Vertical relationships between total, upper, and lower facial heights of the anterior face should be determined. Finally, the analysis should evaluate the soft tissue prole and the position of the lips in relation to the teeth, nose, and chin. A cephalometric analysis requires two reference lines to orient the position of the teeth and jaws. Historically, the Frankfort horizontal plane has been used as the horizontal reference line because it was thought to be parallel to the true horizontal plane when the patient was looking at a distant point. e Frankfort horizontal plane connects the upper rim of the external auditory • Figure 31.44 Printouts of computer-generated cephalometric analyses often take a form similar to the ones illustrated here (Dolphin Imaging and Management Solutions, Chatsworth, CA). The resulting mea-surements can even be combined with a graphic image of the face. The content can be customized by altering the anatomic landmarks and measurements to provide those most useful to the individual clinician. 446 Part 4 The Transitional Years: Six to Twelve Yearsupper facial height should compose approximately 45% of the total facial height in a well-proportioned face.46 Vertical facial height can be indirectly determined from the mandibular plane angle (the angle between the mandibular plane and the Frankfort horizontal plane). A long-faced person tends to have a large mandibular plane angle, whereas a short-faced person has a smaller mandibular plane angle (Fig. 31.49).Vertical facial proportions can be measured in two ways. e most direct method of determining vertical proportions is to measure total, upper, and lower anterior facial heights and to construct facial height ratios or compare linear measurements with age-appropriate norms.44,45 Total facial height is normally measured from nasion to menton. e division between the upper and lower facial heights is made at the anterior nasal spine (Fig. 31.48). e Frankforthorizontal• Figure 31.45 Cephalometric analysis requires two reference lines to orient the position of the head and teeth. Historically, the Frankfort hori-zontal plane has been used as the reference line because it is felt to be parallel to the true horizontal when the patient is looking at the horizon. The Frankfort horizontal plane is constructed by connecting the upper rim of the external auditory meatus (porion) with the inferior border of the orbital rim (orbitale). The vertical reference line is either a true perpendicular line to the nasion, the bony bridge of the nose, or a line perpendicular to the Frankfort plane through the nasion. True horizontalTrueverticalpointPogonionA• Figure 31.46 The position and size of the maxilla and mandible are evaluated by comparing the A point (maxilla) and pogonion (mandible) with a vertical reference line. In a well-positioned maxilla, the A point is located near the vertical reference line. The pogonion is normally 5 mm behind the vertical line in a properly positioned mandible. A pointB pointANB angle• Figure 31.47 The relative positions of the maxilla and mandible are also compared by using an angular measurement. In normally related jaws, the angle formed by connecting A and B points with nasion (ANB) is between 2 and 5 degrees. Larger positive values suggest a class II relationship, whereas negative values indicate a class III tendency. NasionUpperfacialheightPalatal planeTotalfacialheightLowerfacialheightMenton• Figure 31.48 Vertical facial proportions are determined by measuring total, upper, and lower facial heights. Total facial height is normally mea-sured from the nasion to the menton. The division between upper and lower facial height is made at the palatal plane (a line connecting the anterior and posterior nasal spines). The measurements are used to con-struct facial height relations or are compared with age-appropriate norms. CHAPTER 31 Examination, Diagnosis, and Treatment Planning 447 Nevertheless, lip position is usually compared with the nose and chin. e Ricketts E line, which is convenient to use, is a line connecting the tip of the nose with the anterior contour of the chin (Fig. 31.52). In the permanent dentition, the upper lip is normally 1 mm behind the line and the lower lip is on the line or slightly behind it.48It is important to realize that the numbers derived as norms serve as references and not as the diagnosis itself. Certain measure-ments may suggest a discrepancy, and this should be veried by the clinical examination. e clinician also should remember that hard and soft tissue analyses vary according to the ethnic background of the patient. Appropriate analyses and standards should be used. Serial cephalometric radiographs obtained before treatment, before and during treatment, or before and after treatment are often useful for evaluating growth, treatment progress, or treatment result, respectively.Serial cephalometric head lms can be superimposed to illustrate changes in jaw and tooth positions. e observed changes are a combination of tooth movement and growth, and it is dicult to dierentiate one from the other. To superimpose head lms, one must locate an area in the head that is relatively unchanged over the time period in question—that is, an area that is not aected by growth or treatment from which change can be determined. Traditionally, three superimpositions are made with each pair of serial cephalometric radiographs when growth and treatment changes are being evaluated.e rst superimposition illustrates overall changes in the face. e comparison is made by superimposing the structures of the anterior cranial base or along the sella-nasion line register-ing at the sella. e amount and direction of change in the soft tissue prole and position of the jaws are readily apparent (Fig. 31.53A). To demonstrate the amount and direction of dental change, structures of the maxilla and mandible are superimposed to eliminate all skeletal change from the evaluation (see Fig. 31.53B and C). In the maxilla, the zygomatic process and anterior palatal vault are superimposed to nd the best t. In the mandible, the inner surface of the mandibular symphysis, the outline of Maxillary and mandibular dental position is evaluated by measuring overjet, overbite, and the axial and bodily position of the incisors. Overjet and overbite are simple measurements taken from the facial surfaces and incisal edges of the incisors, respectively (Fig. 31.50). e axial and bodily position of the maxillary incisor is determined relative to the nasion–A point line; the mandibular incisor position is related to the nasion–B point line. Axial inclina-tion is determined from the angle formed by the intersection of the long axis of the incisor with the appropriate nasion–A point or nasion–B point lines. Bodily position is a measure of linear distance from the facial surface of the incisor to the reference line (Fig. 31.51).47A number of soft tissue analyses exist to describe the facial prole. e major problem with soft tissue analysis is that the head lm is a static representation of a dynamic object. Lip position may be dierent on the head lm depending on whether the patient was in a relaxed posture (as recommended) or was straining to put the lips together when the lm was made. is makes clinical assessment of the profile all the more important. Frankfort horizontalMandibularplaneFrankfort horizontalMandibular plane• Figure 31.49 (A) Vertical facial height is determined indirectly from the mandibular plane angle (the angle between the mandibular plane and the Frankfort horizontal plane). This angle is usually approximately 24 degrees. A large mandibular plane angle is normally indicative of a long lower facial height. (B) Conversely, a small mandibular plane angle is indicative of a short lower facial height. OBOJ• Figure 31.50 The position of the maxillary and mandibular incisors and indirectly the entire dentition is evaluated by measuring the overjet and overbite. Overjet (OJ) is a horizontal measure of the distance between the most anterior points on the facial surfaces of the maxillary and mandibular central incisors. Overbite (OB) is a vertical measure of the overlap between the incisal edges of the maxillary and mandibular incisors. 448 Part 4 The Transitional Years: Six to Twelve Yearsimage produced from the radiographic scan allows the clinician to study the area of interest from multiple vantage points. Computer software can render the image in three dimensions so the patient and clinician can better understand the spatial relationships of the teeth and skeletal structures. ere are several advantages of CBCT. For example, if a maxillary canine is impacted, traditional panoramic and cephalometric lms yield information in two dimensions of a 3D situation. e clinician has historically gathered additional information from periapical radiographs, yet there is still some guesswork of where the canine is positioned. e cone beam scan can give the clinician precise information on the position of the impacted canine, its angulation, its proximity to other teeth, possible resorption of teeth, and the amount of bone surrounding the tooth. is allows the orthodontist and the surgeon to make a more detailed plan regarding the status of the impacted or ectopic tooth and the adjacent teeth. is can be translated into a surgical and orthodontic plan (Fig. 31.54). e main disadvantage of the cone beam scan is the amount of radiation the patient is exposed to compared with a traditional radiographic exam. However, this may change as the technology is improved and the scan time is reduced. A method to address this issue currently is to obtain truncated maxillary views (smaller elds of view) to reduce radiation, assuming this is the only area of interest (Fig. 31.55). Advocates of CBCT also point out that the traditional exam materials can be created out of the data set gathered from the scan. ese exam materials include a cephalometric radiograph, a panoramic radio-graph, and a virtual set of orthodontic models. Depending on the views and the specic machine and requested resolution, full scans may exceed truncated scans supplemented with traditional digital images, as mentioned earlier.the mandibular canal, and the unerupted third molar crypts are superimposed.CBCT is a relatively new technology that may replace the lateral cephalogram in the future or at least supplement the information gained from the cephalogram and the panoramic radiograph. e NasionNasionAngularmeasurementA pointB pointLinear measureNA line toincisorLinear measureNB line toincisor• Figure 31.51 (A) The axial and bodily positions of the maxillary incisor are determined by making angular and linear measurements. Axial position is determined by drawing an angle formed by the intersection of the long axis of the incisor with the nasion–A (NA) point line. A large angle (more than approximately 22 degrees) suggests that the incisor is axially protrusive; a small angle suggests that the incisor is upright. The bodily position of the incisor is determined by measuring the linear distance between the facial surface of the incisor and the nasion–A point line. On the average, this distance is 4 mm. A large measurement suggests that the incisor is positioned too far anteriorly, whereas a small or negative measurement indicates that the incisor is positioned too far posteriorly in relation to the maxilla. (B) The position of the mandibular incisor is similarly evaluated, although the nasion–B (NB) point line is used as a reference line. For these measurements, the average inclination is 25 degrees and the average linear distance is 4 mm. • Figure 31.52 The Ricketts E line is a convenient reference line used to assess the position of the lips in relation to the nose and chin. In the permanent dentition, the upper lip is normally 1 mm behind a line con-necting the tip of the nose to the anterior contour of the chin. The lower lip is usually on or slightly behind this line. CHAPTER 31 Examination, Diagnosis, and Treatment Planning 449 If the canines cannot be palpated on the facial aspect of the alveolus at approximately 10 years of age, labial or palatal positioning of the canine is best determined using the panoramic radiograph to determine whether any of the other associated conditions are also present. e rst step in determining the position of the canine is to closely examine the panoramic lm and compare the size of the right and left canines. Similar to using a ashlight to create a shadow, the closer the object is to the light source (or radiation source), the larger the shadow cast. As the object moves away from the light source, the shadow is smaller. e panoramic beam comes from behind the head, so a palatal positioned canine is closer to the beam and will appear larger than the other canine on the panoramic lm. Because of the rendering of a 3D object on a 2D lm, this technique can still leave question as to the position of the canine.To make detailed determinations regarding the position of the canines, other images may also be necessary. If orthodontic treatment is being considered and a cephalometric head lm has been obtained, one may look at the cephalo-metric head lm to determine the anteroposterior position of the canine. However, a truncated CBCT lm may be the simplest and most decisive lm used to supplement the panoramic radiograph (see Fig. 31.55).CBCT has become an important imaging tool in dentistry. e use of CBCT imaging in the pediatric dental patient Radiographic EvaluationTransition into the mixed dentition requires modication of the basic pediatric survey. Some considerations for radiographs of children in this period are the following.1. Identication of missing teeth, supernumerary teeth, and the developmental status of permanent anteriors and premolars require greater periapical coverage on lms. e maxillary lateral incisors should be evident early in this period. e permanent second premolars are usually evident on radiographs at age 4 years, but they may not be apparent until age 8 years.2. Absence of erupted maxillary lateral incisors that are of normal size and shape should be apparent early. If not, they should be conrmed with a panoramic radiograph. e reason for this approach is that the missing or peg-shaped lateral incisors are also associated with missing second premolars, distally erupting mandibular canines, palatally erupting maxillary canines, and transpositions of the canines and adjacent teeth.3. Potential eruption problems may be diagnosed from the radiographs by study of the unerupted teeth. Ectopic eruption of permanent rst molars has been discussed and is diagnosed from routine bitewing radiographs. Ectopic eruption of incisors and canine impaction, which are other maxillary eruption problems, are often diagnosed from panoramic radiographs but can be erroneously evaluated in this manner if only a panoramic radiograph is used (Fig. 31.56).16,49AC B• Figure 31.53 (A) Serial cephalometric head lms are superimposed to illustrate changes in jaw and tooth positions during growth and orthodontic treatment. To assess overall change, a stable area within the head that is not inuenced by growth or treatment is located. These overall changes in the face are illustrated by superimposing them on structures of the anterior cranial base. In this case, the solid line represents the patient before orthodontic treatment was initiated. The second or dashed line represents the patient after treatment was completed. During treatment, the maxilla moved slightly forward and downward. The horizontal position of the mandible remained virtually unchanged. However, the mandible did move vertically. The position of the lips improved during the treatment period as well. (B) To illustrate the amount and direction of dental change, structures in the maxilla and mandible are superimposed. In this case, the maxillary superimposition, based on a best t of palatal morphologic appearance, shows that the incisor and molar were both tipped distally. In addition, there was a change in the vertical position of the incisor. The change in incisor and molar position contributed to an improvement in molar relation-ships and overjet reduction. (C) The mandibular superimposition, made by overlaying the inner aspect of the mandibular symphysis, the canal of the inferior alveolar nerve, and the unerupted third molar crypt, shows that both the incisor and molar erupted vertically. 450 Part 4 The Transitional Years: Six to Twelve Yearsalso determine the location and morphology of the fracture. Guidelines suggest that standard periapical and occlusal radiographs are sucient for most cases, but as radiation exposure decreases, CBCT may become the standard technique. Images obtained shortly after trauma are used to assess the extent of the trauma and help determine the proper treatment. After the traumatic incident, CBCT imaging provides a tool to measure the eectiveness of the initial treatment and the current state of healing.CBCT is also used to assess the volume of the airway in children with obstructive sleep apnea and other airway issues. Currently there is signicant interest in this area to see if CBCT is a reliable screening, diagnostic, and treatment assessment tool. At this time, there is not sucient evidence to provide a denitive answer.is very limited until patients begin to transition into per-manent dentition. CBCT becomes more important in this age group. ere has been debate on how much or how often this technique should be used. e debate has not been about the information gained but the amount of radiation needed to image the patient. Dierent machines expose the patient to varying amounts of radiation.50 Newer machines have been introduced that not only reduce the amount of radiation needed to obtain an image but are also able to limit the size of the eld to the area of interest so the radiation is diminished even further.CBCT imaging is beginning to be used to assess the health of teeth, supporting structures, and temporomandibular joints (TMJs) after dental trauma. e image can establish not only if tooth and bone are intact or fractured but can BARLC• Figure 31.54 (A) A conventional panoramic reconstruction showing the ectopic eruption of the maxil-lary right canine. The root morphology of the maxillary right lateral and central incisors also looks suspi-cious. (B) Three-dimensional reconstruction of the patient from a small eld of view cone beam computed tomography reveals that the canine is superior to the lateral and central incisors. (C) This view demon-strates the root resorption of the central incisor.

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