10-210524031745 Surgical treatment objective .pptx

SURGICAL TREATMENT
OBJECTIVES (STO)
DR. SHEHNAZ JAHANGIR
FINAL YEAR MDS
DEPT. OF ORTHODONTICS & DENTOFACIAL
ORTHOPAEDICS
NOORUL ISLAM COLLEGE OF DENTAL SCIENCE

CONTENTS
• INTRODUCTION
• DEFINITION
• METHODS
▫ CEPHALOMETRIC PREDICTION
 MANUAL METHOD
 COMPUTERIZED METHOD
 SOFTWARES
 VIDEO IMAGING
 3D PREDICTION METHODS
 STEREOLITHOGRAPHY

• THE INITIA STO
▫ PRE SURGICAL ORTHODONTIC GOALS
 INITIAL
 FINAL
 SURGICAL GOALS
 SINGLE JAW STO
 MANDIBLE
 MAXILLA
 DOUBLE JAW STO
 MANDIBLE
 MAXILLA
 CHIN STO
 AP HIN POSITION
 VERTICAL CHIN POSITION

• THE FINAL STO
▫ MAND. ADVANCEMENT
▫ MAXILLARY SUPERIOR REPOSITIONING
▫ COMBINED MAX. AND MAND CASES
▫ SOFT TISSUE PREDICTION
 MAND. PROCEDURES
 MAX. PROCEDURES
 CHIN PROCEDURES
 CONCLUSION
 REFERENCES

INTRODUCTION
• Orthognathic surgery involves the surgical
manipulation of the elements of the facial skeleton to
restore the proper anatomic and functional
relationship in patients with dentofacial skeletal
anomalies.
▫ The word Orthognathic comes from the Greek word,
“Orthos” meaning to straighten, and “ Gnathos”
meaning jaw.
• Orthognathic surgery thus means to straighten a jaw.

• Over the past decade a growing number of adult
patients are seeking orthodontic treatment.
• A noteworthy part of the adult population
reporting for orthodontic treatment is associated
with severe skeletal discrepancy.
• Correction of such skeletal discrepancy in adults
cannot be achieved by growth modification
procedures, as the patient is no longer growing.

• This necessitates surgical repositioning of one or
both the jaws and or the dento-alveolar
segments.
• The goals of surgical management of
malocclusion therefore should include structural
integrity, functional balance and esthetic
harmony.

• The prediction of orthognathic treatment
outcome is an important part of orthognathic
planning and the process of patient’s inform
consent.
• Cephalometric prediction plays an important
role in orthognathic surgery by increasing
patient understanding and acceptance of the
recommended treatment.

• In planning objectives for orthognathic
surgery, predicting surgical outcomes by surgical
treatment objective (STO) is mandatory.
• It is a vital tool for assessment, communication
and patient education. STO helps the
orthodontist in assessing the goals of pre
surgical orthodontics.
• For the surgeon, it helps in deciphering the
surgical sequence.

• As for the patient, his perception of esthetics
should be disregarded with prime importance,
for which a visual aid to show the surgical
outcome is mandatory.
• Therefore, the determination of the final surgical
outcome should be compiled by predicting the
results of a series of feasible treatment options.

• There are five general methods of visualizing,
planning, and predicting surgical orthodontic
outcomes:
1. Manual acetate tracing.
2. Manipulation of patient photographs to
illustrate treatment goals.
3. Computerized diagnostic and planning
software that produces a soft tissue profile
"line drawing"; as a result of manipulation of
digitized structures of lateral cephalometric
radiographs.

4. Computerized diagnostic and planning
software that integrates video images with the
patient's lateral cephalogram to aid in planning
and predicting surgical orthodontic procedures
(Video cephalometrics).
5. Three-dimensional computer technology for
planning and predicting orthognathic surgery.

SURGICAL TREATMENT OBJECTIVE
• Surgical treatment objective or prediction
tracing is a two dimensional projection of the
osseous, dental and soft tissue changes resulting
from surgical orthodontic correction of
orthodontic and orthopaedic deformities.
• Bell, Profitt, and White proposed the use of
cephalometric prediction using templates.
Wolford LM, Hilliard FW, Dugan DJ. Surgical
Treatment Objective. 1985.

The purposes of the S.T.O. are threefold:-
• To establish orthodontic and presurgical
orthodontic goals.
• To develop surgical objectives
• To create the predicted facial profile

The S.T.O. has significant importance in two phases of treatment
planning.
• The initial S.T.O. It is prepared before
treatment to determine orthodontic and surgical
goals.
• The final S.T.O. It can be prepared after initial
S.T.O using the pre-treatment cephalogram or it
can be prepared after active orthodontic treatment
and before surgery to determine the exact vertical
and antero-posterior changes to be achieved.

Before performing the S.T.O. presurgical orthodontic goals must
be established by,
• Clinical examination
• Dental model evaluation
• Cephalometric analysis.

CEPHALOMETRIC PREDICTION
• Currently, there are three methods for
cephalometric analysis: hand tracing and direct
measurement of the desired angles and distances
with the use of a protractor and ruler,
• and direct and indirect computer digitization of
the radiograph.

• For direct computer digitization the anatomical
points are entered from the cephalometric
radiograph into computer memory using an
electronic pen or the crosshair cursor.
• For indirect digitization, a scanner or a video
camera captures an image of the radiograph and
stores it in the computer. The video camera is
calibrated in co-ordination with the
cephalometric radiograph.

• Another method of cephalometric film entry into the
computer and analysis is the use of digital radiology.
• Computerized cephalometric analysis is rapid and
the clinician can run as many analyses as the
computer program allows arriving at a diagnosis.
• Cephalometric prediction in orthognathic surgery
can be performed, as well, manually or by computer.
• Several methods of prediction have been suggested.

MANUAL METHODS
• Traditionally, acetate tracings have been used for
cephalometric determination of the movement
of hard tissue and the prediction of the response
of the soft tissue to those movements.
• Historically, the first method to determine the
amount of posterior movement of the mandible
needed to produce satisfactory facial esthetics
following mandibular surgery was described by
Cohen.

COHEN
• A tracing of the maxilla, maxillary teeth, mandible,
mandibular teeth, and soft tissue profile was made
from the original cephalogram.
• A divider was used to record the posterior
movement of the mandible.
• A regional tracing of the lower face alone including
only the mandible and mandibular teeth as well as
the soft tissue outline of the upper throat, chin,
and lower lip was made and cut-out.

• This cut-out section was moved distally along
the plane of occlusion following the amount of
posterior movement of the mandible recorded
with the divider.
• The soft tissue changes were then inspected.
• The cut-out section is outlined in a different
colour than the original tracing and thus it was
easier to visualize the soft tissue changes.

McNeill et al.
• Another cephalometric prediction technique for
the soft tissue profile after surgical repositioning
of the mandible has been proposed by McNeill et
al. including the following steps:
• (a) Use of dental casts to establish the tentative
post-treatment dental relationship. This could be
done easily by using an articulator on which the
casts could be mounted. Sometimes a diagnostic
set-up before repositioning of the casts was
necessary.

• (b) Construction of an overlay cephalometric
tracing that included the outlines of the hard and
soft tissues, which would not be affected during
treatment.
• (c) Sliding of the overlay tracing until the parts
that are to be changed in the treatment,
duplicate their desired position as shown on the
pre oriented casts. Molar and incisor
relationships on the casts serve as guides for
correct overlay positioning.

• The preferable skeletal relationship is traced in a
different colour, on the overlay.
• (d) Completion of the prediction tracing by
adding soft tissue profile outlines. According to
this technique lip thickness will vary inversely
with changes in facial vertical dimension and
soft tissue chin thickness will not be affected by
treatment.

Hohl et al.
• A photo cephalometric technique for the prediction
and evaluation of skeletal and soft tissue changes
following dentofacial and craniofacial surgery was
advocated by Hohl et al.
• Lateral and frontal cephalograms and photographs
were taken. Photographic negatives were enlarged
allowing the photographic images to be
superimposed upon the radiopaque images on the
cephalograms.

• Transparent photographs were produced from
the projection of the enlarged negatives that can
be superimposed over the cephalometric films.
• By drawing the line from nasion to pogonion
onto the photograph, soft tissue measurements
could be made directly in vertical and horizontal
directions.
• This technique allowed detailed soft tissue
analysis in the lateral projection that was
difficult to obtain by standard cephalometric
techniques.

Fish and Epker
• Another method of surgical-orthodontic
cephalometric soft tissue prediction tracing for
mandibular advancement, maxillary superior
repositioning and combined maxillary and
mandibular surgery was proposed by Fish and
Epker.
• Their method was adapted in part from Ricketts’
cephalometric analysis, growth prediction and
visual treatment objective construction as
presented by Bench et al.

• The Frankfort horizontal and a perpendicular line
from nasion were drawn to indicate the optimum
facial depth as a guide to begin the prediction for
either mandibular advancement or set-back
surgery.
• The teeth were placed as described by Bench et al.
The change in lower incisor position was found and
marked by superimposing the mandible on corpus
axis at pterygo-maxillary fissure.
• The prediction tracing for maxillary superior
repositioning, auto-rotates the mandible clockwise
around the condyle.

Proffit.
• The use of cephalometric prediction to forecast
changes in bony relationships and associated soft
tissue changes has been also systematically
advocated by Proffit.
• According to the author, cephalometric prediction
can be done manually by moving templates or by
repositioning an overlay tracing of the patient’s
cephalogram.

• The template method should be used in any case where
vertical maxillary surgical movement is planned and it is very
useful when large dental movements are planned, as well as in
chin repositioning.
• It is not widely used because it is time-consuming. Typically,
this method is used in maxillary osteotomies and in double
surgeries (bi-maxillary surgery).
• In one- or two-piece osteotomies, the entire maxilla outline is
drawn.
• In three-piece osteotomies, the outlines of anterior and
posterior maxillary pieces, as well as two mandibular outlines
(extraction and non-extraction) are drawn. During the
prediction course, the mandible rotates around the condyle.

• The overlay method is the simplest prediction
method for mandibular osteotomies. Its use is
limited to surgeries that do not affect vertical
maxillary position and the method is not time
consuming.
• For this method there is no need for
intermediate tracings.
• Steps to be followed by using the overlay method
are:

• (a) The initial cephalogram is traced and the
surgical reference line is drawn.
• (b) All structures that will not be affected by the
mandibular osteotomy are traced on a second paper
placed over the original pre-surgical tracing, so
called the overlay tracing.
• (c) The overlay tracing is held stable and the
underlying pre-surgical tracing is moved backwards
until desired overjet, overbite and proper occlusion
are achieved. The mandible and lower teeth as well
as the surgical reference line are drawn.

• (d) The two tracings are superimposed on the
cranial base and the distance of mandibular incisor
backward movement is measured in mm. Data
regarding ratios of soft tissue changes relative to
respective skeletal movements is used to estimate
the predicted lower lip position relative to surgical
incisor movement. The distance between surgical
references line will be measured to determine the
surgical movement in mm.
• (e) Tracings are superimposed on the mandible
and lower lip outline and soft tissue chin are
drawn.

• (f) Superimposition on the cranial base and
completion of predicted soft tissue profile by
using the data from Jensen et al. Wolford and
Proffit have presented the most systematic
approaches for prediction tracings.
• In these prediction methods the cephalogram is
obtained, in natural head position, teeth at
maximum intercuspation and with the patient’s
lips in repose.

• However, acetate tracings are of lesser value for
visualization of the profile outcome. The final
esthetic outcome is heavily dependent on the
experience and the artistic skill of the clinician
who makes the treatment plan.
• Moreover, the manual methods of cephalometric
prediction of the orthognathic outcome are time
consuming.

COMPUTERIZED METHODS
• Prediction of the orthognathic surgery outcome
can also be done by computer, using various
available software programs, alone or in
combination with video images.
• Historically the first computer program designed
by Bhatia and Sowrayto aid diagnosis and
treatment planning in orthognathic surgery and
prediction of postoperative soft tissue profile.

• The general software could collect, store and
analyze graphic data such as radiographs of the
skull and photographs of the face and dentition.
• The operator manipulated graphics to attempt
different possible surgical procedures and was
able to produce different predicted profiles.
• To predict soft tissue changes, the program first
produced a bodily movement of the soft tissues
corresponding to the hard tissue movement and
then produced a change in the soft tissue shape.

• Later, Harradine and Burnie described a computer
program that was capable of providing the user with
superimposition tracings in order to visualize where
and how much the patient deviates from “Bolton’s
standard” and with quantitative measurement of
the hard and soft tissue changes for comparison.
• Prediction could be carried out after the user selects
the surgical procedure and enters the required
vertical and horizontal dimensions of change.
• Soft tissue change predictions were performed
automatically using hard to soft tissue ratios.

• Another computerized program for the planning of
maxillofacial osteotomy and its applications was developed
by Walters and Walters .
• A suggested operation was generated spontaneously by the
computer.
• The computer then adjusted the position of the soft tissue
according to the degree of the bone movements as
suggested by Freihofer and produced the predicted soft
tissue profile.
• The surgeon or the patient had the option to accept or
reject the suggestion of the computer in part or whole by
altering the esthetic prediction generated by the computer.

• Currently there is a wide variety of computerized
cephalometric software systems for orthognathic
surgery prediction.
•

Quick Ceph
• Quick Ceph was the first commercially available software
for orthognathic surgery prediction. The Quick Ceph
Image (Quick Ceph Systems, San Diego, California).
• it is designed for Macintosh computers. It permits a wide
range of functions based on a 28-point digitization.
• When orthodontic and surgical movements are simulated,
horizontal and vertical changes are recorded by the
computer. The soft tissue adjusts automatically according
to predetermined ratios.
• The majority of these ratios are derived from Wolford et
al.

Quick Ceph2000
• Recently, the release of the latest version (Quick
Ceph2000) incorporated many advantages,
including capture and storage of high resolution
images, treatment simulations, growth forecasts,
compatibility with any operating system and
digital image enhancement of tracing accuracy

dentofacial planner
• The dentofacial planner is a product of Dentofacial Software
Inc. (Toronto, Canada).
• It has been designed for IBM-compatible computers.
• The program is capable to perform a variety of cephalometric
analyses including Steiner, Downs, McNamara, Ricketts,
Grummons, Harvold, Legan, and Jarabak.
• It is also capable to perform CO–CR conversions, to estimate
facial growth, simulate any combination of orthognathic
surgery procedures including one piece or segmental
maxillary surgery, mandibular advancement or setback, total
or anterior mandibular sub apical surgery and chin surgery.

• When a surgical movement is manipulated,
vertical and horizontal changes are calculated by
the computer.
• The soft tissue profile is automatically displayed
after each treatment planning manipulation,
according to predetermined ratios.

Vistadent
• Vistadent (GAC International, Birmingham, AL)
it has been developed by GAC Techno Center. It
is an orthognathic surgical program that uses
Ricketts, VTO for treatment simulations.
• It is compatible with all digital X-ray systems
and digital cameras.

Orthodontic treatment planner (OTP)
• Orthodontic treatment planner (OTP) (Pacific
Coast Software, Inc., Wayzata, MN) is a surgical
prediction program distributed by ortho–vision
technologies.

Dolphin imaging software
• Dolphin imaging software (Dolphin Imaging and
Management Solutions, Chatsworth, CA) is
another popular software orthognathic surgical
program, presently commercially available.
• The version 11.0 software involves the indirect
digitization of multiple dental, skeletal and soft
tissue landmarks of the scanned cephalogram,
using a mouse-controlled cursor.

• An aid in landmark location is the capability of
the image to be enhanced and enlarged. The
program can also demonstrate landmarks
expected position, thereby minimizing errors in
landmark definition.
• The software links up the points to give a trace
image, which can be manually manipulated for
improved fit.
• The user can then select the analysis of choice.

ADVANTAGES OF COMPUTERIZED PREDICTION
• (1) The best available data on the soft tissue
changes associated with each operation is always
at the clinician's disposal.
• (2) Although there is the possibility of errors in
landmark recognition which is inherent in any
cephalometric technique, there are no
measurement errors in the movement of hard
and soft tissues during the prediction process or
in the cephalometric analysis of any record.

• (3) No artistic skill is required in smoothly
progressing from one ratio of hard to soft tissue
change to the next.
• (4) The records of stages in treatment and of
predicted results are not easily lost. Back-up
copies of the disc files are easily made and
additional copies of the plot can be produced at
any stage.
• (5) The program enforces a standardized method
of recording data and performing predictions.

• (6) The method is rapid in comparison with
other techniques. This combination of speed and
accuracy which is characteristic of all
computerized processes, encourages the
clinician to explore the predicted results of
several different combinations of orthodontic
and surgical procedures.

Disadvantages
• relatively expensive equipment is required,
although a microcomputer linked to a digitizer
and plotter can be used for many other purposes.
• software is required. However, as with computer
hardware, the ability to write or purchase
programs is becoming increasingly widespread
and existing programs can be translated to
conform to different hardware.

• the graphic output is a silhouette rather than a
picture. This is a potential disadvantage when
discussing treatment options with patients, but
not, in the authors' opinion, a large one.
• A further problem shared by all methods is the
variability in ratio of hard to soft tissue change.
For some procedures, this variability is small.

VIDEO IMAGING
• More recently, the introduction of computer
software programs with video imaging by Sarver
et al.

Orthographic software
• was first used in the mid 1980s.
• With this software an image of known size was
capture and then calibrates the imaging software so
that the computer was capable of internal software
measurement of image on the screen in real size.
• However, direct visualization of the bony structures
in coordination with soft tissue profile was not
easily accomplished.

TRUE VISION IMAGE PROCESSING SYSTEM
(TIPS) AND ORTHOGRAPHIC SOFTWARE
• The use of true vision image processing system
(TIPS) and orthographic software in the
superimposition of the lateral cephalometric
tracing or cephalogram over a profile image as
an aid of planning and predicting the
orthognathic surgery outcome was further
evaluated

main advantages
• the capability of the software to overlay images,
the calibration of the images on the computer
screen to actual dimensions and the
quantification in x and y axis of the movement of
defined areas.

Grubb
• Another computer software program with video
imaging was used by Grubb .
• Preselected skeletal and soft tissue landmarks
were digitized and then anatomic areas were
traced.
• If desirable, an occlusogram could be created by
digitizing the photocopy of the occlusal view of
each dental arch.

• After cephalometric and study cast data were
entered into the system, a variety of analyses and
treatment options could be selected and
simulated.
• To simulate anatomic structures, electronic
templates were created.

THREE-DIMENSIONAL PREDICTION METHODS
• Computer methodology integrating cephalometric
data with three-dimensional (3D) computerized
tomographic (CT) data has been found to aid in
the clinical planning of orthognathic surgery,
especially in craniofacial anomalies cases.

• A patient’s 3D tracing is compared to a similarly
generated “ideal” for every age and sex corresponding
Bolton tracing.
• After the type and number of osteotomies to be
performed have been selected, the program calculates
the postoperative movements of all osteotomy
fragments required to have the surgical outcome most
closely approximate the Bolton “ideal” form.
• The user can modify the orientation and position of
each osteotomy fragment, if needed. The surgical
planning cephalometric treatment may be performed
on 3DCT scan reconstructions for superior
visualization of the planned surgical changes.

• Today, three-dimensional prediction methods
are available, such as three-dimensional
computerized tomography (3DCT), 3D magnetic
resonance imaging (3DMRI) and surface
scan/cone-beam CT.
• The combination of surface scanning and cone-
beam CT scan uses hard tissue imaging data
from the tomogram and soft tissue data from the
surface scan, which are processed through
special software.

STEREOLITHOGRAPHY
• Stereolithography has become a well known
technique in the rapid prototyping sector.
• In preoperative model planning and surgery
simulation, this technique has been used in the
field of craniofacial surgery, tumour surgery,
reconstructive surgery, orthognathic surgery,
preprosthetic surgery and dental implants.
(Lambrecht, 1989; Kärcher, 1992; Millesi et al.,
1994; Ono et al., 1994; Wolf et al., 1994; Bill et al.,
1995; Kermer et al., 1998).

THE INITIAL STO
• It is prepared before treatment to determine the
orthodontic and surgical goal. It is both a
diagnostic aid and a treatment planning aid.
This part will discuss the development of the
initial STO. It is divided into two sections.
• Presurgical orthodontic goals
• Surgical goals

PRESURGICAL ORTHODONTIC GOAL
• Before constructing an initial STO, presurgical
orthodontic treatment must be established by
clinical examination, dental model
evaluation.cephalometric analysis.

Initial presurgical orthodontic goal
• Position the long axis of the maxillary incisor at 22
degrees tonasion-point A (NA) line with the labial face
of the incisor 4anterior to that line (Fig. 2-1, A).
• Position the long axis of the mandibular incisor at 20
degrees to nasion-point B (NB) line with the labial face
of the incisor 4 mmanterior to that line (Fig. 2-1, B).
• Satisfy arch length requirements (crowding or
spacing).

• Removal of dental compensations is necessary before
surgery for maximal skeletal correction.
• Surgical skeletal correction to an ideal 2-degree ANB
angle will produce an ideal interincisal angle of 136
degrees when the proper incisor positionareachieved
presurgically. Anincrease or decrease in the ANB angle
will require changes in incisor angulation to maintain
the ideal interincisal angle of 136 degrees. As the ANB
angle is increased, it is necessary to decrease the upper
incisor angle to the NA line and the distance from the
labial face to that line. It is also necessary to increase
the lower incisor angle to the NB and the distance from
its labial face to that line (Fi g. 2-2, C).

• . Relocation of the molar teeth will depend on the arch
length requirements and mechanics used by the
orthodontist to achieve the ideal incisor position.
• The original cephalometric radiograph is traced in black
pencil on manual acetate. Once the initial orthodontic goals
are established, the teeth must be redrawn on the original
CT. we prefer to do this with colored pencil, since the CT is
traced in the black. A mandibular advancement was planned
for the patient in fig 2-3 A. Relocation of the incisors to
satisfy ideal presurgical orthodontic goals is demonstrated in
fig 2-3,B.

• After the teeth have been relocated on the CT
tracing, the initial STO is constructed. The
technique used is the same as that used for the
final STO. The initial STO is helpful to:
• Establish the final presurgical orthodontic goals
• Establish the surgical dentoskeletal objective
• Establish the genioplastic procedure with chin
evaluation
• Establish the soft tissue facial profile objective

Final presurgical orthodontic goal
• After the completion of the initial STO, the relationship
of the lower incisor to the NB line is changed because
predominant clockwise movement of the body of the
mandible (fig 2-4, B)
• The lower incisor is now 5mm anterior to the NB line at
29 degrees and thus the initial presurgical goal may be
modified to upright the incisor and move it distally
1mm. unless extreme skeletal movement with the STO,
usually only slight modification (if any) of the initial
goal is necessary.

• In the maxillary segmental surgical procedures
abnormal incisor angulation may be partially or
totally corrected with the surgical procedure to
properly align that segment.
• Completion of the initial STO will establish the
final presurgical preorthodontic goal. Usually
only slight adjustment of the initial goal is
necessary.

SURGICAL GOAL
• Accurate determination of skeletal movements is
very important in treatment planning. It not only
affects the presurgicalmachanics but will have
definite effects on the functional and esthetic
results.
• This section is divided into three parts:
• Single jaw STO
• Double jaw STO
• Chin STO

Single jaw STO
• Surgical repositioning of single jaw units greatly
depends on the opposite jaw position, occlusion
and presurgical orthodontic goals.
• Establishing surgical reference lines on the CT is
very important to determine accurate movement
of the single jaw or parts thereof.

Mandible
• NON SEGMENTAL.
• The presurgical position of the maxillary and
mandibular teeth dictates the vertical and AP
position of the mandible. An appropriate
reference line is placed in the area of osteotomy
to determine the AP change.

• A vertical reference line is drawn in the area of
the vertical buccal osteotomy. A short horizontal
reference line is drawn 2 to 3 mm below the
alveolar crest.

SEGMENTAL.
• Mandibular segments can be repositioned in all
three dimensional planes via subapical or
bilateral body osteotomies and depend on:
• Occlusion
• Angulation of lower incisors
• Arch length requirements
• Lower dental height

MAXILLA
• Alterations in position of the maxilla in single jaw surgery
depend on the position of the mandible, the occlusion and
presurgical orthodontic goals, upper tooth relation to lip,
and upper lip length.
• The primary decision that the clinician must make is the
desired vertical position of the maxillary central incisor. The
vertical position of the central incisor is based on normal
interrelationships from Burstone Lip length measured from
subnasale to upper lip stomion; men, 22 mm +/-2 mm;
women,20 mm +/- 2 mm; upper tooth to lip relation, 1to 4
mm.

VERTICAL POSITION OF MAXILLA.
• Aftertracing all stable skeletal and tissue
structures on the STO, a horizontal line is drawn
to indicate the desired incisor level (Fig. 2-9).
• As the maxillary incisor is moved more
superiorly, the maxilla must move more
anteriorly to accommodate the mandibular
autorotation.

• Itis difficult to alter upper lip length and maintain
optimal upper esthetics. Therefore with abnormal
lip lengths the upper tooth to lip relationcan be
altered tomaximize esthetic balance.
• If the upper lip is excessively long,we usually
minimize the upper tooth to lip relation (0 to 2
mm). If theupper lip is short, we will maximize
the tooth to lip relation (3 to 5 mm).

NONSEGMENTAL
• When a deformity is to be corrected with isolated
nonsegmental maxillary surgery, the only option
available to the clinician is the vertical position
of the maxillary incisor.
• The resultant AP position of the Maxilla and the
maxillary teeth is dictated by the autorotation of
the maxillary and the mandibular teeth.

SEGMENTAL.
• In addition to vertical incisor position, the clinician controls
the angulation of the maxillary teeth with segmental
procedures, but the AP position of the maxillary incisal edge is
still dictated by the mandibular auto-rotation.
• More angulation control is available with a four-tooth anterior
seg
ment that a six-tooth anterior segment.
• The curve of the dental arch limits the surgical correction of
overangulated incisors in a six-tooth.segment be
cause the
more the incisors are uprighted, the more superior the
cuspids become (Fig. 2-10).

DOUBLE JAW STO
• Mobilization of both jaws requires
predetermination of following relations in the STO
that must also correlate with the clinical
examination and model surgery:
• Vertical position of maxillary incisor
• AP position of maxilla
• Occlusal plane angulation
These factors will dictate the position of the mandible
and will affect to functional and esthetic results.

Mandible
• NONSEGMENTAL. Mandibular position is
dictated by the reposition. maxilla, maxillary
teeth, and occlusal plane angulation.
• SEGMENTAL.Additional control of mandibular
segments is available as previously discussed.

Maxilla.
• In double jaw surgery the vertical and AP
positions of the maxilla and the occlusal plane
angulation can be selected. The desired position
determined from clinical and cephalometric
evaluations.

VERTICAL, POSITION OF THE MAXILLA.
• As in single jaw maxillary surgery the vertical
position of the maxilla is determined by the
upper tooth to lip relation.
• After the stable cranial base and soft tissue
landmarks are traced on the STO, the desired
vertical position of the Maxillary incisor marked
with a horizontal reference line.

AP POSITION OF THE MAXILLA
• AP position of the maxilla is determined from
cephalometric analysis and clinical examination.

Cephalometric measurements helpful in determining AP maxillary
position are, maxillary depth, McNamara's nasion perpendicular and SNA.
• Maxillary depth: the angle formed by Frankfort
horizontal and a line from the nasion to point A;
average: 90 degrees = 3.

• McNamara's nasion perpendicular: the distance
(in mm) from point- A, to a line from nasion
constructed perpendicular to Frankfort horizon
tal; average: 0 mm, ±-2 min.
• SNA: the angle formed by the sella-nasion (SN)
and NA lines; average: 82 degrees, 2 degrees.

OCCLUSAL PLANE ANGULATION.
• The average relationship of Frankfort horizontal
to the occlusal plane is 8 degrees +5 degrees.
• If alteration of the maxillary occlusal plane is
desired, the posterior maxillary position may be
selected- before the mandibular movement.

A summary of the options available for the
double jaw STO is presented in Table

Chin STO
• The chin position should be evaluated after major
skeletal relocation has been completed on the STO,but
before completion of the soft tissue projection.
• For the STO the chin position is evaluated in two
dimension: AP and vertical.
• Average soft tissue thickness of the upper lip, lower lip,
and chin is approximately 11 to 14 mm, but more
important is an equal balance between the structures.

• Normally there should be approximately a 1 : 1 : 1
relation in the AP soft tissue thick
ness of the
upper lip, lower lip, and chin (Fig. 2-13).
• The CT must reflect the soft tissues of the lips
and chin in the relaxed position to adequately
evaluate thickness.
• If the AP and vertical soft tissue thickness of the
chin is less than desired, then the osseous tissues
of the chin can be positioned in a more anterior
relation than determined by the osseous analyses
to add support to the deficient soft tissues.

• However, if the mandible and/or maxilla are to
be repositioned, the chin analysis is performed
on the STO after the repositioning of those
structures and after the soft tissues of the
forehead, nose, and upper lip have been
completed.

AP Chin Position
• The determination of AP chin position can be
analyzed relative to the osseous or soft tissue
structures.
• The object of analysis is to position the soft
tissue chin in the most desirable position, and
the osseous chin position is adjusted
accordingly.

• The hard and soft tissues of the chin should be
carefully evaluated in the AP dimension. We
found the following analyses to be most helpful
in con
struction of the STO.
• NB line (Fig. 2-14): Distance from NB line to
lower incisor arid to pogonion
• Average: Lower incisor and pogonion equal
distance from NB line (4 to 6 mm)

• Apo line(Fig. 2-15) Distance from A pogonion
line to lower incisor
• Average: 2 mm +/- 2 mm

• Angle of facial convexity (Fig 2-16) Angle
between soft tissue glabella – subnasale (GaSn)
line and subnasale – soft tissue pogonion
(SnPo’) line.
• Average: 11 degrees +4 degrees

•
• Subnasale vertical (Fig 2-17) Distance from
soft tissue chin to a line perpendicular to
Frankfort horizontal through subnasale.
• Average: -3 mm +/- 3 mm

• 0-degree meridian (fig 2-18) Distance from
soft tissue chin to line perpendicular to
Frankfort horizontal through soft tissue nasion
•
• Average: 0 mm +/- 2 mm

•
• E line (Fig 2-19) Distance between lower lip and
esthetic (nose-chin) plane
•
• Average: 2 mm +2 mm

Vertical Chin Position
• The vertical chin position is determined
primarily analysis of anterior vertical
mandibular dental height and correlated upper
lip length, vertical facial proportions, and
vertical soft tissue length the chin.
•

• If the upper lip length is greater than normal,
then vertical chin position should be greater
than normal to maintain appropriate vertical
balance in the lower third of the face.
• If the upper lip is long and chin is positioned
vertically in a normal dimension, the vertical
length of lower lip and chin will be out of balance
with the upper lip.

• To evaluate the hard and soft tissues of the chin
in the vertical demission, we find the following
analyses most useful:
• 1.Lower anterior dental height (Fig. 2-20):
Distance from incisal edge of lower incisor to
lower border of mandible

• 2.Lower anterior soft tissue (lower lip
length)
• Distance from lower lip stomion to soft tissue
mention

A summary of chin evaluations is presented
in table.

THE FINAL STO
• OVERLAY METHOD
• Various surgical procedures for which
S.T.O can be used
• Mandibular advancement
• Mandibular setback
• Maxillary impaction
• Maxillary advancement
• Maxillary setback
• Combined Maxillary and mandibular procedures
• Adjunctive Genioplasty

I. Cephalometric Prediction Tracing for Mandibular
Advancements.
The basic reasons for doing predictions for
isolated mandibular surgery (advancement or set-
back) are:
To accurately assess the profile esthetic results
this will result from the proposed surgery,

• To consider the desirability of simultaneous
adjunctive procedures such as genioplasty,
suprahyoidmyotomy, etc.,
• To help determine the sequencing of surgery and
orthodontics (i.e., if the surgery is done first will
it be more difficult or easier to do the indicated
orthodontics),

• To help decide what type of orthodontics might
best be employed (i.e., extraction versus non-
extraction) and
• To determine the anchorage requirements

Step 1 - Trace the Stable Structures.
• The first step in producing a prediction tracing is
to overlay a piece of acetate paper on the original
cephalometric tracing and trace all structures
which will not be significantly altered by the
surgery and/or orthodontics.
• For mandibular surgery, these structures will
include the deep cranial features, the maxilla, the
maxillary occlusal plane, the mandibular ramus
and the profile to the base of the nose.

• Draw in Frankfort Horizontal and a line from
nasion to indicate the optimum facialdepth, i.e.,
89° in females, 90° in males (Fig. 2A).
• optimum facial depth is a convenient guide
forbeginning a prediction for either mandibular
advancement or set-back surgery.
• Nasal esthetics and sex have a directinfluence on
optimum chin prominence.

Step 2 - Add Skeletal Portion Changed by Surgery
• Slide the prediction tracing to the left and rotate it slightly to
position bony pogonion at the optimum facial depth, keeping the
mandibular occlusal plane in proper relation to the maxillary
occlusal plane. Once a satisfactory position is achieved.
• Trace the distal portion of the mandible, the corpus axis, and the
soft tissue chin in this position (Fig. 2B). There is little change in
soft tissue chin thickness, so the soft tissue chin may be drawn in
just as it was originally.
• However, this isso only if the original cephalometric radiograph
is taken with the lips in repose.

Step 3 - New A-Po Line.
• Construct a new line from Point A to pogonion.
If a genioplasty is to be included in the
procedure, the anterior portion of this altered
chin, be it bone or alloplast, is now construed to
be pogonion for purposes of placing the teeth.

Step 4 - Placing the Teeth.
• The teeth are placed exactly as described by
Bench, et al. First the lower incisor is placed in
its optimum position 1 millimetre ahead of the
A-Po line, 1 millimetre above the occlusal plane,
and at 22 degrees to the A-Po line. Old and new
mandibles are then superimposed on Corpus
Axis at PM and the change in lower incisor
position is noted.

• The upper first molar is then placed in the
desired occlusion and the upper incisor is
likewise placed in the optimum position with its
long axis 5 degrees more upright than the new
facial axis (dotted line on the prediction tracing).

Step 5 - Tracing the New Lip Contours.
• Once the teeth are placed, the lip contours are
traced to correspond to the new incisor
positions.
• The result of Steps 4 and 5 are shown in Figure
2D which is the completed prediction tracing.
Once completed, the prediction tracing must be
viewed as a goal toward which one is working.

II. Cephalometric Prediction for Maxillary Superior
Repositioning.
• Step 1 - Trace the Stable Structures.
• As is the case with all prediction tracings,
we again begin by tracing the structures which
will not be modified either surgically or
orthodontically(Fig. 4A). This should include
point A

Step 2 - Determination of Ideal Vertical Position for the Upper
Incisor.
• Regardless of how accurate your cephalometric
technique, we recommend that the measurement
of the amount of upper central incisor exposed,
i.e., that from stomion of the upper lip to incisal
edge, be made clinically with the patient
standing in a relaxed posture.

• This is the single most important measurement in
preparation for superior repositioning of the maxilla
and can be confirmed cephalometrically.
• Once the amount of incisor exposed beneath the upper
lip is determined, the "ideal" amount of superior
repositioning of the upper incisor can be determined
by the formula:X = (y-2)/0.8 where X is the amount of
superior repositioning necessary and Y is the amount
of upper incisor showing.
• Once the desired amount of vertical incisor
repositioning is determined, draw a line parallel to
Frankfort horizontal on the prediction tracing to
represent the desired vertical position (Fig. 4B).

Step 3 - Autorotation of the Mandible.
• Superimpose the original and prediction tracings
and, keeping the mandibular condyle in the same
position, rotate the prediction tracing clockwise
until the occlusal plane is 1 mm above the line
indicating the desired position of the upper
incisor.
• Trace the mandible in this position. The corpus
axis and the occlusal plane are also traced in at
this time (Fig. 4C).

Step 4 - Genioplasty Determination.
• The second feature which must be noted is the
new soft tissue chin position.
• If the chin is adequate, then genioplasty is not
necessary. However, if the chin is still weak, as in
our example either mandibular advancement or
some type of genioplasty must be added to the
treatment plan for optimum esthetics.

Step 5 - Placement of Teeth in Ideal Positions.
• This step is carried out exactly as described
by Bench, et al. After placing the teeth in their
ideal position (Fig. 4E), we are now ready to
trace the new profile.
• (The excessive overjet in this patient is produced
by a missing lower incisor.)

Step 6 - Nasal Outline.
• With superior repositioning of the maxilla, the
nasal tip is generally elevated slightly. This is more
pronounced if the maxilla is moved upward and
forward, less pronounced if upward and backward.
• The lower border of the nose is relatively
unchanged though it too may be elevated a small
amount. Accordingly, the prediction tracing should
be placed on the original with the fixed landmarks
superimposed and the nasal outline traced with
the aforementioned alterations (Fig. 4F).

Step 7 - Upper Lip.
• The upper lip reacts to superior repositioning in the
following ways:
• 1) the length from subnasale to upper lip stomion shortens
1/5 of the amount of superior repositioning,
• 2) the thickness increases by 1/3 of the amount of incisor
retraction, and
• 3) the lip thins out slightly if the upper incisor is moved
forward, but in all but the most extreme instances this is
unnoticeable.
• To trace the new upper lip one should superimpose on the
fixed cranial structures and study the change in incisor
position.

Step 8 - Lower Lip.
• In most instances the lower lip vermillion is
traced in the same relation to the lower incisors
as existed prior to treatment.
• Superimpose the lower incisor on the prediction
tracing over that on the original and trace the
lower lip.

Step 9 - Chin.
• If no genioplasty is projected, the soft tissue chin
will be relatively unaffected by treatment and
should be traced bysimply superimposing on the
mandibular symphysis.
• If a sliding genioplasty is done, the chin is traced
by first superimposing on the original symphysis
and then sliding the prediction tracing back 6/10
of the amount of the genioplasty and tracing the
new chin contour.

III. Cephalometric prediction tracing for combined maxillary
and mandibular cases.
• The basic technique involved is to trace the
stable structures, place the maxilla in the desired
position both vertically and anterior-posteriorly
and then place the mandible in its desired
position .

• Step 1 - Trace the Stable Structures (Fig.
7A).
• Step 2 - Determine the Ideal Vertical
Position for the Upper Incisor.
• In the patient with an obtuse nasolabial angle,
where the maxilla will come forward to increase
lip support, slightly more shortening of the lip
will be produced than might otherwise be
expected.

• Superimpose the original and the prediction
tracings and draw a line parallel with Frankfort
horizontal to indicate the desired vertical
position of the upper incisor. Trace a line from
original point A tangent to the labial of the upper
incisor as a reference for the original upper lip
support (Fig. 7B).

Step 3 - Autorotation of the Occlusal Plane.
• Keeping the condyle in the same position, rotate
the prediction tracing clockwise until the
occlusal plane is 1mm above the line indicating
the desired position of the upper incisor.
• Trace the occlusal plane and the mandibular
ramus in this position.

Step 4 - Mandibular Movement.
• This is done exactly as was done in Step 2 under
mandibular advancement (Fig. 7D).

Steps 5-10 - Completing the Tracing.
• Once the new position of the mandible has been
traced, the balance of the tracing is done as
outlined in Steps 4-9 under Maxillary Superior
Repositioning.
• The finished prediction tracing is seen in Figure
7E.
• In Figure 7F the superimposed tracings are
illustrated.

SOFT TISSUE PREDICTION
• Soft tissue changes are very important in the
determination of final profile results and should be
projected as accurately as possible.
• The soft tissue may move significantly different than
the osseous structures, creating difficulties in
determining accurate soft tissue changes on the STO.
• These differences are more apparent in maxillary
surgery.

The more commonly soft tissue landmarks are.
• P(pronasale): The most prominent or anterior point of the nose.
• Sn: The most posterior-superior point on the nasolabial curvature.
• A’(soft tissue A point) : The point of greatest concavity of the upper
lip between subnasale and labralesuperius.
• UL(labralesuperius): The most anterior point on the upper lip.
• St (stomion-upper lip) :The most inferior on the upper lip
• LL (labraleinferius) :The most anterior point on the lower lip.
• B’(soft tissue B point) : the point of greatest concavity of the lower lip
between labraleinferius and soft tissue pogonion.
• PO’ (soft tissue pogonion): The ,ost anterior point on the soft tissue
chin.
• Me’ (soft tissue menton) :The most inferior point on the soft tissue
chin.

The soft tissue discussion will be divided in to three sections :
• Mandibular procedures
• Maxillary procedures
• Chin procedures

Mandibular procedures
• A summary of the following material can be seen
in the following table and in the figure
• Soft tissue changes expressed as percentage of
dentoosseous movement for linear change
degrees per millimetre for angular change.
• +LL- Most anterior point onlower lip
• +/- H – Horizontal
• UL – Most anterior point on upper lip

Procedure Soft tissue anatomic
points
Dimension
measured
% change
Advancement LL+
B’
Po’
H+
H
H
67-85
100
100
Setback UL
LL
B’
Po’
H
H
H
H
20
90
90
90
Subapical
development LL H 60
Subapical setback LL H 75

Total Advancement
• In mandibular advancement the soft tissue
change at pogonion and labiomental fold is
approximately 100% relative to the bone .
• Although no data are available, if dental
interferences are present preoperatively , the
lower lip should assume a more superior
position relative to the mandibular incisors after
advancement.

Total setback.
• Posterior repositioning of the mandible via
ramus procedures yields a 90 % soft tissue
change at the chin, labiomental fold, and lower
lip relative to the AP bone change.
• The upper lip may also move posteriorly 20%.
Bilateral mandibular body ostectomies should
produce the same soft tissue change.

Subapical Advancement.
• A study of two patients showed that a mandibular
subapical brought the lower lip forward by 60% and that
the soft tissues of the chin remained relatively stable.
• In this type of procedure the labiomental fold will
decrease in prominence.
• Careful soft tissue management is necessary to maintain
good lower lip to mandibular incisor vertical
relationship.

Subapical setback.
• An anterior or total subapical setback brings the
lip posterior 75% and the soft tissues of the chin
remain relatively unchanged.
• The labiomental fold will increase in prominent.
Careful soft tissue management is necessary to
maintain good lower mandibular incisor vertical
relationship.

Subapical inferior repositioning.
• The horizontal soft tissue effect subapical
inferior repositioning will depend on the AP
dentoalveolar change relative to lower lip
support.
• The vertical relationship of the lower lip
mandibular incisor relationship should be
improved.

Maxillary Procedures
• Soft tissue change with maxillary surgery depends on the
dental-osseous movements and the management of the soft
tissue.
• Superimposition of preoperative and postoperative tracings
demonstrates the change in lip support.
• The maxilla was moved straight superiorly. Although the incisal
edge was also moved straight superiorly, the resultant
postoperative support is more anterior.
• Preoperative lip support was in the cervical area of the incisor,
and the incisal edge was well below the inferior margin of the
upper lip.

• . Because of the incisor angulation, the lip
support becomes more anterior as the tooth is
repositioned.
• As expected, the soft tissue in the superior labial
sulcus area reflects the AP change.

• Superimposition of preoperative and
postoperative tracing of superoposterior
maxillary movement shows no change in the AP
position of the superior labial sulcus.
• Although the incisal edge was moved
significantly superiorly and lightly posteriorly,
the lip support has changed from the cervical
area of the incisor to an area closer to the incisal
edge.

• The use of the alar base cinch suture has significantly
improved the quality of results. Previously, flaring of the
alar bases was common in maxillary surgery.
• After base flaring occurs because of detachment of muscles
and periosteum in the area, oedema , and changes in the
osseous support to the nasal structures.
• Passing a “figure 8’ suture intraorally through the lateral
aspect of the alar bases will control the width, narrow the
alar bases, minimize the shortening of the lip, and improve
the AP thickness of the lip.
• In addition, closing the vestibular incision in a V-Y fashion
also helps minimize lip shortening and increases the AP
thickness if the lip.

A summary of the following material can be seen in the below
table and in the figure.

Advancement
• The classic soft tissue management techniques
for maxillary advancement move the upper lip
forward 50% of the dental-osseous movement.
• The nasal tip advances approximately 30%
(significant variability), and the nasolabial angle
decreases .1.2 degrees per 1mm, upper lip length is
unpredictable.
• The greater the maxillary advancement is, the less
percentage AP change of the upper lip occurs.

Setback
• Soft tissue changes for maxillary setback by either
anterior or total maxillary osteotomy are similar.
• The upper lip moves posteriorly50% to 65% of the
dentoosseous movement, the base of the nose and
superior labial sulcus move posteriorly
approximately 30% and the nasolabial angle
increases 1.2 degrees per 1mm .
• although the tip of the nose may move posteriorly,
no quantitative values have been established.

Superior repositioning
• Soft tissue changes from the literature report approximately
20% to 40% shortening of the upper lip, the base of nose moves
up 20%, the nasal tip moves up 20%, and the upper labial
superioris moves 60% to 70% of the AP change in lip support
position.
• Usually with vertical maxillary excess, dental-osseous support
to the lip is located higher on the dentoalveolus.
• When the maxilla is moved superiorly the lip support shifts
lower on the dentoalveolus or incisor but subsequently more
anteriorly because the incisors are angulated forward.
Therefore, with straight superior movement of the maxilla, the
lip support will be more anterior.

Inferior repositioning
• Inferior repositioning of the maxilla usually has a lengthening effect
on the upper lip.
• The closer the incision is made towards the attached gingiva, the
greater the increase in length.
• The nasal tip usually drops inferior slightly.
• When the maxilla is inferiorly repositioned, the lip support area on
the dentoalveolus moves superiorly and also posteriorly.
• If the maxilla is repositioned directly downward, the lip should
assume a more posterior position.

Chin procedure
• Chin procedure can affect both the AP and
vertical soft tissue dimensions and the AP and
vertical position of the lower lip.
• A summary of the following material is
presented in the table below depicts simplified
diagrammatic representations of average soft
tissue changes.

Augmentation Genioplasty
• The chin can be augmented in two dimensions
on the STO: AP and vertical.
• In augmentation procedures the soft tissue
thickness in the pogonion are will decrease in
the AP dimension.

Osseous AP Augmentation
• Reports in the literature vary from 60% to 75% soft
tissue advancement relative to bony advancement.
• Also, it is the best to avoid a pressure dressing
directly over the pogonion area. With this type of
soft tissue management, we project 75% to 90% soft
tissue chin change.
• The labiomental fold will become more prominent.

Alloplastic AP Augmentation
• Proplast and silastic implants are the most
commonly used materials, and both provide
approximately the same soft tissue change.
• The literature reports an 80% to 85% soft tissue
change relative to the AP dimension of proplast
implants but with significant variability.
• larger the implant is, the less the soft tissue
percentage change.

Osseous vertical Augmentation
• Vertical mandibular deficiency can be corrected by an
anterior horizontal osteotomy with downgrafting of
the chin.
• This procedure usually requires stripping the
periosteum off the inferior border of the mandible to
decrease shortening of the lower lip relative to the
mandibular teeth.
• the vertical soft tissue change will be approximately
100% relative to the osseous change. The labiomental
fold will lose some of its prominence.

Alloplastic Vertical Augmentation
• Alloplastic implants can be used to augment the
inferior border of the mandible. To place the
implant the soft tissues must be stripped from
the inferior border of the mandible.
• This technique should provide approximately
100% vertical soft tissue change relative to the
vertical height of the implant.

Reduction Genioplasty
• Chin excesses in the vertical and AP direction
can be reduced by osteotomy or ostectomy.
Predictability of results depends or the surgical
procedure selected.

VERTICAL REDUCTION
• Removal of the inferior border by a horizontal
ostectomy yields only about a 30% vertical and
25%. AP soft tissue change, but this is
significantly variable.
• By maintaining a maximal soft tissue attachment
to the inferior segment, approximately 90%
vertical soft tissue change relative to the bone
can be expected.

AP REDUCTION
• Decreasing the AP prominence of the chin can be
accomplished by two techniques.
• An ostectomy that removes the anterior portion of the chin is
quite unpredictable, resulting in only about 25% soft tissue
change relative to the bone in the AP direction.
• A horizontal osteotomy moving the inferior segment
posteriorly is predictable when the soft tissue remain attached
to the inferior segment.
• With this technique the soft tissue change is approximately
90% relative to the bone. The labiomental fold will become
more obtuse.

CONCLUSION
• Cephalometric prediction in orthognathic surgery can be
performed manually or by computer, using several currently
available software programs, alone or in combination with
video images.
• The manual methods of cephalometric prediction of the
orthognathic outcome are time consuming, whereas,
computerized methods facilitate and speed the performance of
the visualized treatment objective.
• Both manual and computerized cephalometric prediction
methods are two-dimensional and will always have
limitations, because they are based on correlations between
single cephalometric variables and cannot fully describe a
three-dimensional biological phenomenon.

• Today, three-dimensional prediction methods
are available, such as three-dimensional
computerized tomography (3DCT), 3D magnetic
resonance imaging (3DMRI) and surface
scan/cone-beam CT.
• Despite the promising capabilities of 3D
technology there is not yet a reliable technique
for orthognathic prediction.
• Although, the different method of prediction are
useful tools for orthognathic surgery planning
and facilitates patient communication.

REFERENCES
• Sarver DM.Videocephalometric treatment prediction.
In: Sarver DM, editor. Estetics orthodontics and
orthognathic surgery. St Louis: Mosby Inc; 1998.
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prediction tracing. J Clin Orthod.1980;14:36-52.
• McNeill RW, Proffit WR, White RP.Cephalometric
prediction for orthodontic surgery. Angle
Orthod. 1972; 42:154–164.
• Wolford LM, Hilliard FW, Dugan DJ. Surgical treatment
objective.A systematic approach to the prediction
tracing. St Louis: Mosby Year Book; 1985. pp. 54–74.

• Sarver DM, Johnston MW. Video imaging: techniques
for superimposition of cephalometric radiography
and profile images. Int J Adult OrthodonOrthognath
Surg. 1990
• Sarver DM.Videocephalometric treatment prediction.
In: Sarver DM, editor. Estetics orthodontics and
orthognathic surgery.
• Sarver DM. Video imaging, a computer facilitated
approach to communication and planning in
orthognathic surgery. Br J Orthod. 1993;20:187–191
• Grubb JE. Computer assisted orthognathic surgical
treatment planning: a case report. Angle Orthod

• Proffit WR. Treatment planning: The search for
wisdom. In: Proffit WR, White RP, editors. Surgical
orthodontic treatment. St Louis: Mosby Year Book;
1991. pp. 142–191.
• Bhatia SN, Sowray JH. A computer-aided design for
orthognathic surgery. Br J Oral Maxillofac
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