VTO (visualised Treatment objective)

Good Morning…
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VVISUALISUAL
TTREATMENTREATMENT
OOBJECTIVEBJECTIVE

ContentsContents
• Introduction
• Importance of V.T.O in Orthodontics
• Construction of V.T.O ( by Ricketts)
• Dental V.T.O
• Computer cephalometric and Video Imaging
Prediction
• Image editing system
• Photo cephalometric treatment visualization

• Three Dimensional planning & visualization
• Current status of Three Dimensional
Imaging
• S.T.O
–Initial S.T.O
–Final S.T.O
• Conclusion
• References

Definition :
A treatment planning and communication
aid that may be used to define the tooth
movements and / or surgical changes
required to achieve the desired facial goals.

IntroductionIntroduction

• Holdaway coined the term visual
treatment objectives but it more often
associated with Rickets and Rocky
Mountain Data system (RMDS).
• A visual treatment objective is like a
blue print used in building a house.
• It is a visual plan to forecast the normal
growth of the patient and the
anticipated influences of treatment, to
establish the individual objectives we
want to achieve for the patientwww.indiandentalacademy.com

• Treatment for a growing patient must
be planned and directed to the face
and structure that can be anticipated
and not to be skeletal structure patient
presents initially.
• Essentially V.T.O. consists of patient’s
cephalogram modified to demonstrate
changes that are anticipated in the
course of treatment which is
accomplished manually or using a
computer programme

Importance of V.T.O. in Orthodontics:Importance of V.T.O. in Orthodontics:
For a child V.T.O. incorporates the expected
growth or any growth changes induced by
treatment i.e., by repositioning of teeth from
orthodontic tooth movements.
In a child with normal facial proportions,
average growth increments are reasonably
likely and growth modification is not likely a
part of treatment so growth changes can be
predicted quite well.

So for a skeletally normal child, preparing a
V.T.O. using average growth increments can
be quite helpful in understanding the
amount of tooth movement needed for
correction of malocclusion.
But for a child with skeletal problem, given
the uncertainity of both growth pattern and
response to treatment, a V.T.O. is more
often a presentation of what is hoped than
what is likely to happen.

The visual treatment objective permits
development of alternative treatment
plans.
Then the orthodontist must decide how far
he must go with the mechanics and
orthopedics to achieve his goals, whether
it is possible to achieve them and what the
alternatives are

During treatment it can be used to monitor
measure the treatment progress.
Any deviation from the expected progress will
be recognized and can be instituted early.
This type of monitoring is important in
accommodating treatment to individual
variability.
V.T.O also helps in patient education and
motivation and helps to achieve a better
cooperation.

For an adolescent and adult where the associated
variables with growth are not present (or where
little growth is remaining) predicting treatment
effects becomes easier and more reliable.
V.T.O. forecast is valuable for the orthodontists
self-improvement in that it permits him to set his
goals in advance and compare them with result
at the end of treatment.
This gives him an objective picture of the areas
in which his treatment could be improved.www.indiandentalacademy.com

V.T.O by FrankelV.T.O by Frankel
( FR-VTO )( FR-VTO )

• This gives the operator an excellent clue to as to
whether the functional appliance that postures the
mandible forward will improve the facial appearance
and profile.
• First the patient is asked to swallow and then lick the
lips and relax.
• Then the patient is instructed to close the teeth in
habitual occlusion, again licking the lips first and
then to keep the teeth tightly together and lips
relaxed.
• These two profile relationships are carefully studied
and may be photographed to obtain an instant print.

• Patient is then asked to posture the mandible
forward into correct sagittal relationship, reducing
the overjet.
• Photograph of this profile may be compiled with the
original snapshot depicting the teeth in occlusion.
• If this clinical exercise makes the facial balance
look better, the functional appliance will probably
be beneficial.
• The photograph taken can be used to motivate the
patient to an achievable treatment goal.

• If the profile is not improved by forward mandibular
positioning or is actually made worse other forms of
treatment may probably be needed.
• Obviously a cursory visualization is no substitute for
cephalometric analysis to determine the best possible
appliance.

ConstructionConstruction of V.T.Oof V.T.O
(by Ricketts)(by Ricketts)

The growth prediction is presented in the
following sequence
Cranial base prediction
Mandibular growth prediction
Maxillary growth prediction
Occlusal plane position
Location of dentition
Soft tissue of the face

Cranial base prediction
Place the tracing paper over the
original tracing. Starting at the
CC point following steps are
used to construct the cranial
base.
Trace the basion nasion line
Grow the nasion 1mm / year
(grow for the estimated amount
of time)
Grow basion 1mm / year
Slide tracing back so nasion
coincide and trace nasion back
Slide tracing forward so the
basion coincides and trace
basion area

ii) Mandibular growth
prediction :
Construction of mandible in its
new position starts with the
rotation of mandible.
Rotation :
Mandible either opens or closes from
the effects of mechanics used &
facial pattern.
With mechanics :
Convexity reduction – facial
axis open 10
for 5mm
Molar correction – facial axis
open by 10
for 3 mm
Overbite correction – facial axis
open 10
for 4mm
Cross bite correction – facial
axis open by 10
to 1 ½0
, recovers
half the distance. www.indiandentalacademy.com

For facial patterns :
For every standard
deviation on the dolicofacial
pattern side, it opens by 10
.
And for every standard
deviation towards the
brachyfacial side, it tends to
close one degree.
Facial axis may close as with
the use of high pull headgear or
due to extraction.

Now go to the original
tracing
Superimpose at basion
along the basion-nasion
plane.
Using Dc point rotate up at
nasion to open the bite and
rotate down at nasion to
close the bite. This rotation
depends on anticipated
treatment effects.

Condylar axis and corpus axis growth
Trace the condylar axis,
coronoid process and
condyle.
On the condylar axis make
mark 1mm per year down
from point DC.
Slide the mark up to the
basion nasion line.

Extend the condylar
axis to the Xi point,
locating a new Xi
point.
With the old and new
Xi points coinciding,
flare corpus axis,
extend it 2mm per
year forward of the old
PM point (PM point
moves forward 2mm /
year in normal
growth). www.indiandentalacademy.com

Symphysis construction
go to original tracing
Slide back along the corpus
axis superimposing the new
and old PM points.
Trace the symphysis and
draw in mandibular plane.
Construct the facial plane from
NA to PO.
Construct a facial axis from
CC to Gn. (where facial plane
and mandibular plane cross).

iii) Maxillary growth prediction
Return to original
tracing
To locate the new
maxilla within the face,
superimpose at nasion
along the facial plane
and divide the distance
between the original and
new mentons into third
by drawing two marks.

To outline the body
of maxilla,
superimpose mark #
1 (superior mark) on
the original menton
along the facial plane
Trace the palate (with
exception of point A).

Point A change related to BA-NA :
Point A changes with various mechanics (maximum change)
Mechanics Maximum range
Head gear - 8mm
Class II elastics - 3mm
Activator - 2mm
Torque - 1-2 mm
Class III elastics + 2-3 mm
Face mark + 2-4 mm

As point A changes as a
result of growth and
mechanics.
Point A and a new APO
plane are drawn by
following steps.
Return to original tracing
Point A altered distally
with treatment – for each
mm of distal movement.
Point ‘A’ will drop ½ mm.

IV) V.T.O. – occlusal plane
position :
. Superimpose mark #
2 on original menton
and facial plane, then
parallel mandibular
planes rotating at
menton.
Construct a occlusal
plane (may tip 3
degrees either way
depending on class II
or class III treatment)

V) V.T.O. dentition :
Lower incisor
it is placed in relation to the
Symphysis of mandible
The occlusal plane
APO plane
Return to original tracing

. Superimpose on the corpus axis
at PM.
Place a dot representing the
tip of the lower incisor ideal
position which is 1mm above the
occlusal plane and 1mm in front of
the APO plane.
. Aligning over the original incisor
outline draw the lower incisor in
final position.
The angle is at 220
at 1mm to
the APO plane and +1mm to the
occlusal plane, but the angle
increases 20
with each mm of
compromise

Lower molar :
Without treatment, the lower molars
will erupt directly upwards to the
new occlusal plane.
With treatment 1mm of molar
movement equals 2mm of arch
length.
For example
If the incisors are moved by 2mm
we gain 4mm of space.
There is leeway space
So there was a net gain of 8mm
space so lower molars can be moved
by 4mm on each side.
. Superimpose lower molar on the
new occlusal plane at the new molar
position

Upper molar :
Return to original
tracing
Trace the upper
molar in good class I
relationship to the
lower molar by
using old molar as
template.

Upper incisors :
place upper incisors in good
overbite
Overbite position (2 ½mm of
overbite and overjet) with an
interincisal angle of 1300
± 100
.
In open bite pattern  keep a
greater angle
In deep bite pattern  keep at
a lesser angle
Do this by using the original
incisor as template.

VI) V.T.O. of soft tissues
a) Nose :
Superimpose at nasion along
facial plane
trace bridge of the nose
Superimpose, at ANS along
palatal plane
. Move prediction back 1mm
per year along the palatal
plane, trace the tip of nose
fading into bridge.

Superimpose along the facial plane
at occlusal plane.
Divide the horizontal distance
between the original and new
upper incisor tips into thirds by
using two marks.
Soft tissue point ‘A’ remains at the
same relationship to point A as in
the original tracing superimpose
new and old point A, and make a
mark at soft tissue point A.
Keeping the occlusal planes
parallel, superimpose mark # 1
(posterior mark) on the tip of
original incisor slide forwards by
2/3 rd.
Trace the upper lip connecting with
point ‘A’. www.indiandentalacademy.com

c) Lower lip, point B, soft
tissue chin :
In constructing the lower lip
Bisect overjet and overbite of
the original tracing and mark a
point.
Then bisect the overjet and
overbite of the V.T.O. and mark
the point.

Go to original tracing :
Superimpose interincisal points
keeping occlusal planes parallel.
Trace lower lip and soft tissue B
point.
The soft tissue below the lower lip
remains in the same relationship to
point B as in original tracing. Soft
tissue point B drops down as the
lower lip recontours.
Superimpose on the symphysis and
arrange the soft tissue of the chin.
It ‘drops down’ and should be
evenly distributed over the
symphysis.
(take into consideration reduction
of strain and bite opening)www.indiandentalacademy.com

Completed V.T.O. :
When all the steps
are completed we have
our V.T.O
Take the V.T.O
and superimpose in
the five areas to
establish individual
objectives for case.

Superimposition (area # 1) basion
nasion at CC.
To evaluate the facial axis change
To evaluate chin growth
Upper molar position
Superimposition area # 2  basion
– nasion at nasion for evaluating
Maxillary change
To evaluate point A change
Superimposition area # 3  corpus
axis at PM
To evaluate dentition
To evaluate anchor requirements

Superimposition area # 4
 palate at ANS
To evaluate change within
maxilla – Molars& Incisor
changes
Superimposition area # 5
 Aesthetic plane at the
intersection with occlusal
plane.
This is to evaluate the soft
tissues

DENTAL V.T.ODENTAL V.T.O

The dental V.T.O was designed to provide
organized and simplified information to help in
diagnosis, treatment planning and extraction / non-
extraction decision.
It should be used as a adjunct and not substitute
for conventional Cephalometric analysis.
It takes little time to complete and occupies
only a small part of the treatment card.
Dental V.T.O. provides specific information
concerning the movements of the midlines, canines
and molars after desired incisor position has been
established.

It can be used for both orthodontic cases
(using three charts) and surgical cases (using
five charts).

Using the three charts for
orthodontic case:
Chart 1 : is provided to record midline and molar relationship.
It is essential that these factors be recorded with the mandible in
centric relation.

Arrows are used to record the direction of class II or
class III molar relationship and left or right midline
deviation.
Midline deviations due to functional side shifts are not
recorded, since they represent deviation from centric
relation. (CR)

Chart 2 :
It records lower arch discrepancy in two columns.
The 3 to 3 column on the left, for factors occurring from canine
to canine and
The 7 to 7 column on right ; for factors related to the entire
lower arch.
Each column is further divided into right and left sides.

The following factors are recorded.
1. Crowding or spacing in anterior segment:
This recorded from canine to midline. It is recorded as
positive number for spacing and negative for crowding.
It is recorded in the 3 to 3 column. The same figures are
automatically recorded to 7 to 7 column.

2. Crowding or spacing
in premolar region :
this recorded in 7 to 7
column.
3. Crowding or spacing
in the molar area : this
is also recorded only in 7
to 7 column.

4. Curve of spee : recorded by placing a ruler from the distal molar to
the central incisor on each side of the lower arch. The deepest point in
the curve of spee can be measured in millimeters.
These are divided in half and placed on the left and right side in 3 to 3
column (curve of spee may be different on the left and right side).
Similar amounts are recorded in 7 to 7 column.

5. Midlines : negative and positive values are recorded in both 3 to
3 column and 7 to 7 column.
If lower skeletal midline deviation exists, and a decision is
made to correct these deviations with dental compensations, the
correction must be added to the lower dental midline area of chart 1
and then to chart 2.
If the skeletal deviation is to be corrected surgically, then no
correction is added to chart 2.

6. Incisor position :
Anterior and posterior movements of the lower incisors is
recorded as positive and negative values.
For eg : 1mm of anterior movement of incisor provides 1mm of
space per side.
This should be recorded on both sides of 3 to 3 column same
thing is recorded in 7 to 7 column.
Similarly if 2mm of posterior incisor movement is required
then it is recorded as minus 2mm on both 3 to 3 column and 7 to 7
column

7. Initial discrepancy :
This represents the total information gathered till this
point in the lower arch analysis.
This is an appropriate time to decide the case will be
treated on a non-extraction basis (whether it is possible
to treat the ease by proximal slenderization, expansion or
distallizing of first molars) or if extraction treatment is
indicated.

8) Interproximal enamel reduction :
If interproximal enamel reduction is indicated the
figures are recorded as positive figures in 3 to 3
column, same amount is recorded in 7 to 7 column.
If enamel reduction is needed in premolar or molar
region then it is recorded in 7 to 7 column.

9. Expansion :
If intercanine expansion is planned then it is
recorded in 3 to 3 column (source amount recorded) in 7
to 7 column.
If expansion is carried in premolar and molar region
it must be added to 7 to 7 column.

10. Distallization of lower molars :
If an attempt is made to upright or distallize the
lower first molars. The numbers are recorded in 7 to 7
column.
12. Remaining discrepancy :
This records a total initial discrepancy which is
gained.

Chart 3 :
It provides specific information on the planned movements of the
midlines, canines and molars.
Lower midline correction : this is based on the original lower dental
midline position recorded in chart 1.
Lower canine movements : this is based on the remaining discrepancy
in chart 2.
If there is a negative value then the canine should move to an
equivalent amount. A positive value requires a mesial movement of
the canine.

Lower premolar / molar space : this is space gained in the premolar,
molar area by procedures like slenderization extraction, expansion
and distallization of molars.
Lower first molar movements : this movement is based on the
required movement of canine and available space in premolar
region.
Upper first molar movement : the planned movement in the upper
arch is based on the initial molar relationship recorded in chart 1
and the movement recorded for the lower molars.
(This calculation does not take into account the growth changes)

Upper premolar / molar space : first mesial to the upper first molar
mentioned in the figure. This represents the original crowding and
spacing in the premolar region and the space gained in this region
by extraction, slenderiation arch expansion etc.
Upper canine movement : this movement is recorded based on the
movement of upper molars and space available in the premolar
region.
Upper midline correction : this is based on the original upper dental
midline position recorded in chart 1.

V.T.O in surgical cases
Here the chart 1 and
chart 2 are similar to
how we use in a non-
surgical case.
Chart 3 : planning of
lower arch tooth
movements.
It is completed in the
same way as the lower
half of chart 3 in a
non-surgical case.

Chart 4 :
Recording of upper arch
discrepancy completed
the same way as chart 2
for a non surgical case
but only for upper arch.
Chart 5 :
Planning the upper arch
tooth movements.
This is completed in the
same way as the upper
half of chart 3 of a non-
surgical case.

Computer Cephalometric
and
Video Imaging Predictions

cephalometric information into computer memory
is accomplished by digitizing points on the
cephalometric tracing.
First computer cephalometric programs were used
primarily for planning surgical treatment for
adults.
Now the commercially available programmes
allow superimposition of profile images. Either
the direct images or conventional images digitized
by scanning are used onto the tracing, so that the
doctor and patient can readily visualize the
treatment effects.

Many orthodontists routinely use cephalometric software for
case diagnosis, treatment planning and also for formulation
complete generated visual treatment objectives.
Different steps involved are:
Digitization
Display
Analysis
Treatment planning
Hard copywww.indiandentalacademy.com

Digitization is a process by which analog information in converted
into digital form.
During process of digitization the x-y coordinates of the
cephalometric landmarks are recorded and stored in a data base from
which various cephalometric measurements are made.
Digitizers may be opaque translucent or transparent. Translucent and
transparent digitizers can be backlit.

Modes of digitization
- Point mode
- Stream mode
Point mode digitization
refers to discrete location
of individual landmarks.
This is time
consuming but
landmarks can be located
more accurately.

Stream mode here the
stream of co-ordinated pairs
is recorded as the as the user
traces a radiographic
contour.
This requires the user to use
the mouse or the cursor to
trace the contour so it is
more technique sensitive.

Application in treatment
visualization
Two visualization approaches are prevalent
Image editing system
Photo cephalometric treatment visualization

Image editing system :
Here the facial images are modified using a
variety of simple image editing tools to stimulate
the effects of treatment on facial form.
The artistic skill of the operator controls the
quality of the final image.
Simple image editing applications lets the use
copy a rectangular region of pixels from one
region to another, in an cut and paste process

These rectangular
region of pixels may
also be stretched in a
horizontal or vertical
direction or
proportionately
enlarged or reduced.
These basic image
transformation
capabilities, when
performed in various
combinations, can be
used crudely to
stimulate treatment
induced facial changes.www.indiandentalacademy.com

Unfortunately the human face is rarely represented
as a collection of rectangles. So it cannot show
complex movements and changes occurring due to
this. A more sophisticated image editing approach
is to sue a process known as “tessellation”.
Digital image wrapping methods are used to
transform the pixels within the tessellated surface
to smoothly blend with the edges of the image in
the stimulated post treatment image.

Photo cephalometric treatment
visualization :
The preferred approach to treatment visualization
involves the software that extends the algorithms
used in cephalometric treatment planning
software to embrace lateral facial images.

Lateral and frontal photographs are takes with a
35mm camera are mounted on cephalometric x-ray
machine such that it is aligned with the central ray.

Positive photographic transparencies are made at a enlargement factor
required to superimpose precisely the visible metallic markers over
their radiographic equivalents.
To use cephalometric prediction as a guide for image
manipulation, the pre treatment cephalogram must be linked in a
meaningful way to the facial image.
The cephalometric profile tracing is superimposed over the image
profile and scaled, translated and rotated by the operator so that it
matches the underlying contour of the facial bit map as closely as
possible

The orthodontist performs the treatment
visualization by manipulating the skeletal and
dental structures on the Cephalometric portion of
the pair.
The predicted cephalometric profile changes are
automatically applied to the facial image regions.
The differences between the pretreatment and
predicted cephalometric profiles, when
superimposed on the image, guide the
manipulation of the regions of the bitmap during
automatic generation of image

Image standardization for
vediocephalometry
Proper vedio imaging technique has
virtually the same requirements like
radiocephalometry.
Standardization of rotational head position
Desirability of natural head position
Minimization and standardization of image
magnification
Reproducibility

Vedio imaging has other requirements like
Control of magnification and distortion of image
introduced by hard ware (like camera, monitor,
software and cephalogram)
Facial lighting requirements
Should minimize shadowing, which makes
visualization of facial contours difficult.
Relaxed facial muscles is an requirement for
appropriate evaluation, accurate prediction and
reproducibility of images.

Uses of vedio cephalometry :
Patient communication :
Impact of vedio imaging as a communication tool is
tremendous.
In a study by Kiyak and associates.
In non imaged patients 45% of patients should
satisfaction with esthetic outcomes.
Whereas in vedioimaging 85% of patients reported
satisfaction with their esthetic outcome.
This may be because the patients expectations of the
outcome are successfully modeled

Treatment in adolescent and adults :
Treatment visualization using computer vidioimaging
is different for growing and non-growing patients.
In a growing patient there are variables like
Dynamics of facial growth
In growing patients it not only involves the hard tissues
(like maxilla, mandible and teeth) but also involves the
soft tissues. This soft tissue profile in the final, adult
profile is important.
Treatment timing : treatment response is more dramatic
when it is coordinated with the growth spurt.
Local environmental factors and habits

So the use of computer vedio cephalometric
imaging is less predictable in adolescents when
compared with the adults, as the adults more static
and their treatment outcomes are more predictable.

Limitations of photocephalometric
analysis :
Facial image acquisition methods are much less well
established
variables such as
- Camera resolution.
Focal length
Distance from the camera to patient
Lighting conditions
Patients head positioning
Lip position
Mandibular postural position can and do vary greatly

Therefore the cephalometric tracing do not
accurately superimpose over the facial image.
The soft tissue changes cannot be mapped
accurately
Hence the orthodontist should exercise caution and
restraint when providing image hard copy of
treatment simulation to patients and should counsel
patients as to limitations of imaging systems

Studies done on photocephalometric
analysis :
Hohe et al  first to describe superimposition of clinical
photograph over cephalograms.
Phillips et al have measured the errors inherent in
photocephalometric superimposition i.e. whether lateral
and frontal photographs can be accurately superimposed
over lateral and frontal cephalograms.
They reported that photographic images and
radiographic images cannot be superimposed accurately at
any depth.
So photocephalometric technique cannot be implemented
accurately www.indiandentalacademy.com

Thomas J. Cangialosi et al :
Did a study on commercially available computer
prediction programme (quick ceph II) and the
computer prediction programme was compared with
the manual method of prediction was sufficient to
give a good graphic changes
However the computer offers a added advantage.
Quicker access of information and greater accuracy
in producing the tracing

Glenn ,Sameshima et al :
Did a study to evaluate soft tissue changes
prediction in an all 4 extraction case.
Result showed both V.T.O.& vedioimages were
accurate. The predicted images resembled the
treatment outcome. But one should be careful,
particularly of the lower lip area where variable soft
tissue response to treatment were noted.
They also did study on vedioimaging for mixed and
adolescent treatment and found that computer
generated V.T.O. was more accurate in mixed
dentition but unacceptable for adolescent group

THREE-DIMENSIONAL PLANNINGTHREE-DIMENSIONAL PLANNING
&&
VISUALIZATIONVISUALIZATION

To be more precise in establishing orthodontic
treatment objectives, it is useful to have tracings in
three dimensions, where the original teeth, the
bones, and the facial soft tissues are shown in the
pretreatment and posttreatment positions.
This visual representation of treatment helps the
orthodontist avoid surprises during treatment since
the actual treatment can be visualized on the
treatment-plan tracings

. These initial tracings also provide a basis for
comparison with progress tracings as well as a
comparison with the posttreatment tracings. This
final evaluation is of utmost importance in
establishing a retention plan.

Because orthodontic treatment is three-
dimensional, proper treatment planning requires
three tracings :
the lateral view (the Y-Z plane) made from the
lateral cephalometric headfilm,
the frontal view (the Y-X plane) made from the
posteroanterior cephalometric headfilm,
The occlusal view (the X1-Z1 plane) made from
the occlusogram, a 1:1 photo of the occlusal aspect
of the dental casts.

The three-dimensional
treatment objectives
are shown in three
tracings.
The lateral view, the
Y-Z plane, displays the
original tooth and
bone relationships
(black), the growth
prediction (blue), and
the final tooth position
(red).

The occlusogram shows
the planned treatment in the
X1-Z1 plane. The original
tooth position is shown in
black.
First, the final arch form is
determined;
this is shown as a red line
through the incisal edges
and the tips of the buccal
cusp
The inner gray arch
connects the future contact
areas of the teeth.

Then the treatment midline is
established ; this is shown as a
vertical gray line at the incisors
.
The mesiodistal diameters of
the teeth are marked off on the
inner gray arch so that the arch
length inadequacy can be
determined.
The distance between the
original mesial of the first molar
and the horizontal gray line is a
direct measurement of the arch
length inadequacy.

. After determining an arch
length inadequacy for each
quadrant, the decision is made
to extract upper first premolars.
The new mesial – distal contact
areas are marked.
The distance between the
horizontal red line and the
original first molar position
(black) shows the amount of
mesial movement that is
required of the molar.

Initial malocclusion
Treatment objectives
achieved

The frontal view (Y-X
plane) originating from the
posteroanterior head film.
Planning in this view is
helpful for midline
determination and the
establishment of a desirable
transverse plane of
occlusion
.
This view is particularly
important in the treatment
planning of orthodontic
asymmetries requiring
orthognathic surgery.www.indiandentalacademy.com

Current status
of three
dimensional
imaging

The craniofacial imaging database currently in
clinical use are designed primarily image
management system for storage, retrieval and
viewing of two dimensional patient images Dolphin
imaging and quick ceph systems.
These systems allow for two dimensional
measurements on a uncaliberated and uncorrelated
cephalometric images for the purpose of orthodontic
assessment.

The two dimensional images are composed of
subunits called the picture elements (pixels).
Whereas the three dimensional digital images are
composed of volumetric elements the (voxels).
The newer generation of multiscrew detector (cone
beam computed tomography) CT scanner and CBCT
allow for the acquisition of isotrophic voxels. Here
the X, Y, Z are equal in dimension.

Tremendous amount of anatomic information is contained
within the voxel volumes and this information can be
retrieved analyzed and viewed at a computer workstation
using visualization and analytical software.
From this data a three dimensional model can be created
that can be rotated as an object to be viewed from any angle.
These allow the orthodontic practitioner to manipulate the
digital patient model to stimulate treatment and dynamically
test feasibility of various treatment approaches.

SSurgicalurgical
TTreatmentreatment
OObjectivebjective

The STO is an essential two-dimensional tool in
surgical orthodontic correction of dentofacial
deformities.
The purpose of the STO is threefold:
To establish the presurgical orthodontic goals
To develop an accurate surgical objective that
will achieve the best functional and esthetic result
To create the facial profile objective, which can
be used as a visual aid in consultation.

The STO has significant importance in two phases
of treatment planning:
1) The initial STO is prepared before treatment to
determine the orthodontic and surgical goal;
2) The final STO is prepared before surgery to
determine exact vertical, anteroposterior (AP)
skeletal, and soft tissue changes to be achieved.
The STO is invaluable to the orthodontist and
surgeon in establishing treatment objectives and
projected results. It is both a diagnostic aid and a
treatment planning aid.

Initial STOInitial STO
In the initial STO, presurgical orthodontic
treatment goals must be established so that the
teeth can be relocated on the original
cephalometric tracing. An initial STO may then be
completed to relocate the hard tissues.

PRESURGICAL ORTHODONTIC GOALPRESURGICAL ORTHODONTIC GOAL
Presurgical orthodontic treatment goals must be
established by clinical examination, dental model
evaluation, and cephalometric analysis.
Orthodontic goals should be to upright the teeth
over their respective basal bone, while also
satisfying spatial requirements.

Ideal presurgical
orthodontic goals are
Position the long axis of
the maxillary incisor at 22
degrees to the nasion-point
A(NA) line with the labial
face of the incisor 4 mm
anterior to that line.
Position the long axis of
the mandibular incisor at
20 degrees to the nasion-
point B(NB) line with the
labial face of the incisor 4
mm anterior to that line.www.indiandentalacademy.com

Removal of dental compensations is
necessary before surgery for maximal
skeletal correction. Correcting the incisors
with respect to their basal bone (NA and
NB lines) will remove the dental
compensations

Ideal incisor positions and the
corresponding acceptable ANB
angles for orthodontic treatment
as advocated by Root and
Sagehorn.
Surgical skeletal correction to an
ideal 2-degree ANB angle will
produce an ideal interincisal angle
of 136 degrees when the proper
incisor goals are achieved
presurgically.
An increase or decrease in the
ANB angle will require changes
in incisor angulation to maintain
the ideal interincisal angle of 136
degrees. www.indiandentalacademy.com

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.
Thus, as the ANB angle is
increased, the upper incisors must
become less protrusive and the
lower incisors more protrusive to
achieve an acceptable interincisal
angle.
Conversely, as the ANB angle is
decreased (below 2 degrees), the
upper incisors must become more
protrusive and the lower incisors
less protrusive. www.indiandentalacademy.com

The exact orthodontic treatment plan and
anchorage requirements necessary to
position the teeth to satisfy the presurgical
orthodontic treatment must be designed by
the orthodontist to achieve that goal.
Relocation of the molar teeth will depend
on the arch length requirements (space) and
the mechanics used by the orthodontist to
achieve the ideal incisor positions.

The original cephalometric radiograph is traced in black
pencil on matt acetate. Once the initial orthodontic goals
are established, the teeth must be redrawn on the
original CT. With colored pencil.
After the teeth have been relocated on the CT tracing,
initial STO is constructed. The initial STO is helpful to :
Establish the final presurgical orthodontic goals
Establish the surgical dentoskeletal objective
Establish the genioplastic procedures with chin
evaluation
Establish the soft tissue facial profile objective.

Cephalometric parameters required to
evaluate the dental compensation due
to underlying skeletal discrepancy are:
Frankfurt horizontal plane-a line
constructed from the porion to the
orbitale
Facing axis angle -a line constructed
from basion to nasion with the
intersection at CC point. This
determines the growth pattern of an
individual.
N perpendicdular to point A- Linear
distance measured from nasion
perpendicular to point A. Evaluates the
relationship of the maxilla to the
cranial base.
N perpendicular to Pogonion – Linear
distance measured from nasion
perpendicular to pogonion. This
evaluates the relationship of the
mandible to the cranial base.

Upper incisor to facial axis – A
line passing through the long
axis of upper incisor
comparable to the parallel of
facial axis. It determines the
final torque requirements
Upper incisor to Point A
vertical – The linear distance
measured to assess the position
of the incisor in relation to its
skeletal base..
Lower incisor to MPA – This
is the angle measured from the
long axis of the lower incisor
to the MPA. It helps in
determining the relation of the
incisor to its skeletal base.
Lower incisor to A pogonion –
A line drawn from point A to
the pogonion and the position
of lower incisor is evaluated

This involves the following steps
Draw the initial tracing with orientation
reference marks including the dentition,
hard tissues and soft tissues in black.
Measure the mesio-distal width of the
first pre-molar.
Assess the existing molar and incisal
relationship to determine the anchorage
requirements and plan for the amount
of molar mesialization and anterior
retraction. E.g. template of a patient,
the molars are in end-on relation, with
the incisors in class II div. I. On
evaluation of the parameters the
dentition appears to have compensated,
indicating a requirement for dental
decompensation. www.indiandentalacademy.com

The objective is to decompensate to attain a class II
molar relation, a class II incisor relation and to
create sufficient overjet for surgical correction. If
the upper molar has to be brought into a class II
relationship it must be mesialized by approximately
3 mm and the upper incisors are retracted minimally
by 4 mm to get them into their ideal inclinations in
the skeletal base.

This can be carried out by
drawing a vertical reference
line at the extraction space
of first premolar
perpendicular to the occlusal
plane at a point
approximately 3 mm from
the second pre-molar in the
upper arch. Similarly
considering the anchorage
requirements, the total
extraction space in the lower
arch can be utilized for
maximum retraction of the
lower incisors.

Construction of vertical
reference line – To simulate the
above planned tooth movement a
vertical reference line
perpendicular to the occlusal
plane is constructed at the
extraction space. For example if
the extraction space is of 7 mm.
The vertical reference line is
constructed 3mm mesial to
second premolar dividing the 7
mm space into 3 mm (for molar
mesialization) and 4 mm for
anterior retraction

On a third tracing sheet the
occlusal plane is traced along
with the vertical reference line.
Keeping the occlusal plane and
the vertical reference line as your
guide shift the tracing forwards
in such a manner that the vertical
reference line coincides with the
mesial aspect of the second pre-
molar.
At this point the molar and pre-
molar teeth are traced and the
tracing is re-oriented.
This shows the amount of molar
mesialization to be achieved.

To simulate the amount of
anterior retraction, slide the
tracing backwards along the
occlusal plane such that the
vertical reference line
coincides with the anterior
limit of the extraction space.

In the lower arch, to
simulate anterior retraction
the tracing is slid along the
occlusal plane such that
the vertical reference line
coincides with the anterior
limit of the extraction
space.
Trace the incisors
changing its axial
inclination as desired
depicting a controlled
tipping movement.

Make the necessary
remodeling changes in
the hard and soft tissues
following dental
decompensation.
This is traced on a
fourth tracing paper with
a colored pencil. This
completes the initial
STO.

Final S.T.O
Accurate determination of skeletal movements is very
essential in treatment planning prior to the surgery. This
section is divided into three sections
1) single jaw S.T.O
2) Double jaw S.T.O
3) Chin S.T.O
The final STO is performed on the CT after the presurgical
orthodontic treatment has been completed.
Immediately before surgery a cephalometric radiograph is
taken and accurately traced with pencil on matt acetate. It
is advisable to trace all teeth to accurately determine
dental structures.

Maxillary Segmental Superior Repositioning ;
Mandibular advancement; Vertical Reduction
and APAugmentation Genioplasty
Select surgical sites and draw
appropriate surgical reference lines.
For multiple maxillary osteotomies,
extraction of maxillary first
bicuspids, bilateral mandibular
ramus osteotomies, and osseous
genioplasty, draw the following
lines:
Maxillary surgical reference lines
A horizontal line parallel to
Frankfort horizontal from the
piriform rim to the zygomatic
buttress area a minimum of 5 mm
above the cuspid apex.
A vertical line in the zygomatic
buttress area, extending inferiorly
approximately 5 mm from the
anterior horizontal reference line.

A horizontal line parallel to
Frankfort horizontal,
extending from the vertical
line to the pterygoid plates
(The completed surgical
reference lines represent the
inferior cut of the maxillary
step ostectomy.)
short vertical lines in the area
of the cuspid and the second
molar through the horizontal
surgical reference lines.
A vertical line bisecting the
first bicuspid, extending from
the occlusal surface to the
horizontal surgical reference
line of the maxilla

Mandibular surgical
reference lines
A vertical line in the area
of the vertical buccal
ramus osteotomy
A horizontal line above
the inferior border of the
mandible at the level of
the inferior cut of the
chin ostectomy

Step 1. Trace all
skeletal and soft tissue
structures that remain
unchanged by the
surgical procedures.
They include the
cranial structures and
soft tissues of the
forehead and upper
nose.

Select the desired vertical
position of the maxillary
incisor by drawing a
horizontal line parallel to
Frankfort horizontal at the
predetermined vertical
level
Then draw a vertical
reference line crossing the
horizontal line to represent
the desired anterior
position of the maxillary

Step 2. The occlusal
plane must now be
determined..
Autorotate the mandible
by placing a pencil or
other instrument in the
condylar head area.
Rotate the STO
clockwise until the
horizontal reference line
for the maxillary incisor
is approximately 2 mm
below the mandibular
incisal edge.
The amount of lower
incisor above the
horizontal reference line
indicates the desired
overbite

Step3
Trace the proximal mandibular
segment, including the vertical
surgical reference line.
The new occlusal plane can now
be established.
Occlusal plane as dictated by
the mandibular autorotation. A
line is constructed through the
cusp tips of the mandibular
molars and bicuspids and
connecting with the vertical and
horizontal reference lines
previously drawn.

. Step 4.
Position the anterior maxillary
segment.
Move the STO so that the
labial face of the maxillary
incisor is adjacent to the vertical
line and the incisal edge is on
the horizontal line.
. The more the STO is rotated
counterclockwise, the more the
incisors are uprighted.
The more the incisor teeth are
uprighted, the higher the cuspid
becomes in relation to the
newly established occlusal
plane.

Step 5.
Trace the anterior
maxillary segment, teeth,
and surgical reference
lines.
Superimposition of the
STO on the cranial base
structures will
demonstrate the
movement of the anterior
maxillary segment.

Step 6. Advance the
mandible by moving
the STO until the
mandibular teeth align
with the established
occlusal plane, with
appropriate overjet and
overbite relative to the
maxillary anterior teeth

Step 7.
Complete the
advancement by tracing
the mandibular teeth,
mandibular vertical
surgical reference line,
inferior border of the
mandible, and the
anterior portion of the
mandible above the
genioplasty reference
line

Step 8.
Position the posterior
maxillary segments.
Move the STO until the
maxillary posterior
teeth interdigitate in
Class II molar
occlusion with the
mandibular teeth of the
STO.
Align the mesial
surface of the second
bicuspid crown with the
distal surface of the
cuspid crown www.indiandentalacademy.com

Step 9.
Trace the posterior
maxillary segment,
teeth, and surgical
reference lines..

Step 10.
Remove the STO and
construct an NB line on the
STO.
This line is can be used to
determine the desired AP
position of the chin.
Measure from the labial
surface of the lower incisor
to the NB line on the STO.
This measurement is
approximately 5 mm.
For proper facial balance,
the chin should be an equal
distance in front of the NB
line.
Superimpose the
mandibles of the STO and
the CT.

Determine the desired vertical
position of the chin from the
clinical evaluation and
cephalometric analysis.
A horizontal line is drawn from
this mark posteriorly to the
inferior border of the mandible.
This represents the desired
superior osteotomy.
The space between the two
surgical reference lines
indicates the amount of bone to
be removed with the procedure
Step 11. Superimpose the
superior surgical reference line
of the chin and the inferior
surgical reference line of the
chin. www.indiandentalacademy.com

Step 12. Slide the chin
forward keeping the
surgery lines
superimposed, until the
anterior portion of the
chin approximates the
vertical reference line.

Step 13.
Trace the osseous
chin segment.

Step 14.
Superimposition of
the cranial base
structures
demonstrates the
surgical movements.
. Positional alteration
of the dentoalveolus
will influence soft
tissue change of the
lip and nose
.

Step15
As the supporting lip
structures are moving for
ward; the soft tissues of
the lip and nose will
move forward also.
The amount of soft
tissue change of the
upper lip and nose will
depend on the method of
soft tissue management.
Trace the soft tissues in
the new position.

Step 16.
To determine soft tissue
change in the chin area,
align the chin of the STO
as well as possible with
the chin of the CT,
keeping the Frankfort
horizontal planes
relatively parallel to each
other.

Step 17.
Draw in the soft
tissues of the chin up
to the level of the
horizontal reference
line of the chin.

Step 18. Align the labial
surface of the
mandibular
dentoalveolus of the
STO with the
dentolveolus of the CT.
For a vertical reduction
genioplasty, vertically
align the horizontal
genioplasty surgical
reference lines, and align
the labial aspect of the
dentoalveolus and
incisors as well as
possible.

Step 19.
Trace the remaining soft
tissues of the chin and
lower lip area.
The lower lip will be
elevated relative to the
lower incisors because
of the vertical reduction
and increased AP chin
position.
Note that some artistic
interpretation is
necessary in the
positioning of the lower
lip on the STO. www.indiandentalacademy.com

Step 20.
Superimposition of the
cranial base structures
will demonstrate the
osseous and soft tissue
changes.

SOFT TISSUE PREDICTION
Soft tissue changes are very important in the
determination of final profile results and should be
projected as accurately as possible.
However, determining soft tissue changes in
orthognathic surgery is less exacting than
predicting dental-osseous alterations.
The soft tissue may move significantly different
than the osseous structures, creating difficulties in
determining accurate soft tissue changes on the
STO.

P (pronasale) : The most prominent or anterior
point of the nose
Sn (subnasale) : 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 labrale superius.
UL (labrale superius) : The most anterior point
on the upper lip.
St (stomion upper lip) : The most inferior point
on the upper lip.
LL (labrale inferius) : The most anterior point
on the lower lip
B’ (soft tissue B point) : The point of greatest
concavity of the lower lip between labrale
inferius and soft tissue pogonion.
Po’ (soft tissue pogonion) : The most anterior
point on the soft tissue chin.
Me’ (soft tissue menton) : The most inferior
point on the soft tissue chin.

PROCEDURE SOFT TISSUE
ANATOMIC POINTS
% CHANGE
Advancement LL+
B’
PO’
67-85
100
100
Setback UL
LL
B’
Po’
20
90
90
90

ANATOMIC POINTS
% CHANGE
Subapical advancement LL 60
Subapical setback LL 75

ANATOMIC POINTS
CHANGE
Advancement P
UL
St
30%
50%
Unpredictable
Setback Sn
A
UL
St
30%
30%
50%-65%
Unpredictable

ANATOMIC POINTS
CHANGE
Superior repositioning P
Sn
UL
St
20%
20%
30-40%
20%-40%
Inferior repositioning St 15%

ANATOMIC POINT
LITERATURE
REVIEW CHANGE
AP augmentation (osseous) Po’ 75% -80%
AP augmentation
(alloplastic)
Po’ 80%-85%
Vertical augmentation
(osseous)
Me’ 100%

ANATOMIC POINT
LITERATURE
REVIEW CHANGE
Vertical reduction (inferior
border ostectomy)
Me’
Po’
- 30%
-25%
Vertical reduction (wedge -
Kole)
Me’ 90%

ANATOMIC POINT
LITERATURE
REVIEW CHANGE
AP reduction (anterior
ostectomy)
Po’ 25%
AP reduction (sliding
osteotomy)
Po’ 90%

Conclusion
The dependence of the orthodontists
towards cephalometrics has grown since the
time of its inception in the field of
orthodontics. It would be wiser however to
look on the cephalometric readings with a
clinical eye to make the ideal use of this
tool.

Proffit-Contemporary Orthodontics
Ricketts –Bioprogressive therapy
Arnett ,McLaughlin – Facial And Dental Planning For
Orthodontists And Oral surgeons
Vizas – Atlas Of Advanced Orthodontics
Burstone , Marcott – Problem Solving In Orthodontics
Graber,Vanarsdall – Orthodontics Current Principles
and Techniques -3rd
Edition
ReferencesReferences

Graber ,Vanarsdall – Orthodontics Current principles and
techniques -4th
edition
Renkye – Orthognathic surgery
Wolford, Hillard,Dugan- Surgical treatment objective.
Athanasios – Orthodontic Cephalometry.
Jacobson - Radiographic cephalometry
Graber ,Rakosi, Petrovic -Dentofacial orthopaedics with
functional appliances
Frankel & Frankel- Orofacial Orthopaedics with
functional regulator
References…References…

McLaughlin, Bennett. The Dental VTO: an analysis
of orthodontic tooth movement. JCO 1999,23:394-
403.
Hoss, Sameshima et al. The accuracy of video
imaging for mixed dentition and adolescent
treatment. The Angle orthodontist, 1997, 67:355-
364.
Thuan ,Sameshima et al. The role of computerized
video imaging in predicting adult extraction
treatment outcomes. The Angle orthodontist, 1998,
68:391-400.
John Eastman. Computer assisted orthognathic
surgical treatment planning. The Angle orthodontist,
1992, 62:227-234.

Philips et al-Photocephalometry errors of projection and hand
mark location. Am J Orth 1984,vol 86,239-245.
Image analysis and superimposition of 3D cone beam computed
tomography model-AMJODO 2006;129 611-618
B.Mollenhauer,Vto course notes ribbon arch brackets news letter
Aug 1993 1-6
Ricketts. The value of cephalometrics & computerized technology.
The Angle orthodontist, 1972, 42:179-199.
Thomas Cangialosi –Relaibility of computer generated prediction
tracing -The Angle orthodontist, 1995, 65:277-284.

David M. Sarver. Video cephalometric diagnosis- a
new concept in treatment planning. AMJODO
1996,11:128-134.
Bonham Magness ,Mini visual treatment objective
A.J.O.DO May 1987,361-374
Reed Holdaway ,Soft tissue cephalometric analysis
and its use in orthodontic treatment planning –part-I
AJO 1983 vol84 ;1-28
Reed Holdaway ,Soft tissue cephalometric analysis
and its use in orthodontic treatment planning –part-II
AJO 1984; 85:271-293.

Thank youwww.indiandentalacademy.com

VTO (visualised Treatment objective)

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