3.model analysis

Model Analysis
By,
DR KARAN PUROHIT
DEPT OF ORTHODONTICS
M.S.R.D.C.

contents
Introduction on Study models
Study model analysis
Pont’s analysis
Linderharth analysis
Korkhaus[ ant. dental arch length] analysis
Korkhaus[ palatal ht.]analysis
Ashley howe’s analysis
Bolton’s analysis

Nance analysis
Carey’s Arch perimeter analysis
Lundstorm analysis
Peck& peck analysis
Little’s irregularity index
Mixed dentition analysis--
Huckaba’s analysis
Moyer’s
Tanaka &johnston
Nance analysis
 hixon oldfather

Total space analysis
Merrifield
Tweed analysis
Computerized Digital Model Analysis
E-models
Orthocad Technology
Conclusion
References

DEFINITION
• Positive reproductions of the maxillary and
mandibular dental arches and alveolar processes,
including the hard palate, mucobuccal, mucolabial,
sublingual folds and associated muscle and
frenum attachments.
Orthodontic study models are essential diagnostic
records, which help to study dentition and
occlusion from all three dimensions.

 Purpose of Making
Study Models

1. It is a valuable aid in planning treatment as
they are three-dimensional records of patients
dentition.
2. Occlusion can be visualized from all aspects.
3. Provide a permanent record of the
intermaxillary relationships and the occlusion
at the start of therapy..
4. Help us to monitor changes taking place
during tooth movements.

5. Helps to motivate the patients as they can visualize
the treatment progress.
6. They are needed for comparison purposes at the end
of treatment and act as a reference for post treatment
changes.
7. In case the patient has to be transferred to another
clinician , study models are an important record.

Objectives of Ideal
orthodontic Study
Models

ARTISTIC PORTION
ANATOMIC PORTION
ARTISTIC PORTION

In a well fabricated set of study models the ratio of
the anatomic portion to artistic portion should be
3:1
artistic
anatomic

Study model (Study Cast) analysisStudy model (Study Cast) analysis
is a three-dimensional assessment of the maxillary
and mandibular dental arches and the occlusal
relationships.

Space availability & requirement
Tooth size – arch width discrepancy
Tooth size – arch length discrepancy
u/l tooth size discrepancy
Tooth shape discrepancy
Estimation of size of unerupted teeth
ADVANTAGESADVANTAGES

DISADVANTAGESDISADVANTAGES
Model analysis is not correlated with other important
diagnostic criteria such as cephalograms and
panoramic radiographs.
 In model analysis actual value of the individual case
is compared with the standard values of the ‘Normal
arch’. With present day knowledge, this method is
often considered to have minimal diagnostic value.

Sum of Incisors- anterior and Posterior arch width
In 1909 Pont devised a method of
predetermining an “ideal” arch width based
on the mesiodistal widths of the crowns of the
maxillary incisors.

Pont suggested that the ratio of combined incisors to
transverse arch width (as measured from the centre of
the occlusal surface)was ideally 0.8 in bicuspid area
and 0.64 in first molar area.
The maxillary arch be expanded 1 to 2mm more during
treatment than his ideal to allow for relapse.

Sum of upper Incisors (SI
u):
The maximal mesiodistal
width of each maxillary
incisor is measured and the
single values are added
together.

Anterior and posterior arch width
Reference points:
 Maxilla anterior:
Lower-most point of the
transverse fissure of the
first premolar (distal pit)
 Maxilla posterior :
Point of intersection of the
transverse fissure with
the buccal fissure of the
first permanent molar
(mesial pit)

Determination of the ideal values of the anterior
and posterior arch width from the Pont index formula:
Ideal value for anterior arch width (at premolars)
= SI X100
80
Ideal value for posterior arch width (at molars)
= SI X100
64

Pont’s analysis helps in determining
Dental arch is narrow or normal
Need for lateral arch expansion
How much expansion is possible at PM and molar
area.

The deviation in the transverse development of the arch width is
represented by the difference between the actual and the standard
(calculated) values.
If the actual value is greater than calculated normal
value, the arch is wider for the sum of incisor width and
no scope for expansion.
If the actual value is less than calculated normal value
then the arch is narrow for the sum of incisor width and
there is scope for expansion

Drawback’s of Pont’s analysis:
Pont has carried out his study on French population. So
the standard can not be taken for granted for other
population.
 All his measurements and predictions were related to the
maxillary dental arch only.
Sum of upper incisors can be variable e.g. peg laterals, so
inference can be misleading.

Tonn formula(SI L):-
If upper central or lateral
incisors are missing,
determinations may be made
based on the sum of the
lower incisor width using the
Tonn Formula for all four
upper incisors which
calculates the approximate
width.
Tonn Formula
SI u= SI L X 4 + 0.5
3

Correlation table between the sum of upper
incisors and dental arch width
Table of mean values for arch width assessment according to different investigators (Weise
and Benthake, 1965)

Pont’s Index as applied on Indians: D.S.Gupta et
al: Angle Orthodontist: Vol: 49: No:4, Oct 1979
One hundred dental models of normal occlusion was
evaluated to check the reliability of Pont’s Index on a
Indian population.
Premolar index and molar index were found to be
81.66 and 65.44 as compared with Pont’s original 80
and 64.

 Similar to Pont-Index
 He made a variation in the formula to determine the calculated
premolar and molar value (Rhine-land population)
 Ideal value anterior arch width = SI u X 100
85
Ideal value posterior arch width = SI u X 100
65

Anterior Dental Arch Length
Perpendicular distance from the most anterior labial
surface of the central incisors to the connecting line of the
reference points of the anterior width in the midsagittal plane.
L U: maxilla, L L : mandible
measurements reveal
anteroposterior malpositioning
of the anterior teeth.
L U and L L - not only altered
by malpositioning of the
anterior teeth, but also by
migration of first premolars.

Correlation between maxillary and mandibular arch
lengths
Standard Value L L = standard value L u -2mm
 Anterior arch length of the
mandible (LL) is shorter than
the maxillary arch length (L
u) by labiolingual width of
the incisal edge of the upper
central incisor.

Correlation table between SI u and L u
 Korkhaus (1938): Formula for calculating the standard value of
the upper anterior arch length
L u = SI u X 100
160
SI u 27 27.5 28 28.5 29 29.5 30 30.5 31 31.5 32 32.5 33 33.5 34 34.5 35 35.5 36
Korkhaus 16 16.3 16.5 16.8 17 17.3 17.5 17.8 18 18.3 18.5 18.8 19 19.3 19.5 19.8 20 20.5 21
Weise 16.4 16.6 16.8 17 17.2 17.4 17.6 17.8 18 18.2 18.4 18.6 18.8 19 19.2 19.4 19.
6
19.8 20
Brune 16.6 16.8 16.9 17.1 17.2 17.3 17.5 17.6 17.8 17.9 18 18.2 18.4 18.6 18.7 18.8 18.
9
19 19.2

Interpretation of measurements of anterior arch length
Finding Anterior arch length
Bilateral mesioversion of posterior teeth L u / L L shortened
Linguoversion of anterior teeth L u / L L shortened
Labioversion of anterior teeth L u / L L increased
Bimaxillary dental protrusion
L u
+L L increased
Distoversion of premolars L u / L L increased
Mandibular prognathism L L increased

In 1939
Evaluates palatal shape acc. to index..
Vertical line perpendicular to the midpalatal raphae
which runs from the surface of the palate to the level
of occlusal plane .
 Measured between the reference points of the Pont-
Index for posterior teeth.

Palatal height is defined as the distance of perpendicular
from connecting line between the midpoint of the fissure of
both Upper 1st
molars to the surface of palate.
[3 dimensional orthodontic divider]

Palatal height index= Palatal height X 100
Posterior arch width
 Average index value- 42%
 > when the palatal vault relative to the transverse
arch development is high,
 < when the palate is shallow.

 Ashley Howe considered tooth crowding to be
due to deficiency in arch width .
 Relationship between the total width of the MD
diameters of the teeth anterior to the 2nd
permanent molars & the width of the dental
arch in the 1st
PM region.
 It is a Formula for determining whether the
apical bases could accommodate the patient’s
teeth.

PROCEDURE
Refers to sum of the
mesiodistal width of
the teeth from first
molar to first molar
TTM:- Total Tooth Material

PMD:- Premolar
Diameter
arch width measured
from the buccal cusp
tips of the first
premolar on one side
to the buccal cusp tip
on other side

PMBAW:-Premolar basal
ach Width
measured from the root
apices of the first premolar
on one side to the first
premolar on other
side(CANINE FOSSA TO

Howe believed that the PMBAW(he called it
the canine fossa diameter) should equal
approximately 44% of the mesiodistal width
of the 12 teeth in the maxilla if it is to be
sufficiently large to accommodate all the
teeth.

When the ratio of PMBAW/TM is less than 37%,
Howe considered this to be a basal arch deficiency
necessitating extraction of premolars.
If the PMBAW is greater than premolar coronal arch
width (PMBAW > PMD) expansion of the premolar
can be undertaken safely whereas expansion is
contraindicated if PMBAW < PMD.

Thus Howe’s analysis is useful in planning treatment of
problems with suspected apical base deficiencies and deciding
whether to
 Extract teeth
 Widen the dental arch
 Or expand rapidly the palate
Howe’s analysis is more logical and superior to the Pont’s
index as it is applicable to each arch and and is widely used.

(Wayne A Bolton, 1958)
 Bolton studied the interarch effects of discrepancies in
tooth size to devise a procedure for determining the
ratio of
1.Total mandibular versus Total maxillary tooth size
and
2. Anterior mandibular versus Anterior maxillary
tooth size.

Study of these ratios helps in:
 Estimating the overbite and overjet relationships
that will likely be obtain after treatment is finished.
 Effects of contemplated extractions on posterior
occlusion and incisor relationships.
 Identification of occlusal misfit produced by
interarch tooth size incompatibilities.

Overall Ratio = Sum of mandibular “12” X 100
Sum of maxillary “12”
 A mean ratio of 91.3 will result in ideal overbite
and overjet relationships, as well as posterior
occlusion.

 Overall Ratio > 91.3 : Difference between the actual
and desired mandibular measurement is the amount of
excessive mandibular tooth material.
 Overall Ratio < 91.3 : Difference between actual
maxillary size and desired maxillary size is the
amount of excess maxillary tooth material.

If overall ratio is less than 91.3%
indicate maxillary tooth material excess….
amount of max. excess is determined using the formula
max.12 -- mand.12 × 100
91.3
if overall ratio is more than 91.3%
indicate mand. Tooth material excess
Amt of mand excess determined by formula
Mand 12 -- max.12 × 91.3
100

Anterior Ratio = Sum of mandibular “6” X 100
Sum of maxillary “6
A mean ratio of 77.2 will provide ideal overbite and
overjet relationships, if the angulation of the incisors is
correct and if the labiolingual thickness of the incisal
edges is not excessive.

 Anterior ratio > 77.2 : There is excessive mandibular
tooth material.
 Anterior ratio < 77.2 : There is excessive maxillary
tooth material.

Table of average values for overall and anterior ratio

Limitations:
Bolton analysis is applicable only to permanent
dentition.
 Bolton Analysis predictions do not take in to
account the sexual dimorphism, particularly with
maxillary cuspid widths.
 Since maxillary cuspids are disproportionately
larger in men than in women and ideal overbite
and overjet, as defined by Bolton is less apt to be
achieved in men.

Space Analysis
To quantify the amount of crowding within
the arches since the treatment varies
depending on the severity of the crowding.
Principle : Since malaligned and crowded
teeth usually result from lack of space, this
analysis is primarily of space within the
arches.

It requires a comparison between the amount of
space available for the alignment of crowded teeth
and amount of space required to align them
properly.
Analysis can be done directly on the dental casts.
Analysis can be done by 2 methods—
1.nance& carey analysis
2.lundstrom segmental analysis

The Nance and
Carey’s Analysis
:

 Arch length discrepancy.
 Originally Nance (1947) described a method of determining
mandibular arch length in mixed dentition.
 Later in 1949 Carey modified Nance’s method for permanent
dentition. This analysis is usually done in lower arch.

 The same analysis when carried out in upper arch is
called as Arch
Perimeter
analysis.

 Recording the mesiodistal width
of each tooth mesial to the first
permanent molar.
The sum total width corresponds
to the necessary space required
(ideal dental arch length).

 The actual length is
measured with the aid of
a soft brass wire.
This is contoured to the
individual arch shape and
placed on the occlusal
surfaces over the contact
points of the posterior
teeth and the incisal edges
of the anteriors.

The brass wire should be passed along the cingulum of
the anterior teeth if anteriors are proclined and along the
labial surface if anteriors are retroclined.
The distance between the mesial contact points of the first
permanent molars(recorded from the straightened wire) is
the amount of space available in the dental arch (actual
arch length

The assessment of space relationship is the result of the
difference between the ideal and actual arch length.
 Negative value = space deficiency.
 Positive value = space excess.
 If the arch length discrepancy is
 0 to 2.5mm :- Proximal stripping can be carried out to reduce
the minimal tooth material excess.
 2.5 to 5mm :- Extraction of second premolar is indicated.
 Greater than 5mm :- Extraction of first premolar is usually
indicated.

The Lundstorm
Segmental
Analysis

Indirect assessment of dental arch perimeter
 Division of the dental arch in to six straight line segments
of two teeth per segment, including first permanent
molars.
 Recording the mesiodistal width of the twelve teeth.
 Summing the individual tooth width of each segment.

The available
mesiodistal space on
the study cast
separately for each
segment is recorded.
 sum of the
differences between
ideal and actual length
of each segment
expresses the space
relationship.

Peck and Peck presented data which indicated that the
presence or absence of lower incisor crowding was related to the
shape of the lower anterior teeth.
It is based on the finding that individuals with ideal incisal
arrangement had smaller mesiodistal width and larger
labiolingual width than in persons with incisal crowding.
 Measure the MD width of lower incisor individually
 Measure the FL width of lower incisors individually.

The Peck and Peck index is calculated by the
formula:
MD mandibular incisor crown width mm × 100
FL mandibular incisor crown width mm

 This Index is calculated separately for lower centrals and
laterals and compared with ideal mean values and expressed in
%.
 Ideal mean values :
 Lower Centrals: 88-92%
 Lower Laterals: 90-95%.
If the calculated value is greater than the mean value, then it is
suggestive that MD width is more than FL width.
 Hence proximal stripping can be indicated to relieve crowding
and there by alter the ratio so that it is in favourable range.

• 1Robert.m little [1975]
• A quantitative score of mandibular anterior alignment
• the linear displacement of the anatomic contact
point is measured and the sum of these five
displacements is calculated which represents the
relative degree of anterior irregularity.

Material and methods
Dial caliper calibrated to at least tenth of a mm
.
Mandibular casts
Measurements are obtained directly from the
mandibular cast.
Caliper is held parallel to the occlusal plane.
Each of the five measurements represents a horizontal
linear distance between the anatomic point of the
adjacent teeth.

Each cast was subjectively ranked on a scale ranging
from 0-10
 0 perfect alignment
 1-3 minimal irregularity
 4-6 moderate irregularity
 7-9 severe irregularity
10 Very severe irregularity

 determine the difference between
space available and space required for
the unerupted permanent canines and
first and second premolars.
 supporting zone-- distance between
the distal surface of the permanent
lateral incisor and the mesial surface
of the first permanent molar.
 Comprises of deciduous canines
and the first and second deciduous
molars.

Moyers Mixed Dentition
Analysis (1967)

Prediction from Proportionality Tables
Lower incisors are measured to predict the size of upper as
well as lower posterior teeth
 Erupt early into the mouth in the mixed dentition.
 Easily measured accurately.
The maxillary incisors are not used in any of the predictive
procedure since they show too much of variability in size and
their correlations with other group of teeth.

Procedure --
 Measure the greatest mesiodistal width of each of the
four mandibular incisors with tooth measuring gauge
or a pointed Boley gauge.
 Record these values in mixed dentition analysis form.

Determine amount of space needed for alignment of the
incisors:
Set the Boley gauge to a value equal to sum of the widths
of left central and lateral incisors.
 Place one point of the gauge at the midline of the alveolar
crest between the central incisors and let other point lie
along line of the dental arch on the left side.
 Mark on the tooth or the cast the precise point where the
distal surface of the lateral incisor will be when it has been
aligned.
Repeat the process for the right side of the arch.

 Compute the amount of space available after incisor
alignment to,, do this
measure the distance from the point marked in the line of
the arch to the mesial surface of the first permanent molar.
Record the data for both sides.
This distance is a space available for the cuspid and two
bicuspids .

Measurement of supporting zones

Prediction of size of combined width of the
mandibular cuspid and bicuspid:
Done by using probability charts. The value at 75% level is
chosen as the estimate, since it has been found to be the
most practical from a clinical standpoint.
Record these values for both the sides and each arch.

 Compute the amount of space left in the arch for molar
adjustment by subtracting the estimated cuspid and
bicuspid size from the measured space available in the
arch after alignment of incisors.
 Record these values for each side.

Mixed Dentition
Analysis Form
Method of Localization
of Space needs in the
mixed Dentition

Probability tables for Predicting the Sizes of
Unerupted Cuspids and Bicuspids

• The predicted tooth size of 3,4 and 5 is compared
with the arch length available for them to
determine the discrepancy
• If the predicted value is greater crowding of the
teeth can be expected.

Tanaka and Johnston Analysis
Tanaka and Johnston prediction values
One half of the
mesiodistal width of
the four lower
incisors
+10.5mm =
Estimated width of mandibular canine
and premolars in one quadrant
+11.0mm =
Estimated width of maxillary canine
and premolars in one quadrant
Advantage:
 Does not require radiographs and reference
tables.
Drawback:
 Method is less accurate for populations other
than European.

 The mesio-distal width of the mandibular central and lateral
incisor is obtained from the casts.
Determine the width of the un-erupted premolars from the
intra-oral peri-apical radiographs .
Hixon and Oldfather’s
method—

Add the width of central and lateral incisors with the width of
un-erupted premolars of that particular side.
The estimated sum total width of the cuspids and bicuspids of
that particular side can be obtained from the given chart

Every measured sum width of incisors and bicuspids has a
corresponding sum width of the cuspids and bicuspids in the
chart.
Measured values in mm.Measured values in mm. Estimated tooth size in mm.Estimated tooth size in mm.
2323 18.418.4
2424 19.019.0
2525 19.719.7
2626 20.320.3
2727 21.021.0
2828 21.621.6
2929 22.322.3

Combined
Radiographic-
Prediction Table
Method
The method of Hixon and Oldfather(1956), modified
by Staley and Kerbers(1980) is restricted to the
analysis of supporting zone in the mandible.

Measurement of size of unerupted first and second
premolars in one mandibular quadrant from a periapical
radiograph.
 Determination of mesiodistal tooth width of the lower
central and lateral incisors on the study cast corresponding
to the side of the radiograph.
 After adding together both figures, the probable width of
the permanent canine, first and second premolars for the
corresponding quadrant can be read off in the prediction
graph under the column of sum total.

Chart for combined radiographic-
prediction table method
Prediction Graph
 X-axis: Sum of mandibular incisor width measured on the dental cast and the
total width of the first and second premolars measured on the periapical
radiograph.
 Y-axis: Predicted total width of permanent mandibular canine, first and second
premolars.

Huckaba’s analysis.
Both study models as well as radiographs are used for
determining the width of un-erupted tooth.
With radiograph, it is necessary to compensate for the
enlargement of the radiographic image.
This can be done by measuring an object that can be seen
both on radiograph and and on the study model, such as a
primary molar tooth.

After the measurement, a proportional relationship can
then be established as follows:
Actual width of primary molar(X1) =
Apparent width of primary molar(X2)
Actual width of unerupted premolar(Y1)
Apparent width of unerupted premolar(Y2)
Or Y1= X1×Y2.
X2
This technique can be used for all ethnic groups.

Amount of space required
width of the erupted four mandibular permanent
incisors are measured.
width of unerupted mandibular canines, first and
second premolars on the radiographs are measured.

Amount of space available
 A piece of .026 inch brass ligature wire is placed on
the lower cast extending from the mesial surface of
the first permanent molar on one side of arch to the
mesial surface of the first permanent molar on the
opposite side.
 wire should pass over the buccal cusp of the
posterior teeth and the incisal edges of anterior teeth.
Two measurements are compared .

CONVENTIONAL METHOD
Space required-
Four mand. Incisors-greatest MD dia. measured.
 MD width of Unerupted canines & PM’s [ on R/f]
 All added
Space available-
Carey’s AND arch perimeter
Discrepancy found

Tweed method;-
Here the values for space required and space available
were obtained from conventional method.
Assessment of relation b/w axial inclination of
mandibular Incisors & basal bone made on tracing of
lateral cephalogram.
Amt. of alveolodental protrusion or retrusion assessed &
incorporated in analysis.
Tweed established foll. Relationships—
When FMA [21 -29], FMIA shud be [68]
When FMA [30 or >],FMIA shud be [65]
When FMA [20 or<] IMPA shud not exceed [92]

If for a specific FMA , FMIA did not correspond,
an objective line was traced to form the required FMIA..
Distance btw this objective line & line that passed thru the
actual axial inclination of the mand. Incisors measured vid
calipers..
This figure multiplied by 2 to include rt & lt sides.
This was then added to diff. btw space required & space
available to yield total discrepancy..

Total space analysis
Divided into 3 areas—
Anterior area & Middle area& Posterior area
Anterior area—Measurmnt of mand incisors
on cast & canine 4rm R/F.
Cephalometric correction as per Tweed method
Here, the cephalometric correction done by
Actual FMIA [in degrees],subtracted from proposed angle
and The diiference was multiplied by constant (0.8) to
give difference in mm.

Soft tissue modification—
Measure ‘Z’ angle of merrifield & add ceph correction to
it.
If z angle> 80,mand incisor inclination
modified[IMPA92]
IF angle<75, additional uprighting of mand. Incisors
Upper lip thickness was measured[vermillion bordr to
greatest curvature of labial surf. Of C.I.
Total chin thickness measured[soft tissue chin to NB line]
If lip thickness >chin thickness difference was determined
× 2 & dis added to space requiremnt
If lip thickness was less or equall to chin thickness no soft

Middle area—
Tooth measurement is done by adding MD width of perm
mand. 1st
molar, to measurement of PM’s [r/f]
 Curve of occlusion —
Space req to level the mand curve of occlusion which is
determind by using Flat object placed on occ surfaces of
mand teeth contacting 1st
perm molars & incisors..
Deepest pt. btw this flat surf & occ surf of primary molars
was measured. Formula to evaluate curve of occlusion
Rt side depth+lt side depth +0.5
2
All added to tooth measurement to complete space
required..

Posterior area—
Space required—
Sum of MD of two 2nd
& 3rd
molars[if unerpted, r/f]
If 3rd
molars not visible on R/F, then wheeler’s measurement
used---
x= y- x’
 y’
X= estimated value of perm mand. 3rd
molar
X’ = wheeler’s value for 3rd
molar
Y=actual size of the 1st
perm molar on the cast
Y’=wheeler’s value for 1st
molar.

SPACE AVAILABLE—
Brass wire method in all 3 areas
Anterior area— place brass wire from MB of primary 1st
mand. Molar to opposite molar,wire is straightened &
measured with caliper.
Middle area—2 wires used ,MB of primary 1st
molar to
DB of the permanent 1st
molar.

Posterior area—
space available consisted of space presently available &
estimated increase or prediction.
Estimated increase was 3 mm per year[1.5 mm side] Until 14
yrs for girls & 16 yrs for boys
Age of patients was subtracted by 14 or 16
Result was multiplied by 3 to obtain estimated increase for
individual .
To determine Space presently available-
Measure distance on occlusal plane btw perpendicular drawn
from occlusal plane tangent to distal surf of perm 1st
molar to
anterior Border of ramus on lat ceph.
Diff in space available & required---discrepancy..

Computerized
Digital Model
Analysis

Plaster models are digitized by 3D surface scanning using laser
beam and converting into a 3D Image.
Tooth dimensions and arch width are measured on the digital
cast virtually using measuring tool.
The analyses are done by a computer algorithm/software
automatically.

Computerized software are now capable of scanning
study models and storing the scanned data as 3D
images.
3D digital study models are designed to over come
the problems –
Storage and Retrieval
Diagnostic Versatility
Transferability
Durability

Constructed through a laser
scanning process that digitally
maps the geometry of a
patient’s dental anatomy to a
high resolution 3D digital
image with an accuracy of +.
01mm.
A laser stripe is projected onto
the surface of the plaster cast &
a digital camera is used to
analyze distortions in the stripe.
The plaster cast is oriented on
all axes to expose all its
surfaces for scanning.
e - models:

This process produces 3D
vertices that are connected into
thousands of triangles to form the
3D image.
The software then displays the e-
model on the computer screen by
assigning color shades to each
triangle based on its relative
orientation to a digital light
source.
This results in a high-resolution
3D image that can be viewed
measured & manipulated on the
computer screen as if the cast is in
your hand.

Ortho CAD TM Technology
OrthoCADTM software has been developed by CADENT,
Inc. (Computer Aided DENTistry, Fairview, NJ) to
enable the orthodontist to view, manipulate, measure and
analyze 3D digital study models easily and quickly.
The operator can browse and
view the models separately
and together from any
direction and in any desired
magnification on screen.

The software comes with
several diagnostics tools
such as:
 Measurement analyzes
e.g. Bolton analysis,
arch width and
length analysis

Advantages
OrthoCADTM are simpler and more effective method of
measuring and storing data taken from the ‘virtual’
models.
Simpler storage and integration into the patients ‘digital’
file, along with digital photographs, x-rays and clinical
notes.
Simpler retrieval and viewing along with the patients
other clinical data.
Easy transferral to others in the patient healthcare circle.

Disadvantages
Virtual models cannot be mounted and articulated in
reference to the patient’s tempero-mandibular joint
function, although the jaw alignment assessment software
does approach this partially.

Conclusion
There are numerous model analysis based on different
criterias.
Now it is left to the orthodontist to accept which ever
analysis he feels best suits his group of population and his
diagnosis and treatment planning.
The basis remains the same only the ways to express it
differs

References--
Proffit WR: Contemporary Orthodontics
Moyers : Handbook of Orthodontics
Thomas rakosi:orthodontic diagnosis
Bolton WA: Disharmony in tooth size and its relation to the
analysis and treatment of malocclusion. Angle Orthod
1958;28:113.
Ponts analysis ;AO- vol 40,april ,1970

Harvey peck,sheldon peck—peck&peck analysis ajo,vol
61,384-401;1972
Littles analysis, ajo 1975,vol 68
Richard d faler,burstone,david-computerised interactive
ortho t/t planning ajovol73,36-46,1978
Orthocad-digital model for digital era-journal of
orthodontics,vol 31,344-347,2004
Computer based digital models—ao ,vol 74,2004

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