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ORIGINAL ARTICLE

Novel method of 3-dimensional soft-tissueanalysis for Class III patients

Marko Bozic,a Chung How Kau,b Stephen Richmond,c Maja Ovsenik,d and Natasa Ihan Hrene

Ljubljana, Slovenia, Houston, Tex, and Cardiff, United Kingdom

Introduction:The aim of this study was to evaluate 3-dimensional facial shells by incorporating a population-

specific average template with a group of Class III subjects preparing to have orthognathic surgery. Methods:

The Class III group included 14 male (MCIII) and 15 female (FCIII) subjects. We used 43 male and 44 female

Class I subjects to construct average male (AvM) and female (AvF) faces. Coordinates of 3 points on the facial

templates of groups MCIII and FCIII and the templates AvM and AvF were compared. MCIII-AvM and

FCIII-AvF superimpositions were evaluated for differences. Results: Vertical distances (sella to soft-tissue

pogonion) were statistically significantly higher for the AvM (9.1%) and MCIII (10.1%) than for the AvF and

FCIII, respectively (P\0.05). The distances of soft-tissue pogonion in the horizontal x-axis were positive in

80% of the FCIII group and 85.7% of the MCIII group. The Class III subjects differed from the average face

in the lower two thirds, but, in 50% (MCIII) and 60% (FCIII), they differed also in the upper facial third.Conclusions: (1) The average and Class III Slovenian male morphologic face heights are statistically signifi-

cantly higher than those of the female subjects. (2) The Slovenian Class III male and female subjects tend to-

ward a left-sided chin deviation. (3) Differences between Class III patients and a normative data set were

determined. (Am J Orthod Dentofacial Orthop 2010;138:758-69)

Three-dimensional (3D) imaging in maxillofacial

surgery and orthodontics is a fast developing

field. Several noninvasive and radiographic

methods have been introduced in the last 20 years, and

they have proved valid and reliable compared with direct

anthropometry.1 The methods that render 3D imaging

possible are photogrammetry, laser acquisition systems,structured light systems, video imaging, computerized

tomography, cone-beam computerized tomography,

magnetic resonance imaging, and ultrasound.2 Because

of ever improving techniques, the acquisition of 3D data

today is safe, affordable, and precise. The software

applications are also being reengineered to efficiently

handle and analyze these highly precise 3D data

formats.3

Three-dimensional imaging is now being used for var-

ious orthodontic and maxillofacial assessments: 3D

treatment planning, preorthodontic and postorthodontic

evaluations, preoperative and postoperative evaluations,

3D prefabricated archwires, research, distinction between

syndromes involving craniofacial deformities, and more.4-6

Soft-tissue prediction software has also been usedsuccessfully in patients with skeletal Class III

malocclusion treated with bimaxillary surgery.7

Three-dimensional imaging with a laser scanning sys-

tem has proven to be reliable, with accuracy within

0.85 mm.8 A study with a photogrammetric tool for

3D acquisition showed a lower system error: within

0.2 mm.9 On the other hand also, a recent study

showed that the 3D cone-beam computerized tomog-

raphy measurements were statistically significantly

different from measurements performed on ex-vivoskulls in two thirds of the measurements, but the

authors concluded that this statistical significancewas probably not clinically relevant.10

Despite the favoring trends in 3D imaging, 2-dimen-

sional diagnostic methods are still the main tools (lateral

and frontal cephalograms, dental panoramic tomograms,

intraoral and extraoral photographs) in maxillofacial

surgery and orthodontics. This might be a direct result

of the lack of 3D evaluation tools to accompany newer

imaging modalities.

A Class III malocclusion is a common condition

that, along with Class I and Class II malocclusions,

has physical, psychological, and social effects on

aResident and Fulbright scholar, Clinical Department of Maxillofacial and Oral

Surgery, University Medical Center Ljubljana, Ljubljana, Slovenia.bAssociate professor, University of Texas Health Science Center at Houston,

Houston, Tex.cProfessor, Dental Health and Biological Sciences, Cardiff University, Cardiff,

United Kingdom.dAssistant professor and chair, Department of Orthodontics, Division of Stoma-

tology, University Medical Center Ljubljana, Ljubljana, Slovenia.eAssistant professor, Clinical Department of Maxillofacial and Oral Surgery,

University Medical Center Ljubljana, Ljubljana, Slovenia.

The authors report no commercial, proprietary, or financial interest in the

products or companies described in this article.

Reprint requests to:ChungHowKau, University of Texas HealthScience Center

at Houston, 6516 M. D. Anderson Blvd, Ste 371, Houston, TX 77030; e-mail,

[email protected].

Submitted, November 2008; revised and accepted, January 2009.

0889-5406/$36.00

Copyright 2010 by the American Association of Orthodontists.

doi:10.1016/j.ajodo.2009.01.033

758
mailto:[email protected]:[email protected]:[email protected]

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quality of life.11 Class III patients most common fea-

tures are retrusive maxilla, protrusive maxillary inci-

sors, retrusive mandibular incisors, protrusive

mandible, and long lower facial height.

12

Facial asym-metry is a 3D problem that often accompanies other fa-

cial deformities. Many analyses compare right and left

measurements with a constructed midline reference

plane for the estimation of asymmetries.13 This method,

however, has raised concerns, and new methods of

asymmetry evaluation are still emerging.14

The aim of this study was to evaluate 3D facial

shells by incorporating a population-specific average

template with a group of Class III subjects preparing

for orthognathic surgery. To date, 3D data of such nature

have not been used to determine differences between

Class III patients and a normative data set.

MATERIAL AND METHODS

Two groups from the University Medical Center in

Ljubljana, Slovenia, were included in the study. The

first group consisted of normal subjects (Class I) at

the Division of Stomatology, and the second group

consisted of Class III subjects who came for surgery

at the Department of Maxillofacial and Oral Surgery.

The inclusion criteria for the Class I group were (1)

white descent, (2) between 18 and 30 years of age, (3)

no adverse skeletal deviations (a basic orofacial

examination was performed to exclude them), (4) nor-

mal body mass index of 18.5 to 25, and (5) no gross cra-

niofacial anomalies.

The inclusion criteria for the Class III group were (1)

white descent, (2) normal body mass index of 18.5 to 25,(3) diagnosed Class III condition that required combined

orthodontic and surgical treatment, and (4) no other

forms of pathology (eg, condylar hypolasia). The Class

III group was further divided into subgroups by sex.

The study was approved by the Slovenian National

Medical Ethics Committee. It was conducted accordingto the principles of the Helsinki-Tokyo declaration.

Informed consent was obtained from all subjects.

The laser scanning system consisted of 2 high-

resolution Vivid VI900 3D cameras (Konica Minolta,

Tokyo, Japan) with a reported manufacturing accuracy

of 0.1 mm, operating as a stereo pair. Each camera emitsan eye-safe Class I laser, 690 nm at 30 mW, with an

object-to-scanner distance of 600 to 2500 mm and

a fast mode scan time of 0.3 seconds. The system uses

a one half frame transfer charged couple device and

can acquire 307,000 data points. The scanners output

data are 640 3480 pixels for 3D and red, green, and

blue color data. The data were recorded on a desktop

workstation, and, for surface capture, a medium-range

lens (Konica Minolta) with a focal length of 14.5 mm

was used. The cameras were placed 1350 mm from thesubjects. The scanners were controlled with multi-scan

Fig 1. An average facial template showing the locations

of sella (S), subspinale (A), and Pog (P).

Table I. Class III female subgroup coordinates of Pog

(px, py, and pz) and subspinale (ax, ay, and az), with

S as the zero point (0, 0, 0)

Subject/coordinate px py pz ax ay az

1 1.68 103.98 2.01 0.89 51.15 3.64

2 8.70 103.35 0.45 1.24 56.14 0.98

3 0.13 97.18 4.50 0.81 50.74 4.80

4 5.49 99.47 5.73 0.44 48.94 4.03

5 2.56 100.79 0.90 1.24 54.17 2.04

6 6.72 100.88 0.59 0.90 48.47 1.07

7 4.33 93.23 0.14 0.31 52.03 0.44

8 0.23 103.04 2.18 2.22 54.04 3.17

9 4.07 86.81 5.78 0.59 50.24 2.24

10 1.18 103.33 0.08 0.64 59.73 0.34

11 2.70 98.15 1.28 0.76 48.49 0.76

12 9.78 97.67 2.53 0.71 51.64 1.39

12 1.51 104.79 0.34 2.35 59.80 0.49

14 1.85 97.70 0.88 1.64 52.89 0.57

15 6.53 103.65 1.77 1.37 56.87 0.28Average* 3.83 99.60 1.95 1.07 53.02 1.75

Mean 1.92 99.60 0.96 0.58 53.02 1.19

AvF 1.18 95.21 4.09 1.54 55.05 2.83

Mean direction Left Down Forward Left Down Forward

*Represents the average value of the absolute values (distance from 0)

of the coordinates; Average female facial template.

American Journal of Orthodontics and Dentofacial Orthopedics Bozic et al 759Volume138,Number6

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software (Cebas Computer, Eppelheim, Germany), and

data coordinates were saved in a vivid file format. Infor-

mation was transferred to a reverse modeling software

package, Rapidform 2006 (RF6) (INUS Technology,

Seoul, Korea), for analysis.

The images were acquired with the subjects in naturalheadposture. NHP has proven to be clinically reproduc-

ible.15 The subjects sat on an adjustable chair and were

asked to look at an object located centrally between the

cameras. Adjustments to the height and angle were

made to achieve the NHP and appropriate positioning.

The subjects were asked to keep their facial musculature

as relaxed as possible and to remain as still as possible

during the scan. The image acquisition took approxi-

mately 10 seconds for every patient and was repeated if

any movement in the head position or mimics wasnoted.8

The images were analyzed by using the RF6 software.

Absolute mean shell deviations, standard deviations oferrors during shell-to-shell overlaps, maximum and mini-

mum range maps, histogram plots, and color maps weregenerated. The data were furtherprocessed before analysis

to obtain an image with preserved shape, surface, and vol-

ume by using custom-made macros for the RF6.16 Surface

defects were filled automatically or manually without loss

of raw data. The result was 1 composite shell per subject.

The construction of an average face was performed

by using a previously validated software subroutine

available in the RF6. The Class I group was divided by

sex. The results were an average male (AvM) shell and

an average female(AvF) shell. The steps required to pro-

duce an average face have already been described and

are summarized as follows: (1) the images are

prealigned to determine the principal axes of rotation;

(2) manual corrections are made to positioning;

(3) best-fit alignment is done with the built-in algorithm

Table II. Class III male subgroup coordinates of Pog

(px, py, and pz) and subspinale (ax, ay, and az), with

S as the zero point (0, 0, 0)

Subject px py pz ax ay az

1 1.27 105.54 5.52 0.24 55.93 5.81

2 1.90 102.43 0.85 0.70 52.41 2.38

3 1.28 102.23 10.81 0.47 58.73 1.12

4 2.04 115.68 8.69 1.03 56.48 3.81

5 1.89 111.53 6.15 0.72 58.40 6.66

6 2.41 129.64 2.08 0.81 71.47 4.83

7 2.15 112.53 0.62 0.00 58.60 5.03

8 0.40 103.14 0.47 1.90 64.58 2.45

9 2.16 103.66 2.86 0.86 60.43 1.48

10 5.48 114.50 1.93 3.32 61.00 3.36

11 2.52 114.14 2.57 1.77 58.82 4.98

12 7.12 108.13 0.09 2.27 55.57 2.08

13 2.01 114.58 3.60 0.99 64.42 0.42

14 4.48 97.94 4.48 3.16 54.33 2.35

Average* 2.65 1 09.69 3.62 1.30 5 9.37 3.34Mean 2.32 109.69 0.67 1.27 59.37 0.84

Value on AvM 0.83 103.96 5.49 0.37 55.60 3.33

Mean direction Left Down Forward Left Down Forward

*Represents the average value of the absolute values (distance from 0)

of the coordinates; Average male facial template.

Table III. The difference of Pog (px, py, and pz) and

subspinale (ax, ay, and az) of the average female tem-

plate and the female Class III subjects

Subject Diff px Diff py Diff pz Diff ax Diff ay Di ff az

1 0.50 8.77 6.10 2.43 3.89 0.81

2 9.88 8.14 3.64 2.78 1.09 1.85

3 1.32 1.97 8.59 2.35 4.31 1.97

4 6.68 4.26 9.82 1.98 6.11 1.20

5 1.38 5.57 4.10 0.31 0.88 4.87

6 5.54 5.67 4.68 0.65 6.58 3.90

7 3.15 1.99 3.95 1.85 3.02 2.40

8 0.96 7.83 6.27 0.67 1.00 0.34

9 2.89 8.40 9.87 0.96 4.81 0.59

10 0.01 8.11 4.17 0.90 4.69 2.49

11 1.51 2.94 2.81 0.79 6.56 2.07

12 8.59 2.46 1.56 0.84 3.41 1.45

13 0.32 9.58 3.75 0.81 4.76 3.32

14 0.67 2.48 3.21 0.10 2.16 3.40

15 5.34 8.44 2.32 0.17 1.82 2.55Average* 3.25 5.77 5.05 1.17 10.90 2.21

Mean 0.74 4.39 5.05 0.96 2.03 1.64

Direction Left Down Forward Right Down Back

Diff,Difference.

*Represents the average of absolute differences.

Table IV. The difference of Pog (px, py, and pz) and

subspinale (ax, ay, and az) of the average male template

and the male Class III subjects

Subject Diff px D iff py Diff pz D iff ax D iff ay Di ff az

1 2.10 1.57 11.02 0.61 0.33 2.49

2 1.07 1.54 4.64 0.33 3.19 5.71

3 2.11 1.74 16.31 0.10 3.13 2.20

4 2.87 11.71 3.19 0.65 0.88 7.14

5 2.72 7.57 11.65 0.35 2.80 3.34

6 3.23 25.68 7.58 0.44 15.87 1.51

7 2.98 8.57 4.87 0.37 2.99 8.36

8 0.43 0.83 5.02 1.53 8.98 5.77

9 2.99 0.30 8.35 0.49 4.83 4.81

10 6.31 10.54 3.57 2.95 5.40 0.04

11 3.35 10.18 8.06 1.40 3.21 1.66

12 7.95 4.16 5.58 1.89 0.03 1.25

13 2.84 10.62 1.89 0.62 8.81 2.91

14 5.31 6.02 1.02 2.79 1.28 5.67

Average* 3.30 7.22 6.62 1.04 4.41 3.77Mean 3.15 5.73 6.17 0.90 3.77 2.49

Mean direction Left Down Forward Left Down Back

Diff,Difference.

*Represents the average of absolute differences.

760 Bozic et al American Journal of Orthodontics and Dentofacial OrthopedicsDecember 2010

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in RF6; (4) the z-coordinates of the images are averaged

based on normals to a facial template; (5) the point cloud

is triangulated to obtain an average face; (6) defects

and unwanted areas are removed, and holes are filled;

(7) color texture is applied; and (8) shells are created

with 1 positive and 1 negative standard deviation.17

All images were oriented in the virtual space to have

a NHP before analysis. Sella (S), subspinale (A), and

soft-tissue pogonion (Pog) were chosen as described

before and shown inFigure 1.18 The surface shell was

translated in the 3D space so that S represented thezero point (x, y, and z values were 0, 0, and 0). The values

of the other points coordinates therefore representeddistances from S in the chosen axis in millimeters, and

their corresponding positive or negative value sign (the

plus sign was omitted for positive values) indicated the

directions (ie, positive x, left; positive y, up; positive z,

to the front). The coordinates of points A and Pog

were summated in the following manner. (1) As absolute

values to demonstrate the absolute differenceie, dis-

tance from S not taking the direction into account; in

this way, by dividing the sum by the number of subjects,

average distances of points A and Pog from S (zero) for

the male and female Class III groups were calculated.

(2) With their positive and negative values and divided

by the number of subjects to give the mean value of

the coordinate, showing also the direction. The differ-

ences of the A and Pog coordinates of the template

AvM and group MCIII (AvM MCIII) and the differ-

ences of thetemplateAvFand group FCIII (AvF FCIII)

were also summated and divided in these 2 ways to give

the average distances regarding the average face and the

means showing also the direction of the points in theClass III groups compared with the average facial

templates (AvM and AvF). Means of the coordinates

and means of their differences (AvM MCIII and

AvF FCIII) were compared and tested for significant dif-

ferences between thesexes.The differences (AvM MCIII,

AvF FCIII) of coordinates of points A (ax) and Pog (px)

were also compared for significant differences.

Superimpositions of the shells from the Class III

group were performed with the AvM and AvF shells

by using a previously described technique.19 The mor-

phologic differences between the shells were depicted.

Fig 2. Coordinates px (Pog) of the male and female Class III (MCIII and FCIII) patients compared with

the px of the average female (AvF) and male (AvM) patients.


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The process of comparing the facial average shells

involved a manual alignment of the 5 points on the facial

scans (4 points at the outer and inner canthus of the eyes

and 1 point on the nasal tip) followedby fine alignment

performed automatically by the RF6.19 Color histogram

andsurface areas andshapes were theparameters used in

the study. The color histogram indicates the difference

between the average facial shells: the blue areas show

negative values, and the red areas show positive values.

Surface areas and shapes were automatically generated

by theRF6. These shapeswere obtained when a previous

tolerance of 0.85 mm was applied to the paired surface

shell studies.8 The areas corresponding to 0.85 mm

were deemed to be similar between the 2 shells, whereas

the shapes above this tolerance represented differences

and were shown as surface shapes and color deviations.

The percentage of the areas corresponding to the

tolerance of 0.85 mm was calculated by the RF6 and

represented the similarity of 2 shells.

Statistical analysis

The data were tested for significant differences

by using the independent-samples 2-tailed Student

t test in SPSS for Windows (version 11.0.0, SPSS,

Chicago, Ill).

RESULTS

One hundred sixteen subjects were included in this

study; 43 male and 44 female subjects constituted the

normal group that made up the average templates, and

14 male and 15 female subjects constituted the Class

III group.

Coordinates of the points Pog (px, py, and pz) and A

(ax, ay, and az) with the average distance from S

(average of the absolute values) for the groups FCIIIand MCIII as well as for the AvM and AvF facial tem-

plates are presented in Tables I and II, respectively.

Their mean values and corresponding directions are

also shown. Tables III and IV show the differences

between the coordinates Pog and A chosen on the

AvF and AvM templates and the coordinates of Pog

and A chosen on the subjects of groups FCIII and

MCIII, respectively. The values of the coordinates of

points A and Pog of FCIII and MCIII and values of

the A and Pog coordinates of the average facial

templates (AvF and AvM) are also presented in

Fig 3. Coordinates py (Pog) of the male and female Class III (MCIII andFCIII) patients compared with

the py of the average female (AvF) and male (AvM) patients.


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Figures 2 to 7. Coordinates py and ay of the groups

MCIII and FCIII were statistically significantly

different (P \0.05). The other coordinates did not

show statistical significance.

The average distances of Pog from S in the vertical

dimension (ie, y-axis) were 109.69 mm (103.96 on

AvM) for the MCIII subjects and 99.60 mm for the

FCIII subjects (95.21 on AvF). The distance differences

were 10.09 mm between MCIII and FCIII and 8.75 mm

between AvM and AvF.

The subtractions of the female ax and ay coordinates

(AvF FCIII) were statistically significantly (P\0.05)different from the subtractions of the male ax and ay

coordinates (AvM MCIII).

Differences of the px were statistically significantly

higher than differences of the ax (P \0.05).

In the template analysis, the results of differences

between the average faces (AvM and AvF) and Class

III patients (MCIII and FCIII) are shown with color

histograms inTable V. The similarities to the average

face ranged from 21.30% to 46.07% among the MCIII

subjects and from 23.71% to 52.02% among the FCIII

subjects. The average percentages of similarity were

38.34% for FCIII to AvF and 32.85% for MCIII to

AvM. The differences were mainly in the lower facial

two thirds. However, in 50% (MCIII) to 60% (FCIII),

there were also differences in the upper facial third.

Figure 8shows a face with a protruded mandible, with

the upper two thirds mostly within the accepted

0.85-mm tolerance when superimposed on the corre-

sponding average face. Asymmetry can also easily be

noted from the image. Figure 9 shows a subject with

mandibular prognathism and maxillary retrognathism,

whereas the upper facial third is mostly within the

accepted 0.85-mm tolerance when superimposed onthe corresponding average face.Figure 10shows a sub-

ject whose mandible is protruded and whose maxilla is

retruded, and there is also a significant difference from

the average face in the upper third of the face: the area

around the eyes and forehead.

DISCUSSION

Three-dimensional imaging is a fast developing

field of medical diagnostics. It was shown that 3D im-

aging with laser scanning devices can be used reliably

Fig 4. Coordinates pz (Pog) of the male and female Class III (MCIII andFCIII) patients compared with

the pz of the average female (AvF) and male (AvM) patients.


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and with great accuracy.20,21 A 3D average face has

been used in several studies: to distinguish people

with Noonans syndrome,4 to compare different

groups of orthodontic patients (postextraction to non-

extraction groups),22 to distinguish growth changes

among children,23 and to compare distinct geographi-

cally remote white populations (Slovenian and

Welsh).24

In our study, the 3D data were obtained with a nonin-

vasive laser scanning device. A previously described

method of averaging faces was used.17 Differences and

asymmetry of Class III patients and their comparisonsto average female and male facial templates of their pop-

ulation were noted. To our knowledge, previous studieshave not used an average face for the objective of linear

measurement.

Symmetry and averageness were considered in this

study, since they play important roles in a faces

attractiveness, although extraordinary beauty probably

depends on the addition of special characteristics

(child-like and mature characteristics and expressive-

ness) for the females, whereas male attractiveness is

more controversial, depending on the great influence

of the menstrual cycle and the environment on female

observers. The ideal of beauty is also subject to fluctu-

ations in fashion.25

Our findings show that the male and female faces of

Class III patients in Slovenia are statistically signifi-

cantly different in the vertical (y) direction. This agrees

with a recent international anthropometric study where

the mean morphologic face height was determined as

the distance from nasion to gonion. Thirty male and

30 female subjects from Slovenia were included, and,

for the males, the mean morphologic face height

was 7.1% higher than for the females (116.6 mm vs108.8 mm).26 In our study, the morphologic face height

was estimated as the distance between S and Pog inthe y-axis. On the AvM facial template, the Pog dis-

tance in the y-axis was 9.1% higher than on the AvF,

and, in the MCIII group, it was 10.1% higher than in

the FCIII.

Asymmetry makes the human face less attractive,

and its objective estimate is therefore important.25 In

FCIII, the deviation of Pog to the left or right was on

average 3.8 mm (2.65 mm in MCIII), whereas on the

AvF template it was 1.18 mm (0.83 mm on AvM).

Fig 5. Coordinates ax (point A) of the male and female Class III (MCIII and FCIII) patients compared

with the ax of the average female (AvF) and male (AvM) patients.


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This could lead to a conclusion that Class III patients are

more likely to have a deviation of the chin than the

Class I population. Differences of the px were statisti-cally significantly higher than differences of the ax,

meaning that the mandible deviates in the x-axis more

than the maxilla. It has been previously shown that

asymmetry among Class III patients is seen frequently

and not by chance and is more pronounced in the

mandible than in the maxilla.27

The px values were positive in 12 of 15 (80.0%) sub-

jects of the FCIII group and in 12 of 14 (85.7%) subjectsin the MCIII group. A positive px value means left-sided

chin deviation; this also agrees with previous studies27

and probably is a consequence of prenatal (genetic

and teratogenic) factors.28,29

The subtraction of the ax (AvM MCIII) that was

significantly different from the subtraction of the ax

(AvF FCIII) leads us to conclude that Class III

men have a maxilla deviated more to the left, whereas

the women tend to have a maxilla deviated more to the

right. Considering the small dimensions of these

means of deviations (10.96 mm and 0.90 mm), it

is also possible that these can be ascribed to technical

errors.

The similarity of the Class III patients and theaverage facial templates was low (FCIII similarity,

38.3%; MCIII similarity, 32.8%). To our knowledge,

no previous studies have used 3D digital data to

show this.

The data of this study also suggest that the upper fa-

cial third might be of importance for the final result of

orthognathic surgery. The upper facial third was differ-

ent from the average facein 9 of15 (60%) FCIII and in 7of 14 (50%) MCIII patients. Since the upper third is not

surgically corrected, these patients might have a disad-

vantage when compared with those whose upper third is

more similar to the average face.

This study included average faces built only from

our small database; larger studies are needed and

ongoing. Further 3D imaging studies will help to cre-

ate 3D norms that will eventually replace the tradi-

tional 2-dimensional cephalometric norms and lead

to better surgical and orthodontic corrections of facial

irregularities.

Fig 6. Coordinates ay (point A) of the male and female Class III (MCIII and FCIII) patients compared

with the ay of the average female (AvF) and male (AvM) patients.


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CONCLUSIONS

The following can be concluded from this novel

method of 3D analysis.

1. Facial morphologic differences between Angle

Class III patients and average Slovenian male and

female faces were noted by using commercially

available laser scanning system and software.

2. The average and Class III Slovenian male morpho-

logic face height is statistically significantly higher

than female.

3. The Slovenian Class III males and females tend tohave a left-sided chin deviation.

4. Differences between Class III patients and a norma-tive data set were determined (FCIII similarity,

38.3%; MCIII similarity, 32.8%).

Marko Bozic thanks the Fulbright Commision for

the scholarship that enabled him to work at the Univer-

sity of Texas Health Science Center at Houston and the

Slovenian Research Agency.

Fig 7. Coordinates az (point A) of the male and female Class III (MCIII and FCIII) patients compared

with the az of the average female (AvF) and male (AvM) patients.

Table V. Percentages of similarity between the average

face templates and Class III patients calculated with

color histograms

Female subject Similarity (%)* Male subject Similarity (%)*

1 30.83 1 27.15

2 47.69 2 39.59

3 27.18 3 36.10

4 52.02 4 34.29

5 26.66 5 38.78

6 49.05 6 21.43

7 52.64 7 32.47

8 28.72 8 34.449 38.46 9 21.30

10 34.42 10 25.93

11 41.81 11 35.98

12 39.26 12 35.85

13 34.81 13 30.56

14 23.71 14 46.07

15 47.84

Average 38.34 32.85

*Tolerance 5 0.85 mm (values less than this are deemed similar).


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Fig 8. A Slovenian female Class III face superimposed on an average Slovenian female face showing

a protruded mandible, with the upper two thirds mostly within the accepted 0.85-mm tolerance. Note

the asymmetry of the mandible.

Fig 9. A Slovenian male Class III face superimposed on an average Slovenian male face showing

mandibular prognathism and maxillary retrognathism, with the upper facial third mostly within the

accepted 0.85-mm tolerance.


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