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10.5005/jp-journals-10021-1113
ORIGINAL ARTICLE
Amit Kumar Khera et al
Relationship between Dental Arch Dimensions
and Vertical Facial Morphology in
Class I Subjects
1
Amit Kumar Khera, 2Gulshan K Singh, 3Vijay P Sharma, 4Alka Singh
ABSTRACT
Introduction: A well-balanced face has its good proportions in all three dimensions of space, i.e. transverse, sagittal and vertical. The vertical
proportions of the face are important in determining the esthetics and harmony of the face. The objectives of this study were to evaluate the
relationship between dental arch dimensions and the vertical facial pattern determined by the Jarabak ratio, and to examine the differences in dental
arch dimensions between male and female untreated adults.
Materials and methods: Lateral cephalograms and study models were obtained from 90 untreated subjects (45 males, 45 females) between 17
and 24 years of age with no crossbite, no/minimal crowding and spacing. The Jarabak ratio (posterior facial height/anterior facial height) was
measured on cephalograms of each patient. Study models were used to obtain comprehensive dental measurements, including maxillary and
mandibular cumulative mesiodistal width, intercanine, first interpremolar and first intermolar widths as well as arch perimeter, arch length, overbite,
palatal height and curve of Spee.
Results: The results showed that, for both males and females, there was a trend that as vertical facial height increased, arch width, arch perimeter
and overbite decreased but palatal height and curve of Spee increased and males have significantly larger arch dimensions than those of females.
Conclusion: It was concluded that dental arch dimensions were associated with facial vertical morphology and gender. Thus, using individualized
archwires according to each patient’s pretreatment arch form and width is suggested during orthodontic treatment.
Keywords: Normodivergent, Hypodivergent, Hyperdivergent, Arch dimensions.
How to cite this article: Khera AK, Singh GK, Sharma VP, Singh A. Relationship between Dental Arch Dimensions and Vertical Facial
Morphology in Class I Subjects. J Ind Orthod Soc 2012;46(4):316-324.
INTRODUCTION
An individual’s facial pattern may be considered as one of the
key determinants of treatment selection because facial type
influences the anchorage system, growth prediction of
maxillofacial structures and goal of orthodontic treatment.
Knowledge of arch forms is important for an orthodontist,
as it is related to future growth and treatment outcome.
However traditionally, change in the arch form has been
analyzed in terms of the behavior of various linear dimensions,
such as arch width, length and perimeter. Arch form has been
defined as a linear formulation by Penrose1 as ‘form = size +
shape’. The upper and lower dental arches can be considered
1
4
Senior Resident, 2Associate Professor, 3Former Head and Professor,
Assistant Professor
1-4
Department of Orthodontics and Dentofacial Orthopedics, Faculty
of Dental Sciences, CSMMU (Upgraded KGMC), Lucknow
Uttar Pradesh, India
Corresponding Author: Amit Kumar Khera, Senior Resident,
Department of Orthodontics and Dentofacial Orthopedics, Faculty of Dental
Sciences, CSMMU (Upgraded KGMC), Lucknow, Uttar Pradesh
India, e-mail: [email protected]
Received on: 21/1/12
Accepted after Revision: 8/5/12
316
as kind of flexible ribbons, adapted to varying jaw relationships
to maintain normal relationship between dental arches for
esthetic and function.
The two extremes of vertical facial dysplasia have been
described as hypodivergent and hyperdivergent by Schudy2 or
short face syndrome (SFS) and the long face syndrome (LFS)
by Opdebeeck.3 Hypodivergent subjects are characterized by
a forward rotating mandible due to relatively large vertical
condylar growth and small amount of vertical growth of
alveolar process and/or anterior facial sutures. Hyperdivergent
subjects are characterized by backward rotating mandible due
to the opposite differential growth pattern. It is generally
accepted among orthodontists that a relationship exists
between dental arch width and vertical facial morphology. A
long face (leptoprosopic) individual usually has narrower arch
dimensions and a short face individual (euryprosopic) has
wider arch dimensions according to Rickets et al.4
Nowadays, preformed archwires are routinely used by
many orthodontists regardless of the facial type, facial
proportions and gender of the patients. However, using
individualized archwires according to each patient’s pretreatment arch form and width is suggested during orthodontic
treatment.
The present study was carried out in order to evaluate the
relationship between dental arch dimensions and vertical facial
pattern.
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Relationship between Dental Arch Dimensions and Vertical Facial Morphology in Class I Subjects
The objectives of present study were as follows:
1. To evaluate the dental arch dimensions in different
vertical-facial pattern.
2. To evaluate the correlation between dental arch
dimensions and different vertical facial pattern.
3. To evaluate the differences in dental arch dimensions
between male and female subjects.
MATERIALS AND METHODS
Sample
The present study was conducted on 90 subjects comprising
of 45 males (ranging from 18-24 years) and 45 females
(ranging from 17-21 years) with a mean age of 20.53 ± 1.23
and 19.63 ± 1.06 years for males and females respectively.
The lateral cephalograms and study models for the purpose of
study were obtained from the records of patients visiting the
outpatient department of the Department of Orthodontics and
Dentofacial Orthopedics, Faculty of Dental Sciences, CSM
Medical University, Lucknow (UP), India.
The subjects were selected on the basis of following
inclusion and exclusion criteria:
Inclusion Criteria
1. All permanent teeth should be present in each arch (3rd
molar may or may not be present) and sufficiently erupted
to permit measurement of mesiodistal crown dimensions.
2. Subjects with skeletal Class I pattern and Angle’s Class I
molar relation having minimum/no crowding, spacing,
rotation were selected.
3. No history of previous orthodontic treatment.
4. There should be no gross carious lesions or any proximal
restoration, which can change the mesiodistal dimensions
of arch.
Exclusion Criteria
1. Subjects with craniofacial anomalies like cleft lip and
palate and syndromes were not included in study.
2. Subjects with deleterious oral habits, like mouth-breathing,
tongue thrusting and thumb sucking, were excluded.
3. Subjects with anterior and posterior crossbite were also
excluded.
4. No history of trauma to dentofacial region.
5. Individuals with marked jaw asymmetries and temporomandibular joint (TMJ) abnormality were excluded from
the study.
Subjects were divided into two groups according to sex as
follows:
• Group I male (n = 45)
• Group II female (n = 45)
On the basis of Jarabak ratio (Table 1), group I male
subjects were further subdivided into three subgroups, i.e.
subgroup Ia (hypodivergent male), subgroup Ib (neutral/
normodivergent male) and subgroup Ic (hyperdivergent male).
Similarly, group II female subjects were subdivided into three
subgroups, i.e. subgroup IIa (hypodivergent female), subgroup
IIb (neutral/normodivergent female) and subgroup IIc
(hyperdivergent female).
Measurements
High quality orthodontic impressions for study models were
taken with alginate impression material using rim lock
impression trays. The lateral cephalograms of the selected
subjects were taken using the standard technique employed in
the Department of Orthodontics and Dentofacial Orthopedics,
CSM Medical University (Erstwhile KGMC). The lateral
cephalograms were traced on acetate tracing sheets, 0.5
micron in thickness using a sharp 4H pencil on a view box
using transilluminated light in a dark room.
For each subject, Jarabak ratio (Siriwat and Jarabak 1985)5
was measured. The posterior facial height was drawn from sella
to gonion (Go) and anterior facial height was drawn from
nasion to menton (Me).
Study model measurements were performed using a
Korkhaus three-dimensions caliper (Dentaurum) and digital
caliper. The following maxillary and mandibular dimensions
were measured (Figs 1 to 4):
1. Cumulative mesiodistal crown width [mesiodistal width
of the crown at the greatest mesiodistal diameter of each
tooth (Fig. 1)].
2. Intercanine width [from buccal cusp tip (Fig. 2)].
3. First interpremolar width [from buccal cusp tip (Fig. 2)].
4. First intermolar width [from buccal, and lingual surface,
(Fig. 2)]: The average of buccal and palatal/lingual widths
were taken.
5. Arch length: From the contact point between the
permanent central incisors to the line joining the distal
surface of the permanent first molar (Fig. 2).
6. Palatal height: From the connecting line between the
midpoint of the fissures of both upper first molars to the
surface of the palate (see Fig. 2).
Table 1: Distribution of subjects
Groups
Group I
Male (n = 45)
Group II
Female (n = 45)
Subgroups
Hypodivergent
(n = 40)
Normodivergent
(n = 30)
Hyperdivergent
(n = 20)
Jarabak ratio
(64-80%)
Jarabak ratio
(59-63%)
Jarabak ratio
(54-58%)
Subgroup Ia (n = 20)
Subgroup Ib (n = 15)
Subgroup Ic (n = 10)
Subgroup IIa (n = 20)
Subgroup IIb (n = 15)
Subgroup IIc (n = 10)
The Journal of Indian Orthodontic Society, October-December 2012;46(4):316-324
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Amit Kumar Khera et al
Fig. 1: Mesiodistal width measurement by digital caliper
Fig. 4: Measurement of curve of Spee
9. Overbite: Vertical distance between the incisal tips of
maxillary and mandibular central incisors (Fig. 3).
10. Curve of Spee: Perpendicular distance between the
deepest buccal cusp tips and a scale that was laid on the
top of the mandibular dental cast (Fig. 4).
Korkhaus three-dimensional caliper was used to measure
the parameters: Arch length, intercanine width, first
interpremolar width, first intermolar width and palatal height,
while the mesiodistal crown width was measured with digital
caliper and overjet, overbite and curve of Spee were measured
with scale and divider.
STATISTICAL ANALYSIS
Fig. 2: Arch length, arch width and palatal height measurement by
Korkhaus caliper
Arch dimensions were evaluated using 16 linear parameters.
Six maxillary, six mandibular and four other parameters were
measured over the maxillary and mandibular study models. The
data so obtained was subjected to the statistical analysis using
statistical package program STATA version 10.2. Descriptive
statistics, including the mean and standard deviation values,
were calculated for all the parameters in each group. Student
t-test was used to determine the significant differences
between the mean and standard deviations of various
parameters in the male and female groups. Subgroups of both
groups were compared using one way analysis of variance
(ANOVA) followed by Bonferroni post-hoc test.
RESULTS
Fig. 3: Measurement of overbite and overjet
7. Arch perimeter: Using formula
2
2
2
Y  (4 x /3) given by
Mills and Hamilton (1965).6
8. Overjet: From the labial surface of the lower incisor to
the incisal edge of the upper incisor (Fig. 3).
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The arch dimension measurements of hypodivergent,
normodivergent and hyperdivergent subgroups of male and
female were shown in Table 2 (Figs 5A to C) and Table 3
(Figs 6A to C) respectively.
The hypodivergent subgroup had larger arch dimensions
than hyperdivergent subgroup for most of measurements except
for palatal height and curve of Spee which were larger in
hyperdivergent subgroup.
The mean of maxillary and mandibular first interpremolar
width, first intermolar width, arch perimeter and overbite were
decreased from hypodivergent to hyperdivergent but palatal
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Relationship between Dental Arch Dimensions and Vertical Facial Morphology in Class I Subjects
Table 2: Comparison of arch dimension measurements between hypodivergent (subgroup Ia),
normodivergent (subgroup Ib) and hyperdivergent (subgroup Ic) of Group I (male)
Parameters
Maxillary parameters
1. Cumulative mesiodistal
crown width (TTM)
2. Intercanine width
3. First interpremolar width
4. First intermolar width
5. Arch length
6. Arch perimeter
Subgroup Ia
(n = 20)
Subgroup Ib
(n = 15)
Subgroup Ic
(n = 10)
ANOVA
p-value
Mean ± SD
Mean ± SD
Mean ± SD
90.34 + 5.63
89.6 + 3.60
90.27 + 3.75
0.915
37.13 + 2.53
44.60 + 2.50
49.23 + 2.30
37.02 + 2.23
65.20 + 2.79
35.31 + 1.60
42.38 + 1.80
47.19 + 1.36
35.88 + 2.06
63.00 + 2.38
34.89 + 1.76
41.56 + 3.05
46.84 + 1.93
37.7 + 1.79
61.43 + 2.09
p-value
Ia vs Ib
Ia vs Ic
Ib vs Ic
1.00
1.00
1.00
0.002**
0.005**
0.003**
0.110
0.002**
0.045*
0.044*
0.019*
0.403
0.058
0.038*
0.010**
0.014*
1.00
0.002**
1.00
1.00
1.00
0.131
0.601
Mandibular parameters
1. Cumulative mesiodistal
crown width (TTM)
2. Intercanine width
3. First interpremolar width
4. First intermolar width
5. Arch length
6. Arch perimeter
82.19 + 4.59
83.59 + 2.40
82.41 + 3.01
0.562
0.893
1.00
1.00
27.43 + 1.84
36.17 + 1.88
45.60 + 1.58
32.52 + 2.29
59.03 + 2.28
25.31 + 1.83
34.65 + 1.91
43.81 + 2.36
31.77 + 2.39
57.07 + 2.62
25.14 + 1.59
33.72 + 2.46
42.54 + 2.69
33.56 + 1.24
56.6 + 2.60
0.004**
0.009**
0.002**
0.102
0.022*
0.05*
0.123
0.064
0.403
0.092
0.010**
0.013*
0.002**
1.000
0.050*
0.082
0.883
0.519
0.131
1.000
Other parameters
1. Overjet
2. Overbite
3. Palatal height
4. Curve of Spee
2.20 + 0.92
2.82 + 1.06
21.10 + 3.06
1.91 + 0.61
2.12 + 1.08
2.35 + 1.07
22.00 + 2.55
2.04 + 0.72
1.89 + 0.89
1.78 + 0.51
24.33 + 2.45
2.59 + 0.22
0.272
0.033*
0.022*
0.022*
1.00
0.526
1.000
1.00
1.00
0.032*
0.019*
0.020*
1.00
0.558
0.183
0.115
p-value: > 0.05 nonsignificant; *:<0.05 just significant; **: <0.01 moderately significant
Table 3: Comparison of arch dimension measurements between hypodivergent (subgroup IIa),
normodivergent (subgroup IIb) and hyperdivergent (subgroup IIc) of Group II (female)
Parameters
Maxillary parameters
1. Cumulative mesiodistal
crown width (TTM)
2. Intercanine width
3. First interpremolar width
4. First intermolar width
5. Arch length
6. Arch perimeter
Subgroup IIa
(n = 20)
Mean ± SD
Subgroup IIb
(n = 15)
Mean ± SD
Subgroup IIc
(n = 10)
Mean ± SD
ANOVA
p-value
p-value
IIa vs IIb
IIa vs IIc
IIb vs IIc
87.94 + 3.71
89.9 + 3.32
88.73 + 5.77
0.704
1.00
1.00
1.00
34.60 + 1.83
42.4 + 2.51
46.6 + 2.86
36.48 + 2.72
62.86 + 2.20
34.40 + 1.68
42.7 + 2.40
45.5 + 1.30
36.53 + 2.56
62.97 + 3.32
34.05 + 1.83
40.00 + 2.40
44.50 + 1.53
35.30 + 3.50
60.08 + 2.91
0.728
0.024*
0.048*
0.508
0.024*
1.00
1.00
0.442
1.000
1.000
1.000
0.041*
0.050*
0.883
0.039*
1.000
0.028*
0.803
0.889
0.043*
Mandibular parameters
1. Cumulative mesiodistal
crown width (TTM)
2. Intercanine width
3. First interpremolar width
4. First intermolar width
5. Arch length
6. Arch perimeter
80.03 + 3.44
81.98 + 2.68
80.60 + 4.54
0.265
0.325
1.000
1.000
25.7 + 1.71
34.70 + 1.94
43.77 + 2.14
32.6 + 2.40
57.47 + 3.22
25.7 + 1.67
34.6 + 1.23
42.97 + 1.88
32.67 + 1.99
57.17 + 2.05
25.2 + 2.00
34.05 + 2.06
41.75 + 1.34
31.50 + 2.92
55.55 + 1.73
0.600
0.625
0.030*
0.402
0.046*
1.000
1.000
0.664
1.000
1.000
1.000
1.000
0.027*
0.637
0.047*
1.000
1.000
0.376
0.719
0.154
Other parameters
1. Overjet
2. Overbite
3. Palatal height
4. Curve of Spee
2.70 + 1.17
3.48 + 0.94
20.05 + 2.24
1.85 + 0.80
1.93 + 0.70
2.47 + 1.30
21.73 + 2.81
2.0 + 0.82
2.55 + 1.21
2.10 + 1.13
23.05 + 3.00
3.15 + 0.80
0.103
0.004**
0.0143*
0.001***
0.116
0.033*
0.201
1.000
1.000
0.008**
0.015*
0.000***
0.474
1.000
0.675
0.003**
p-value: > 0.05 nonsignificant; *: <0.05 just significant; **: <0.01 moderately significant; ***: <0.001 highly significant
height and curve of Spee increased from hypodivergent to
hyperdivergent (see Tables 2 and 3).
Table 4 (Figs 7A to C) shows that dental arch dimension
measurements of male and female subjects. It was clearly
demonstrated that males had larger arch dimensions than females.
DISCUSSION
The facial growth pattern differs from individual to individual
and the variations in the dentofacial patterns are quite high.
The assessment of relationship of dental arch dimensions with
the vertical dentofacial pattern is essential to understand the
The Journal of Indian Orthodontic Society, October-December 2012;46(4):316-324
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Amit Kumar Khera et al
Figs 5A to C: Comparison of variables in different subgroups (Ia, Ib,Ic) of Group I (male)
variation in size and shape of dental arches. Research has
established the importance of vertical dimension. It has been
suggested that a subject with a high MP-SN angle tends to
have a longer face and narrower arch dimensions and one with
a low MP-SN angle often has a shorter face and wider arch
dimensions (Ricketts et al 19824, Enlow and Hans 19967). A
well-established sexual dimorphism in the arch dimensions
has been found to exist in the vertical plane [Wei (1970),8
Christie (1977), 9 Eroz et al (2000) 10 and Forster et al
(2008)11]. They found that males had sufficiently larger arch
widths as compared with females. Therefore, the subjects were
320
segregated according to sex to maintain the homogeneity of
the sample. Jarabak and Siriwat (1985),5 Bishara and Jakobsen
(1985)12 had also found a sexual dimorphism to exist among
various facial types.
In the present study, subjects were divided into subgroups:
Hypodivergent, normodivergent and hyperdivergent on the
basis of Jarabak ratio (Table 1) because it is a reliable
measurement, constructed from anatomic landmarks (Bishara
and Jakobsen, 198512) and the chance of human error is also
minimized by using a ratio instead of linear parameter. Only
skeletal Class I subjects were selected because considerable
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Relationship between Dental Arch Dimensions and Vertical Facial Morphology in Class I Subjects
Table 4: Comparison of arch dimension between Group I (male) and Group II (female)
Parameters (in mm)
Group I (n = 45)
Group II (n = 45)
Mean ± SD
Mean ± SD
p-value
Maxillary parameters
1. Cumulative mesiodistal crown width (TTM)
2. Intercanine width
3. First interpremolar width
4. First intermolar width
5. Arch length
6. Arch perimeter
90.11 + 3.62
36.08 + 2.31
43.26 + 2.72
48.31 + 2.24
36.83 + 2.16
64.31 + 2.66
88.50 + 3.07
34.41 + 1.75
42.00 + 2.60
45.97 + 2.75
36.23 + 2.84
62.28 + 2.96
0.086
0.001**
0.030*
0.001**
0.272
0.001**
Mandibular parameters
1. Cumulative mesiodistal crown width (TTM)
2. Intercanine width
3. First interpremolar width
4. First intermolar width
5. Arch length
6. Arch perimeter
82.67 + 3.69
26.87 + 1.83
35.18 + 2.22
44.69 + 2.23
32.51 + 2.19
58.32 + 2.55
80.80 + 3.52
25.95 + 1.74
34.32 + 1.74
42.92 + 2.22
32.41 + 2.39
57.11 + 2.69
0.017*
0.067
0.047*
0.004**
0.838
0.034*
Other parameters
1. Overjet
2. Overbite
3. Palatal height
4. Curve of Spee
2.11 + 0.95
2.17 + 0.97
23.02 + 2.85
2.06 + 0.59
2.41 + 1.00
3.06 + 1.17
20.69 + 2.67
2.14 + 0.77
0.199
0.001**
0.001**
0.567
p-value: NS > 0.05 nonsignificant; *: <0.05 just significant; **: <0.01 moderately significant
natural dentoalveolar compensation is expected in skeletal
Class II or Class III subjects, which might obscure the
relationship between vertical facial morphology and arch
dimensions. When intragroup comparisons were done between
hypodivergent, normodivergent and hyperdivergent subgroups
of both male and female groups (see Tables 2 and 3), the mean
value of cumulative mesiodistal crown width did not show any
statistically significant difference (p > 0.05) suggesting that
the tooth size appear to be a variable independent of the vertical
growth pattern. This finding was also supported by studies done
by Nasby et al (1972).13
For maxillary arch, there was a statistically significant inverse
relationship between vertical facial morphology and dental arch
width at maxillary canine, first premolar and first molar region in
males and only between first molar widths in females. For
mandibular arch, it was found that males had statistically
significant correlation between vertical facial morphology and
mandibular intercanine, first interpremolar and first intermolar
widths but, in females, only first intermolar width was
significant. These findings were supported by Nasby et al
(1972),13 while they were in contrast to Eroz et al (2000)9
and Forster et al (2008)10 who demonstrate that mandibular
first intermolar width was similar in hypodivergent and
hyperdivergent subjects, however, the present data did not
support such a relationship. In the present study, it was also
observed that males had larger maxillary and mandibular first
intermolar width than females. Similar findings have also been
reported by the Eroz et al (2000)9 and Foster et al (2008).10
Isaacson et al (1971)14 reported that steep mandibular plane
individuals generally had narrower maxillary first intermolar
width than flat mandibular plane individuals. They suggested
that the backward rotation of mandible in high MP-SN cases
cause an increase in facial height which tends to lengthen the
musculature. As the muscles are elongated, the passive stretch
tension increases, which in turn causes the maxillary arch to
be constricted. Conversely, the low MP-SN growth pattern
has less facial height tending to permit maxillary teeth to move
toward buccoversion. Nasby et al (1972)13 also reported that
backward rotating mandible (hyperdivergent pattern) were
associated with narrower intermolar widths. Musculature has
been considered as a possible link in this close relationship
between the transverse dimension and vertical facial
morphology.
The present study also suggests that maxillary and
mandibular arch lengths are similar in hypodivergent,
normodivergent and hyperdivergent subgroups, whereas the
arch perimeter was greater in hypodivergent than hyperdivergent sujects. Similar findings were reported by Nasby
et al (1972).13 No significant difference was found for overjet
in hypodivergent, normodivergent and hyperdivergent
subgroups for both the sexes, but overbite was found to
decrease with increase in vertical dimension. So, the overbite
was more in hypodivergent and less in hyperdivergent subjects
for both the groups. Nasby et al (1972)13 also reported that
hyperdivergent subjects were associated with longer anterior
and posterior alveolar heights that will result the dental open
bite or reduced overbite in these subjects. Palate was found to
be high in hyperdivergent subgroup and shallow in
hypodivergent subgroup for both males and females. Curve of
Spee was found to increase as the facial height increased. These
findings suggest that the depth of curve of Spee was more in
hyperdivergent as compare with hypodivergent male and
female subjects, because of decrease in arch perimeter in
hyperdivergent group, there may be compensatory increase in
curve of Spee to accommodate the tooth material. Schudy
(1968)15 explained the importance of dentoalveolar dimension
to establish the overbite. According to him, mandibular
incisors are the best compensator in preventing the open bite.
The Journal of Indian Orthodontic Society, October-December 2012;46(4):316-324
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Amit Kumar Khera et al
Figs 6A to C: Comparison of variables in different subgroups (IIa, IIb, IIc) of Group II (female)
Another possible explanation for the increased curve of Spee
in hyperdivergent subjects was that, because of vertical
skeletal dysplasias, the natural dentoalveolar compensation
in mandibular anterior region will take place to establish
normal overbite (Anwar et al 2009).16
A possible explanation to our findings regarding the
different influence of the vertical facial pattern on arch
dimensions for both the sexes can be attributed to the different
impact of genetic factors on males and females. A genetic
study of cephalometric variables performed in twins showed
that the genetic determination for vertical variables was 77.3%
for boys and 72.8% for girls (Carels C 2001).17 This could
322
explain the gender differences found in our study, in the sense
that females have a weaker genetic determination than males
for the vertical craniofacial morphology.
The results of present study provide normative data for
the arch dimensions of hypodivergent, normodivergent and
hyperdivergent male and female subjects. The study also
provides a comparative evaluation of arch dimension in
different vertical-facial pattern which is an important adjunct
for selection of treatment plan.
Many authors have acknowledged that there is variability
in size and shape of human archforms. People from different
ethnic groups present with different physiologic conditions,
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Relationship between Dental Arch Dimensions and Vertical Facial Morphology in Class I Subjects
Figs 7A to C: Comparison of variables in male and female groups
and clinician should anticipate the difference in size and form
rather than treating all cases to a single ideal.
Little, 18 based on more than 35 years of research,
recommended as a clinical guideline that patient’s pretreatment
archform be used as a guide to posttreatment archshape.
The limitations of present study must be acknowledged
because of the large individual variation encountered and dental
arch dimensions are certainly a multifactorial phenomenon
(Schulhof et al, 1978). 19 The general consensus is that
individuals with strong or thick mandibular elevator muscles
tend to exhibit wider transverse head dimensions (Hannam and
Wood, 1989,20 Kiliaridis and Kalebo 199121).
This study can be made more exhaustive by observing the
effect of the muscle activity (using ultrasonography) on arch
dimensions in different dentofacial patterns.
CONCLUSION
Following conclusions were drawn from present study:
1. Maxillary and mandibular first intermolar width, arch
perimeter and maxillary first interpremolar width were
The Journal of Indian Orthodontic Society, October-December 2012;46(4):316-324
323
Amit Kumar Khera et al
2.
3.
4.
5.
6.
7.
maximum in hypodivergent followed by normodivergent
and minimum in hyperdivergent in males as well as in
females.
Maxillary intercanine width, mandibular intercanine width
and first interpremolar width were higher in the
hypodivergent as compared with hyperdivergent in males.
The overbite had a negative correlation with vertical facial
height for both the sexes. This concludes that overbite was
more in hypodivergent as compared with hyperdivergent
subjects.
The palate height was more in hyperdivergent and shallow
in hypodivergent in males as well as in females.
Curve of Spee was high in hyperdivergent as compared
with hypodivergent in males as well as in females.
Maxillary and mandibular first interpremolar width, first
intermolar width and arch perimeter were greater in males
as compared with females.
Maxillary intercanine width and palatal height were more
in males as compared with females, while overbite was
more in females.
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