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Drs. Lindsay E. Grosso, Morgan Rutledge, Donald J. Rinchuse, Doug Smith, and Thomas Zullo investigate
buccolingual inclinations of patients with dolichofacial, brachyfacial, and mesofacial vertical facial growth
patterns
Abstract
Objective:
The
purpose
of
this
observational study was to investigate
whether the buccolingual inclinations
of pretreatment orthodontic patients’
occlusions vary for the maxillary and
mandibular first molars in accordance
with facial patterns (i.e., dolichofacial,
brachyfacial, or mesofacial).
Materials and Methods: Records of
30 pretreatment orthodontic patients
were taken from a population of 523 and
divided into three groups of 10 according
to vertical facial patterns (dolichofacial,
mesofacial, and brachyfacial) based on
cephalometric analysis. Pre-existing CBCT
images were used to take the following
angle measurements relative to the
occlusal plane:
1-2)long axis of the maxillary right first
molar and maxillary left first molar
3-4)long axis of the mandibular right first
molar and mandibular left first molar
5-6)buccal surface of the maxillary right
first molar and maxillary left first molar
7-8)buccal surface of the mandibular right
first molar and mandibular left first
molar
Lindsay E Grosso, DMD, MBA, is a graduate of Seton
Hill University Center for Orthodontics, Greensburg,
Pennsylvania.
Morgan Rutledge, DMD, MS, is a graduate of Seton
Hill University Center for Orthodontics, Greensburg,
Pennsylvania.
Donald J Rinchuse, DMD, MS, MDS, PhD, is Professor
and Program Director, Seton Hill University Center for
Orthodontics, Greensburg, Pennsylvania.
Doug Smith, DMD, MDS, is Clinical faculty, Seton
Hill University Center for Orthodontics, Greensburg,
Pennsylvania.
Thomas Zullo, PhD is Adjunct Professor, Seton Hill
University Center for Orthodontics, Greensburg,
Pennsylvania.
Volume 5 Number 2
Educational aims and objectives
The aim of this article is to discover whether the buccolingual inclinations
of pretreatment orthodontic patients’ occlusions vary for the maxillary and
mandibular first molars in accordance with facial patterns (i.e., dolichofacial,
brachyfacial, or mesofacial).
Expected outcomes
Correctly answering the questions on page 49, worth 2 hours of CE, will
demonstrate the reader can:
• Review some of Andrews’ “The Six Keys to Normal Occlusion.”
• Compare differences in buccolingual inclinations of maxillary and
mandibular first molars in pretreatment patients with dolichofacial,
brachyfacial, and mesofacial vertical facial growth patterns.
• Recognize if orthodontists may need to implement bracket prescriptions
for dolichofacial patients with greater mandibular buccal crown torque and, subsequently,
greater maxillary buccal crown torque to keep cuspal heights of molars more even.
• Realize the various concepts that are in use regarding tooth and arch parameters related to
facial type.
• Identify the American Board of Orthodontics’ measuring gauge that scores the buccolingual
inclinations of maxillary and mandibular first molars.
Three additional measurements were
analyzed at a separate time:
1-2) the right angle of the mandible and the
left angle of the mandible, and
3)the buccolingual cuspal height
differences of the mandibular first
molars.
Results: Multivariate analysis of variance
(MANOVA) indicated statistical significant
differences (p = .019) between the buccolingual cuspal height differences of
the mandibular first molars (known as
buccolingual inclinations of the mandibular
molars to the American Board of
Orthodontics) relative to the occlusal plane.
The pretreatment orthodontic patients with
a dolichofacial vertical pattern showed
greater lingual crown inclination with
respect to the mandibular molars than
brachyfacial and mesofacial types.
Conclusions: If the American Board
of Orthodontics (ABO) is correct in
its assessment of the buccolingual
inclination of molars, orthodontists may
need to implement bracket prescriptions
for dolichofacial patients with greater
mandibular buccal crown torque and,
subsequently, greater maxillary buccal
crown torque to keep cuspal heights of
molars more even.
Introduction
For years orthodontists have tried
to mainstream clinical practice while
maintaining the quality and long-term
stability of treatment. One development
that revolutionized orthodontics was
the straight-wire appliance. In 1972, Dr.
Lawrence Andrews published his classic
article entitled “The Six Keys to Normal
Occlusion,” in which he described the
results of his static occlusion study of
120 non-orthodontic dental casts with
“normal” untreated occlusion, juxtaposed
with 1,150 posttreatment American
Board of Orthodontics’ dental casts.1
His study was an effort to discern what
characteristics were common among the
120 naturally occurring optimal occlusions
(no orthodontic treatment), as compared to
very successfully treated orthodontic case
occlusions. Subsequently, Andrews’ “Six
Keys” findings led to the development of
the straight-wire appliance.
Andrews’ third of his six keys
discussed standards for crown inclination
Orthodontic practice 43
CONTINUING EDUCATION
Buccolingual inclinations of maxillary and mandibular
first molars in relation to facial pattern
CONTINUING EDUCATION
Measurement
Dolichofacial
Brachyfacial
Mesofacial
FMA (MP-FH) (°)
22.9 - 31.8
2.4 - 14.1
19.2 - 28.9
Palatal-Mand Angle (PP-MP) (°)
25.4 - 40.8
7.5 - 23.8
26.1 - 36.6
Gonial/Jaw Angle (Ar-Go-Me) (°)
116.7 - 149.7
109.8 - 130.7
119.1 - 133.2
P-A Face Height (S-Go/N-Me) (%)
56.5 - 64.5
68.8 - 81.2
59.5 - 68.2
RH/LFH (ArGo/ANSMe) (%)
62.2 - 84.1
80.7 - 111.0
66.0 - 85.2
Table 1: Range of cephalometric values for the 10 patients in each facial pattern group
Group
Males
Females
Average Age
Dolichofacial
6
4
13.76
Brachyfacial
6
4
15.79
Mesofacial
3
7
15.31
Table 2: Number of males and females, and average ages for each group
in “optimal” occlusions, and as he noted,
the maxillary and mandibular posterior
crowns were lingually inclined, albeit to
varying degrees.1 Recall, Andrews-judged
inclination, or facial-lingual “slanting” of the
teeth, from the crowns of the teeth, not the
long axis through the roots of the teeth as
can be gleaned from radiographic imaging.
Lingual inclination of the maxillary posterior
teeth from canine to molar was found to
be relatively constant with slightly more
inclination in the molars, while inclination
of the mandibular molars progressively
increased from the canine to second
molar.1
A question in search of an answer is
whether the same buccolingual inclination is
appropriate for most patients, considering
variation in facial/skeletal types and
alveolar bone structure in a given patient
population. More specifically, each bracket
prescription is manufactured to position
teeth with specified inclinations, assuming
that brackets are bonded to ideal position
on each tooth with little to no variability in
facial surface contours for those teeth, and
44 Orthodontic practice
that clinicians use full-size wires.
Controversy has existed for years
regarding tooth and arch parameters
related to facial type. It is widely accepted
that dolichofacial patients have narrower
arches, higher-arched palates, and more
tendency toward open bite and significantly
smaller maximum biting force, while
brachyfacial patients tend toward deep bites
and have much stronger maximum biting
force.2,3 Some authors have suggested
that patients with long lower anterior face
heights (i.e., dolichofacial) have molars that
are more upright buccolingually, whereas
patients with short lower anterior face
heights (i.e., brachyfacial) have molars that
are more lingually inclined.4,5 Janson, et al.,6
found that when dental casts from patients
with different facial patterns were studied,
“maxillary posterior teeth in subjects with
vertical growth patterns (dolichofacial) [had]
a statistically significantly greater buccal
inclination as compared with those with
horizontal growth patterns (brachyfacial).”
They did not find any statistically significant
differences in inclination of mandibular
posterior teeth between the groups.
Janson, et al.,6 takes this concept further
and argues that because there tends to be
greater palatal inclination in upper molars
of brachyfacial patients, they can withstand
more palatal expansion since a common
collateral effect of rapid palatal expansion
is buccal tipping of molars. This implies
that greater expansion and potential buccal
tipping could be carried out for brachyfacial
patients without causing harm to the
molars that have been tipped. However,
the brachyfacial patients are typically the
ones with wider arches who are less likely
to need expansion.
Conversely, Ross, et al.,7 found
that there were no statistically different
buccolingual inclinations of maxillary or
mandibular molars between different
vertical growth patterns when dental casts
were used to evaluate crown inclinations.
Furthermore, Tsunori4 argues that patients
with long-face patterns have comparatively
more narrow arches yet have tongue
sizes similar to those patients with shortface patterns. The more narrowed arches
allows the tongue to have a greater effect
on the buccolingual inclination of the
teeth by placing force on the molars and
uprighting the teeth.4 Additionally, some
conjecture that the weaker musculature of
the dolichofacial pattern8,9,10 could prevent
tipping of the molars or at least provide less
resistance to the forces from the tongue.4
To this end, many “non-extractionists”
believe that if the mandibular molars are
lingually inclined, there is a need to upright
these teeth and expand the dental arches,
regardless of natural variations in inclination
that may not yet be known.11
It should be mentioned that the final
inclination of the posterior teeth is not
solely dependent on prescription; final
tooth position also depends on variables
including appliance slot size, archwire size,
anterior tooth inclination, arch width, Curve
of Wilson, and so on. Nonetheless, further
investigations are needed to determine
whether certain aspects of treatment —
such as inclination — can be standardized,
while other aspects must continue to be
prescribed for each individual patient. The
purpose of this study was to investigate
whether the buccolingual inclinations of
maxillary and mandibular first molars in
pretreatment orthodontic patients vary
according to patients’ vertical facial
patterns (i.e., brachyfacial, mesofacial,
or dolichofacial). The null hypothesis was
that there are no statistically significant
Volume 5 Number 2
differences in the buccolingual inclinations
of mandibular or maxillary first molars
relative to vertical facial patterns.
Materials and methods
After receiving Institutional Review Board
(IRB) approval, 30 patient records were
selected by a single examiner (M.R.) from
a total of 523 patients with pre-existing
i-CAT® (Imaging Sciences International)
cone beam computed tomography (CBCT)
images available at a private practice in
Pennsylvania. These 30 patient records were
chosen because they highly characterized
the three facial types, i.e., brachyfacial,
mesofacial, or dolichofacial. The sample
consisted of Caucasian patients with pretreatment CBCT images available, a fully
erupted permanent dentition, no missing
or impacted teeth with the exception of
third molars, no significant molar rotations,
no posterior crossbite and no previous
orthodontic treatment. All pretreatment
lateral cephalometric images were traced
by one examiner (D.S.) using Dolphin
Imaging 11.7 software (Dolphin Imaging
& Management Solutions, a Patterson
Technology). A separate cephalometric
analysis was created in Dolphin Imaging to
evaluate and categorize the vertical facial
pattern of each patient and included FMA
(MP-FH), palatal mandibular angle (PPMP), gonial/jaw Angle (Ar-Go-Me), P-A
face height (S-Go/N-Me) expressed as
a percentage and RH/LFH (ArGo/ANSMe) expressed as a percentage (Table 1).
Volume 5 Number 2
Using these cephalometric measurements,
10 subjects out of the 523 who could be
best characterized to represent each facial
type (i.e., brachyfacial, mesofacial, or
dolichofacial) were selected for a total of 30
subjects. When possible, those selected
for the brachyfacial and dolichofacial
groups had cephalometric measurements
that were two standard deviations beyond
the corresponding normal values (Table 1).
The mesofacial group included subjects
with values within the normal range for at
least two measurements, and no values
more than one standard deviation away
from normal (Table 1). The subjects were
between the ages of 11 and 20 years.
The group consisted of 15 males and 15
females; six males and four females in
the dolichofacial and brachyfacial groups,
and three males and seven females in the
mesofacial group (Table 2).
Existing cone beam images were
retrieved for each patient; extraneous
portions of the images were removed; and
a slice was taken to bisect the maxillary
and mandibular first molars. The image
was positioned with the occlusal plane
perpendicular to the floor and rotated to
view the first molars from the distal (Figure
1). The occlusal plane was established
by drawing a line to connect the buccal
cusp tips of the mandibular molars. CBCT
images were used to take the following
angle measurements relative to the
occlusal plane (Figure 2,1-2) long axis of
the maxillary right first molar and maxillary
left first molar
3-4) long axis of the mandibular right first
molar and mandibular left first molar
5-6) buccal surface of the maxillary right
first molar and maxillary left first molar
7-8) buccal surface of the mandibular right
first molar and mandibular left first molar
The first four angles measured were
the inner angles formed by the long axes
of the four first molars (including crown
and root). The other four measurements
consisted of four inner angles formed
between the occlusal surface and lines
tangent to the buccal surface of the clinical
crowns of each first molar.
The CBCT images were also used
to take three additional measurements
relative to the occlusal plane that were
analyzed at a separate time from the
aforementioned measurements: (9-10)
the right angle of the mandible and the
left angle of the mandible, and 11) the
buccolingual cuspal height differences
of the mandibular first molars (Figure 3).
The right and left angles of the mandible
were measured by using the inside angle
of a line drawn to bisect the mandible on
both sides and the established occlusal
plane. The buccolingual cuspal height
differences of the mandibular first molars
(known as buccolingual inclinations of the
mandibular molars to the American Board
of Orthodontics) was established for each
subject by drawing a line from the buccal
cusp of the left mandibular first molar to
the buccal cusp of the right mandibular first
Orthodontic practice 45
CONTINUING EDUCATION
Figure 1: Sample CBCT of the angle measurement of the
buccolingual cuspal height differences of the mandibular
first molars. The measurement was established
by drawing a line from the buccal cusp of the left
mandibular first molar to the buccal cusp of the right
mandibular first molar and a line from the lingual cusp
of the left mandibular first molar to the lingual cusp of
the right mandibular first molar, and then measuring the
vertical distance between the two lines at the center
Figure 2: Schematic of measurement taken on CBCT
images. 1-2) Example of long axis of the maxillary right
first molar and maxillary left first molar, 3-4) long axis of
the mandibular right first molar and mandibular left first
molar, 5-6) buccal surface of the maxillary right first molar
and maxillary left first molar, 7-8) buccal surface of the
mandibular right first molar and mandibular left first molar
Figure 3: Schematic of measurement taken on CBCT
images. 9-10) Example of angle measured from the
occlusal plane to a line bisecting the mandible on right
and left sides. 11) Milimeter measurement found by
drawing a line from the buccal cusp of the left mandibular
first molar to the buccal cusp of the right mandibular
first molar and a line from the lingual cusp of the left
mandibular first molar to the lingual cusp of the right
mandibular first molar, and then measuring the vertical
distance between the two lines at the center
CONTINUING EDUCATION
Facial Type
UR6
UL6
B UR6
B UL6
LR6
LL6
B LR6
B LL6
N
Mean
Std. Deviation
DOLICHOFACIAL
10
87.000
5.5638
BRACHYFACIAL
10
89.490
54.384
MESOFACIAL
10
88.990
5.4204
Total
30
88.493
5.3945
DOLICHOFACIAL
10
82.960
6.9451
BRACHYFACIAL
10
86.950
6.2179
MESOFACIAL
10
84.440
4.4410
Total
30
84.783
5.9912
DOLICHOFACIAL
10
89.350
4.9417
BRACHYFACIAL
10
94.600
10.9191
MESOFACIAL
10
96.250
8.8862
Total
30
90.203
12.7814
DOLICHOFACIAL
10
86.560
13.4257
BRACHYFACIAL
10
94.020
8.9674
MESOFACIAL
10
94.030
15.3190
Total
30
90.203
12.7814
DOLICHOFACIAL
10
105.420
6.2833
BRACHYFACIAL
10
102.900
2.7793
MESOFACIAL
10
102.570
2.8956
Total
30
103.630
4.3506
DOLICHOFACIAL
10
104.650
7.1581
BRACHYFACIAL
10
105.550
5.6086
MESIOFACIAL
10
105.550
5.6086
Total
30
104.247
5.4387
DOLICHOFACIAL
10
124.920
5.8719
BRACHYFACIAL
10
125.790
12.4512
MESOFACIAL
10
126.160
12.0418
Total
30
125.623
10.2027
DOLICHOFACIAL
10
130.090
13.7909
BRACHYFACIAL
10
131.010
7.9442
MESOFACIAL
10
131.330
10.4192
Total
30
130.810
10.6107
F Value
Between Subjects
0.579
1.145
1.750
0.846
Results
1.312
0.796
0.036
0.034
Table 3: Descriptive Statistics for molar inclination measurements
All findings were Insignificant. F = .933 for the MANOVA. Code: UR6 = Maxillary Right 1st Molar, UL6 = Maxillary Left
1st Molar, B UR6 = Buccal Surface of Maxillary Right 1st Molar, B UL6 = Buccal Surface of Maxillary Left 1st Molar, LR6
= Mandibular Right 1st Molar, LL6 = Mandibular Left 1st Molar, B LR6 = Buccal Surface of Mandibular Right 1st Molar, B
LL6 = Buccal Surface of Mandibular Left 1st Molar
46 Orthodontic practice
molar and a line from the lingual cusp of
the left mandibular first molar to the lingual
cusp of the right mandibular first molar,
and then measuring the vertical distance
between the two lines at the center. In total
there were 11 measurements taken using
the CBCT images.
All measurements were taken by
the same examiner (M.R.). Standard
descriptive statistics were calculated for
each measurement, which included the
mean and standard deviation for each
variable analyzed. A multivariate analysis
of variance (MANOVA) was first used to
test for differences in angles formed by the
long axes and buccal surfaces of the teeth
across the three facial types, as measured
in the first eight measurements. A separate
MANOVA was used to test for differences
in angles for the right and left sides of the
mandible, and the buccolingual cuspal
height differences of mandibular molars.
A Bonferroni (post hoc) test was also used
done to account for multiple comparisons.
The data were analyzed with IBM SPSS
v.19 software.
Regarding the first set of data, the largest
mean angles measured for the long axis
of the maxillary first molars were found
in the brachyfacial type, with mean
measurements of 89.490° for the maxillary
right first molar (UR6) and 86.950° for the
maxillary left first molar (UL6). The highest
mean angles measured for the line tangent
to the buccal surfaces of the maxillary first
molars were found in the mesofacial group,
with means of 96.250° (B UR6) and 94.030°
(B UL6). For the long axis measurements
of the mandibular arch, no facial type
consistently had the largest or smallest
angles, and it should be noted that there
is very little difference among the mean
values for the three facial types for these
two measurements (Table 3).
For the second set of data, the highest
mean measured for the buccolingual cuspal
height differences of the mandibular molars
was found in the dolichofacial group, with a
mean of 2.010 mm. The brachyfacial group
again had the smallest measurement for
buccolingual inclinations, with a mean of
1.030. Although the mesofacial group fell
in the middle with a mean of 1.100, this
measurement is very close to the mean
brachyfacial measurement, and both are
almost half of the dolichofacial group mean
(Table 4).
Volume 5 Number 2
Discussion
The results of the present study
demonstrated that in this particular
population of pretreatment orthodontic
patients, there was only a statistically
significant difference with respect to
buccolingual cuspal heights of the
mandibular first molars among facial types.
The dolichofacial group demonstrated
more lingual crown inclination of
mandibular molars leading to greater
cuspal height differences as compared to
the brachyfacial and mesofacial groups.
The null hypothesis was therefore rejected.
Isaacson, et al.,12 argued that patients
with vertical facial patterns had narrower
maxillae and were therefore more likely to
be in posterior crossbite. This argument
further supports the results of this
study showing that buccolingual cuspal
height differences should be greater for
dolichofacial patients due to the narrow
maxilla and other facial aspects that go
along with the vertical pattern.
Conversely, Janson et al.,6 found
that when dental casts from patients with
different facial patterns were measured,
“maxillary posterior teeth in subjects with
vertical growth patterns [had] a statistically
significantly greater buccal inclination
as compared with those with horizontal
growth patterns.” They did not find any
statistically significant differences in
inclination of mandibular teeth between the
groups. The results of the present study
Volume 5 Number 2
Facial Type
N
Mean
Std. Deviation
DOLICHOFACIAL
10
111.62
5.1865
BRACHYFACIAL
10
106.13
4.8208
R Md °
1.283
MESOFACIAL
10
108.04
11.4642
Total
30
108.597
7.8553
DOLICHOFACIAL
10
111.25
5.7504
BRACHYFACIAL
10
105.02
4.4758
MESIOFACIAL
10
108.26
6.5554
Total
30
108.117
6.0425
DOLICHOFACIAL
10
2.01
0.6740
BRACHYFACIAL
10
1.03
0.7646
MESIOFACIAL
10
1.100
0.6342
Total
30
1.380
0.8083
3.032
L Md°
Cuspal
6.222*
Height
Diff. (mm)
F Value
Table 4: Descriptive Statistics for mandibular measurements
Data revealed statistically significant differences among the facial types for the set of three
variables for the MANOVA (F = 2.812, p = .019).
Code: R Md° = Right mandibular angle, L Md° = Left mandibular angle,
CHD of Md molars = Cuspal Height Difference of mandibular molars
support Janson’s6 findings that there were
no significant differences in the buccal
inclinations of the maxillary teeth of any
facial type. However, the present study
demonstrates significant differences were
found in the buccolingual cuspal height
differences of the mandibular first molars
among facial types, while Janson’s6 study
did not study this particular variable.
The findings of the present study
are clinically relevant with respect to the
American Board of Orthodontics grading
system of clinical treatment outcomes
for board certification. As previously
mentioned, the buccolingual cuspal height
differences of the mandibular first molars
(known as the buccolingual inclination
of the mandibular molars according to
American Board of Orthodontics)13 were
measured in the present study by drawing
a line from the buccal cusp of the left
mandibular first molar to the buccal cusp
of the right mandibular first molar and
a line from the lingual cusp of the left
mandibular first molar to the lingual cusp
of the right mandibular first molar, and then
measuring the vertical distance between
the two lines at the center. Currently, the
American Board of Orthodontics utilizes a
measuring gauge to score the buccolingual
inclinations of maxillary and mandibular first
molars.13 According to the model grading
system, the gauge is placed on the occlusal
surface of the right and left posterior teeth
and should contact the buccal cusps of the
mandibular first molars. With the gauge in
place, the lingual cusp should be within 1
mm of the surface of the straight edge. If
the mandibular lingual cusps are between
1 mm and 2 mm from the straight-edge
surface, 1 point will be scored for that tooth;
and if it is more than 2 mm from the straight
edge surface, 2 points will be scored for
that tooth. High scores on individual
segments or combinations of segments
can lead to a failure from the Board.13 The
ABO states in the model grading system,
“The buccolingual inclination is used to
Orthodontic practice 47
CONTINUING EDUCATION
Although some patterns were noted in
the measurements of the first set of data,
results of the MANOVA analysis revealed
no statistically significant differences
among the three facial types for any of the
first eight angles measured (F = .933, p =
.540) (Table 3). The MANOVA analysis for
the second set of data revealed statistically
significant differences among the facial
types for the set of three variables (F =
2.812, p = .019) (Table 4). The tests of
between subjects effects further revealed
a statistically significant difference among
the buccolingual cuspal height differences
of the mandibular molar measurements for
the three facial types. The Bonferroni (post
hoc) test showed the buccolingual cuspal
height differences of the dolichofacial
group to be significantly larger, indicating
more lingual crown torque of mandibular
first molars, than the brachyfacial (p = .012)
and mesofacial (p = .020) groups with no
statistically significant differences between
the brachyfacial and mesofacial groups.
CONTINUING EDUCATION
assess the buccolingual angulation of the
posterior teeth. In order to establish proper
occlusion in maximum intercuspation
and avoid balancing interferences, there
should not be a significant difference
between the heights of the buccal and
lingual cusps of maxillary and mandibular
molars and premolars.”14 However, due
to differing schools of thought on occlusal
intercuspation and balancing interferences,
the stance taken by the Board is equivocal
and not supported by high quality
evidence.15
If in fact the ABO is correct in its
assessment of buccolingual inclination
of molars, orthodontists may need to
properly diagnose dolichofacial patients
and implement bracket systems for these
patients that would achieve more buccal
crown torque. This would allow for less
cuspal height differences of maxillary
and mandibular molars, avoid balancing
interferences due to plunging lingual
cusps, and permit practitioners to achieve
treatment results in line with standards set
by the ABO. However, another thought
could be that the ABO may need to look
into revising the grading system with
respect to the buccolingual inclinations of
the mandibular first molars in patients with
dolichofacial vertical patterns, since this
view is not unequivocally supported by
evidence.
Currently in orthodontics, a straightwire appliance with one prescription for
buccolingual inclination of maxillary and
mandibular first molars is usually used,
irrespective of vertical facial pattern.
However, according to the present
study’s findings, there were statistically
significant differences in the initial
buccolingual cuspal height differences of
mandibular first molars for dolichofacial
patterns. It can be argued that if only one
prescription is being utilized, buccolingual
cuspal height differences of mandibular
molars in patients with true dolichofacial
patterns may result in balancing
interferences with maxillary molar cusps
posttreatment unlike their brachyfacial and
mesofacial counterparts.
There were several limitations of this
study. Ideally, a larger sample of subjects
in each of the three facial types would have
been preferred. However, the method in
the present study allowed the researchers
to select the best characterized 30 subjects
from the total of 523 patients in a private
practice office. While additional subjects
could have been included in this study
from the 523 study population, they would
not have represented the facial type’s
groupings as well. Next, researchers
have been recently working to develop
standards for evaluating and measuring
CBCT.16,17 Thus far, no standards
are universally accepted among the
orthodontic
community
regarding
orientation and reference planes for
CBCT images. Nonetheless, even with
the lack of subjects in each sample group,
statistical significance was still found in
the buccolingual cuspal height differences
of mandibular molars among the three
facial types. The dolichofacial group was
found to be significantly larger than the
brachyfacial and mesofacial groups.
Future investigations are still needed to
test additional angles and measurements
in an effort to discern any existing
relationships. Perhaps determination of a
common method for selecting patients for
facial pattern would increase reliability and
validity.
Conclusions
The present study compared differences
in buccolingual inclinations of maxillary and
mandibular first molars in pretreatment
patients with dolichofacial, brachyfacial,
and mesofacial vertical facial growth
patterns. The results indicate that there
were statistically significant differences in
the buccolingual cuspal height differences
of the mandibular first molars (known as
the buccolingual inclination of the molars
according to the ABO) among the three
facial types. The dolichofacial patients
in a group of pretreatment orthodontic
patients demonstrated greater cuspal
height differences and more lingual crown
inclination of mandibular, and subsequently
maxillary molars than the mesofacial or
brachyfacial patients. OP
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