dental arch widths in class i normal occlusion and class ii division 2 ...

Dental Arch Widths
ORIGINAL ARTICLE
DENTAL ARCH WIDTHS IN CLASS I NORMAL OCCLUSION AND CLASS II
DIVISION 2 MALOCCLUSION
1
CH REHAN QAMAR, BDS, FCPS (ORTHODONTICS)
2
USMAN YOUSAF, BDS, FCPS-II TRAINEE (DEMONT)
3
MARRYAM RIAZ, BSC, BDS
ABSTRACT
The purpose of this study was to compare dental arch widths in Class II division 2 malocclusion
with Class I normal occlusion subjects. The Intercanine, Interpremolar and Intermolar widths were
measured on 100 dental casts (50 class I and 50 class II/2 malocclusion subjects). The data were
developed on SPSS 16 for windows. Independent-samples t-test was applied for comparing the two
groups. Lower Intercanine and Intermolar width was larger in class II/2 malocclusion group.
Interpremolar width between the two groups did not reveal any significant difference. Lower
Intercanine and Intermolar width was significantly larger in class II/2 malocclusion than the
subjects with normal class I occlusion.
Key Words: Dental arch width, Class I malocclusion, Class II div 2 malocclusion.
INTRODUCTION
Class II is a common type of malocclusion that
demonstrates a significant diversity in skeletal and
dental pattern in three planes of space. 1,2,3 Dental class
II malocclusion presents with mandibular teeth being
posteriorly related to their maxillary counterparts
and is further categorized as Class II division 1 and
division 2 types. 3-7 Amongst these, the Class II/2 malocclusion
is less common and little data is available in
the literature. 8 The Orthodontists grant a significant
importance to the dental arch width for diagnoses and
treatment planning to address the dental esthetics
and stability of the dentition. 9,10,11 The literature confirms
a significant difference among the dental transverse
dimensions among class I, class II malocclusion
groups. 12,13 Numerous studies advocate that the extreme
deep bite may result in deficient growth of
mandibular dentoalveoaler segment in antero-posterior
dimension. 14-17 The contemporary orthodontics
propose a number of treatment options for the correction
of these divergence of the dental arches. 18 The
findings determined for other regions might be insufficient
for application to different racial or ethnic
groups and may exhibit variations. The present study
was carried out to determine the difference between
dental arch widths of class I normal occlusion and class
II/2 malocclusion in this region for better understanding
that might be significant for diagnosis and treatment
planning.
The purpose of the study was to compare the
dental arch widths in patients with Class I normal
occlusion and Class II/2 malocclusion.
METHODOLOGY
The study was carried out on 100 dental casts of
patients with age range 16-20 years. (50 class I normal
occlusion and 50 Class II/2, both genders). Demographic
data of patients were recorded and the measurements
were taken using vernier scale. Following
criteria was used: Class I normal occlusion: All teeth
present except third molars, class I canine and molar
relation, no or minor crowded arches. Class II/2 maloc-
1
Address for correspondence: Dr Ch Rehan Qamar, Associate Professor
University College of Dentistry, The University of Lahore, Res: 421/2/C-1, Township, Lahore
Email: rehanqamar@live.com, Cell: 0345-9219219
2
Demonstrator (Dept of Orthodontics) University College of Dentistry, The University of Lahore
Pakistan Oral & Dental Journal Vol 32, No. 3 (December 2012)
427

Dental Arch Widths
clusion: All teeth present except third molars, class II
canine and full cusp class II molar relation, retroclined
upper incisors. The following measurements were used
in this study.
Maxillary cast Maxillary Intercanine width (UC-
C): Distance between the cusp tips of right and left
maxillary permanent canines. Maxillary Interpremolar
width (UP-P): Distance between buccal cusp tips of
right and left maxillary permanent first premolars.
Maxillary Intermolar width (UM-M): Distance between
the mesiobuccal cusp tips of right and left
maxillary permanent first molars.
Mandibular cast Mandibular Intercanine width
(LC-C): Distance between the cusp tips of right and left
mandibular permanent canines. Mandibular
Interpremolar width (LP-P): Distance between buccal
cusp tips of right and left mandibular permanent first
premolars. Mandibular Intermolar width (LM-M):
Distance between the mesiobuccal cusp tips of right
and left mandibular permanent first molars.
TABLE 1: COMPARISON OF DENTAL ARCH
WIDTHS
Parameter Class I Mean Class II/2 Mean
Value (mm) Value (mm)
UC-C 34.2 ± 1.3 34.3 ± 1.2
UP-P 40.3 ±1.9 40.5 ± 1.9
UM-M 52.3 ± 1.8 52.7 ± 1.4
LC-C 26.3 ± 2 29.3 ± 1.3*
LP-P 33.9 ± 1.3 32.9 ± 1.9
LM-M 44.1 ± 2.3 46.8 ± 1.1*
* Significant value (p < .05)
RESULTS
There was no statistically significant difference
recognized between the first and the second
measurements.Table No.1 indicates the comparative
result of dental arch widths in class I normal occlusion
and Class II/2 malocclusion. The Class II/2 sample had
significantly greater mandibular Intercanine and
Intermolar arch widths as compared to class I normal
occlusion. Both groups revealed similar values for
maxillary Intercanine, Interpremolar and Intermolar
and mandibular Interpremolar widths, indicating no
significant differences. These results were in agreement
to various studies conducted previously on different
population. 8,17,18,20
DISCUSSION
The current study was carried out to compare the
dental arch widths in normal Class I occlusion with
Class II/2 malocclusion patients. The mean age of the
study sample was 18.54±2.3 years. The literature
reveals that class II/2 malocclusion is often associated
with extreme deep bite that might inhibit mandibular
dentoalveoalr development in sagittal plane. 16
Fig 1: Interarch Widths
STATISTICAL ANALYSIS
The mean and standard deviation for each parameter
was computed using the SPSS Version 16 for
Windows. Both group measurements were compared
using independent t-test. 30 randomly selected casts
were remeasured after one week of first measurement
and was compared to find out any method error using
paired t-test.
The current investigation indicated no significant
difference between the maxillary Intercanine dental
arch widths among the two groups. However, the
lower Intercanine width was significantly larger in
class II/2 malocclusion as compared to class I subjects.
These results were similar to Usyal 8 , Joel 19 and
Fröhlich 20 study.
No significant difference was found in the maxillary
and mandibular Interpremolar width between
the two groups. The same was found out in previous
studies. 8,18-20
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Dental Arch Widths
The difference between maxillary Intermolar arch
widths was insignificant for both class 1 and class II/
2 group while mandibular Intermolar arch width was
significantly larger in class II/2 malocclusion. This
was in agreement to previous studies carried out by
Usyal 8, Christofer 18 and Frohlich 20 . In contrary to current
study findings, Joel 19 indicated that maxillary
Intermolar width was slightly narrow in class II/2
malocclusion as compared to class I normal occlusion.
CONCLUSION
It was concluded from the above study that lower
Intercanine and Intermolar width is significantly larger
in class II/2 malocclusion as compared to class I normal
occlusion.
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