The Journal
or more pairs of teeth from opposite sides of the
arch, whereas 80% revealed discrepancies of
at least 0.5 mm. In 1949, Neff 2 developed the
"anterior coefficient," a method to compare the
widths of the anterior teeth in opposing arches.
Neff concluded, "that everything else being
normal an orthodontic or non orthodontic
normal will settle to the degree of overbite
indicated by the anterior coefficient." Ballard 7
reported in 1956 that, in a study of 400
orthodontic cases, over 50% revealed an
excess of at least 2 mm of mesiodistal tooth
width in the mandibular anterior segment when
compared to the maxillary anterior teeth.
Bolton analysis is made directly on study casts.
The overall Bolton ration is the percentage
obtained by summing the widths of 12
mandibular teeth divided by the sum of width of
12 maxillary teeth, where as anterior ratio is the
percentage obtained by summing the width of 6
mandibular anterior teeth divided by the sum of
width of 6 maxillary anterior teeth.
8
Smith et al studied the intermaxillary tooth size
discrepancy of three different population and
concluded that the intermaxillary tooth size
relationship are population and gender specific.
Arya et al 9 showed that there were differences in
tooth size between sexes. Lavelle10 showed
that there was sexual dimorphism in tooth
dimensions and the ratio of maxillary to
mandibular arch tooth size.
11
Santoro et al reported that the overall ratio was
found to be 91.3, equivalent to the Bolton
overall ratio, whereas the anterior ratio was
78.1, larger than the 77.1 Bolton ratios.
Uysal and Sari 12 determined the tooth size ratios
for the maxillary and mandibular dentitions, and
sex differences for those variables in a Turkish
population and statistically significant sex
difference was found only in overall ratio. So,
taken in account gender and population factor
in different malocclusion groups, the present
study was designed:
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29
23
22
10
3
1
19
1. To calculate the overall and anterior Bolton
ratio in different malocclusion groups from
Punjab region applying for orthodontic
treatment and to compare their results with
Bolton standard.
2. To compare Bolton’s tooth size ratios
between gender.
Material and Method
The sample comprised of 100 pre-treatment
study casts, selected from models of 500
patients, who during 2011 to 2013 came to
department of orthodontics and dentofacial
orthopaedics, Baba Jaswant Singh Hospital
and Research Institute, Ludhiana, Punjab.
The study group comprised of:
50 males
50 females
The diagnosis of malocclusion was based on
Angle’s classification, basically on the basis of
canine and 1st molar relationships.
The study model selection criteria included:
1)Good quality pre-treatment models of the
malocclusion groups. /Good quality models of
normal occlusion and pretreatment models of
patients
2) Fully erupted permanent teeth especially till
1st molar.
3) Absence of any tooth anomalies regarding
form, number (eg, missing, supernumerary)
and development.( eg, conic- form lateral
incisor teeth)
4) Absence of tooth abrasion, interproximal
caries, or any prosthetic crowns or bridges.
All measurements of the casts were undertaken
by one operator, with the help of digital vernier
calliper (Fig. 1) (DIGIMATIC CALIPER,
MITUTOYO, CHINA with a measuring range of
150 mm, resolution of 0.01 mm and
instrumental error of _.03 mm).
Vol. 13
12 No. 1
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May-August
Sept-Dec 2017
Jan-April
2016
2016