Effect of Crowding on Frequency of Bolton Tooth Size Discreapncies Among Orthodontic patients
Date
2002-10-30
Authors
Nagarathne, N.
Journal Title
Journal ISSN
Volume Title
Publisher
The university of Peradeniya
Abstract
The aim of the study was to examine the frequency of Bolton tooth size discrepancies
and the effect of severity of crowding on tooth size discrepancies among orthodontic patients.
A random sample of 146 orthodontic patients 74 males and 72 females who satisfied the
selection criteria were selected from the records of the orthodontic patients taken up between
year 1997 to 2000. Mesio distal dimensions of the teeth mesial to both maxillary and
mandibular first permanent molars were measured on pre treatment study models and
subjected to Bolton analysis. Both overall and anterior Bolton ratios were calculated for each
case. The severity of crowding was assessed using Little's Irregularity Index.
Data analysis was done to investigate the frequency of tooth size discrepancies among
both crowded and non-crowded groups and the effect of severity of crowding on tooth size
discrepancies. There were 68 in crowded group and 78 in non-crowded group. 26.91 % of the
crowded group showed clinically significant (2SD out side of Bolton mean) anterior tooth
size discrepancies which can compromise the final occlusal outcome. Mean overall ratio for
non-crowded group was 90.95%±2.49% and for crowded group was 90.95%±2.94%. Mean
anterior ratio for non-crowded group was 76.41%±3.09% and for crowded group was
78.10%±3.23%. Statistically significant difference was seen only in anterior retios between
crowded and non-crowded groups. (P=. 002). Results of the study reveals that special
emphasis should be given to the Bolton analysis of anterior ratios, during treatment planning
stage of orthodontic cases with crowding in order to reduce the failure rate which can result
due to tooth size discrepancies in the study population.
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Citation
Proceedings and Abstract of the Annual Research Sessions, October 30,2002, University of Peradeniya, Sri Lanka P 69