Analysis of tooth sitze discrepancy (Bolton index) among patients of orthodontic clinic at Kaunas Medical University

Abstract

The purpose of the study was to determine the total (TBI) and anterior (ABI) Bolton indexes among patients treated in the Clinic of Orthodontics at Kaunas University of Medicine, and to evaluate the clinical significance of the estimated tooth size discrepancies, the dependence of Bolton index on gender, teeth width variability, and to estimate the Bolton index changes that mostly have influence on teeth. 108 diagnostic models (37 boys and 71 girls) were examined. It was determined that in 62.3% of the cases (68 patients) normal total Bolton ratio was found (no tooth size discrepancies), 21.3% of patients (23 patients) - had wider upper than lower teeth, 15.7% (17 patients) the opposite. Estimated ABI was normal in 48.1% (52 patients) of the cases, in 20.4% (22 patients) - upper front teeth appeared to be wider than lower front teeth, in 31.5% (34 patients) the opposite. Significant tooth size discrepancies in both posterior and anterior segments were detected in 5.5% of examined patients (91.3- 3.86(2S)<=TBI<=91.3+3.86(2S)), in 18.5% - only in the anterior part of the dentition (77.2-3.30(2S)<=ABI<=77.2+3.30(2S)). Both TBI and ABI values showed no dependence on patients gender and occlusion. BI was mostly influenced by the width differences of the first permanent molars, upper central and lateral incisors.