The Effect of Premolar Extraction on Overall Bolton Ratio in Class III Malocclusion in RSGMP FKG USU

Abstract

Abstract-Tooth extraction is a treatment of choice in the tooth size discrepancy cases in order to achieve appropriate alignment, angulation, and inclination of the teeth. The objective of this study was to determine the effect of premolar extraction on overall Bolton ratio in Class III malocclusion. Samples in this study consisted of 40 study models of subjects with Class III malocclusion that meets the inclusion criteria. Measurements were performed directly on 12 maxillary and mandibular teeth in study model using an electronic digital caliper with accuracy 0.01 mm. Furthermore, the initial overall Bolton ratio was calculated on the whole samples and continued with several hypothetical extractions. After that, the calculation of the overall Bolton ratio in the fifth combination of premolar extraction was done and the results were statistically tested. The results showed that the initial overall Bolton ratio consisted of 5 subjects (12.5%) with small overall Bolton ratio, 24 subjects (60%) with normal overall Bolton ratio, and 11 subjects (27.5%) with large overall Bolton ratio. Wilcoxon test showed the effect of premolar tooth extractions on overall Bolton ratio in Class III malocclusion (p=0.001). Overall Bolton ratio decreased significantly after the extraction of the premolars in all hypothetical extractions, where normal Bolton ratio was observed in the combination of upper first premolar and lower second premolar extractions. As the conclusion, premolar tooth extraction affects the overall Bolton ratio in Class III malocclusion.