Effect of Premolar Extraction on Overall Bolton Ratio in Class II Malocclusion in RSGM FKG USU

摘要

Tooth extraction to overcome the functional and aesthetic outcomes has become an issue in orthodontic treatment. Tooth size discrepancy was determined through a Bolton analysis. Overall Bolton ratio has changed after the tooth extraction, and affected by different extraction. The aim is to determine the effect of premolar extraction to overall Bolton ratio in Class II malocclusion. Subject was 40 patients with Class II malocclusion in accordance with the inclusion criteria. Measurements performed directly on 12 maxillary and mandibular teeth using an electronic digital caliper. 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 after hypothetical extractions were done and the results were statistically tested to see the effect of the premolar extraction on overall Bolton ratio in Class II malocclusion. The initial overall Bolton ratio consisted of small overall Bolton ratio (86.27±3.19) the number of 7 subjects (17.5%), normal overall Bolton ratio (91.63±1.19) with the number of 23 subjects (57,5%) and large overall Bolton ratio (95.65±2.47) with the number of 10 subjects (25%). Wilcoxon test showed the effect of premolar tooth extractions on overall Bolton ratio in Class II malocclusion (p= 0.001). Overall Bolton ratio shifted significantly into the normal Bolton ratio were observed in the combination of maxillary first premolar and mandibular second premolar extractions, while the maxillary first premolar extraction increased the overall Bolton ratio. Premolar tooth extraction affects the overall Bolton ratio in Class II malocclusion.