The prevalence of Bolton discrepancy and associated malocclusion in patients attending the orthodontics department of Kerman Dental School and private clinics: 2012-2015

Introdution: For the proper occlusal interdigitation or coordination of arches in the finishing stage of orthodontic treatment with proper overjet and overbite, there must be a proper mesiodistal tooth size ratio between maxillary and mandibular teeth. The Bolton analysis should be taken into consideration while diagnosing, treatment planning and predicting prognosis in clinical orthodontics. The purpose of this study was to evaluate the prevalence of Bolton discrepancy in the patients attending to Orthodontics Department of Kerman Dental School and private clinics to determine the effects of gender and unilateral maxillary canine impaction on Bolton ratio.
This cross sectional study was performed on 311 pretreatment orthodontic casts of patients attending to Orthodontics Department of Kerman Dental School and private clinics between 2012- 2015. The greatest mesiodistal dimensions of teeth were measured with digital caliper with accuracy of 0.01 mm. Independent t-test and chi square were applied to analyze the data by SPSS 18 software and values were considered to be significant when P The mean anterior and overall Bolton’s ratios were 78.49% and 91.73%, respectively without considering malocclusion and gender. The most prevalent anterior and overall Bolton ratios were 41.5% and 25.7%, respectively. The anterior and overall Bolton ratios for female patients were greater than male patients. There were no significant relationship between canine impaction and Bolton’s ratios.
Conclusion This study indicated a noticeable prevalence of tooth- size discrepancies in the patients. Regarding tooth- size discrepancies and their effects on occlusion and dental relations, it is suggested that Bolton’s tooth size analysis must be performed before starting the orthodontic treatment