Prevalence of Bolton’s Discrepancy in patients at the Orthodontics Clinic of Universidade Federal Fluminense

Abstract

Objective: to assess the prevalence of Bolton's discrepancy in patients who were selected for treatment at the Orthodontics clinic of the Faculty of Dentistry of the Universidade Federal Fluminense between 2011 and 2017, through the analysis of plaster casts obtained prior to the start of orthodontic treatment. Material and Method: plaster models of the upper and lower arches were used, selected according to the inclusion and exclusion criteria. Measurements of mesiodistal diameters were performed with a dry point caliper and millimeter ruler. The intraclass correlation coefficient (ICC) was used to calculate the method error (intra and inter-observer). Results and conclusion: The values ​​showed excellent intra-examiner reliability (ICC > 0.75). Regarding the total ratio, 85% of the sample were within the range of variation of normality proposed by Bolton, as well as 66.6%, with respect to the previous ratio. There was an excess of dental material in the upper arch in 51.6% of the cases, and a lower excess in 46.6%, in relation to the total ratio. In the partial ratio, 40% of the cases had a higher excess, against 60% with a lower excess. In only one case (1.6%) there was no excess for the total ratio (r = 91.3).

Keywords: Bolton discrepancy; tooth size discrepancy; model analysis.