Bolton ratio in a North Indian population with different malocclusions

Objective: The objective was to evaluate the Bolton ratio in a North Indian population in Lucknow with different malocclusion.

Materials and methods: Totally, 110 study cast [Age: Female (14.2 ± 1.5 years, Male (13.9 ± 2.3 years)] were taken from the patients undergoing orthodontic treatment and Subjects were divided into three groups: Group I (Angle's Class I, n = 40), Group II (Angle's Class II, n = 50) and Group III (Angle's Class III, n = 20) according Angle's classification of malocclusion. The mesiodistal widths of all maxillary and mandibular teeth from right first molar to left first molar were measured with a digital caliper to calculate the Bolton ratio. The readings were then used to compute the anterior and total Bolton ratios. ANOVA and Tukey's test were used for the statistical analysis.

Results: A mean total Bolton ratio of 91.36 ± 2.13 and a mean anterior Bolton ratio of 78.14 ± 4.09 were found for the sample, Significantly higher mean anterior tooth ratios were found for Group II (Angle's Class II) patients (P < 0.01). All other ratios were within close range of Bolton's norms.

Conclusions: Angle's Class II patients showed a tendency toward wider mesiodistal widths of teeth in the mandibular anterior region or smaller tooth sizes in the maxillary anterior region.