A morphometric study of Bonwill’s triangle for gender differences in dry mandibles of the Indian population

Abstract

Bonwill's triangle, an imaginary equilateral triangle of the mandible, can cause mandibular alignment issues in post-dental occlusion, complete dentures, and mandibular fractures due to incorrect measurements across genders. This study aimed to analyze Bonwill's triangle size in dry mandible bones of the Indian population, focusing on gender differences to create error awareness in dental treatments and mandibular fractures. The study involved fifty-three dry human mandibles, segregated into male and female based on metric and non-metric parameters. The study measured the distances between the center of the right condyle to the midpoint of medial mandibular incisors (X-Y), the center point of the left condyle to the midpoint of medial mandibular incisors (Y-Z), and the center point of both condyles (Z-X). The mean lengths of Bonwill's triangular measurements in males were X-Y (101.08 mm), Y-Z (100.39 mm), and Z-X (97.06 mm), while females had 100.3 mm, 99.45mm, and 93.41mm respectively. Only two sides of the triangle were in accordance with Bonwill's theory. In the Indian population, Bonwill's triangle was significantly larger in male mandibles, and the intercondylar distance (Z-X) was less than 100mm in both genders, resulting in an isosceles triangle. Bonwill's triangle serves as a basis for modern technology to find geometric parameters for fractured mandibles and dental procedures, sex identification in forensic dentistry, anthropological studies, and bone grafts.