Heritability of teeth angulation and inclination in patients with overt malocclusion

Abstract

To use 3-dimensional cone beam computed tomography (CBCT) images obtained on patients before treatment with dental malocclusion to calculate the heritability estimates of full-tooth angulation and inclination. A heritability estimate is a number between zero and one indicating the percentage of genetic factors involved in determining the phenotypic variation observed. CBCT images of 111 patients (51 sibships) were analysed measuring both tooth angulation and inclination using the Anatomage Invivo5 software for central incisor to second molar. The long axis of each tooth was defined and traced as the cusp tip of the most mesiobuccal cusp to 6mm coronal to the apex of the mesiobuccal root. SPSS statistical software was used to analyse the data and calculate the heritability estimates for each tooth type in the maxilla and in the mandible regardless of the side. Teeth inclination showed higher heritability estimates than tooth angulation. Furthermore, maxillary teeth showed higher heritability estimates than mandibular teeth and anterior teeth showed higher heritability than posterior teeth. Genetic effect was more evident on tooth inclination than tooth angulation, on anterior teeth more than posterior teeth, and on maxillary teeth more than mandibular teeth.