Variation of chin morphology and mandibular incisor length in different facial divergence patterns: New insights from CBCT records

Abstract

Aim: Evaluate constitutional differences in chin morphology and volume, and mandibular tooth size, between different facial divergence patterns. Materials and Methods: The sample consisted of 284 pretreatment cone beam computed tomography (CBCT) images of growing and non-growing patients who were stratified into 4 groups based on mandibular plane inclination to cranial base (SN) angle. Linear and angular measurements were made on the lateral CBCT images: mandibular lateral incisor crown (I-C) total (I-A) lengths, the distances between point D (centre of symphysis) and both incisor apex (D-A) and menton (D-Me) and between cemento-enamel junction and menton (CEJ-Me); chin width at the level of the central incisor apex (CWA) and point D (CWD); and the angles of the anterior and posterior symphyseal slopes. The volume of the symphysis was measured using a specialized 3D imaging software. Group differences and associations between parameters were gauged through the three-way ANOVA analysis. Results: I-C, I-A, D-A, D-Me and CEJ-Me were greater in the hyperdivergent group (p.05). The anterior slope angle decreased with hyperdivegence (p