Dentofacial traits in association with lower incisor alveolar cancellous bone thickness: A multiple regression analysis.

Objective: To identify dentofacial anatomic traits associated with lower incisor cancellous bone thickness (LICBT) and then to assess their separate contributions and their combined contributions to the variation in LICBT. Materials and Methods: A consecutive sample of cone beam computed tomography (CBCT) data taken in a university hospital within the same setting was retrospectively reviewed. Within the sample, CBCT data of 252 eligible subjects were reconstructed and measured for LICBT, facial traits, and mandibular symphyseal traits. A backward multiple linear regression was employed to explore the association between LICBT and seven representative dentofacial traits. Results: Four dentofacial traits (vertical facial pattern, transverse jaw relationship, lower incisor cervical diameter, and mandibular symphyseal width) were identified as significantly associated with LICBT. The combination of these four factors could predict 64.3% of variations in LICBT (adjusted R-2 = 0.643). Further comparison of LICBT among different transverse jaw relationships suggested that the LICBT of the normal (5.94+/-1.58 mm) group and the inferior convergent group (5.38+/-1.32 mm) were significantly larger than that of the crossbite group (4.34+/-1.27 mm) and the superior convergent group (4.53+/-1.67 mm). Conclusions: The bony support of lower incisors is significantly associated with several dentofacial traits. Reduced lower incisor bony support was statistically associated with increased vertical facial pattern, transverse jaw discrepancy, thinner mandibular symphyseal width, and smaller lower incisor cervical diameter.