An investigation of maxillary and mandibular morphology in different overjet groups

It has been suggested that overjet may be related to the form of the maxilla and mandible.

The aims of this study were to compare the gender differences in the maxillary and mandibular morphology in different overjet groups, and to determine the associations between overjet and craniofacial morphology in the same subjects.

The material consisted of lateral cephalometric radiographs of 80 untreated subjects 140 boys, 40 girls), aged 13 to 15 years, selected from records held in the Orthodontic Department, Atatürk University. The subjects were divided into four overjet groups. Thirteen linear, one angular, and three area measurements were used to assess maxillary and mandibular form in the male and female subjects.

The results showed that there were statistically significant differences in the maxillary anterior and posterior dentoalveolar heights (MxAABH, MxPABH), effective mandibular length (Cd-Gn), corpus length (Go-Gn), and ramus width (RW) between the overjet groups. In 15 out of 17 measurements the males were significantly larger than the females. There were no gender differences in antegonial notch depth (AND) and the gonial angle. Furthermore, significant negative correlations were found between overjet and Cd-Gn, and between overjet and Go-Gn in the girls. Significant positive correlations were found between overjet and MxAABH, and overjet and RW in the boys.

Evaluation of the maxillary dentoalveolar heights and some mandibular parameters, such as Cd-Gn, Go-Gn and RW, in different overjet patterns may be useful in the analysis of the malocclusion, and prediction of treatment success.