Cervical column morphology in patients with skeletal Class III malocclusion and mandibular overjet

Introduction: The cervical column morphology of adults with skeletal Class III malocclusion and mandibular overjet was examined and compared with the cervical column morphology of a control group with neutral occlusion and normal craniofacial morphology. Methods: The mandibular overjet group consisted of 57 patients (32 women, 25 men). The control group consisted of 21 subjects (15 women, 6 men). A visual assessment of the cervical column and measurements of the craniofacial dimensions were performed on a profile radiograph of each subject. Results: In the mandibular overjet group, 61.4% had cervical column fusion, and 12.3% had posterior arch deficiency. Morphologic cervical column deviations occurred significantly more often in the mandibular overjet group than in the control group (P <.001). The most important craniofacial parameters for fusion of the cervical column were maxillary retrognathism (P <.05) and mandibular overjet (P <.05) (R2 = 0.22). The most important factor for posterior arch deficiency was mandibular inclination (P <.05) (R2 = 0.12). Conclusions: These results are considered an important first step in phenotypic differentiation of skeletal Class III malocclusions that can be associated with different genotypes. This is important for the diagnosis and the correct treatment of these patients.