Anomalies of the cervical vertebrae in patients with skeletal Class II malocclusion and horizontal maxillary overjet

Introduction: Cervical column morphology was examined in adult patients with skeletal Class II malocclusion and horizontal maxillary overjet; the findings were compared with cervical column morphology in an adult control group with neutral occlusion and normal craniofacial morphology. This has not previously been investigated. Methods: The overjet group consisted of 34 patients: 28 women (ages, 18-42 years) and 6 men (ages, 18-38 years). Their horizontal overjets ranged from 5.47 to 15.29 mm. The control group consisted of 21 subjects: 15 women (ages, 23-40 years) and 6 men (ages, 25-44 years). A visual assessment of the cervical column was made, and craniofacial dimensions were measured on each subject's profile radiograph. Results: In the overjet group, 52.9% had fusion of the cervical column, and 5.9% had posterior arch deficiency. Fusions occurred significantly more often in the overjet group compared with the control group (P <.01). Associations were found between fusions of the cervical column and mandibular retrognathia (P <.05), large cranial base angle (P <.05), and large horizontal overjet (P <.05). Conclusions: The results could provide a new method to phenotypically subdivide skeletal maxillary overjets. This is important for the diagnosis and the correct treatment of these patients.