Cervical vertebral body fusions in patients with skeletal deep bite.

Cervical column morphology was examined in 41 adult patients with a skeletal deep bite, 23 females aged 22-42 years (mean 27.9) and 18 males aged 21-44 years (mean 30.8) and compared with the cervical column morphology in an adult control group consisting of 21 subjects, 15 females, aged 23-40 years (mean 29.2 years) and six males aged 25-44 years (mean 32.8 years) with neutral occlusion and normal craniofacial morphology. None of the patients or control subjects had received orthodontic treatment. For each individual, a visual assessment of the cervical column and measurements of the cranial base angle, vertical craniofacial dimensions, and morphology of the mandible were performed on a profile radiograph. In the deep bite group, 41.5 per cent had fusion of the cervical vertebrae and 9.8 per cent posterior arch deficiency. The fusion always occurred between C2 and C3. No statistically significant gender differences were found in the occurrence of morphological characteristics of the cervical column (females 43.5 per cent, males 38.9 per cent). Morphological deviations of the cervical column occurred significantly more often in the deep bite group compared with the control group (P < 0.05). Logistic regression analysis showed that the vertical jaw relationship (P < 0.05), overbite (P < 0.001), and upper incisor inclination (P < 0.01) were significantly correlated with fusion of the cervical vertebrae (R(2) = 0.40).