Differential diagnosis of skeletal open bite based on sagittal components of the face.

Aims: This study examined the morphology of skeletal open bite with respect to the sagittal components of the face.

Methods: The material consisted of cephalometric and hand-wrist films of 49 girls and 22 boys with skeletal open bite. The samples were grouped into Class I, II, and III facial types on the basis of ANB angle. In addition to conventional dentofacial variables, nasopharyngeal airway area was also measured on lateral headfilms. All measurements were examined by analysis of variance and Duncan test. Subsequently the factors leading to open bite were evaluated using multiple-regression analysis.

Results: Dentofacial morphology differed in the sagittal components of skeletal open bite, and the differences were most obvious between the Class II and Class III open bite groups. Posterior maxillary dentoalveolar height and mandibular incisor inclination were important factors in the development of open bite in the skeletal Class I and Class II open bite groups, while in the skeletal Class III open bite group, the nasopharyngeal airway and the gonial angle were involved.

Conclusion: Sagittal components of skeletal open bite should be considered in the differential diagnosis and treatment planning of such cases.