Transverse skeletal and dental asymmetry in adults with unilateral lingual posterior crossbite.

BACKGROUND: Posterior unilateral lingual crossbite (PUXB) is a common malocclusion in children. However, the extent to which PUXB affects the dentition and craniofacial structures in adults has not been fully defined. We investigated dental and skeletal asymmetry in adults with PUXB. METHODS: We randomly selected 15 crossbite subjects (mean age, 26.2 years) and 15 matched controls (mean age, 30.6 years) from 3000 records. Mounted pretreatment dental casts were measured to assess dentoalveolar asymmetry, and posteroanterior radiographs were used to evaluate left-right skeletal asymmetry and positional deviations of the mandible. RESULTS: A statistically significant difference in mandibular transverse dental asymmetry was observed between adults with PUXB and the control group. However, no significant differences were found in the right-left skeletal asymmetry, although the PUXB group showed more positional deviation of the mandible. Moreover, condylar position analysis indicated that the crossbite group did not show any greater functional shifts than the control group. CONCLUSIONS: We concluded that PUXB in adults is primarily due to dentoalveolar asymmetry and positional deviation of the mandible and not simply to right-left skeletal asymmetry of the mandible. These data suggest that untreated PUXB in children might lead to progressive asymmetric compensation of the condyle-fossa relationship and result in a positional deviation of the mandible, which, along with a distinct dentoalveolar asymmetry, maintains the crossbite occlusion in adults.

Treatment of a Class I malocclusion with severe bimaxillary protrusion.

This report describes the treatment of a 20-year-old woman from Nigeria who had severe bimaxillary dentolveolar protrusion. The main issue in determining the appropriate treatment plan was the severity of the dentoalveolar protrusion. Four first premolars were extracted to reduce lip procumbancy. The change in the patient's facial esthetics was dramatic. Significant retraction of the upper and lower lips was achieved, and lip eversion and dentoalveolar protrusion were significantly improved. As the lips were retracted, mentalis strain was reduced; this improved chin projection. This case report was presented at an AAO meeting as part of the ABO student case display. It was chosen by committee to be published in the AJO-DO.