Condylar asymmetry in adults with unilateral posterior crossbite and the changes in condylar position after treatment.

Objective:To examine condylar asymmetry in adults with unilateral posterior crossbite and to study the changes in condylar position after crossbite correction.Method:Twenty-one adults aged 18 to 23 years (mean,21.8years) with unilateral posterior crossbite were compared to 21 adults aged 19 to 23 years(mean,22.1years) exhibiting Angle Class Ⅰ noncrossbite malocclusions.Pretreatment panoramic radiographs were used to study condylar asymmetry and condylar asymmetry indices were analyzed.In addition,the anterior,superior,and posterior joint spaces were measured to determine differences of relative condylar position before and after crossbite correction with the use of TMJ transcranial lateral cephalometric radiographs.All data were analyzed with SPSS 12.0 software.Result:The patients with unilateral posterior crossbite had more asymmetrical condylar relative to the controls.There were no statistically significant differences in condylar position between left and right sides before and after treatment in crossbite group.However,relative condylar position was more concentric after treatment(R decreased from 13.52 to 9.48).Conclusion:Patients with unilateral posterior crossbite have asymmetrical condylar head,but symmetrical relative condylar position.Remodelling changes take place in TMJ response to the changes in occlusion and the position of the mandible.The correction of crossbite results in a more symmetric condylar position.