AIM: This clinical study evaluated, through helicoidal computed tomography (CT), the effects of rapid maxillary expansion in the condylar position of patients with functional posterior crossbite in mixed dentition stage. METHODS: Ten patients aged between 7 years and 2 months and 11 years and 2 months were selected. This patients which presented functional unilateral posterior crossbite with mandibular midline deviation of at least 2.5mm to the crossbite side were submitted to rapid maxillary expansion. After obtaining sagittal CT slices of the temporomandibular joints, measurements of the anterior, posterior and superior joint spaces were carried out and the relative positioning of the condyle was calculated. Axial slices of the temporomandibular joint were also used to evaluate the anteroposterior and transversal position of the condyles in relation to the cranial base structures. RESULTS: Before treatment, significant differences were observed in the posterior joint spaces, in the relative positioning of the condyle and with the non-crossbite side condyle displaced more anteriorly and medially in relation to midsagittal line. After treatment there was no statistically significant difference. CONCLUSION: After the rapid maxillary expansion, a more centralized position of the condyles in the joint cavities was observed, and a greater anteroposterior and transverse symmetry between them.
Functional posterior crossbite; TMJ; Computed tomography
