Three-dimensional analysis of tooth movements after palatal miniscrew-supported molar distalization

摘要

Introduction: The aim of this prospective clinical study was to evaluate the dentoalveolar effects of a palatal miniscrew-supported molar distalization appliance using a 3-dimensional reverse engineering method. Methods: This study sample comprised 21 patients at an average age of 13.6 years with a bilateral Class II molar relationship. Distalization was performed using skeletal anchorage. Dental casts were obtained just before treatment and after appliance removal, and they were scanned with a 3-dimensional dental scanner. The digital dental cast images were aligned. Four points and 2 lines were determined on each tooth, and the correlations between tooth movements and the linear and angular changes were analyzed 3 dimensionally. Results: In the sagittal direction, the first molars showed a mean linear movement of 4.10 +/- 1.57 mm, with distal tipping of 11.02 degrees; the central incisors showed a mean distal movement of 0.95 +/- 0.40 mm, with retroclination of 1.59 +/- 0.59 degrees. In the vertical direction, only the first molars showed intrusion, with a mean value of -0.59 +/- 0.50 mm. Rotation of the first molars was 4.92 degrees +/- 3.09 degrees. The second molars had the greatest rotation. The highest correlation among tooth movements was found between the first and second molars. Conclusions: Through support from the anterior palatal region, the maxillary first molars were distalized without anchorage loss. Furthermore, movement was observed in all 3 planes of space with reduction from the posterior to the anterior in the maxillary arch.