Changes in third molar position after Class II subdivision malocclusion treatment with asymmetric extractions

This study aimed to assess the changes in third molars angulation and their available space after Class II subdivision malocclusion treatment with asymmetric premolar extractions.

The sample consisted of 37 patients (17 male, 20 female and mean age 13.18 ± 1.99 years) in group 1 (Type 1 Class II subdivision) and 25 (10 male, 15 female, mean age 13.56 ± 2.46 years) in group 2 (Type 2 Class II subdivision). In group 1, extractions were performed in the two maxillary quadrants and in the Class I mandibular quadrant. In group 2, extraction was performed in the Class II maxillary quadrant. Panoramic radiographs were used to evaluate third molar angulations and their available space pre- and post-treatment. Radiographic measurements were performed with Dolphin^® Imaging 11.9. Paired t tests were used for intragroup comparison between stages and sides.

In Type 1, there were similar improvements in third molar angulations and increases in the space available on the extraction quadrants in the maxillary arch. In the mandibular arch, there was significantly greater improvement in angulation and greater space availability in the extraction quadrant after treatment. In Type 2, there was significantly greater improvement in angulation and available space for the maxillary third molar on the extraction quadrant. In the mandibular arch, there was a similar improvement in the available space for the third molars.

After treatment, both groups presented better angulation and significantly greater space for third molar eruptions on the extraction quadrants, when compared to the homologous non-extraction quadrants.