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

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Effects of eruption guidance appliance in the early treatment of Class III malocclusion.

OBJECTIVES: To evaluate the dentoskeletal effects and effectiveness of the eruption guidance appliance in Class III patients in the mixed dentition. MATERIALS AND METHODS: The experimental group comprised 22 patients with Class III malocclusion and anterior cross-bite (12 males, 10 females, mean age 7.63 ± 0.96 years) treated with the eruption guidance appliance over a mean period of 1.72 ± 0.48 years. The control group comprised 22 untreated subjects (12 males, 10 females, mean age 7.21 ± 0.60 years) with Class III malocclusion. Lateral cephalometric radiographs were obtained at pretreatment (T1) and posttreatment (T2). Intergroup comparisons were performed with Mann-Whitney and t-tests (P < .05). RESULTS: In the experimental and control groups, the anteroposterior relationship between the maxilla and mandible (ANB angle) remained stable during the treatment period (T1 to T2). The mandibular plane angle decreased in the experimental group and increased in the control group. In the experimental group, the lower anterior face height increase and maxillary molar vertical development were significantly smaller compared to controls. Positive overjet was achieved in 54% of the experimental group. CONCLUSIONS: The eruption guidance appliance produced no change in the skeletal anteroposterior relationship. The anterior cross-bite/edge-to-edge relationship was corrected in only about half of the treated subjects.