ABSTRACT
Objective:To assess the effect and mechanism of ClassⅢ malocclusions treatment with Frankel-Ⅲ appliance and reverse Twin-block appliance. Methods:Twenty subjects of ClassⅢ malocclusion were included in this study(9 males,11 females). Among them, 10 subjects were randomly selected for treatment with reverse Twin-block appliance (T group) and 10 subjects for Frankel-Ⅲ appliance (F group). All patients were treated all the day for total of 4-11 months. The cephalometric records of these subjects were examined before and after treatment. The acquired data were processed with SPSS 10.0. Results: The results showed a mandible receded backward in both groups. Both group could accelerate the development of the maxillary bone. But the Frankel-Ⅲ was more effective. F group had significant effects of uprighting upper frontal teeth and flaring lower teeth. the average treatment time was 6.5 months in reverse twin-block appliance therapy group and 9 months in Frankel-Ⅲ appliance group. Conclusion: Both reverse Twin-block appliance and Frankel-Ⅲ appliance can treat angle classⅢ malocclusions effectively. The effects of maxillary changes of Frankel-Ⅲ appliance is better than reverse Twin-Block. Treatment period is shorter in T group than in F group.