Clinical estimation on treatment option for skeletal class III malocclusion in mixed dentition

Objective To discuss the key point of treatment option for different skeletal class Ⅲ malocclusion in mixed dentition,by comparing clinical effects and skeletal changes.Methods Twenty skeletal class Ⅲ cases with retro maxilla were selected.Two groups were divided according to the mandibular plane angle and the degree of retruding.Group one consisted of 12 cases,with average/high angle and without functional retrusion;group two consisted of 8 cases,with average/low angle and somewhat functional retrusion.Face mask was used in group one to stimulate forward growth of the maxilla;in group two partial edgewise appliance was used on upper incisors and first molars,cooperated with splint on lower arch.Cephalograms were taken before and after active treatment.All the radiographs were traced by the first author,and the measurements were calculated with cephalometric analysis program.Results Anterior crossbites were corrected in both groups,and facial balance improved greatly.Significant sagittal changes were found between them:SNA increased in group 1,suggesting the forward movement of the maxilla,while SNB decreased in group 2,suggesting the backward displacement of the mandible.The increase in the mandibular plane angle in both groups indicated the clock-wise rotation of the mandible.Conclusion The key point of treatment option for different skeletal class Ⅲ malocclusion in mixed dentition is based on the correct diagnosis for etiology and mechanism.Proper early treatment helps guiding the jaws to a more balanced position.