Two-phase Treatment For Class Ⅱ Division1Malocclusion

Objective: To discuss the possibility of two-phase treatment through thetwo-phase growth modification and the effect in growing patients withClassⅡDivision1malocclusion.Materials and methods: A female patient with ClassⅡDivision1malocclusionwas selected from Dalian Ortho clinic in April2011, who was then10.5years old.Protruded Maxillary incisors, Class Ⅱmolar relationship on both sides, increasedoverjet, deepbite. Two phase treatment planning was done through model and lateralcephalometric. Activator functional appliance in phase-1combined with comprehensivefixed appliance treatment consecutively. Observation of the changes from pre-treamentto post-treament through lateral cephalometric values and structural superimpositionanalysis.Results: The course of orthodontic treatment is22months. Treatment resultswere determined by comparisions of cephalometric changes in the patient from lateralcephalometric values and the structural superimpositions: It showed mesialdisplacement in the sagittal skeletal position of the mandibule, so as to significantlyimprove the maxillo-mandibular sagittal skeletal relationships. The treated caseexhibited a significant reduction in overjet and overbite and a significant improvementin molar relationship. Upper incisors retrusion(U1-NA(mm) reduced by3mm, U1-NAreduced by13°), while the lower incisors were significantly proclined(L1-NB(mm)increase1mm， L1-NB increase6°), The mandiblular plane showed clockwisemovement (FH-MP reduce2°), It has been obviously improved the profile.Conclusion：Activator functional appliance in phase-1combined with fixedappliance treatment consecutively is effective in correcting ClassⅡDivision1malocclusion.