Distal Movement Of The Mandibular Dentition In The Treatment Of Patients With Class Ⅲ Skeletal Pattern

Objective To evaluate the skeletal ClassIIImalocclusion treated by extraction of mandibular third molars and distalization of molars by implant anchorage combined with MBT straight wire appliance.Method Fifteen patients with skeletal ClassⅢmalocclusion,concave soft facial profile,crossbite of anterior teeth,ClassⅢbuccal segment relationship(mean age 24.0±5.8) requested non-surgical treatment, so their mandibular wisdom teeth were extracted,then shifted distally by mini-implant associated with MBT straight arch wire technique of camouflage treatment. Onyx analysis was used to analyses the lateral cephalometric films which were taken at the starting and end of therapy.Results After positive corrective,neutralizing inter-arch relationship set, anterior crossbite released,soft tissue profile improved, After active treatment, SNA increased by 0.94±0.76,SNB decreased by 0.78±1.19°,ANB improved by 1.65±1.04±,Wits distance improved by 4.39±1.93 mm,NA-PA increased by 2.71±2.23±,AB-NP increased by 3.20±1.61±,U1-L1 5.87±10.01±,U1-AP distance improved by 1.63±2.14mm,L1-MP increased by 1.21±5.97±,UL-E Line distance improved by 1.38±0.75mm, LL-E Line distance decreased by 0.65±0.41mm,UL-Snpg’ distance increased by 0.17±1.58mm,LL-Snpg’ distance decreased by 1.23±0.8mm,UL-Snpg’-LL-Snpg1 distance improved by 1.13±0.99mm.These differences between before and after treatment were statistically significant.The average correcting time was (27.5±2.72) months。Conclusion The results of the clinical research suggest that success in the trerapy of skeletal Ⅲmalocclusion during the period of permanent dentition can be achieved by fixed MBT straight wire appliances with extraction of lower third molars as well as distalization of mandibular molars by implant anchorage.Besides occlusal relationship and a soft-tissue change were noted.