Permanent molar extraction in correcting adult patient with Class III malocclusion

Objective:To discuss treatment effect of the method which extracting permanent molar to correct the skeletal Class Ⅲ malocclusion.Method:Twelve patients with skeletal class Ⅲ malocclusion,whose growth has already completed,were included in the study.The average age was 20 years old,with age range from 15years old to 38 years old.Cephalometric films and panoramic x-rays were taken before and after the orthodontic treatment.According to the growth of crown-root and the healthy condition,combined with deformity type,design was carried out through extracting first、second or third molars.All cases were treated with straight-wire technique,the average treatment time was 20 months.15 soft and hard tissure's cephalometric indexs were chose to compare the change of hard and soft tissue before and after treatment with the paired t test.Result:Around correction patient's SNA、SNB was not obvious changed,U1-LI remarkably increased as well as L1-MP remarkably reduced.This fully explained the correction of overbite mainly relies on uprighting and retroclinating of lower front teeth.After the correction nasolabial angle remarkably increased while mentolabial angle remarkably reduced which cause very big improvement to enable patient's side appearance.Conclusion:Adult patient of skeletal Class Ⅲ malocclusion as a result of already non-growth potential,can only adjust the tooth jaw relationship through tooth extraction.Design choosed extracting molars has been shown to be a effective way to improve the face shape and adjust the occlusal relationship.