Comparison of two methods for uprighting of mandibular mesially tipped second molar

Objective To introduce two orthodontic methods for uprighting mandibular mesially tipped second molar and to evaluate the differences in clinical efficacy.Methods 12 cases of mesially tipped mandibular second molar with Angle class I malocclusion were selected in this study.The total number of the teeth was sixteen.All the teeth were randomly divided into two groups with eight in each group..In group A,a band welded with stent was made onto the mandibular first molar.The stent and the mandibular second molar were bonded with power chain.Lingual buckle on the occlusal surface of the mandibular second molar was connectted for pulling the second molar to the distal place until it was completely uprighted.The value of the power was about 2.5-3.0 N.In group B,a band welded with hyperbolic or three push spring was made in the mandibular first molar,placing the push sping near the mesial side of the lingual buckle bonded on the occlusal surface of the mandibular second molar for pushing the second molar to the distal place until it was completely uprighted.The value of the power was simillar with that of group A.Comparative analysis was made between the different treatment periods of two methods and the height alteration of the second molar mesial alveolar ridge at the end of the therapy.Results The treatment time in group A was 4.5 to 8.4 months,and the mean period was 6.3 months.The treatment time in group B was 6.5 to 11.5 months,and the mean period was 8.5 months,P0.01.There was significant deviation in statistics.The mean height of the mandibular second molar mesial alveolar ridge increased 4.8mm at the end of the therapy in group A,and the mean height of the mandibular second molar mesial alveolar ridge increased 5.0mm at the end of the therapy in group B,P0.5.There was no significant deviation in statistics.Conclusions The two treatment methods uprighted sixteen measially tipped mandibular second molar successfully,and the height of the mandibular second molar mesial alveolar ridge increased significantly,but the treatment period of group A was shorter,so it was more worthy of promotion in clinics.