| Objective: Investigate the clinical efficacy of treating adult skeletal Class III malocclusion by the method of embedding micro screw implant anchorage in the position of mandible external oblique line and distally moving mandibular dentition.Then compare this method with the treating method of conventionally embedding implant anchorage in alveolar space and pushing molars distally moving.Finally,evaluate the advantages and disadvantages of treating adult skeletal Class III malocclusion through vertically embedding implant anchorage in the position of mandible external oblique line and distally moving mandibular dentition.Methods: Pick out 20 cases of patients coming to see doctors in the Orthodontic Department of Stomatology Hospital of Lanzhou University from the year 2014 to 2017,suffering skeletal Class III malocclusion in permanent dentition with average age of 24,then randomly divide them into two groups,A and B.For experimental group A,embed micro screw implant anchorage in mandible external oblique line position and distally move mandibular dentition.For control group B,embed implant anchorages in alveolar space between the first and second premolars keeping 75°-90°intersection angle with long axis of tooth and successively push molars to move distally.Use MBT technique for both of the two groups,and comparatively analyze the clinical data of group A and B.Results: The two methods of distally moving molars can both achieve the purpose of correcting adult skeletal Class III,and finally establish the first kind relation of molar and canine.Malocclusion in anterior dental region can be relieved and facial type improved significantly.For the experimental group,the average treatment course is 25.7 months,whole molars distally moved(inclination rate 4.3%),mandibular anterior teeth parallel moved with root controlled(backward movement quantities of apical point of infradentale and incisal center point-2.45?2.19 and-2.31?1.80),occlusion plane counterclockwise rotated(OP-FH having decreased by-4.77?1.49)and upper airway volume reduced by-729.40?17.59mm3 with p-value 0.001 which indicates our results have statistical sense.However,the width of dental arch increased.Compared with the experiment group,the average treatment course of the control group is 29.6 months showing significant difference between the two groups.The molars of the control group moved obliquely(inclination rate 23.4%),mandibular anterior teeth lingually inclined(inclination rate 13.1%).For the change of incisors,the distal movement quantities of L1A-PFP and L1E-PFP of experiment group are significantly larger than that of control group and the change of molar L6M-PFP is also larger than that of control group.The occlusion plane clockwise rotated(OP-FH having increased by 0.59 ?2.65).Slight root resorption happened to both groups.However,for the experiment group,root resorption of mandibular first molar,mandibular central incisor and lateral incisor is significantly smaller than that of the control group.Hyoid bones in both groups rotated forward and downward.Conclusion: With the guidance of CBCT,for treating Class III malocclusion embedding micro-screw implant anchorage in the position of mandible external oblique line and distally moving mandibular dentition is a secure and high-performance method,which can effectively shorten treating time,prevent over inclination of molars and lingual inclination of mandibular anterior teeth and be advantageous to control vertical height of molars.Compared with conventional method of embedding anchorage in alveolar space and pushing molars distally moving,the former not only significantly shortens the treating course,but improves sclerous tissues and soft tissue lateral profile more significantly and causes lower root resorption rate. |
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