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目的:探讨发育期第三磨牙牙根在正畸拔除前方磨牙矫治后第三磨牙牙根生长特点及意义。方法:研究组32例下颌第三磨牙牙根未发育完成前接受拔除下颌第一或第二磨牙正畸治疗的青少年,追踪调查其下颌第三磨牙牙根发育完成后全颌曲面断层片上的牙根融合率、根分叉程度及根长,并与对照组35例牙根发育完成后进行拔除磨牙矫治的成人患者的下颌第三磨牙进行比较。结果:研究组牙根分叉率、分叉程度均高于对照组,差异有显著性;牙根长度两者相仿。结论:下颌第三磨牙牙根分叉不足、融合可能是因空间不足受挤压所致,在牙根发育完成前获得充足的空间,牙根将发育得更充分;正畸利用、保留第三磨牙宜选择在第三磨牙牙根未发育完成前进行。
Objective: To investigate the characteristics and significance of root growth of the third molars during development of the third molar root after orthodontic removal of the molars. Methods: The study group, 32 cases of mandibular third molar root before the development is completed before the completion of extraction of the mandibular first or second molar orthodontic treatment of adolescents, follow-up investigation of the mandibular third molar root formation on the whole mandibular curvature of the root canal fusion rate , The degree of root bifurcation and the root length of the mandibular third molar were compared with those of the control group with 35 cases of mandibular third molars. Results: The bifurcation rate and bifurcation degree of the study group were higher than those of the control group, the difference was significant; the root length was similar. Conclusion: The third mandibular molar root bifurcation is not enough, the fusion may be due to the lack of space due to extrusion, adequate root canal development before the completion of adequate root development will be more adequate; orthodontic use, retention of the third molar should choose Before the third molars root is not developed.