目的:应用锥形束CT(cone beam computed tomography,CBCT)研究60g和150g牵引上颌唇侧埋伏阻生尖牙过程中根尖及根周硬组织的变化,为临床治疗埋伏阻生尖牙提供参考.方法:选取20例采用直丝弓矫治技术进行正畸治疗的上颌唇侧埋伏阻生尖牙患者,随机分成2组,每组10人.从外科暴露手术开始,利用链状橡皮环分别对上颌埋伏尖牙施加60g和150g牙体长轴方向的力,到阻生牙完全排入牙弓结束,平均10个月.对牵引前、后上颌尖牙牙根长度及牙根周围骨密度的变化进行CBCT分析,采用SPSS 16.0软件对测量数据进行配对t检验.结果:阻生尖牙以60g的力向牙体长轴方向做整体移动时,牙根长度、牙根周围骨密度与移动前比较,差异无显著性(P>0.05);以150g的力向牙体长轴方向做整体移动时,牙根长度、牙根周围骨密度与移动前比较,差异有显著性(P<0.05).结论:临床上治疗埋伏阻生尖牙采用小于60g的牵引力向牙体长轴方向做整体移动是行之有效的而且是安全的.%Objective Applying cone beam computed tomography (CBCT) to study the changes of apical and root hardtissue during 60g and 150g traction on impacted maxillary canines labial ambush,reference for the clinical treatment ofimpacted canine. Methods Twenty cases with straight wire appliance orthodontic treatment of impacted maxillarycanine labial ambush were selected,randomly divided into 2 groups of 10 people.Using the chain rubber ring to applyrespectively forces of 60g,150g in the direction of major axis of tooth body to maxillary impacted canines,from thebeginning of Surgical exposure surgery until the impacted teeth discharged fully into the arch,an average of 10 months.Using CBCT to analysis the changes of Maxillary canine root length and bone density around root before and aftertreatment,measurement data using SPSS16.0 software paired t-test. Results There were no significant differences onthe tooth root length, bone density around the root when adopting 60g of traction force to move wholly toward major axisof tooth body compared with the previous (P >0.05).But there was significant difference on the tooth root length, bonedensity around the root when adopting 150g of traction force to move wholly toward major axis of tooth body comparedwith the previous (P<0.05). Conclusion It is effective and safe that adopting about 60g of traction force to move whollytoward major axis of tooth body during clinical treatment of impacted canines.
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