摘要目的 通过研究三种不同部位微种植体压低上前牙对牙齿及微笑的影响,对比其临床疗效,为正畸改善露龈微笑提供参考依据.方法 随机选择2015年6月-2016年1月在我院口腔正畸科就诊的上颌前部牙槽骨垂直向发育过度,表现为安氏Ⅰ类或Ⅱ类错(牙合)的患者.根据QCVM颈椎骨龄定量分期法进行分期,并选取QCVM第Ⅲ期～QCVM第Ⅳ期患者30例,其中男3例,女27例,平均年龄24.5岁.将患者随机分为3组,每组10例进行固定矫治.第1组微种植体植入上颌中切牙间;第2组微种植体植入上颌中切牙与侧切牙之间;第3组微种植体植入上颌侧切牙与尖牙之间.在微种植体植入前,先进行排齐整平治疗,再于三组患者的前牙区分别植入微种植体压低上前牙,每侧加力50 g,每四周更换弹性橡皮圈,持续时间5～8个月,覆(牙合)减小改善2.5mm.对治疗前后的各个参数进行比较分析.结果 三组患者露龈微笑均有显著改善,其中27例患者露龈微笑消失,3例患者微笑时露龈量明显减小.三组患者切牙垂直向实际压低量Cr1-PP'第三组＞第二组＞第一组,矢状向位移U1-SN和U1-T均为第一组＞第二组＞第三组,同时第一组和第二组中切牙牙根吸收较明显.结论 微种植体位于侧切牙及尖牙间的加力方式使上颌前牙应力分布更均匀,牙齿整体移动的趋势增加,牙根吸收的趋势减小.

abstractsObjective To evaluate gummy smile reduction through anterior intrusion by microimplants at three different sites,and to provide future clinical references.Methods Patients,from June 2015 to January 2016 in Department of Orthodontics,Remin Hospital of Wuhan University,who presented with Class Ⅰ or Class Ⅱ malocclusion and overgrowth of anterior maxillary alveolar bone were enrolled.Based on Quantitative Cervical Vertebral Maturation(QCVM)30 cases,phase Ⅲ or Ⅳ,including 3 male patients and 27 female patients with a mean age of 24.5 years old,were selected.The patients were randomly divided into three groups and received fixed appliance treatment.In group 1,the micro-implants were implanted between the maxillary central incisors;in group 2,they were inserted between maxillary central incisors and lateral incisors;and in group 3,they were located between the maxillary lateral incisors and the canines.Before the insertion of the micro-implants,the leveling and aligning treatment were performed.Then a force with the magnitude of 50 g per side was applied.The power chain was replaced every four weeks for 5-8 months,and the overbite was improved by 2.5 mm.The parameters before and after treatment were compared and analyzed.Results All the three groups showed significant reduction of gummy smile.Among them,27 patients completely recovered from gummy smile and 3 patients showed a significant improvement.The amount of intrusion (Cr1-PP') of the incisors showed a result of group 3＞ group 2＞group 1,and the sagittal displacements U1-SN and U1-T showed a result of group 1＞ group 2＞group 3.Meanwhile,the root resorption of the central incisors in group 1 and group 2 was more obvious.Conclusions Insertion of the micro-implants between the lateral incisors and the canines can distribute the intrusion force more uniformly,and can result in more bodily movement,with a less tendency of root resorption.