青少年内收上切牙后牙槽骨改建的研究

The remodeling of alveolar bone due to retraction of upper incisors in adolescents

目的:定量分析青少年上前牙内收移动后,上颌中切牙根周牙槽骨厚度的变化。方法:选取双颌前突、需拔除双侧第一前磨牙进行前牙内收矫治的青少年患者15例,于治疗前(T0期)及拔牙间隙关闭完成后6个月(T1期)分别拍摄上颌骨CBCT及头颅侧位片,对矫治前后的30个上颌中切牙根周牙槽骨厚度变化进行分析。结果:矫治后上颌中切牙唇倾度均值减少(7.41±2.06)°(P<0.05),牙冠内收量较牙根内收量均值增加(1.38±0.34) mm(P<0.05);上颌中切牙唇侧牙槽骨厚度均有增加(P<0.05),牙根腭侧靠近牙颈部的牙槽骨厚度减少(P<0.05),腭侧根尖的牙槽骨厚度减少但无统计学意义(P>0.05)。结论:矫治青少年上前牙内收移动时,移动距离过大及过于倾斜移动均可导致腭侧牙颈部区域骨量的减少。

Objective:To investigate the remodeling of alveolar bone of maxillary central incisors due to retraction of upper anterior teeth in adolescents.Methods:15 adolescents with bimaxillary protrusion,treated by retraction of upper anterior teeth with extraction of 4 first premolars were recruited.CBCT and lateral cephalogram scanning were made before the treatment(T0)and 6 months after the space were closed(T1)respectively.The changes of the alveolar bone thickness were analysised by SPSS19.0 software.Results:After the upper incisors retracted,the inclination of maxillary central incisors in 15 adolescents was decreased by(7.41±2.06)°(P<0.05).The crown was retracted by(1.38±0.34)(mm)more than apical(P<0.05).Labial alveolar bone thickness of 30 maxillary central incisors were increased(P<0.05).Palatal bone thickness at crest level(L1)and midroot level(L2)were decreased(P<0.05),but the palatal bone thickness at apical level(L3)did not change significantly(P>0.05).Conclusion:The longer distance and larger change in inclination may lead to significant decrease of palatal bone thickness,especially at crest level(L1)in adolescents.