Abstract:
Objective: To investigate the effect of immediate bone grafting at mandibular first molar extraction socket on maintaining alveolar bone height after space closure. Methods: Thirty adult orthodontic patients who need to extract mandibular first molar, totally 38 target teeth, were included. The samples were divided into two groups randomly: graft group and non-graft group. All extraction space was closed orthodontically. Dental models of all patients were taken before extraction (T0), before space closure(T1) and after space closure (T2). The distance, time of the space closure and the velocity of tooth movement were recorded. Probing depth (PD) and clinical attachment level (CAL) at six sites (mesial buccal, buccal, mesial lingual, lingual, distal buccal and distal lingual) on adjacent teeth were measured before extraction (T0) and after space closure (T2). Cone-beam CT (CBCT) was taken at T0 and T2 to compare the changes of alveolar bone height at six sites on adjacent teeth using Invivo Dental 5.0 software. Results: The extraction space in both graft group and non-graft group was closed successfully. However, the space in graft group was closed more slowly than in non-graft group. In graft group, PD and CAL at the six sites on both the second molar and the second premolar did not change significantly after space closure, and CBCT showed that the alveolar bone height of the second premolar had no significant difference after treatment. In non-graft group, alveolar bone height decreased in both adjacent teeth and periodontal attachment loss was found after space closure. On average, alveolar bone height and periodontal attachment of the second premolar decreased (0.75±0.16) mm and (0.64±0.15) mm, respectively. Meanwhile, alveolar bone height and periodontal attachment of the second molar decreased (0.79±0.23) mm and (0.80±0.24) mm, respectively. Conclusions: Bone graft immediately after mandibular first molar extraction could delay alveolar bone resorption and preserve the periodontal attachment of the adjacent teeth during space closure. However, the procedure could slow down tooth movement.
目的: 分析减数下颌第一恒磨牙即刻植骨对间隙关闭后邻牙牙槽骨的保存作用,为临床提供参考。 方法: 选择2010年12月至2013年1月于北京大学口腔医学院·口腔医院正畸科就诊的30例成年正畸患者,共38个下颌第一恒磨牙减数牙位,采用随机数字表法随机分为植骨组与对照组(每组19个牙位)。植骨组减数后即刻植骨,对照组仅减数不植骨,之后所有患者均行常规正畸治疗,关闭拔牙间隙。制取两组患者治疗前(T0期)、排齐整平后(T1期)、间隙完全关闭后(T2期)牙颌模型,记录间隙关闭的距离及时间,并计算牙齿移动速度。测量T0和T2期拔牙间隙两侧邻牙牙周袋深度及附着丧失的变化;分别拍摄T0和T2期锥形束CT,采用Invivo Dental 5.0软件测量两组拔牙间隙两侧邻牙牙槽骨高度的变化。 结果: 植骨组与对照组均成功关闭拔牙间隙,植骨组间隙关闭时间为(17.4±3.0)个月,对照组为(13.3±2.4)个月。与T0期相比,植骨组T2期拔牙间隙两侧邻牙牙周袋深度与附着丧失均无明显改变;T2期植骨组第二前磨牙牙槽骨高度也无显著改变。与T0期相比,对照组T2期拔牙间隙两侧邻牙牙周袋深度均无显著变化,但发生牙槽骨高度显著降低与附着丧失显著增加,第二前磨牙牙槽骨高度降低(0.75±0.16)mm,附着丧失增加(0.64±0.15)mm;第二恒磨牙牙槽骨高度降低(0.79±0.23)mm,附着丧失增加(0.80±0.24)mm。 结论: 减数下颌第一恒磨牙后即刻植骨能延缓牙槽骨吸收,可在间隙关闭过程中较好地维持拔牙间隙两侧邻牙的牙周附着水平,但可导致牙齿移动速度减慢。.