Abstract: Objective　To access the effect of different periodontal regenerative techniques in preventing the periodontal defects distal to mandibular second molars after surgical removal of impacted third molars. Methods　English literatures about periodontal regenerative techniques in preventing periodontal defects distal to mandibular second molars after extraction of impacted third molars were searched in Embase，Cochrane library，PubMed and Web of Science. Meta-analysis was performed using RevMan 5.3 and Stata 14.0 software. Results　Thirteen randomized clinical trials（RCTs）from eleven literatures were included. Four periodontal regenerative techniques were included：absorbable biological membrane，biological agent filling，bone grafting material alone and bone grafting material combined with absorbable biological membrane. The results showed that all the four techniques could reduce the probing depth of the second molar（P < 0.05）. Biological agent filling，the use of bone grafting material alone to fill the extraction socket and bone grafting combined with absorbable biological membrane could promote the clinical attachment level（P < 0.05）. The use of absorbable biological membrane alone could promote the alveolar bone level（P < 0.05）. Conclusion　All the four techniques analyzed in this paper can prevent periodontal defects distal to mandibular second molars after extraction of impacted third molars in varying degrees. But none of them can promote the clinical attachment level，increase the alveolar bone level and decrease the probing depth simultaneously.

Key words: mandibular impacted third molar, periodontal defects, periodontal tissue regenerative techniques, Meta-analysis

摘要： 目的　评价不同牙周再生技术预防下颌阻生第三磨牙拔除后邻牙远中牙周缺损的效果。方法　计算机检索Embase、Cochrane library、PubMed、Web of Science数据库，查找采用牙周再生技术预防下颌第三磨牙拔除后邻牙远中牙周缺损的英文文献，采用RevMan 5.3和Stata 14.0软件进行Meta分析。结果　纳入11篇相关文献，共13组临床随机对照研究，包括生物制剂充填拔牙窝、仅可吸收生物膜覆盖拔牙创、仅骨移植材料充填拔牙窝、骨移植材料充填拔牙窝联合可吸收生物膜覆盖拔牙创4种牙周再生技术。Meta分析结果显示，4种牙周再生技术均能显著减少邻牙远中探诊深度（P < 0.05）；除仅可吸收生物膜覆盖拔牙创外，其他3种技术均能显著促进邻牙远中临床附着水平的增长（P < 0.05）；但仅有可吸收生物膜覆盖拔牙创能够显著促进邻牙远中牙槽骨高度的增长（P < 0.05）。结论　文章分析的4种牙周再生技术均可不同程度的预防下颌阻生第三磨牙拔除后邻牙远中的牙周缺损，但均不能同时促进邻牙远中牙周附着水平增加、探诊深度减少和牙槽骨高度增加。

关键词: 下颌阻生第三磨牙, 牙周缺损, 牙周组织再生技术, Meta分析