One of the major concerns about endodontically retreated teeth (ERT) is undoubtedly its loss of remnant structure, which could lead to consequently greater fracture risk. Therefore, the objective of this systematic review is to assess the influence of endodontic retreatment on the fracture strength of the dental tooth remnant. In vitro studies assessing the influence of mechanical retreatment on the mechanical properties (static or under fatigue) of restored teeth were searched in PubMed and SCOPUS databases. Three independent reviewers screened titles/abstracts of articles and the full-text of potentially eligible studies. The risk of bias was independently assessed by one researcher and verified by another two. Comparison between the mean load to fracture of teeth after endodontic treatment and after endodontic retreatment were estimated using pairwise random effects meta-analysis to calculate pooled mean differences. Three studies were included for the systematic review and 2 for the meta-analysis. The pooled effect indicated a statistical difference (Mean difference: −121.03 95%CI: −183.02, −59.05) between conditions favoring the endodontically treated teeth. However, the low number of studies combined with their heterogeneity made it difficult to prove such phenomenon. ERT might present lower fracture strength than endodontically treated teeth. However, more coherent laboratory tests may provide better evidence and quantitative parameters on how much reliability can be attributed to an endodontic retreatment, in addition to which technique can provide more predictable results in this conservative approach.

牙髓治疗后牙齿（ERT）的主要问题之一无疑是其残余结构的丧失，这可能会导致更大的骨折风险。因此，本系统综述的目的是评估牙髓治疗对牙齿残余牙的断裂强度的影响。在PubMed和SCOPUS数据库中搜索了评估机械再处理对修复后的牙齿的机械性能（静态或疲劳状态）影响的体外研究。三名独立审稿人筛选了文章的标题/摘要以及可能符合条件的研究的全文。偏倚的风险由一名研究人员独立评估，并由另外两名研究人员验证。使用成对随机效应荟萃分析来计算合并的平均差异，以估算牙髓治疗后和牙髓再治疗后牙齿的平均骨折负荷的比较。系统评价包括3项研究，荟萃分析2项。合并的结果表明，在采用牙髓治疗牙齿的条件之间存在统计学差异（均值差异：−121.03 95％CI：−183.02，−59.05）。但是，由于研究数量少，且异质性强，因此难以证明这种现象。ERT的骨折强度可能比牙髓治疗的牙齿低。但是，更连贯的实验室测试可能会提供更好的证据和定量参数，说明根管治疗可归因于多少可靠性，