Effect of partial ferrule on fracture resistance of endodontically treated teeth: A meta-analysis of in-vitro studies

Purpose: The present meta-analysis aimed to answer the following research question: In endodontically treated teeth (ETT), what is the effect of partial ferrule (PF) on fracture resistance compared to complete ferrule (CF) and/or no ferrule (NF)?Study selection: PubMed, Scopus, Web of Science, and Google Scholar were searched for relevant studies published until May 20, 2022. In vitro studies that compared the effect of partial ferrule with that of complete ferrule and/or no ferrule on fracture resistance of ETT were included. The studies were assessed for risk of bias, and a meta-analysis was performed.Results: Seventeen in vitro studies comprising 807 teeth were included. Nine studies were at a high risk of bias and eight presented a moderate risk of bias. Overall, the results showed that CF was superior to PF in increasing fracture resistance (SMD= 0.93, CI95%= 0.57-1.29, P< 0.0001), with no change in the effect based on the type of teeth (P< 0.001). However, the subgroup analysis found that PF 2 mm buccal, lingual, and buccal and lingual ferrule were comparable to CF (P= 0.06). Additionally, the PF group showed significantly higher fracture resistance than the NF group (SMD= 2.02, CI95%= 1.54-2.49, P< 0.00001).Conclusions: Although CF design provided the highest fracture resistance to restored ETT, PF can still be a viable option for restoring ETT in cases where CF is not feasible.