The effect of retrograde material type and surgical techniques on the success rate of surgical endodontic retreatment: systematic review of prospective randomized clinical trials

Background Endodontic surgical procedures, when performed, require retrograde filling materials that are biocompatible, non-toxic, non-irritant, dimensionally stable, and ideally promote bone formation. Precise evaluation of retrograde filling materials in clinical trials is necessary to give holistic view for properties of material and potential outcome from its use. The purpose of this review is to evaluate the effect of retrograde material type and surgical techniques on the success rate of surgical endodontic retreatment. Methods An electronic search was performed in the time frame between 1st of January 2000 to 1st of September 2020 using database. Sources Web of Science, PubMed and redundant hand searches through their references. Seven inclusion-exclusion criteria were set for the selection and identification of relevant articles. Risk of bias was conducted for the included studies. Results Nine randomized clinical trials (RCTs) fulfilled the inclusion criteria for this systematic review. The outcome of this review revealed that none of the reviewed trials totally-fulfilled CONSORT 2010 criteria. Conclusions In light of the outcome of this review, there is no enough evidence to support the superiority of certain retrograde filling material or surgical technique over another in the success rate of surgical endodontics retreatment. The variety of methodologies and strategies, such as patient selection, the method of treatment and study analysis, led to doubtful credibility of the obtained clinical evidence. Further prospective randomized controlled clinical trials evaluating the specific effect of the various used materials are needed.