LAUSR

BACKGROUND Adjunct therapy refers to any intracanal procedure going beyond chemomechanical preparation with instruments and traditionally delivered irrigants (excluding interim dressings). It is not clear whether and which of these adjunct therapies have a significant impact on the outcome of root canal treatment (healing of apical periodontitis and other patient-related outcomes). OBJECTIVES This systematic review aimed to analyse available evidence on the effectiveness of adjunct therapy for the treatment of apical periodontitis in permanent teeth, according to a population, intervention, comparison, outcome, time and study design (PICOTS) framework formulated a priori by the European Society of Endodontology. METHODS Five electronic databases (PubMed, Embase, Scopus, Cochrane, and Web of Science) were searched up to October 2021 to identify clinical studies comparing adjunct therapy to no adjunct therapy in adult patients with apical periodontitis. Animal studies, reviews, studies with less than 10 patients per arm, studies with a follow-up time of less than 1 year, or less than 7 days for postoperative pain, were excluded. The quality of the included studies was appraised by the appropriate tools (Risk of Bias 2 (RoB2) for randomized clinical trials (RCTs) and Newcastle Ottawa Scale for observational studies). Meta-analysis was performed using a random-effects model. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. RESULTS Fourteen studies (13 RCTs, and 1 retrospective cohort) fulfilled the inclusion criteria for this review. They evaluated different types of adjunct therapy: antimicrobial photodynamic therapy (aPDT) (3 studies), diode laser canal irradiation (3), Nd:YAG laser canal irradiation (2), Er;Cr:YSGG laser canal irradiation (1), ozone therapy (2), and ultrasonically activated irrigation (UAI) (4). Radiographical healing was reported in 7 studies, but meta-analysis was only possible for UAI (2 studies), showing no statistically significant difference in healing after 12 months. Pain after 7 days was reported in 7 studies. Meta-analysis on three studies that used aPDT, and on 2 studies using diode laser irradiation showed no significant difference in the prevalence of pain after 7 days between the control and adjunct therapy. According to RoB2 tool, 6 studies had a high risk of bias, 5 studies had some concerns, and 2 studies low risk of bias. The GRADE assessment revealed a very low strength of evidence for diode laser, and low strength of evidence for PDT, ozone, and UAI studies. DISCUSSION The included studies displayed significant heterogeneity in terms of type of adjunct therapy, technical details per adjunct therapy, outcome reporting, and several combinations of these, limiting the potential for meta-analysis. CONCLUSIONS There is insufficient evidence to recommend any adjunctive therapy for the treatment of apical periodontitis.