Effectiveness of root canal treatment for vital pulps compared with necrotic pulps in the presence or absence of signs of periradicular pathosis: A systematic review and meta-analysis.

Background: Preoperative pulpal status may influence the outcomes of root canal treatment (RCTx) according to various measures used.

Objectives: To compare the effectiveness of RCTx of teeth with a vital pulp versus a necrotic pulp, using a range of clinical and patient-related outcomes proposed for the development of S3-level clinical practice guidelines.

Methods: A search was conducted in the PubMed-MEDLINE, Scopus, EMBASE, Google scholar databases and available repositories, followed by hand searches, until 29 March 2022. Clinical studies published in the English language comparing the stipulated outcomes of RCTx of teeth with vital versus necrotic pulp were included. The Newcastle-Ottawa Scale was adapted to assess study quality. Effects of pulpal status were estimated and expressed as risk ratio (RR) using fixed- and random-effect meta-analyses. The quality of evidence was assessed through the Grading of Recommendations Assessment, Development and Evaluation tool.

Results: Twenty-eight studies published between 1961 and 2021 were included. Five studies have investigated the "tooth survival" outcome, four reported pulpal status was not a significant predictor, consistent with meta-analysis findings (RR: 1.00; 95% CI: 1.00, 1.00; n = 3). Seven studies reported pulpal status had no significant influence on postoperative pain, regardless of duration after treatment. Sixteen studies have analysed "periapical health," and 11 revealed pulpal status had no significant influence. Meta-analyses revealed the influence was not significant if preoperative periapical radiolucency was absent (RR: 0.95; 95% CI: 0.90, 1.00; n = 9) but significant if it was present (RR: 1.12; 95% CI: 1.05, 1.19; n = 11). Most studies were classified as "some concerns" (n = 17) to "low" (n = 9) risk of bias RoB.

Discussion: Evidence is limited and only available for three outcomes when comparing the effectiveness of RCTx in permanent teeth with vital pulp versus pulp necrosis. Nevertheless, the quality of available evidence was moderate to high. The "periapical health" data heterogeneity could be explained by preoperative radiolucency, thus RCTx was found more effective for prevention than the resolution of apical periodontitis.

Conclusions: There was no significant difference in the "tooth survival," "postoperative pain" and "evidence of apical radiolucency" outcomes of RCTx in teeth with vital or necrotic pulps.

Registration: PROSPERO database (CRD42021260280).