Assessing the influence of Katana Cleaner on the clinical performance of bulk-fill restorations in endodontically treated teeth: study protocol for a randomized clinical study.

BACKGROUND: Complete cleaning of the pulp chamber interior is a mandatory step before the restorative process. Ethanol is the most commonly used substance for cleaning the dentin surface; however, studies report that ethanol is ineffective at completely removing residues. Although Katana is recommended for prosthetic purposes, in vitro studies have shown it delivers results equal to or better than ethanol. The study aims to evaluate the influence of Katana Cleaner on cleaning the pulp chamber of teeth treated endodontically with an epoxy or bioceramic sealer and on the clinical performance of bulk-fill resin restorations over an 18-month follow-up period, using two clinical performance criteria: World Dental Federation (FDI) and United States Public Health Service (USPHS). METHODS: The study will be a blinded randomized clinical trial conducted according to the Consolidated Standards of Reporting Trials (CONSORT) statement. Selected patients (n = 224) will undergo pulp chamber cleaning following endodontic obturation with epoxy and bioceramic sealers, divided into four treatment groups (Katana and AH Plus, Katana and Bioceramic, Ethanol and AH Plus, Ethanol and Bioceramic), followed by bulk-fill resin restorations. The clinical performance of the restorations will be evaluated at the following intervals: 1 week, 3, 6, 9, 12, 15, and 18 months, using two evaluation criteria: FDI and USPHS. Results will be analyzed using survival analysis with the Kaplan-Meier estimator to assess failure occurrence over time for the two treatments. A Cox regression analysis will be conducted to evaluate the risk of failure. A 5% significance level will be adopted for all tests. DISCUSSION: The proposed study will be the first to examine the clinical effects of a new cleaning protocol on the removal of endodontic sealer residues. We will also explore potential improvements that Katana may provide in the bond strength of a self-etch adhesive to dentin in teeth restored with composite resin. If promising results are observed in clinical trials, this would suggest that individuals could benefit from the intervention using the proposed protocol, highlighting the potential for improved outcomes in the restorations of endodontically treated teeth. Additionally, it could pave the way for future studies in this field. TRIAL REGISTRATION: Registered in the Brazilian Registry of Clinical Trials (REBEC: RBR-86ycwq7) on February 29, 2024.