Bleaching Techniques for Discolored Endodontically Treated Teeth: a Scoping Review

Objectives: To map and summarize the current scientific evidence concerning the effectiveness and adverse effects of the bleaching techniques performed on discolored endodontically treated teeth.
Methods: This study was conducted according to the PRISMA-ScR Guidelines for Scoping Reviews and registered on the Open Science Framework platform. The systematic search was conducting in PubMed, Embase and Scopus databases up to September 2024. Two independent reviewers (VFM and ARF) performed the screening, and a third reviewer (OEP) was consulted in case of disagreement. Only clinical trials, case reports or case series were included. A descriptive analysis of the included studies was performed. The studies that use at least one bleaching technique for discolored endodontically treated teeth, describing the bleaching protocol used, were selected. The initial diagnosis, the success of the technique used, and the identification of the step-by-step bleaching treatments were described.
Results: The search identified 2,019 potentially eligible studies. After removing duplicates (639) and irrelevant articles (1,329), 51 citations met eligibility criteria based on title and abstract. After the full-text analysis, 32 studies were included. The main causes of tooth darkening were endodontic post-treatment (63.6%) and dental trauma and pulp necrosis (27.3%). The most commonly used bleaching agents and techniques were hydrogen peroxide (38.3%) and carbamide peroxide (25.5%), and walking bleach (69.2%) and the use of combined (external and internal) techniques (12.8%), respectively. 78.1% of the studies showed a satisfactory result for the color obtained after teeth bleaching, but recurrence of discoloration was reported after one year of treatment (9.38%). 34.38% of the articles showed no post-treatment root resorption and 65.62% did not specify whether evaluation was performed.
Conclusions: Bleaching of non-vital teeth is a safe, effective, and conservative approach for the aesthetic restoration of discolored teeth, with predictable outcomes such as long-term color stability and positive psychosocial effects in patients.