Alternative Strategies for Managing Dental Black Stains: A Systematic Review

Background/Objectives: Dental black stains (BSs) are a form of extrinsic tooth discoloration of bacterial origin, with a prevalence ranging from 2.4% to 20%. As scaling and polishing remain the standard of care, recurrence is frequent. Therefore, this systematic review assessed alternative or adjunctive treatments, such as probiotics, chemical agents, and photodynamic therapy, for managing BSs. The primary objective was to evaluate clinical changes in BS recurrence and severity, while the secondary objective was to analyze microbiological changes. Methods: Conducted following PRISMA 2020 guidelines and registered on PROSPERO (CRD420261357137), this review searched PubMed, Cochrane Library, Scopus, Web of Science, and Dentistry & Oral Sciences Source through EBSCOhost as well as clinical trial registers (ClinicalTrials.gov and ISRCTN) and grey literature, up to 30 April 2026, with no language or date restrictions. We included randomized and non-randomized clinical trials. Two independent reviewers performed study selection and data extraction; a third resolved disagreements. We assessed risk of bias using RoB 2 and ROBINS-I V2, and quality of evidence using GRADE. Results: Of 716 records identified, eight clinical trials (five randomized clinical trials and three non-randomized clinical trials were included), with 250 patients enrolled and 227 assessed at follow-up. Four intervention categories were investigated: probiotics, antimicrobial mouthwashes (0.1%, 0.12% chlorhexidine and 0.1% chlorine dioxide), enzyme-containing toothpaste, and antimicrobial photodynamic therapy (aPDT). Probiotics may reduce BS indices, though the effect was inconsistent over time. In a single small, randomized study, chlorine dioxide showed a short-term reduction in bacterial viability greater than chlorhexidine. aPDT and enzyme-containing toothpaste did not show a significant benefit in the included studies. High risk of bias, heterogeneity, and the small sample prevented quantitative synthesis. Conclusions: Evidence supporting alternative strategies for managing recurrent dental BSs or reducing chromogenic bacterial load remains insufficient. Larger RCTs with standardized outcomes and longer follow-up are needed.