Black Stain: Prevalence, Etiology, and Therapeutic Approaches

Abstract

Introduction: Extrinsic black stain is a dental pigmentation characterized by the presence of dark deposits adhered to the enamel surface, usually located near the gingival margin. Although it does not represent a direct risk to oral health, this condition presents a relevant esthetic impact and a high recurrence rate after clinical removal. Objective: To analyze, through a literature review, the main aspects related to the prevalence, etiology, associated microbiology, and therapeutic approaches of extrinsic black stain. Methods: A narrative literature review was conducted through searches in the EMBASE, Web of Science, Scopus, BVS, and PubMed databases. Search terms related to black stain and extrinsic dental pigmentation were used in Portuguese, English, and Spanish. Articles published since 2000 were analysed with regard to prevalence, etiological factors, microbiology, and treatment of the condition. Results: The prevalence of extrinsic black stain ranges from 2% to 20% in the population and is more frequently observed in children. The most accepted etiology involves the reaction between hydrogen sulfide produced by chromogenic bacteria and iron ions present in saliva, resulting in the formation of ferric sulfide responsible for the dark pigmentation. Microbiological studies indicate that the biofilm associated with this condition presents a diversified bacterial composition. Professional prophylaxis remains the main therapeutic approach, although new strategies such as the use of probiotics, antimicrobial photodynamic therapy, and antimicrobial substances have been investigated and used. Conclusion: Extrinsic black stain presents a multifactorial etiology involving interactions between oral microbiota and chemical and environmental factors. Despite advances in understanding the microbiological aspects of this condition, further studies are necessary to clarify the microbiological mechanisms involved in the formation of black stain and to develop more effective methods for its prevention and treatment.