Effectiveness of Vitamin C in managing gingival hyperpigmentation: A systematic review and meta-analysis

Gingival hyperpigmentation is a significant esthetic concern, particularly in individuals with high smile lines. Traditional surgical methods for depigmentation often face the challenge of recurrence. Vitamin C, due to its antioxidant properties and role in melanin inhibition, has emerged as a promising adjunctive agent for gingival depigmentation.

This systematic review and meta-analysis aimed to evaluate the effectiveness of Vitamin C in managing gingival hyperpigmentation, either as a standalone treatment or in combination with other modalities.

The protocol of this systematic review was registered in PROSPERO (CRD42024613787), and it was in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines. A comprehensive literature search was conducted across multiple databases, including PubMed, Scopus, Cochrane Library, and Google Scholar, for studies published between 2018 and 2024. The review included randomized controlled trials (RCTs) and clinical trials comparing Vitamin C interventions to conventional depigmentation techniques, and a meta-analysis was conducted using the standardised mean difference (SMD) as the effect measure.

Eight studies were included for qualitative synthesis and three RCTs for quantitative analysis. The meta-analysis revealed a statistically significant improvement in depigmentation scores at 1-month follow-up (SMD: 1.93; 95% confidence interval: 1.37-2.48). However, no significant differences were observed at baseline or at the 3-month follow-up, where high heterogeneity was present.

Vitamin C demonstrates promising short-term efficacy in the treatment of gingival hyperpigmentation, especially when used as an adjunct to conventional therapy. However, variability in protocols and long-term outcomes highlights the need for further standardized trials.