Evaluation of enamel staining after application of Malva sylvestris solutions for the prevention of dental caries on enamel covered or not with biofilm

Objective: The study evaluated the effect of Malva sylvestris hydroalcoholic extract on tooth enamel color, with and without previously microcosm biofilm presence. Materials and Methods: a total of 108 bovine enamel samples (6 mm × 6 mm) were prepared and randomized distributed based on initial enamel color (L = 60.8±6.5), measured using a digital spectrophotometer (Vita Easyshade ^® ). Six groups were tested: 1) Malva sylvestris (35 mg/mL), 2) Xylitol (5%), 3) NaF (225 ppm F), 4) Malvatricin Plus ^® , 5) Chlorhexidine-CHX Periogard ^® (0.12% CHX), and 6) PBS (control). Half of the samples were exposed to microcosm biofilm and the other half to McBain saliva only (no biofilm) (n = 9/group). Solutions were applied once a day from days 2 to 5. Enamel color comparison (ΔE ₀₀ ) was assessed at baseline (T0) and after treatment (TF) using the CIEDE 2000 color system (CIE Technical Report). Data analysis involved t-tests or two-way ANOVA/Brown-Forsythe (p<0.05). Results: Significant changes were observed in a, b, and L values for all groups (p<0.005), except for parameter b (yellow-blue scale) in the NaF-treated enamel. However, final ΔE ₀₀ values showed no significant differences between treatments (ANOVA, p=0.6637), though enamel with biofilm exhibited significant differences compared to enamel without biofilm (p<0.0001). Conclusion: None of the tested treatments, including Malva sylvestris , altered enamel color, regardless of biofilm presence. Clinical Relevance: The findings suggest that Malva sylvestris does not cause noticeable enamel staining, making it a viable option for oral health applications without posing aesthetic concerns.