In Vitro Evaluation of Stain Inhibition and Color Stability of a Multifunctional Dentifrice under Coffee and Black Tea Staining Conditions

Objective: This in vitro study aimed to evaluate the stain inhibition effect and color stability of a multifunctional dentifrice under coffee-and black tea-induced extrinsic staining conditions using objective color measurement methods.Methods: Bovine enamel specimens were prepared and randomly assigned to either a control dentifrice group or an experimental multifunctional dentifrice group.Specimens were subjected to daily simulated tooth brushing and continuous immersion in coffee or black tea solutions for 7 days.Tooth color changes were assessed using VITA classical shade measurements and CIE L*a*b* color parameters.Color differences (L* and E*) were calculated relative to baseline.Intergroup comparisons were performed using independent two-sample t-tests.Results: Under both coffee and black tea staining conditions, the experimental group exhibited significantly smaller changes in VITA shade lightness and CIE L*, a*, and b* values compared with the control group throughout the experimental period (p<0.001).In addition, E* values after 7 days were significantly lower in the experimental group, indicating reduced cumulative color change and enhanced color stability. Conclusion:Within the limitations of this in vitro study, the multifunctional dentifrice effectively inhibited extrinsic tooth staining and maintained color stability compared with the control dentifrice.These findings suggest that the tested formulation may be beneficial for the prevention of extrinsic tooth discoloration rather than for tooth whitening.Further clinical studies are required to confirm these effects under real oral conditions.