Coloring Effect of 0.02165% Gentian Violet on Dental Biofilm: A Viable Tool for Oral Health Promotion

Objectives: Community-based oral health promotion and education employs the use of disclosing agents to reveal unclean tooth surfaces by leaving a color. The commonly used agent is erythrosine, a red dye which has been found to be irritating and potential carcinogen. Gentian violet (GV) is an economically accessible and potent dye for staining tissue specimen and as medication for oral candidiasis when used at different concentrations. This study aimed to identify the least concentration of gentian violet (GV) that effectively stains dental biofilm and to compare its potential use in a clinical setting with erythrosine.
Methods: Dental biofilm samples were cultured and treated with 0.00165 to 0.1% concentrations of GV at increments of 0.02%, which yielded varying proportions of stained and unstained biofilms.
To investigate its potential clinical application, 40 clinician-child patient pairs were randomly assigned to use the identified least concentration of GV that significantly stains dental biofilm, and erythrosine as disclosing solutions. They were asked to evaluate GV and erythrosine in terms of ease of use, color vividness and contrast using desirability Likert scale.
Results: Chi-square analysis for independence showed that the least GV concentration where the number of stained samples is significantly higher than unstained samples, χ²(4, N=150)=15, p=0.000 was 0.02165%.
Kolmogorov-Smirnov analysis for the overall clinical evaluation of GV and erythrosine also showed significant differences in the distribution of Likert scores, D_40,.05=.055, p=0.008.
Conclusions: GV at 0.02165% concentration effectively discloses dental biofilm as it leaves a vivid violet color that stands out against the conventional colors of oral cavity structures. Hence, GV can be a beneficial cost-effective alternative disclosing agent for community-based dental health education and promotion that aims to raise awareness on the presence of dental biofilm, and as positive operant for toothbrushing behaviors.