Chitosan Hydrochloride: Tooth Enamel Film Formation As Acid Resistance Protection

Tooth decay or erosive wear often results from the contact of acid with hydroxyapatite in tooth enamel. Traditional methods for restoring enamel involve fluoride-based products, but frequent fluoride intake can lead to fluorosis, deterring consumers. This study aimed to investigate the potential of chitosan hydrochloride (mushroom-sourced, vegan-friendly) and chitosan (chitin-sourced) in enhancing the acid resistance of bovine enamel blocks in vitro. Enamel blocks were sectioned from bovine teeth, and the percentage of relative erosion resistance (%RER) was measured. After demineralizing them in a solution at a pH of 4.5 for 60 minutes, the enamel samples were treated with the respective solutions for 16 hours at a pH of 6.5. Acid exposure involved immersing the samples in 8 ml of citric acid solution for 1 hour at 37°C. The results indicated that chitosan hydrochloride at concentrations of 0.25% (-41.9±11.8; p<0.05) and 0.5% (-30.67±16.34; p<0.05) provided protection against acid erosion comparable to the positive control, fluoride (-44.44±15.89; p<0.05), while the result for deionized water was -91.25±30.01; p<0.05. To understand the mechanism, the ability of the compounds to adhere to the enamel surface was examined using a light microscope. Representative images of the enamel samples were captured before and after a single 3-minute application of the test compound, followed by immersion in deionized water three times and reimaging. The images showed that 0.2% chitosan hydrochloride remained on the sample surfaces. In conclusion, chitosan hydrochloride demonstrates potential as a vegan alternative to fluoride for enhancing acid resistance by adhering to the tooth surface.