Effect of a flavonoid on  dentin collagen degradation in situ

Objective: This split-mouth study was designed to assess the effect of hesperidin (HPN), a citrus flavonoid antioxidant, on dentin collagen degradation in situ. Methods: Seventeen healthy volunteers, wearing a partial prosthesis, received two completely demineralized dentin specimens placed contralaterally. After complete demineralization (incubation in 0.1M acetic acid; 9 days; pH 4.5) the specimens were covered by Dacron gauze to enhance plaque accumulation. Twice daily the participants immersed each specimen extraorally in a test solution (HPN suspension; 1000 ppm) or a control solution (distilled water) during 3 min. After 4 weeks the specimens were retrieved, incubated with bacterial collagenase type VII (SIGMA CO773-3KU) and hydrolyzed (6N HCl) after which the collagen content was determined by amino acid analysis. Predefined exclusion criteria included low responders ( 95% confidence interval of the in vitro control specimens; n=10; mean collagen content 2.35 ± 0.27 mg/specimen include the collagen content of in situ control specimens). Results: The results (n=13) showed that the mean dentin collagen content in the test group (1.67 ± 0.68 mg/specimen) was statistically significantly larger than in the placebo group (1.35 ± 0.57 mg/specimen; paired t-test; p<0.02). Saliva samples taken before and after the experimental period did not show a correlation between collagen content of the control in situ specimens and collagenase activity, MMP-8 and TIMP-1.Conclusion: This in situ study shows that hesperidin protects dentin collagen against degradation.