Effects of Flavonoids on Artificial Root Caries Remineralization

Abstract

Objectives: Root caries is a major oral health problem among the elderly. It is advantageous to find ways to enhance remineralization of root caries.This study compared the effects of three flavonoids, proanthocyanidin, naringin and quercetin on artificial root caries remineralization and collagen mineralization. Methods: Caries lesions created artificially from seventy-five root fragments were subjected to a pH cycling model. Demineralized root fragments were randomly divided into 5 groups for treatment with the remineralizing agents for 10 minutes: (i) 6.5% proanthocyanidin, (ii) 6.5% naringin, (iii) 6.5% quercetin, (iv) 1000ppm fluoride and (v) deionized water (control). The remineralization effects were evaluated using transverse microradiography (lesion depth and mineral loss), confocal laser scanning microscopy and microhardness. The lesion depth and mineral loss were analyzed with one-way ANOVA; while microhardness at different lesion depths were analyzed with two-way ANOVA and Tukey’s test. For observation of collagen mineralization, TEM grids coated with Type I collagen fibrils were divided into 4 groups for treatment with remineralizing agents for 1 hour: (i) 6.5% proanthocyanidin, (ii) 6.5% naringin, (iii) 6.5% quercetin and (iv) 1000ppm fluoride. Collagen fibrils were then incubated in the remineralization medium for 72 hours. Finally the collagen-coated grids were washed, dried and observed under Transmission Electron Microscopy.

Results: The lesion depths and mineral loss of flavonoid-treated groups were both significantly lower than the control group, but higher than the fluoride-treated group (P<0.05) No significant difference in lesion depths and mineral loss were found among the three flavonoids (P>0.05). Artificial caries lesions treated with fluoride and flavonoids showed significantly greater hardness than control group (P<0.05). Different degrees of mineral deposition were observed in flavonoid-treated collagen.

Conclusions: All three flavonoids showed positive effects on artificial root caries remineralization and collagen mineralization.

(This study was supported by Seed Funding Programme for Basic Research 201011159189)