Effect of flavonoids on the mechanical properties of demineralised dentine

Abstract Objectives This study compared the effect of three flavonoids: proanthocyanidin, naringin and quercetin on the modulus of elasticity (MOE) and ultimate tensile strength (UTS) of demineralised dentine. Methods Thirty teeth were sectioned into 0.5 mm × 1.7 mm × 7 mm beams for MOE measurement. Another 30 non-carious molars were sectioned into 0.5 mm × 0.5 mm thick dentine beams for UTS testing. Demineralised specimens were divided into three groups according to treatments: 6.5% proanthocyanidin, 6.5% quercetin and 6.5% naringin. Specimens were kept in their respective solutions and tested at baseline, 10 min, 30 min, 1 h and 4 h. The MOE of each specimen was determined using a three-point bending test at a crosshead speed of 0.5 mm/min. For UTS evaluation, each specimen was tested in tension until failure using a crosshead speed of 1 mm/min. Means and standard deviation were calculated. Two-way ANOVA and Tukey test were used to evaluate the effect of flavonoid treatment and treatment duration on MOE and UTS. Results Both MOE and UTS were significantly affected by flavonoid treatment ( p < 0.001) and treatment duration ( p < 0.001). Interaction of the two factors was significant for MOE ( p < 0.001), but not for UTS ( p > 0.05). Flavonoid treatment improved the mechanical properties of demineralised dentine in the order: proanthocyanidin > quercetin > naringin. It took a longer time for the flavonoids to produce a significant change in UTS, when compared to MOE. Conclusion Proanthocyanidin was more effective than quercetin and naringin in improving biomechanical properties of dentine matrix, thereby enhancing preventive and reparative dental therapies. Clinical Significance Despite its larger molecular size, proanthocyanidin was more effective than quercetin and naringin, in enhancing the biomechanical properties of demineralised dentine.