Effect of proanthocyanidins-containing natural extracts on the resin-dentin bond strength and stiffness of dentin matrix

Abstract

Objectives: Aim: This study was conducted to evaluate the effect of proanthocyanidin-containing natural cross-linkers on the resin-dentin bond strength and dentin matrix stiffness. Methods: Forty-five specimens were prepared from 9 recently extracted molars for microtensile bond strength (µTBS) testing. Specimens were divided according to the type of extract used for dentin pretreatment into 3 groups (n=15): Control group(CO), Grape seed extract (GSE), Cacao seed extract (CSE). The occlusal enamel of the teeth was removed to expose the superficial dentin. The exposed dentin surface was acid etched using 35% phosphoric acid, then the respective pre-treatment was applied using a microbrush for 1 minute and blot dried, afterwhich the etch and rinse adhesive was applied. Composite was then built onto the pre-treated dentin surface in 2 increments (2mm each) and the teeth were sectioned using an isomet saw into beams (1x1x8mm) and their micro-tensile bond strength was evaluated using a universal testing machine. For dentin stiffness evaluation, nine sound molars were used to obtain 45 dentin beams (1x1x6.5mm). The beams were then fully demineralized using a 10% phosphoric acid solution and rinsed for 10 minutes with distilled water. The beams were then divided into 3 groups (n=15) and treated with the respective extract solution for 1 minute. To evaluate the dentin stiffness the beams were subjected to 3-point loading. Results: Microtensile bond strength results revealed insignificant difference between the tested groups. Concerning dentin matrix stiffness; grape seed extract recorded significantly higher mean value compared to cacao seed extract and control. Conclusion: Treating demineralized dentin for 1 minute using grape seed extract improved the stiffness of dentin matrix, but was insufficient to improve the resin-dentin microtensile bond strength.