Avaliação do potencial de biomodificação dentinária do líquido da casca da castanha de caju

Abstract

Composite resin restorations still present a challenge in bonding durability to the dental structure due to fast degradation of exposed collagen at the resin-dentin interface. The dentin biomodification strategy improves the mechanical and biochemical properties of the dentin matrix, increasing the stiffness and stability of the collagen and, therefore, improving the longevity of restorations. Currently, glutaraldehyde (GA) is the gold standard biomodifying agent, but has a high cytotoxicity disadvantage. Cashew Nutshell Liquid (LCC) is a natural product rich in polyphenols, extracted in a chemical or mechanical process, natural LCC (LCCn), or in a high temperature thermal process, technical LCC (LCCt). The aim of this study was to evaluate the effect of LCCn and LCCt on the mechanical properties of demineralized dentin. Thirty human third molars were sectioned into bars and demineralized in 10% phosphoric acid. Immediately, the dentin matrix was subjected to the three-point bending test to obtain the initial elastic modulus (E). After randomization, specimens were treated for 60 seconds according to the following groups (n=15): negative control (distilled water - AD), positive control (5% GA), LCCn (2%) and LCCt (2%). Then, E was evaluated again immediately and every 7 days for 4 weeks of storage in artificial saliva. In addition to the evaluation of dentinal collagen stiffness, the degradation rate was measured by varying the mass of dentin bars. The data were compared using ANOVA test followed by Bonferroni post- test (p <0.05). ANOVA 1-way was used to compare groups in the same period. ANOVA for repeated measures was used in intra-groups comparison at different periods. The E after 4 weeks of storage was higher for the group treated with LCCt, followed by GA, increasing the collagen stiffness by 422% and 250%, respectively. However, the LCCn showed no statistical difference in the E when compared to the negative control in the same storage period. The mass variation values showed less collagen degradation in the LCCt and GA groups compared to LCCn and AD. Therefore, LCCt has the potential to be used as a dentin biomodification agent in a viable clinical time.