Use of polyphenols as a strategy to prevent bond degradation in the dentin-resin interface.

This study evaluated the effect of dentin pretreatment with the polyphenols quercetin and resveratrol on the resin-dentin microtensile bonding strength (µTBS) and collagen fibrils stability of the adhesive interface. Different concentrations (100, 250, 500, or 1,000 µg ml-1 ) of quercetin or resveratrol, or a mixture of quercetin and resveratrol (3:1, 1:1, 1:3; vol:vol), as well as distilled water or 2% chlorhexidine digluconate, were applied to etched dentin. Then, a two-step etch-and-rinse adhesive was applied followed by composite restoration. Measurements of resin-dentin µTBS were made after 1 and 120 d. The stability of collagen fibrils in the hybrid layer was evaluated using transmission electron microscopy. The Student's t-test and two-way factorial anova with Tukey's test were used to analyze the effects of dentin pretreatment and storage time on µTBS values. Comparisons between µTBS measurements made on 1 and 120 d showed that resveratrol had the best performance, with significantly higher µTBS values after 120 d for all concentrations of resveratrol tested. Quercetin pretreatment resulted in a significant rise of µTBS when used at concentrations of 100 and 500 µg ml-1 . Quercetin + resveratrol at the ratio of 1:1 performed better than when used at ratios of either 3:1 or 1:3. Resveratrol might represent a potential approach to achieve desirable bonding stability and reduce the frequent replacement of composite restorations.

Cytotoxicity of current adhesive systems: in vitro testing on cell cultures of primary murine macrophages.

OBJECTIVES: The aim of this study was to evaluate, in vitro, the potential cytotoxicity of dentinal adhesives on alveolar macrophages of Wistar rats, after diffusion through dentin. METHODS: The cytotoxicity of adhesives [single bond plus (SB), clearfil SE bond (CF) and Xeno V (XE)] applied to the occlusal surface of human dentin disks adapted to a dentin barrier test device were analyzed. The sets placed on a monolayer of cells were incubated for 24, 48 and 72h. Culture medium and Escherichia coli lipopolysaccharides (LPS) were used as negative and positive controls, respectively. Cellular cytotoxicity was evaluated by observing the cell survival rate (MTT assay) and nitric oxide production (NO). The data were analyzed by one-way factorial ANOVA and Tukey's and Tamhane's paired comparisons T2 (α=0.05). RESULTS: All the adhesive systems reduced the percentage of live cells by over 50%, compared with the control group. Within the same period of time, there was a statistically significant difference between the adhesives and LPS compared with the negative control group. SB presented a statistically significant difference between 24h and 72h, and XE between 48h and 72h. The quantity of NO produced in 24h did not differ statistically between the NC and adhesive groups. After 48h there was a significant difference between SB/CF and XE/NC. At 72h only CF showed a significant difference from each of the other groups. LPS differed statistically from all the other groups at all the evaluation times. SIGNIFICANCE: Components of the adhesives tested may permeate the dentin in sufficient concentrations to cause death and damage to cell metabolism in the alveolar macrophages of rats, which indicates potential cytotoxicity to pulpal cells.

Diagnosis and treatment of dentinal hypersensitivity.

This bibliographic review provides a general view of the etiology, characteristics and treatment of dentinal hypersensitivity, so that professionals can use this information in the therapeutic management of this clinical condition. For this purpose, the authors have analyzed whole texts of relevant articles on the subject. This study showed that the predisposing factors associated with the causes of dentinal hypersensitivity must be controlled or eliminated, by educating the patient regarding the excessive intake of acidic food, as well as providing guidance on the proper tooth brushing technique and analysis of occlusion. Effective treatment must be preceded by a proper diagnosis, established after the exclusion of any other possible causes of the pain. These cases must be managed efficiently, quickly and permanently. The availability of a wide variety of treatment could be an indicator that there is still no effective desensitizing agent to completely resolve the patient's discomfort, or that it is difficult to treat, irrespective of the available treatment options. Even with the large number of published studies, it has not been possible to reach a consensus about the product that represents the gold standard in the treatment of dentinal hypersensitivity.