only laser irradiation was capable of immediately sealing the dentinal tubules; however, none of the treatments showed efficacy in maintaining tubule occlusion after the chemical and mechanical challenges.

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Objective: To evaluate if there is any interference when adding coffee or chocolate to cow milk in the enamel des-remineralization process (orange juice/saliva). Material and Methods: 48 specimens of human enamel (4x4 mm) were included in acrylic resin, ground flat, polished and randomly divided into the following experimental groups (n = 8): G1-saliva, G2-orange juice, G3 orange juice / milk; G4-Orange Juice / Chocolate, G5-Orange Juice / Coffee + milk and G6-milk. Each group was immersed for 60 seconds on each solution proposed and then immersed for 30 minutes in saliva. This cycle was repeated 4 times. Prior to these cycles, the Knoop microhardness average of each specimen was obtained. After the challenges proposed, the final microhardness average was calculated. The values obtained from the difference between the initial and final microhardness were subjected to ANOVA followed by Tukey test (p <0,05). Results: The orange juice had the highest change in microhardness and statistically different from all other groups. The microhardness change was statistically similar in the groups submitted to orange juice followed by immersion in milk, in chocolate and in the mixture milk + coffee. The pure milk and saliva caused no change in surface hardness of enamel. Conclusion: Milk or the addition of chocolate and coffee to milk was able to produce a protective effect of the enamel surface against an erosive challenge.

Hyposalivation and dental root exposure in the elderly are problems that require special oral care. In this context, the characteristics of certain toothpastes are of particular importance. Thus, the aim of this study was to evaluate the cytotoxicity and dentin wear caused by seven different toothpastes. For dentin wear analysis, 40 root dentin specimens were submitted to 20,000 brushing cycles with the different toothpastes and distilled water (control group-CG), using a brushing machine. Dentin surface loss (SL) was measured by contact profilometer. The cytotoxicity of each toothpaste was tested using cultured fibroblasts submitted to a cell-culture-conditioned medium. Fresh medium served as the control. Cell viability was assessed by MTT assay after 24 h of contact with the conditioned media. The data were analyzed statistically by ANOVA, followed by Tukey's test (p < 0.05). The SL of the CG was minimal and significantly lower than that of the Oral B Pro Health (OBPH) group (p < 0.05). All other groups presented SL in between that of the CG and the Oral B Pro Health OBPH group, except for the Sensodyne (SEN) group, which presented SL similar to that of CG (p = 0.05). The SEN group presented a percentage of viable cells similar to that of CG: between 60-89%. All the other toothpastes showed high cytotoxicity, with cell viability less than 50% of the CG. Considering study limitations, we concluded that only one of the seven tested toothpastes exhibited the most desirable toothpaste characteristics for the worldwide growing elderly population (e.g. low cytotoxicity and low-abrasive potential).

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