This in vitro study assessed the shear bond strength of human enamel and dentin submitted to a bleaching treatment with 10% carbamide peroxide and treatment with antioxidant agents containing 10% α α-tocopherol and 10% sodium ascorbate formulated in solution and gel. Sixty human dental enamel slabs (E) and 60 human dental dentin slabs (D) were randomly divided into six groups (n=10). Groups E1 and D1 were negative control groups and the bleaching agent was not applied. The bleaching agent was applied daily for two-hours on the dental slabs of all the other groups and, during the remaining 22 hours, the specimens were stored in an artificial saliva solution for a total of 14 days. Groups E2 and D2 were positive control groups and they only received application of the bleaching agents. Antioxidant agents were applied in Groups E3 and D3 (10% sodium ascorbate solution), E4 and D4 (10% α α-tocopherol solution), E5 and D5 (10% sodium ascorbate gel) and E6 and D6 (10% α α-tocopherol gel) for two hours. RT Sasaki • FM Flório • RT Basting Clinical RelevanceA significant reduction in bond strength of restorative materials to dentin and enamel after home-use bleaching treatment has been reported. Antioxidizing agents may be a procedure to increase bond strength values. Although no reversal of bond strength values was found for sodium ascorbate, alpha-tocopherol formulated in solution resulted in a significant increase in bond strength of bleached enamel. 747Sasaki, Flório & Basting: Effects of 10% Sodium Ascorbate and 10% α-tocopherol on SBS After Bleaching Cylinders were made with microhybrid resin composite and a total-etch adhesive system for shear bond strength tests. These tests were performed in a universal testing machine at a speed of 0.5 mm/minute to obtain the values in MPa. ANOVA (p>0.05) showed no significant differences among groups E4, E5, E6 and E1. However, groups E3, E5 and E6 presented statistically similar values to group E2. The Kruskal-Wallis test showed no significant differences among D1 and all the other experimental groups; the same values occurred with D2, which did not differ from the experimental groups. Antioxidant treatment with 10% α α-tocopherol solution was the only effective agent to revert the oxidizing effects of the bleaching treatment on enamel.

No beneficial effects of adding ACP to bleaching formulas on enamel microhardness were observed, but these observations may be attributable to the lower hydrogen peroxide concentrations in association with the remineralizing effect of saliva, when considering the enamel roughness.

Objective:The purpose of this study was to assess the effect of home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide on enamel microhardness and surface micromorphology.Material and Methods:Enamel slabs (n=10) received the bleaching agents for 1 h/day and remained in artificial saliva solution for 23 h/day, during a total period of 21 days. Control group was composed of enamel slabs that were not subjected to treatment with the agents and were maintained in artificial saliva solution. Microhardness tests were performed before treatment application, 21 days of treatment and 14 days after the end of treatment. Scanning electron microscopy analyses were performed after 14 days after the end of bleaching treatment by 3 calibrated observers who attributed scores.Results:The Tukey's test (α=0.05) showed no significant differences in microhardness values among bleaching agents, at 21 days of treatment and a significant increase in microhardness for different agents after 14 days from the end of treatment. Fisher's exact test showed differences in micromorphology of enamel between control and experimental groups (p=0.0342).Conclusions:Bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide may change surface micromorphology of enamel, although no changes in microhardness were observed.

Adult stem cells research has been considered the most advanced sort of medical-scientific research, particularly stem cells from human exfoliated deciduous teeth (SHED), which represent an immature stem cell population. The purpose of this review is to describe the current knowledge concerning SHED from full-text scientific publications from 2003 to 2015, available in English language and based on the keyword and/or abbreviations ‘stem cells from human exfoliated deciduous teeth (SHED)', and individually presented as to the properties of SHED, immunomodulatory properties of SHED and stem cell banking. In summary, these cell populations are easily accessible by noninvasive procedures and can be isolated, cultured and expanded in vitro, successfully differentiated in vitro and in vivo into odontoblasts, osteoblasts, chondrocytes, adipocytes and neural cells, and present low immune reactions or rejection following SHED transplantation. Furthermore, SHED are able to remain undifferentiated and stable after long-term cryopreservation. In conclusion, the high proliferative capacity, easy access, multilineage differentiation capacity, noninvasiveness and few ethical concerns make stem cells from human exfoliated deciduous teeth the most valuable source of stem cells for tissue engineering and cell-based regenerative medicine therapies.