Significant shear bond strength improvements of a resin-modified glass ionomer cement with a resin coating.

Previous evidence has suggested that resin-modified glass ionomer cements (RMGICs) may be sensitive to temperature and moisture changes for the first 24 hours after photopolymerization. To test the hypothesis that a resin coating placed over the surface of an RMGIC restoration would decrease the susceptibility to moisture and temperature conditions, 44 RMGIC samples were prepared in inverted-cone recesses drilled in epoxy resin plates. After abrasion of all samples with 800-grit silicon carbide paper to simulate a diamond bur finish on the surface, a coat of highly filled resin was applied to the experimental group (n = 22) and cured according to the manufacturer's instructions. The plates were thermocycled 500 times between 5°C and 55°C and then maintained at 37°C with 95% humidity. The thermocycled samples were bonded to a second epoxy resin plate filled with RMGIC and subjected to shear bond strength testing. The resin-coated group had a significantly greater mean shear bond strength than the control group (P < 0.05). The resin coating also appeared to affect the mode of failure by significantly increasing the number of mixed failures (P < 0.05). The results suggest that a resin coating protects RMGIC from moisture- and temperature-induced damage and increases shear bond strength.

A high isoflavone diet decreases 5' adenosine monophosphate-activated protein kinase activation and does not correct selenium-induced elevations in fasting blood glucose in mice.

Selenium (Se) has been implicated as a micronutrient that decreases adenosine monophosphate-activated protein kinase (AMPK) signaling and may increase diabetes risk by reducing insulin sensitivity. Soy isoflavones (IF) are estrogen-like compounds that have been shown to attenuate insulin resistance, hyperglycemia, adiposity, and increased AMPK activation. We hypothesized that a high IF (HIF) diet would prevent the poor metabolic profile associated with high Se intake. The purpose of this study was to examine changes in basal glucose metabolism and AMPK signaling in response to an HIF diet and/or supplemental Se in a mouse model. Male FVB mice were divided into groups receiving either a control diet with minimal IF (low IF) or an HIF diet. Each dietary group was further subdivided into groups receiving either water or Se at a dose of 3 mg Se/kg body weight daily, as Se-methylselenocysteine (SMSC). After 5 months, mice receiving SMSC had elevated fasting glucose (P < .05) and a tendency for glucose intolerance (P = .08). The increase in dietary IF did not result in improved fasting blood glucose. Interestingly, after 6 months, HIF-fed mice had decreased basal AMPK activation in liver and skeletal muscle tissue (P < .05). Basal glucose metabolism was changed by SMSC supplementation as evidenced by increased fasting blood glucose and glucose intolerance. High dietary IF levels did not protect against aberrant blood glucose. In FVB mice, decreased basal AMPK activation is not the mechanism through which Se exerts its effect. These results suggest that more research must be done to elucidate the role of Se and IF in glucose metabolism.