Differential effects of coffee on the risk of type 2 diabetes according to meal consumption in a French cohort of women: the E3N/EPIC cohort study

Background: Coffee consumption has been associated with a lower risk of diabetes, but little is known about the mechanisms responsible for this association, especially related to the time when coffee is consumed. Objective: We examined the long-term effect of coffee, globally and according to the accompanying meal, and of tea, chicory, and caffeine on type 2 diabetes risk. Design: This was a prospective cohort study including 69,532 French women, aged 41-72 y from the E3N/EPIC (Etude Epidemiologique aupres de Femmes de la Mutuelle Generale de l`Education Nationale/European Prospective Investigation into Cancer and Nutrition) cohort study, without diabetes at baseline. Food and drink intakes per meal were assessed by using a validated diet-history questionnaire in 1993-1995. Results: During a mean follow-up of 11 y, 1415 new cases of diabetes were identified. In multivariable Cox regression models, the hazard ratio in the highest category of coffee consumption [>= 3 cups (375 mL)/d] was 0.73 (95% CI: 0.61, 0.87; P for trend < 0.001), in comparison with no coffee consumption. This inverse association was restricted to coffee consumed at lunchtime (hazard ratio: 0.66; 95% CI: 0.57, 0.76) when comparing >1.1 cup (125 mL)/meal with no intake. At lunchtime, this inverse association was observed for both regular and decaffeinated coffee and for filtered and black coffee, with no effect of sweetening. Total caffeine intake was also associated with a statistically significantly lower risk of diabetes. Neither tea nor chicory consumption was associated with diabetes risk. Conclusions: Our data support an inverse association between coffee consumption and diabetes and suggest that the time of drinking coffee plays a distinct role in glucose metabolism. Am J Clin Nutr 2010; 91: 1002-12.

Gels Containing MMP Inhibitors Prevent Dental Erosion in situ

Matrix metalloproteinase (MMP) inhibition has been shown to reduce dentin caries progression, but its role in dental erosion has not yet been assessed. This study tested the hypothesis that gels containing MMP inhibitors (epigallocatechin gallate-EGCG and chlorhexidine) can prevent dental erosion. Volunteers (n = 10) wore palatal devices containing bovine dentin blocks (n = 10/group) treated for 1 min with EGCG at 10 (EGCG10) or 400 mu M (EGCG400), chlorhexidine at 0.012%, F at 1.23% (NaF), and no vehicle (placebo). Erosion was performed with Coca-Cola (R) (5 min) 4X/day during 5 days. The wear, assessed by profilometry (mean +/- SD, mu m), was significantly reduced by the gels containing MMP inhibitors (0.05 +/- 0.02(a), 0.04 +/- 0.02(a), and 0.05 +/- 0.02(a) for EGCG10, EGCG400, and chlorhexidine, respectively) when compared with NaF (0.79 +/- 0.35(b)) and placebo gels (1.77 +/- 0.35(b)) (Friedman and Dunn`s tests, p < 0.01). The use of gels delivering MMP inhibitors was shown to prevent erosion and opens a new perspective for protection against dental erosion.

The Effect of Polymerization Cycles on Color Stability of Microwave-Processed Denture Base Resin

Purpose: This study evaluated the effect of different microwave polymerization cycles on the color changes of a microwave-processed denture base resin after accelerated aging and immersion in beverages. Materials and Methods: Specimens of light pink acrylic resin were divided into three groups according to polymerization cycle: (A) 500 W for 3 minutes, (B) 90 W for 13 minutes + 500 W for 90 seconds, and (C) 320 W for 3 minutes + 0 W for 4 minutes + 720 W for 3 minutes. Control groups were a heat-processed acrylic resin (T) and a chemically activated denture repair resin (Q). Eight specimens per group were aged in an artificial aging chamber and evaluated at 20, 192, and 384 hours. Another series of 40 specimens per group were immersed in water, coffee, tea, cola, or red wine and evaluated at 1, 12, and 36 days. Color was measured by a spectrophotometer before and after aging or immersion. Color changes (Delta E) were analyzed by ANOVA/Bonferroni t-test (alpha = 0.05). Results: Mean Delta E (+/- SD) after 384 hours of accelerated aging were (A) 2.51 +/- 0.50; (B) 3.16 +/- 1.09; (C) 2.89 +/- 1.06; (T) 2.64 +/- 0.34; and (Q) 9.03 +/- 0.40. Group Q had a significantly higher Delta E than the other groups. Color changes of immersed specimens were significantly influenced by solutions and time, but the five groups showed similar values. Mean Delta E at 36 days were (water) 1.4 +/- 0.8; (coffee) 1.3 +/- 0.6; (tea) 1.7 +/- 0.5; (cola) 1.4 +/- 0.7; and (red wine) 10.2 +/- 2.7. Results were similar among the five test groups. Conclusions: Color changes of the microwave-polymerized denture base resin tested were not affected by different polymerization cycles after accelerated aging or immersion in beverages. These changes were similar to the conventional heat-polymerized acrylic resin test, but lower than the repair resin after accelerated aging.