Effect of metformin on exercise capacity in metabolic syndrome.

OBJECTIVE: Metabolic syndrome is a constellation of risk factors with increased predilection towards occurrence of cardiovascular diseases. Currently physical exercise and management with metformin are the prevailing treatment modalities for metabolic syndrome. Patients with metabolic syndrome have been found to have reduced exercise capacity over a period of time. Likewise metformin has been shown to decrease exercise capacity among healthy volunteers. Hence this study aims to evaluate the effect of metformin on the exercise capacity of patients with metabolic syndrome. DESIGN: Prospective study with 6 weeks follow up. METHODS: Newly diagnosed patients with metabolic syndrome and to be started on Table Metformin 500mg twice a day were recruited for the study after obtaining written informed consent. Cardiopulmonary Exercise Testing (CPET) was done at baseline before the subjects were started on metformin and after 6 weeks of treatment using cardiopulmonary exercise testing apparatus (ZAN600). RESULTS: Fifteen treatment naïve patients with metabolic syndrome completed six weeks of therapy with metformin. In these patients oxygen uptake [VO2] showed statistically significant decrease from 1.10±0.44 at baseline to 0.9±0.39 (l/min) after six weeks of treatment with metformin [mean difference of -0.20 (-0.31 to -0.09); P=0.001]. Similarly oxygen uptake/kg body weight [VO2/Kg] showed a significant decrease from 14.10±4.73 to 11.44±3.81 (mlkg-1min-1) at the end of six weeks of treatment [mean difference of -2.66 (-4.06 to -1.26); P=0.001]. CONCLUSION: Six weeks of treatment with metformin significantly decreases exercise capacity in newly diagnosed patients with metabolic syndrome.

Illuminant effect on the coverage error of a gingiva-colored composite resin shade guide.

STATEMENT OF PROBLEM: Dental clinicians face challenges when selecting the proper gingiva-colored composite resin. PURPOSE: The purpose of this study was to evaluate the coverage error (CE) of a gingiva-colored dental composite resin shade guide with regard to the optical characteristics of the attached gingiva of a selected population under 2 different illuminants: Commission Internationale de l'Eclairage (CIE) illuminants A and D65. MATERIAL AND METHODS: The spectral reflectance (SR) values of 12 shade tabs of a gingiva-colored composite resin (Amaris gingiva) were measured at 3 different locations without a backing by using a spectroradiometer and an external light source at wavelengths of 380 to 780 nm at 2-nm intervals. All SR measurements were made using 0-degree observer and 45-degree illumination, with target size 1.1 mm in diameter. The attached gingiva (AG) of 120 participants was measured with the same protocol. CIELab values were calculated from the spectral reflectance values. CEs of the attached gingiva for each of the 120 participants for each of the shade tabs and the 2 illuminants and their combination were determined and averaged. The CIEDE2000 color differences were analyzed by a repeated measures ANOVA (using the maximum likelihood estimation method and the Satterthwaite degrees of freedom method) (α=.001). RESULTS: The CIEDE2000 color difference for each person's gingiva to the closest match in color to the shade guide was determined separately for CIE illuminants A and D65. CE was calculated as the averages of these color differences and was found to be 4.0 for CIE illuminant D65 and 5.8 for CIE illuminant A. CONCLUSIONS: The tested gingiva-colored shade guide had different CEs under illuminant D65 than under illuminant A and exhibited metamerism. ΔE for both illuminants was greater than the clinically acceptable range reported in the literature.

Color stainability of CAD/CAM and nanocomposite resin materials.

STATEMENT OF PROBLEM: The color stainability of recently introduced computer-assisted design/computer-assisted manufacturing (CAD/CAM) hybrid ceramic and resin nanoceramic is unknown. PURPOSE: The purpose of this in vitro study was to compare the effect of coffee staining on the color of 3 different CAD/CAM restorative materials and a nanocomposite resin. MATERIAL AND METHODS: Specimens from a hybrid dental ceramic (VITA Enamic), a resin nanoceramic (Lava Ultimate), a lithium disilicate glass ceramic (IPS e.max CAD), and a nanocomposite resin (Filtek Supreme Ultra Universal) were evaluated for color change due to thermocycling in coffee (n=5). Specimens 0.5 to 0.7 mm and 1 to 1.2 mm in thickness were thermocycled for 5000 cycles. CIEDE2000 color differences (ΔE00) due to thermocycling in coffee were calculated using the color coordinates obtained from a spectroradiometer. ANCOVA was used to analyze the color differences among the materials with thickness as the covariate. Significant differences at average thickness were analyzed with the Tukey-Kramer test. RESULTS: For color difference due to staining, thickness was a significant covariate (P<.001). Regarding the analysis of color differences, every pair of the tested materials was significantly different (P<.001). Least squares means of color differences (ΔE00) at mean thickness were 4.34 for the nanohybrid composite resin, 3.66 for the resin nanoceramic, 1.35 for the hybrid ceramic, and 0.43 for the lithium disilicate ceramic. CONCLUSION: When exposed to hot and cold coffee, the color change was beyond clinical acceptability for the tested resin nanoceramic and nanocomposite resin materials. The average color change of the hybrid ceramic was clinically perceivable over the tested thickness values. The color change of lithium disilicate ceramic was not clinically perceivable at any tested thickness.