An evaluation of the color stability of tooth-colored restorative materials after bleaching using CIELAB color technique.

AIMS AND OBJECTIVE: The aim of this laboratory study was to evaluate the effect of three home bleaching agents: Vivastyle Paint On, Vivastyle, and Opalascence PF on the color stability of the microfilled composite Durafill, the nanofilled composite Filtek Z 350, and the glass ionomer cement Fuji II. MATERIALS AND METHODS: There were 3 groups in this study (n=40)-Group I: durafill, Group II: Filtek Z 350, and Group III: Fuji II. Each group was further subdivided into 4 subgroups (n=10), Subgroup A: bleaching with Vivastyle Paint On, Subgroup B: bleaching with Vivastyle, Subgroup C: bleaching with Opalascence PF, and Subgroup D: control specimens stored in distilled water. Bleaching was carried out following the manufacturer's instructions for a period of 14 days. At the end of the bleaching regimen, the specimens were tested for color change using the CIELAB technique and a reflectance spectrophotometer. RESULTS: The data was subjected to statistical analysis. A Kruskal-Wallis variance analysis and Mann Whitney U test were done to determine the significant color change of the restorative materials. All restorative materials demonstrated a significantly higher color change (DeltaE) with Vivastyle (P < 0.0001). The mean color change of GIC (11.4 +/- 0.3) was the highest among the materials followed by Durafill (7.5 +/- 0.1). Filtek z 350 (0.3 +/- 0.1) showed the least color change with all the bleaching agents. CONCLUSION: Glass ionomer cement showed the highest color change followed by the microfilled composite. The nanofilled composite was found to be highly stable in terms of color.

Degree of conversion and residual stress of preheated and room-temperature composites.

The aim of this study was to determine the degree of conversion and residual stress of resin composite preheated to different temperatures and to compare it to room-temperature composite. The composite resin was preheated to 40 degrees C, 50 degrees C, and 60 degrees C and packed into brass rings and light-cured. The degree of conversion and residual stress were analysed using Fourier transform infra-red spectroscopy and X-ray diffraction, respectively. The results obtained were tabulated and statistically analyzed using Kruskal-Wallis test and Tukey's honestly significantly different test. The results showed significant increase in the degree of conversion and residual stress with increase in preheating temperature.

Assessment of malnutrition in alcoholic and non alcoholic cirrhotics.

OBJECTIVE: To study the nutritional status in patients with chronic liver disease using anthropometric techniques. METHODS: A total of 60 cirrhotic patients (30 Alcoholic (AC), 30 Non-alcoholic (NAC) and 30 control (CO) subjects were studied. Nutritional status was assessed using anthropometric measurements such as stature, body weight, body mass index, (BMI), skinfold thickness measurements and mid upper arm muscle circumference. Serum protein, serum albumin and globulin were measured. RESULTS: The skinfold thicknesses were significantly lower in NAC group of patients. In contrast the AC group of patients showed significantly lower mid upper arm muscle circumference values. Both groups of cirrhotic patients showed significantly lower total serum protein and serum albumin levels. CONCLUSION: Body fat is relatively more affected in NAC group of patients and muscle mass is more affected in AC group of patients.