Evaluation of the effect of various beverages on the color stability and microhardness of restorative materials.

OBJECTIVE: The aim of this in-vitro study was to investigate the effects of frequently consumed beverages on the color stability and microhardness of various restorative materials. MATERIALS AND METHODS: Twenty-four samples were prepared in each group to examine the effect of different beverages on coloration and surface hardness of two direct composite resins (Filtek Z250, Filtek Z550); one indirect composite resin (Solidex); and one high viscosity glass ionomer cement (Equia Forte Fil). Samples were stored in four solutions (distilled water, black tea, coffee, and cola) at room temperature for 1 week (n = 6). The color values are taken at the beginning and the color and microhardness values taken at the end of 1 week were evaluated by the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The highest color change was observed in the Equia Fil, while the least color change was observed in the Z550 group. The highest degree of color change was observed in coffee and cola groups. While the lowest values of hardness were observed in the Solidex group, the highest values of hardness were observed in the Z550 group. The highest levels of hardness change were detected in the coffee and cola groups. CONCLUSION: The color and hardness of restorative materials can be negatively affected by consumed beverages. Nanohybrid composite resins are resistant to external coloration and hardness change.

Do ozonated water and boric acid affect the bond strength to dentin in different adhesive systems?

AIM: The aim of this in vitro study was to compare the effects of the application of three different cavity disinfecting agents to dentin on the micro-shear bond strength (µ-SBS) of one self-etch and two universal adhesive systems. MATERIALS AND METHODS: In total, 120 caries-free human permanent molar teeth were used in this study. Mid-coronal dentin surfaces were revealed by cutting occlusal enamel and a standard smear layer was obtained by using 600-800-1200 grid silicon carbide abrasive papers. Specimens were randomly assigned to four groups according to the disinfectant used: Group 1: Control (no disinfectant); Group 2: 2% chlorhexidine based (Consepsis); Group 3: 10 ppm ozonated water (TeknO3zone); Group 4: 5% boric acid (Handmade). Each group was divided into three subgroups according to the type of adhesive (Clearfil SE Bond, OptiBond XTR, and Tokuyama Universal). Specimens were bonded using either Clearfil SE Bond, OptiBond XTR or Tokuyama Universal, which were employed according to the manufacturer's instructions. Resin composite microcylinders were bonded using Tygon® tubes for µ-SBS testing. After specimens were stored for 24 h, at 37°C in distilled water, µ-SBS test was measured with a universal test machine (LF Plus, Lloyd, Instrument). µ-SBS results were analyzed by one-way analysis of variance (ANOVA) and Tukey's tests. RESULTS: When the mean microshear bond strength values of the control group were compared, the difference between the subgroups was not significant (P < 0.05). When the mean microshear bond strength values of the chx, ozonated water, and boric acid were compared, the difference between Clearfil SE Bond and Tokuyama Universal was significant (P < 0.05) and the difference between the other groups was not significant (P > 0.05). CONCLUSION: Ozonated water and boric acid may be as an alternative to other materials used as cavity disinfectants.