Staining Susceptibility Research Articles

COMMENTARY. effect of bleaching on staining susceptibility of resin composite restorative materials

COMMENTARY. <scp>effect of bleaching on staining susceptibility of resin composite restorative materials</scp>

Effects of Carbamide Peroxide on the Staining Susceptibility of Tooth-colored Restorative Materials

This study investigated the effects of an at-home bleaching gel containing 15% carbamide peroxide on the susceptibility of tooth-colored restorative materials to different staining solutions. The tooth-colored restoratives used in this study were a nano resin composite (Filtek Z350), a packable resin composite (Filtek P60), a polyacid-modified composite (Dyract AP) and a glass-ionomer cement (Ketac Molar Easymix). Each material was equally divided into two groups (n = 34): the bleaching group and the control group. This study included two treatment segments. In the first part (days 1-14), the specimens of the bleaching group were bleached with 15% carbamide peroxide gels for eight hours daily, while the specimens in the control group were stored in deionized water. Subsequently, four specimens from each group were randomly selected for observation under an environmental scanning electron microscope. In the second part (days 15-42), the samples were not bleached. Instead, they were stored in five different kinds of solutions. Color measurements for each sample were taken at six different time periods using a spectrophotometer. The data was then analyzed using SPSS statistical software. After two-weeks of bleaching, all the specimens showed statistically significant color changes compared with the control specimens. Furthermore, the bleaching agents seriously affected the surface morphology of Dyract AP and Ketac Molar Easymix. Following exposure to the staining solutions, it was found that the bleached restorative materials exhibited greater staining susceptibility than the control materials. Filtek Z350 and P60 exhibited the best color stability, while Dyract AP exhibited the least color stability.

Enamel susceptibility to red wine staining after 35% hydrogen peroxide bleaching

Concern has been expressed regarding the staining of enamel surface by different beverages after bleaching. This study investigated the influence of 35% hydrogen peroxide bleaching agents on enamel surface stained with wine after whitening treatments. Flat and polished bovine enamel surfaces were submitted to two commercially available 35% hydrogen peroxide bleaching agents or kept in 100% humidity, as a control group (n = 10). Specimens of all groups were immersed in red wine for 48 h at 37°C, immediately, 24 h or 1 week after treatments. All specimens were ground into powder and prepared for the spectrophotometric analysis. Data were subjected to two-way analysis of variance and Fisher's PLSD test at 5% significance level. The amount of wine pigments uptake by enamel submitted to bleaching treatments was statistically higher than that of control group, independently of the evaluation time. Results suggested that wine staining susceptibility was increased by bleaching treatments.

Effects of Thermal Cycling on Surface Texture of Restorative Composite Materials

The purpose of this study was to evaluate the effect of thermal cycling on the surface texture of restorative materials. Disk-shaped specimens made of seven resin composites (Beautifil: BF; Esthet-X: EX; Filtek Supreme: FS; Inten-S: IS; Point 4: PT; Solare: SR; and Venus: VS) were finished with 1-microm alumina suspension, and then thermocycled between 4 and 60 degrees C in distilled water for 20,000 or 50,000 cycles with a dwell time of 60 seconds. Staining susceptibility and mean surface roughness, Ra, were examined, and surface texture was observed by scanning electron microscopy. Dye penetration test showed that the surfaces of all resin composites were more stained after thermal cycling. Mean Ra of all resin composites, except PT, significantly increased after 50,000 thermal cycles. Dislodgement of filler particles was observed for all resin composites after thermal cycling, except FS. It was concluded that thermal cycling significantly affected the surface texture of the seven examined resin composites.

The Effect of 16 Percent Carbamide Peroxide on Enamel Staining Susceptibility

Recently, vital bleaching by carbamide peroxide has become more popular; therefore, it is necessary to study the effect of this agent on enamel and dentin. The purpose of this study was to evaluate the effect of a 16 percent carbamide peroxide bleaching gel, Vivastyle, on enamel staining susceptibility. Thirty bovine specimens were selected and randomly divided into two groups of 15. The experimental group was subjected to Vivastyle gel and then was immersed in coffee for half an hour daily for three weeks. The control group was only immersed in coffee. The teeth were evaluated using a colorimeter to measure L*, a*, b* of each tooth. Value (black to white) is denoted as L*, wheres chroma (a* b*) is denoted as red (+a*), green (_a*), yellow (+b*), and blue (_b*). Total color differences between two colors (deltaE) were calculated using the following formula: deltaE = [(deltaL*)2 + (deltaa*)2+(deltab*)2]: deltaE1.Bleached, AE2: bleached and immersed in coffee, deltaE3: immersed in coffee. Mean differences were: deltaE1 = 9.478, deltaE2 = 13.808 and deltaE3 = 7.230. Paired comparison by use of Duncan test showed there was a significant difference between deltaE1 and deltaE2 (P0.000); and t test showed there was no significant difference between deltaE3 and deltaE1. (P0.08 > 0.05), but deltaE3 showed a significant difference with deltaE2(P0.000). After vital bleaching, the enamel staining susceptibility significantly increased.

Effects of various finishing systems on the surface roughness and staining susceptibility of packable composite resins

Objectives: The purpose of the present study was to investigate the influence of various finishing systems on the surface roughness and staining of three packable resin composites and a conventional microhybrid one. Methods: Three packable composites (Solitaire—Heraeus-Kulzer, ALERT—Jeneric-Pentron, SureFil—Dentsply) and a conventional microhybrid (Z250—3M-ESPE) were used. Composite specimens were prepared and polished with Poli I and Poli II aluminum oxide pastes, Ultralap diamond paste, Enhance finishing points, Politip rubber polishers, fine and extra fine diamond burs, and 30-blade tungsten carbide burs according to the manufacturers' instructions. The polished surfaces were evaluated with a profilometer, and then immersed in 2% methylene blue for 24 h. Afterwards, the specimens were prepared for the spectrophotometric analysis. Results were statistically analyzed by ANOVA and Tukey test. Results: Significant differences were found for the surface roughness and staining recorded, with interaction among composite resins and the finishing systems used. No correlation was found between surface roughness and staining susceptibility ( p=0.5657). Significance: For most of the polishing agents used, Z250 presented the smoothest surfaces and the least dye uptake. ALERT presented the roughest surfaces, and Solitaire, the highest dye concentration. The smoothest surfaces were not necessarily the most stain resistant. Staining is highly influenced by each composite monomer and filler composition.

Brown Stain Susceptibility of Selected Lettuce Cultivars Under Controlled Atmospheres and Temperatures1,2

Abstract Laboratory tests of 11 cultivars of crisphead type lettuce (Lactuca sativa L.) indicated all were susceptible to brown stain. Susceptibility varied among cultivars, with ‘Great Lakes 66’, ‘Calmar’, ‘Valrio’, ‘Merit’ and ‘Great Lakes R-200’ the most susceptible and ‘Greenland’, ‘Climax’ and ‘Francisco’ the least affected. Storage temperature markedly influenced brown stain incidence: lettuce held at 0°C developed more brown stain than that held at 2.5°C. Development of the disorder required that lettuce be subjected to elevated CO2 in storage. Brown stain incidence for a given cultivar varied with date of harvest and production area.