RESUMEN
OBJECTIVE: The purpose of this study was to evaluate the effects of a shade-matching light (Rite-Lite-2, AdDent) and different viewing backgrounds on reliability in a test of shade tab matching. MATERIALS AND METHODS: Four members of the Prosthodontic faculty matched 10 shade tabs selected for a range of shades against the shade guide. All raters were tested for color blindness and were calibrated prior to the study. Matching took place under four combinations of conditions: with operatory light or the shade-matching light, and using either a pink or a blue background. Reliability was quantified with the kappa statistic, separately for agreement of value, hue, and chroma for each shade tab. RESULTS: In general, raters showed fair to moderate levels of agreement when judging the value of the shade tabs, but could not agree on the hue and chroma of the stimuli. The pink background led to higher levels of agreement than the blue background, and the shade-matching light improved agreement when used in conjunction with the pink but not the blue background. CONCLUSIONS: Moderate levels of agreement were found in matching shade tab value. Agreement was generally better when using the pink rather than the blue background, regardless of light source. The use of the shade-matching light tended to amplify the advantage of the pink background.
Asunto(s)
Diseño de Prótesis Dental/métodos , Coloración de Prótesis , Adulto , Anciano , Humanos , Persona de Mediana Edad , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: Failures such as marginal discoloration and composite chipping are still the problems of tooth-colored restorations on the substrate of enamel and porcelain, which some of these problems are consequently as a result of failures in the bonding layer. Using filled resin has been recently introduced to increase the bond strength of this layer. The aim of this study was to compare the microshear bond strength (µ-SBS) of composite resins to enamel incubated in periods of 24 h and 9 months and porcelain with unfilled resin and flowable composites (filled resin). MATERIALS AND METHODS: In this in vitro study, two groups of 75 enamel samples with different storage times (24 h and 9 months) and a group of 75 porcelain samples were used. They were divided into 5 experimental groups of 15 samples in each. Composite cylinders in tygon tubes were bonded on the surface of acid-etched enamel and pretreated porcelain. Wave, Wave MV, Wave HV, Grandioflow and Margin Bond were used as bonding agents. The µ-SBS was measured at the speed of 1.0 mm/min. The bond strengths were analyzed with one-way analysis of variance (ANOVA) test followed by Tukey test. P < 0.05 was selected as the level of statistical significance in this study. RESULTS: The results showed that for enamel (24 h), the µ-SBS of the Wave MV and Wave HV groups were significantly lower than the Margin Bond group. Tukey test indicated the absence of a significant difference between the µ-SBS of the Wave group and the Margin Bond group. However, the µ-SBS of the Grandioflow group was significantly higher than the one for the Margin Bond as a bonding agent. In enamel (9 months), there was a significant difference between the Grandioflow and Margin Bond groups. Regarding bonding to the porcelain the one-way ANOVA test did not show a significant difference among the groups. CONCLUSION: This study revealed that flowable composites (filled resins) can be used instead of unfilled resins in bonding composite resins to enamel and porcelain substrates.