Effect of whitening mouth rinses on the chemical and physical properties of a nanofilled composite

Aim: This study analyzed the effect of whitening mouth rinses on water sorption (WS), solubility (SL), color change, and surface roughness of a nanofilled composite. Whitening perceptibility and acceptability (WID) were also studied. Methods: Forty specimens of Filtek Z350XT, shade EA2 were produced and randomly distributed (n=8) to AS ­ artificial saliva (control); LWE ­ Listerine Whitening Extreme; CLW ­ Colgate Luminous White; LCM ­ Listerine Cool Mint; and CP ­ Colgate Plax. They were immersed in the mouth rinses 2x/day, for one minute, during 28 days. The color was assessed using an Easyshade spectrophotometer (CIE-L*a*b* system). Surface roughness (Ra-µm) was measured with three parallel measures, using an RP-200 roughness meter. The WS and SL (µg/mm-3) were analyzed based on the ISO 4049 recommendations. The data were analyzed using one- and two-way ANOVA/Tukey tests (α=0.05). Results: Surface roughness significantly increased after immersion in AS and LCM, with no significant differences between the groups either before or after immersion. The ΔE* was not significantly different between the groups. All substances produced a ΔWID higher than the 50%:50% perceptibility and acceptability thresholds. The WS and SL were not significantly affected by the mouth rinses. Conclusion: Whitening mouth rinses did not affect WS, SL, surface roughness, and color stability of a nanofilled composite, regardless of the presence of ethanol in the composition

Diferença de cor entre resinas compostas de marcas comerciais diferentes / Color difference between composites of different commercial brands

Este estudo avaliou a cor de duas resinas compostas universais produzidas por diferentes fabricantes. Noventa e seis espécimes das resinas compostas Filtek Z350XT (3M ESPE) e IPS Empress Direct (Ivoclar Vivadent) (n=48 cada) da cor A2E foram confeccionados com 5 mm de diâmetro X 6 mm de altura. Cada camada de 2 mm de espessura de resina inserida foi fotoativada com uma unidade fotoativadora LED com 900 mW/cm2 por 20 s. Os espécimes foram polidos com o sistema Sof-lex Pop-On (3M ESPE). A cor foi aferida com um espectrofotômetro digital portátil Easyshade (Vita Zahnfabrik, Bad Säckingen), com base nos eixos tridimensionais do sistema CIEL*a*b*, e sua diferença entre as resinas foi determinada em cada eixo, calculando o seu respectivo Δ (ΔL*, Δa* e Δb*) e os parâmetros de variação total de cor ΔE* e ΔE00. A diferença de cor entre as resinas em cada eixo foi analisada estatisticamente pelo Teste t de amostras independentes (α=0,05), além de considerar os limiares de 50%:50% de perceptibilidade e aceitabilidade da variação total de cor. Diferenças estatisticamente significativas foram observadas no ΔL* e no Δb* (p<0,001). Os valores de ΔE foram de três a quatro vezes superiores ao limite de perceptibilidade e em até duas vezes ao limite de aceitabilidade da variação total de cor. Verificou-se que diferenças importantes de cor podem ocorrer em resinas da mesma cor, porém, de fabricantes diferentes. Essas diferenças podem ser visualmente perceptíveis e acima dos limites de aceitabilidade, podendo comprometer o resultado estético da restauração.(AU)

This study assessed the color of two universal composites produced by different manufacturers. Ninety-six specimens of Filtek Z350XT (3M ESPE) and IPS Empress Direct (Ivoclar Vivadent) (n=48 each) colored A2E were made with 5 mm of diameter X 6 mm of height. Each 2 mm-thick composite layer inserted was light cured with a LED light curing unit with 900 mW/cm2 for 20 s. The specimens were polished with Sof-lex Pop-On (3M ESPE). The color was measured with a portable digital spectrophotometer Easyshade (Vita Zahnfabrik, Bad Säckingen) based on the tridimensional axes of the CIEL*a*b* system, and the difference between composites was determined in each axis by determining the respective Δs (ΔL*, Δa* e Δb*), along with the parameters for total color variation ΔE* and ΔE00. The color difference between composite in each axis was analyzed statistically using the t-test (α=0,05), besides considering the 50%:50% thresholds for visual perceptibility and acceptability of total color variation. Statistically significant differences were observed in ΔL* and Δb* (p<0.001). The ΔE values were three to four times higher than the perceptibility threshold and twice higher than the acceptability threshold for total color variation. Relevant color differences may occur in composites of the same color, yet, made by different manufacturers. These differences may be visually perceptible and higher than acceptance limits, and may compromise the esthetic result of dental restorations.(AU)