The Effects of Mouthwashes on the Color Stability of Resin-Based Restorative Materials / Efecto de los enjuagues orales en la estabilidad del color de materiales restauradores a base de resina

Abstract: Objective: This study investigated the effects of three types of mouthwash on the color stability of three resin-based restorative materials (nanohybrid resin composite, sonic-activated bulk-fill material, and compomer). Materials and Methods: To this end, 120 cylindrical disc specimens were prepared and polished, after which they were incubated in distilled water for 24 hours for post-polymerization. The baseline color values of each specimen were measured with a spectrophotometer, then the specimens were randomly divided into four groups. Following immersion in the mouthwashes for 24 hours, the specimens were rinsed with distilled water and dried before the color measurement was repeated. The values of color change (ΔE₀₀) were subsequently calculated. A two-way analysis of variance and Duncan's post hoc multiple comparison tests were conducted to determine statistically significant differences among the restorative materials. Results: All samples showed discoloration after immersion, albeit some instances of discoloration were imperceptible. In this respect, a statistically significant difference was found among the restorative materials and mouthwashes (p<0.05). Imperceptible ΔE₀₀ values were derived on the nanohybrid resin composite and compomer, but perceptible and acceptable ΔE₀₀ values were detected on the sonic-activated bulk-fill materials (p<0.05). The clinically unacceptable discoloration was observed on the sonic-activated bulk-fill composite immersed in Listerine®. Conclusions: Clinicians should make recommendations based on the potential staining capacity of mouthwashes prescribed for daily use in restorative materials. In this way, the need for renewal of restorations due to discoloration could be avoided.

Resumen: Objetivo: Este estudio investigó los efectos de tres tipos de enjuague bucal en la estabilidad del color de tres materiales de restauración a base de resina (resina nanohíbrida, resina bulk-fill de activación sónica y compómero). Materiales y Métodos: Para ello se prepararon y pulieron 120 muestras de discos cilíndricos, después de lo cual se incubaron en agua destilada durante 24 horas pospolimerización. Los valores de color de base de cada muestra se midieron con un espectrofotómetro, después las muestras se dividieron aleatoriamente en cuatro grupos. Tras la inmersión en los enjuagues bucales durante 24 horas, los especímenes se enjuagaron con agua destilada y se secaron antes de repetir la medición del color. Posteriormente se calcularon los valores de cambio de color (ΔE₀₀). Se llevó a cabo un análisis bidireccional de la varianza y las pruebas de comparación múltiple post hoc de Duncan para determinar las diferencias estadísticamente significativas entre los materiales de restauración. Resultados: Todas las muestras mostraron decoloración después de la inmersión, aunque algunos casos esta fue imperceptible. Se encontró una diferencia estadísticamente significativa entre los materiales de restauración y los enjuagues bucales (p<0,05). Se obtuvieron valores imperceptibles de ΔE₀₀ en el compuesto de resina nanohíbrida y el compómero, pero se detectaron valores perceptibles y aceptables de ΔE₀₀ en la resina bulk-fill activada sónicamente (p<0,05). Se observó una decoloración clínicamente inaceptable en la resina bulk-fill activada sónicamente inmersa en Listerine®. Conclusiones: Los clínicos deben hacer recomendaciones basadas en la capacidad potencial de coloración de los enjuagues bucales prescritos para uso diario en los materiales de restauración. De esta manera, se podría evitar la necesidad de renovar las restauraciones debido a la decoloración.

Determination and Analysis of Chromatic Value in Abnormal Red Tongue Tip / 中国中医药信息杂志

Objective To measure the chromatic differences of the tongue tip and tongue side and provide quantitative evidence for tongue color diagnosis. Methods Totally 683 healthy people were recruited, and their tongue photos were taken. Then ICC specific documents were used for the correction of all tongue photos, and chromatic values (L*, a*, b*, C*and h°) of tongue tip and tongue side were obtained for further statistical analysis. CIEDE2000 was used for calculating the color differences. Results The average color difference of tongue tip and tongue side in normal pink tongue was 5.4. When pink tongue has abnormal red tongue tip, the average color difference of tongue tip and tongue side was 10.85. Compared with normal tongue tip, the average color difference of tongue tip and tongue side in abnormal color tongue with abnormal red tongue tip increased from 5.4-7.0 to 11.23. Conclusion Red tongue tip is a sensitive sign indicating abnormal heat in the body. Tongue tip quantitative diagnosis is valuable in the determination of heat sign in TCM preventive treatment of disease, and reveal the diagnosis meaning and scientific connotation of red tongue tip.

A Comparison of the Bleaching Effectiveness of Chlorine Dioxide and Hydrogen Peroxide on Dental Composite

This study was carried out to verify if composites could be bleached using chlorine dioxide as compared with hydrogen peroxide. 3M ESPE Filtek Z350 Universal Restorative discs were prepared (n=40), with dimensions 5 mm diameter x 2 mm thickness. The discs were divided into 4 groups of 10 discs each. Color assessment was performed by CIEDE2000. The discs were stained with coffee, tea, wine and distilled water (control) solutions for 14 days, 5 hours daily. Color assessment was repeated on stained discs and followed by bleaching of 5 discs from each group using chlorine dioxide and hydrogen peroxide in-office systems. Finally, a last color assessment was performed and compared statistically. DE2000 after bleaching was very close to baseline for both the bleaching agents, although chlorine dioxide showed better results than hydrogen peroxide. After staining, there was a clinically significant discoloration (∆E2000≥3.43) for the tea, coffee and wine groups, and discoloration (∆E2000) was seen more in the wine group as compared to tea and coffee. Overall, the control group (distilled water) had the least color change in the three intervals. After bleaching, the color in all specimens returned close to the baseline. The color differences between bleaching and baseline were less than 3.43 for all groups. The obtained results show that chlorine dioxide is slightly superior to hydrogen peroxide in the bleaching of composites, while maintaining the shade of the composite close to the baseline.

Este estudo foi realizado para verificar se resinas compostas podem ser clareadas com uso do dióxido de cloro, em comparação com peróxido de hidrogênio. Foram preparados discos com resina restauradora Filtek Z350 3M ESPE (n=40), com dimensões 5 mm de diâmetro × 2 mm de espessura. Os discos foram divididos em 4 grupos de 10 discos cada. A avaliação da cor foi realizada por meio do CIEDE2000. Os discos foram manchados com soluções de café, chá, vinho e água destilada (controle) por 5 h diárias durante 14 dias. A avaliação da cor foi repetida nos discos manchados e seguida por clareamento de 5 discos de cada grupo, utilizando dióxido de cloro ou peróxido de hidrogênio pela técnica de consultório. Finalmente, uma última avaliação da cor foi realizada e as técnicas comparadas estatisticamente. DE2000 após o clareamento foi muito próxima ao baseline, para ambos os agentes clareadores, embora o dióxido de cloro tenha mostrado melhores resultados do que o peróxido de hidrogênio. Após o manchamento, houve uma descoloração clinicamente significativa (ΔE2000≥3,43) para os grupos de chá, café e vinho, sendo que o clareamento (ΔE2000) foi melhor obtido com o grupo do vinho, em comparação com chá e café. No geral, o grupo controle (água destilada) teve a menor mudança de cor nos três intervalos. Após o clareamento, a cor em todos os espécimes voltou próxima ao baseline. As diferenças de cor entre o clareamento e o baseline foram inferiores a 3,43 para todos os grupos. Os resultados indicam que o dióxido de cloro é ligeiramente superior ao peróxido de hidrogênio no clareamento de resinas compostas, mantendo a cor próxima à escala do baseline.