Aim: Both conventional and flexible resins may show color alteration due to intrinsic and extrinsic factors. The aim of this study was to evaluate the color changes of the polyamid and heat polymerized acrylic denture...Aim: Both conventional and flexible resins may show color alteration due to intrinsic and extrinsic factors. The aim of this study was to evaluate the color changes of the polyamid and heat polymerized acrylic denture base materials in storage of different staining solutions. Methods: Two denture base materials were used in this study. The speciemens were stored in two staining solutions (tea, coffee), distilled water and denture cleaner. For each group, 14 speciemens (25 × 15 × 2.5 mm) were prepared. The color of speciemens was measured using a colorimeter according to the CIE L*a*b* color scale. The color changes of speciemens were evaluated before and after 7 and 30 days. All data recorded were taken by the same investigator to minimize inconstancy of technique. The data were analyzed statistically by repeated measures analysis of variance and Tukey honestly significant difference multiple comparison tests. It was found no statistically significant difference between solutions (P > 0.05). Results: Polyamid denture base resin displayed the greatest colour change when compared to polymetyhl methacrylate denture base resin (P < 0.001). Polyamid material indicated the highest value (ΔE: 7.28) in coffee solution for 7 days. Significance: The colour stability of polymetyhl methacrylate denture base resin is greater than polyamid denture base resin.展开更多
This study aimed to evaluate the effect of natural weathering on some surface characteristics and mechanical properties of Styrax wood treated with mixtures of 1.0%,2.0%,or 4.0%rosin sizing agent and 3%copper sulfate....This study aimed to evaluate the effect of natural weathering on some surface characteristics and mechanical properties of Styrax wood treated with mixtures of 1.0%,2.0%,or 4.0%rosin sizing agent and 3%copper sulfate.Wood samples after treatment were exposed to outdoor conditions for one year and changes in color,glossiness,weight loss,compression strength parallel to grain(CSPG),modulus of rupture(MOR),and modulus of elasticity(MOE)were investigated after 6 and 12-month of natural weathering.The results showed that rosin-copper treatment could improve color stability and gloss of samples after weathering.Mass losses of all rosin-copper treated samples after 12 months of exposure were negligible compared with the untreated control samples.In addition,rosin-copper treatment enhanced the CSPG compared to untreated controls,but slightly decreased the MOR and MOE of Styrax wood before weathering.Natural weathering factors induced a reduction for all strength properties,however,the decrease rate for strength properties of rosin-copper treated samples was negligible compared with the untreated control samples after 12-month natural weathering exposure.The FTIR and SEM-EDX confirmed that the use of the rosin-copper formulations to impregnate wood could decrease the hazard of the copper preservative leaching into the environment,while also enhancing more resistance against weathering factors and other biotic factors.展开更多
基金This work was supported by funds from the Department of Science and Technology,Guangdong Province(2010B020313001)The Earmarked Fund for China Agriculture Research System(CARS-36),Ministry of Agriculture,PR China.
基金supported financially by the Department of Scientific Research Projects of Ataturk University(Project No.2003/158)and(Project no.2010/141).
文摘Aim: Both conventional and flexible resins may show color alteration due to intrinsic and extrinsic factors. The aim of this study was to evaluate the color changes of the polyamid and heat polymerized acrylic denture base materials in storage of different staining solutions. Methods: Two denture base materials were used in this study. The speciemens were stored in two staining solutions (tea, coffee), distilled water and denture cleaner. For each group, 14 speciemens (25 × 15 × 2.5 mm) were prepared. The color of speciemens was measured using a colorimeter according to the CIE L*a*b* color scale. The color changes of speciemens were evaluated before and after 7 and 30 days. All data recorded were taken by the same investigator to minimize inconstancy of technique. The data were analyzed statistically by repeated measures analysis of variance and Tukey honestly significant difference multiple comparison tests. It was found no statistically significant difference between solutions (P > 0.05). Results: Polyamid denture base resin displayed the greatest colour change when compared to polymetyhl methacrylate denture base resin (P < 0.001). Polyamid material indicated the highest value (ΔE: 7.28) in coffee solution for 7 days. Significance: The colour stability of polymetyhl methacrylate denture base resin is greater than polyamid denture base resin.
基金the support of the Vietnam National Foundation for Science and Technology Development(NAFOSTED)[Grant No.106.99-2018.16].
文摘This study aimed to evaluate the effect of natural weathering on some surface characteristics and mechanical properties of Styrax wood treated with mixtures of 1.0%,2.0%,or 4.0%rosin sizing agent and 3%copper sulfate.Wood samples after treatment were exposed to outdoor conditions for one year and changes in color,glossiness,weight loss,compression strength parallel to grain(CSPG),modulus of rupture(MOR),and modulus of elasticity(MOE)were investigated after 6 and 12-month of natural weathering.The results showed that rosin-copper treatment could improve color stability and gloss of samples after weathering.Mass losses of all rosin-copper treated samples after 12 months of exposure were negligible compared with the untreated control samples.In addition,rosin-copper treatment enhanced the CSPG compared to untreated controls,but slightly decreased the MOR and MOE of Styrax wood before weathering.Natural weathering factors induced a reduction for all strength properties,however,the decrease rate for strength properties of rosin-copper treated samples was negligible compared with the untreated control samples after 12-month natural weathering exposure.The FTIR and SEM-EDX confirmed that the use of the rosin-copper formulations to impregnate wood could decrease the hazard of the copper preservative leaching into the environment,while also enhancing more resistance against weathering factors and other biotic factors.
