Purpose:To evaluate the effect of adding Al 2 O 3 , SiO 2 , and TiO 2 nanoparticles in ratios of 1, 3, and 5 wt% to different acrylic resins on flexural strength. Materials and Methods: A total of 210 specimens were prepared in 30 groups (n = 7/group) (Control, 1% Al 2 O 3 , 3% Al 2 O 3 , 5% Al 2 O 3 , 1% SiO 2 , 3% SiO 2 , 5% SiO 2 , 1% TiO 2 , 3% TiO 2 , 5% TiO 2 ). The specimens were polished with 200-, 400-, and 600-grit abrasive paper to provide a standard surface before testing and then suspended in distilled water for 30 days. Flexural strength was measured via three-point bending tests. Subsequently, SEM analysis was performed for one specimen from each group. Homogeneity of data was assessed by Kolmogov-Smirnov test followed by two-way ANOVA and Tukey HSD tests (α = 0.05). Results: There was a significant increase in the flexural strength of polymethylmethacrylate (PMMA) after addition of 1% nanoparticles in both heat-polymerized and autopolymerized acrylic resins (p ˂ 0.05). The flexural strength values of the groups to which Al 2 O 3 and TiO 2 nanoparticles were added exceeded those of the group with SiO 2 addition (p ˂ 0.05). The electron microscopy images revealed that the nanoparticles were more homogeneously dispersed in PMMA with higher flexural strength.
Conclusions:The mechanical properties of PMMA can be improved by the addition of nanoparticles to PMMA; however, the flexural strength values of PMMA decrease with the addition of nanoparticles at higher percentages (3-5%). Hence, the ideal filler ratio corresponds to 1%.
Objective. To determine the influence of the home bleaching agent, Opalescence PF, on the surface roughness and microhardness of glazed glassy matrix CAD-CAM ceramics. Materials and Methods. The 28 sintered leucite- and lithium disilicate-reinforced ceramic specimens (IPS Empress CAD and IPS e.max CAD) were divided into control and bleached groups. The home bleaching agent was applied to specimens of bleached groups for 7 days. The surface roughness and microhardness of all specimens were measured. A scanning electron microscope was used to evaluate the surface properties. The data were statistically analyzed by two-way ANOVA. Results. The control e.max CAD showed the lowest surface roughness values. For both Empress and e.max CAD, surface roughness was significantly higher for the bleached group (p<0.05). No significant differences in microhardness were observed. Conclusions. According to our study, patients should be careful when using home bleaching agents because whitening agents can affect the mechanical properties of full ceramic restorations like e.max CAD and Empress CAD. Ceramic polishing may be required in clinical situations where ceramic restorations are accidentally exposed to bleaching gels.
According to our study, patients who have all-ceramic restorations in their mouths should be careful when using home bleaching agents, because whitening agents can affect the translucency of all-ceramic restorations such as e.max CAD and Empress CAD.
Amaç: Dört farklı geçici materyalin 3 farklı sıvıda kısa dönem bekletme sonunda renk ve yüzey pürüzlülük değişiminin incelenmesidir. Gereç ve Yöntem: Bu çalışmada disk şeklinde 4 farklı geçici materyal (Whitepeaks CopraTemp, Integra, Triad, Systemp.c&b II) (renk: A2) kullanıldı (n=15). Hazırlanan materyaller 37°C'deki distile suda 24 saat süre bekletildikten sonra, tüm örneklerin başlangıç renk ve yüzey pürüzlülük değerleri ölçüldü. Her bir geçici materyal daha sonra bekletilecek sıvı tipine göre 3 alt gruba (distile su (kontrol), çay, kahve) ayrıldı (n=5). Örnekler 37ºC'deki ilgili sıvılarda 48 saat süre bekletildikten sonra, tüm örneklerin renk ve yüzey pürüzlülük değerleri tekrar ölçüldü. Materyallerin 48 saat sonraki renk değişim değerleri iki yönlü varyans analizi (ANOVA) ile incelendi. Başlangıç yüzey pürüzlülük değerleri tek yönlü ANOVA ile incelendi. Kırk sekiz saat bekletme sonrası yüzey pürüzlülük değerleri ve yüzey pürüzlülük fark değerleri iki yönlü ANOVA ile incelendi (p=0,05). Bulgular: Geçici materyallerin 48 saat sonraki renk değişimini sadece sıvı tipi anlamlı olarak etkilemiştir (p=0,000). Yüzey pürüzlülük fark değerleri materyal ve sıvı tipi etkileşiminden etkilenmiştir (p=0,001). Bilgisayar destekli tasarım ve üretim sistemi (CAD/CAM) ile üretilen geçici materyal (Whitepeaks CopraTemp), diğer geçici materyaller ile karşılaştırıldığında en az pürüzlülük değişim değeri göstermiştir (p≤0,005). Sonuç: Geçici materyallerin renk ve yüzey pürüzlülük değişim sonuçları beraber değerlendirildiğinde, CAD/CAM sistemi ile üretilen geçici materyal diğer geçici materyallere göre tercih edilebilir.
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