Browsing by Author "Murat, Sema"
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Article Citation Count: 69Comparison of Flexural Strength of Different CAD/CAM PMMA-Based Polymers(Wiley, 2019) Alp, Gulce; Murat, Sema; Yilmaz, BurakPurpose To compare the flexural strength of different computer-aided design/computer-aided manufacturing (CAD/CAM) poly(methyl methacrylate)-based (PMMA) polymers and conventional interim resin materials after thermocycling. Materials and Methods Rectangular-shaped specimens (n = 15, for each material) (25 x 2 x 2 mm(3)) were fabricated from 3 CAD/CAM PMMA-based polymers (Telio CAD [T]; M-PM-Disc [M]; Polident-PMMA [P]), 1 bis-acrylate composite resin (Protemp 4 [PT]), and 1 conventional PMMA (ArtConcept Artegral Dentine [C]) according to ISO 10477:2004 Standards (Dentistry-Polymer-Based Crown and Bridge Materials). The specimens were subjected to 10,000 thermocycles (5 to 55 degrees C). Three-point flexural strength of the specimens was tested in a universal testing machine at a 1.0 mm/min crosshead speed, and the flexural strength data (sigma) were calculated (MPa). The flexural strength values were statistically analyzed using 1-way ANOVA, and Tukey HSD post-hoc test for multiple comparisons (alpha = 0.05). Results Flexural strength values ranged between 66.1 +/- 13.1 and 131.9 +/- 19.8 MPa. There were significant differences among the flexural strengths of tested materials, except for between T and P CAD/CAM PMMA-based polymers (p > 0.05). CAD/CAM PMMA-based polymer M had the highest flexural strength and conventional PMMA had the lowest (p < 0.05). CAD/CAM PMMA-based T and P polymers had significantly higher flexural strength than the bis-acrylate composite resin (p < 0.05), and conventional PMMA (p < 0.0001), and significantly lower flexural strength compared to CAD/CAM PMMA-based M (p < 0.05). Conclusions The flexural strength of CAD/CAM PMMA-based polymers was greater than the flexural strength of bis-acrylate composite resin, which had a greater flexural strength compared to conventional PMMA resin.Article Citation Count: 66In Vitro Evaluation of Adhesion of Candida albicans on CAD/CAM PMMA-Based Polymers(Wiley, 2019) Murat, Sema; Alp, Gulce; Alatali, Canan; Uzun, MeltemPurpose To compare the amount of adherent Candida albicans to different CAD/CAM poly(methyl methacrylate) (PMMA)-based polymers and conventional heat-polymerized PMMA after long-term thermal cycling. Materials and Methods The specimens were subjected to 10,000 thermal cycles (5-55 degrees C) and divided into two groups, uncoated and pellicle-coated. Surface roughness and contact angles of the specimens were measured. The surface morphology was observed with scanning electron microscopy (SEM). An adhesion test was performed by incubating the disk specimens in C. albicans suspensions at 37 degrees C for 2 hours, and the adherent cells were counted under an optical microscope. The data were analyzed statistically using a variance analysis and Tukey HSD post hoc comparison test. The correlation between measurements was tested using a Pearson correlation analysis (alpha = 0.05). Results CAD/CAM polymers generally showed statistically significant lowest Ra and contact angle values, whereas conventional PMMA showed the highest Ra and contact angle values in the uncoated group (p < 0.05). Pellicle coating essentially increased contact angle of all materials and reduced the differences in a number of Candida cells on the materials (p < 0.05). Candida adhesion was statistically significantly greatest on conventional PMMA when compared to CAD/CAM polymers. A strong positive correlation was found between the surface roughness of the specimens (p < 0.05) and the amount of adhered cells, whereas no correlation was found between hydrophobicity of the specimens and the amount of adhered cells (p > 0.05). Conclusions CAD/CAM PMMA-based polymers may be preferable to reduce Candida-associated denture stomatitis in long-term use.