Person: ÖZYILMAZ, ÖZGÜN YUSUF
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Publication Open Access Effect of cleansers on denture base resins- structural properties(2019-02-01) Ozyilmaz, Ozgun Yusuf; Akin, Ceyda; ÖZYILMAZ, ÖZGÜN YUSUFIntroduction: We assessed the effect of different available denture cleansers on the roughness and hardness of polyetherketoneketone, thermoinjection-molded polyamide, and polymethylmethacrylate. Materials and Methods: A total of 150 disc-shaped specimens were fabricated (10 mm × 2 mm) from these three denture base resins, and divided into five subgroups (n = 10) according to immersion procedures. One of these groups subjected to distilled water served as control, whereas other groups were subjected to daily cleansing with four denture cleansers (Corega, Protefix, Curaprox, and Perlodent) for 8 h a day for 140 days. The surface roughness and hardness values of specimens were recorded by measuring twice at baseline, and again after application of chemical solutions. Topography alterations after treatments were assessed with scanning electron microscopy. The data were subjected to statistical analysis and comparison among groups was done using Kruskal Wallis and Wilcoxon Signed Ranks tests. P-value <0.05 was considered significant. Results: The surface roughness of polyetherketoneketone, polymethylmethacrylate, and polyamide dentures was increased significantly by chemical solutions of denture cleansers. While the hardness value of polyetherketoneketone was not affected significantly after immersion in denture cleansers, those of polymethylmethacrylate and polyamide decreased significantly. Compared with Curaprox, the effervescent tablets significantly altered the surface hardness and roughness of polyamide. Conclusion: Denture cleansers can considerably alter the surface roughness and hardness of denture base resins and should be used carefully depending on the material.Publication Metadata only Temperature rises during tooth bleaching with different light-curing units(2015-08-03T00:00:00Z) Ozyilmaz, Ozgun Yusuf; Yavuz, Tevfik; SARI, Tugrul; Aykent, Filiz; Ozturk, Atiye Nilgun; ÖZYILMAZ, ÖZGÜN YUSUFThe aim of this study was to evaluate the influence of three different light-curing units on the temperature rise induced in the pulpal cavity, when bleached with 35% hydrogen peroxide (HP). Forty extracted maxillary central incisors were randomly divided into four groups according to photoactivation procedure (n=10). Whiteness HP (WHP) bleaching agent which contains 35% HP bleach was placed on the facial tooth surface and no photoactivation device was used (control); an blue light-emitting diode (LED, 40s), a diode laser (4W, Continous mode, 20s), and Nd:YAG laser (4W, 60Hz frequency, 20s). Temperature rise in the pulpal chamber was measured with a J-type thermocouple wire that was connected to a data logger before and immediately after each 20-40s application. One tooth of each group was selected for scanning electron microscope analysis. Data were analyzed using one-way ANOVA followed by the Games Howell post hoc test at a preset alpha of 0.05. One-way ANOVA revealed that there was a significant difference among the light-curing units (p<0.05) and between control group and light-curing units (p<0.05). The Nd:YAG induced significantly, which resulted in higher temperature increase than other light-curing units (10.7 degrees C). The LED unit produced the lowest temperature changes (3.2 degrees C) among the light-curing units. The presence of the bleaching gel did not cause a temperature increase in control group (0 degrees C). The results suggested that using light-curing units caused temperature changes in the intrapulpal cavity during tooth bleaching. The use of LED will be more safer for pulpal health when assisted with WHP bleaching gel.Publication Metadata only Effect of Nd:YAG Laser Bleaching and Antioxidizing Agents on the Shear Bond Strength of Brackets(2013-08-01T00:00:00Z) Akin, Mehmet; Ozyilmaz, Ozgun Yusuf; Yavuz, Tevfik; Aykent, Filiz; Basciftci, Faruk Ayhan; ÖZYILMAZ, ÖZGÜN YUSUFObjective:The aims of this study were to evaluate the effect of hydrogen peroxide bleaching agents, both nonactivated and activated by a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, and of antioxidant treatment on the shear bond strength (SBS) of orthodontic brackets. Background data:Nd:YAG laser activation is expected to accelerate the bleaching therapy without decrease shear bond strength. Materials and methods: Ninety extracted maxillary central incisors were divided into two experimental groups and a control group. Group I was the control group, Group II was bleached with 35% hydrogen peroxide and had no photoactivation, and Group III was bleached with 35% hydrogen peroxide with activation by a Nd:YAG laser (4.0 W, 60 Hz frequency, 1mm distance, 20 sec). Each group was divided into two subgroups:Subgroup A was immersed in artificial saliva for 2 weeks, and then bonded using the total etch system, whereas subgroup B was treated with an antioxidant agent (10% sodium ascorbate) and then bonded using the same system. The samples were stored in water for 24 h at 37 degrees C, and thermocycled. The SBS in megapascals (MPa) was determined by a shear test with 1mm/min crosshead speed, and failure types were classified with modified adhesive remnant index scores. The data were analyzed with two way analyses of variance, Tukey, and chi(2) tests at the alpha = 0.05 level. Results:In both Groups II and III, the SBSs of brackets bonded after bleaching (Group II 15.16, Group III 17.50 MPa) were significantly lower than those of brackets in the bonded unbleached group (Group I 22.13MPa); however, sodium ascorbate treatment significantly increased the SBSs of brackets in the bleached groups (Group II 21.52, Group III 22.43MPa), but had an insignificant effect on the SBS of the control group (Group I 23.66MPa). Conclusions: Hydrogen peroxide bleaching agents reduce the SBSs both with and without Nd:YAG laser activation; however, treatment of the bleached enamel surface with 10% sodium ascorbate prior to bonding negates the effect.Publication Metadata only Impact of intracanal calcium hydroxide or triple antibiotic paste on bond strength of root canal sealers: An in Vitro study(2016-01-01T00:00:00Z) GÜNDOĞAR, Mustafa; ERKAN, Erhan; Ozyilmaz, Ozgun Yusuf; ÖZYILMAZ, ÖZGÜN YUSUFPublication Metadata only Effect of Different Surface Treatments on Porcelain-Resin Bond Strength(2017-07-01T00:00:00Z) Yavuz, Tevfik; Ozyilmaz, Ozgun Yusuf; DİLBER, Erhan; Tobi, Elif Sumeyye; Kilic, Hamdi Sukur; ÖZYILMAZ, ÖZGÜN YUSUFPurpose:The aim of this study was to evaluate the effects of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics.Publication Metadata only Effect of sodium ascorbate on the bond strength of silorane and methacrylate composites after vital bleaching.(2013-07-01T00:00:00Z) Guler, Eda; Gonulol, Nihan; Ozyilmaz, Ozgun Yusuf; Yucel, Ali Cagin; ÖZYILMAZ, ÖZGÜN YUSUFWe investigated the effect of sodium ascorbate (SA) on the microtensile bond strengths (MTBSs) of different composites to bovine enamel after vital bleaching with hydrogen peroxide (HP) or carbamide peroxide (CP). Thirty bovine incisors were randomly divided into five groups and treated with no bleaching application (control), 35% HP alone, 35% HP + 10% SA for 10 minutes (HP + SA), 16% CP alone, or 16% CP + 10% SA for 10 minutes (CP + SA). Specimens were restored with Silorane adhesive and Filtek Silorane composite (designated as S/group) or with Clearfil SE bond and Filtek Supreme XT (designated as F/group). Composite build-up was created on the enamel. Sectioned specimens (n = 10 per group; 1 mm(2) cross-sectional area) were created and stressed in a universal testing machine at 1 mm/min crosshead speed. The application of 10% SA immediately after bleaching with 16% CP or 35% HP increased the enamel MTBS, regardless of the adhesive/composite resin used. The resulting MTBS values were similar to those of the control groups. Use of 16% CP and 35% HP alone decreased the enamel MTBS, regardless of the adhesive/composite resin used, with F/CP + SA F/HP + SA F/CP = S/CP + SA = S/HP + SA = S/C > S/CP = S/HP = F/CP = F/HP (p < 0.05). We concluded that the application of SA for 10 minutes immediately after vital bleaching increases the enamel BS for dimethacrylate- and silorane-based composites.