Browsing by Author "Gul, Pinar"

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Effects of Composite Restorations on Oxidative Stress in Saliva: an in Vivo Study
(Elsevier Taiwan, 2015) Gul, Pinar; Akgul, Nilgun; Alp, Hamit Hakan; Kiziltunc, Ahmet
Background/purpose: This study is aimed at detecting and quantifying monomers from dental composite filling materials and investigating effects of the released monomers in saliva malondialdehyde (MDA) levels and in two antioxidant enzyme levels after dental composite filling materials were applied to healthy volunteers. Materials and methods: Fifty-two individuals (32 female and 20 male) participated in the research study. Saliva samples were collected in scheduled time intervals and MDA, superoxide dismutase, and glutathione peroxidase levels were measured. In addition, saliva samples were collected in order to quantify triethyleneglycol dimethacrylate, hydroxyethyl methacrylate, bisphenol-A diglycidyl methacrylate, and urethane dimethacrylate using high-performance liquid chromatography. Statistical analysis of obtained data was performed by repeated measures variance analysis. A P value <0.05 was considered as statistically significant. Results: As a result of the statistical analysis, the MDA and glutathione peroxidase levels measured at all time intervals were significantly higher when compared to the baseline levels (P < 0.05). Superoxide dismutase values measured after 7 days showed a statistically significant decrease (P < 0.001). The residual monomer levels showed a significant increase within 7 days, and the maximum amount of release was observed generally in the 7-day period, and the release in monomers except for bisphenol-A diglycidyl methacrylate showed a significant decrease in 30 days (P < 0.05). Conclusion: Because of monomer release after the restoration process and also differences in antioxidant enzyme activity, composite materials may lead to oxidative stress. Copyright (C) 2014, Association for Dental Sciences of the Republic of China. Published by Else-vier Taiwan LLC. All rights reserved.
Lipid Peroxidation and Dna Oxidation Caused by Dental Filling Materials
(Elsevier Taiwan, 2017) Yildiz, Mehmet; Alp, Hamit Hakan; Gul, Pinar; Bakan, Nuri; Ozcan, Mutlu
Background/purpose: The two direct dental restorative materials most commonly used today are silver-mercury amalgam and resin-based composites. The purpose of this study was to examine the effects of these two restorative materials and substances released by these into the oral environment on lipid peroxidation and DNA oxidation after entering the blood circulation. Materials and methods: Blood samples from 41 patients were collected before and 24 hours after the application of these restorative materials. The 8-hydroxydeoxyguanosine/deoxyguanosine ratio in these samples was measured to determine oxidative DNA damage, and malondialdehyde levels were measured to define lipid peroxidation. The paired samples t test and Pearson correlation analysis were used for the analysis of variables (alpha = 0.05). Results: While no statistically significant difference was observed after amalgam filling application in terms of DNA oxidation, a significant difference was observed after composite application (P < 0.05). Furthermore, a significant increase was determined in malondialdehyde levels of two materials (P < 0.05). In both amalgam and composite applications, a significant difference was observed before and after application in terms of released substances (mercury and unpolymerized monomer, respectively, P < 0.001). Conclusion: Mercury increased lipid peroxidation and Bis-GMA and TEGDMA dental resins increased both lipid peroxidation and DNA oxidation markers. (C) 2017 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.
Monomer Release From Bulk-Fill Composite Resins in Different Curing Protocols
(Nihon Univ, School dentistry, 2020) Gul, Pinar; Alp, Hamit H.; Ozcan, Mutlu
The purpose of this study was to determine the depth of cure and the type and amount of monomers released from bulk-fill composites in different curing protocols. Five different composite resins Filtek Bulk-Fill Posterior, Filtek Bulk-Fill Flowable, SureFil SDR, X-tra Fil, and X-tra base. were used. A light-emitting diode (LED) device was used in 3 different modes (standard, high power, and extra power mode), and a halogen light device was also used as a control. Surface hardness was measured and the depth of cure was calculated. Monomer analysis was performed using high performance liquid chromatography (HPLC). The data were analyzed using Tamhane's T2 post-hoc test (alpha = 0.05). The cure depth for all materials except for Filtek Bulk-Fill Posterior (extra power mode) and Filtek Bulk-Fill Flowable (high power and extra power modes) was over 80%. Under the conditions of this study, the amount of monomer released from composite resins changed according to the type of composite resin and the light mode used.
Monomer Release From Nanohybrid Composites After Bleaching
(Nihon Univ, School dentistry, 2019) Gul, Pinar; Karatas, Ozcan; Alp, Hamit H.; Cam, Ihsan B.; Ozakar-Ilday, Nurcan
The evaluation of the effect of bleaching on monomer release from two composite resins was performed by bleaching two nanohybrid composite resins Filtek Z550 and Tetric N-Ceram using two bleaching products Whiteness HP Maxx and Vivastyle. In total, 20 samples were made from each composite resin from w hich four groups were fabricated (two for each bleaching product). The samples were stored in a 75% ethanol solution, and the solutions were renewed after 1, 7, and 28 days. The monomer release IN as analyzed using high performance liquid chromatography. The data were analyzed using repeated measures analysis of variance and least significant difference multiple comparison test (alpha = 0.05). Monomers were found to be released from both composite resins. The amounts of monomer released were found to decrease over time (P < 0.05); however, the resins were not affected by bleaching, and the released monomers were well below toxic doses.