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    An evaluation of surface roughness after staining of different composite resins using atomic force microscopy and a profilometer
    (Wiley, 2020) Karataş, Özcan; Gul, Pinar; Gundogdu, Mustafa; Iskenderoglu, Demet T.
    Aim The aim of this study was to compare the surface roughness of different composite resins using atomic force microscope (AFM) and a profilometer after storage in different solutions. Materials and methods Eight different composite resins were used in this study. Twenty specimens of each composite resin material were prepared using a 2-mm thick and 8-mm diameter stainless steel mold. After the composites had been placed in the mold, they were polymerized with a LED curing unit. The surfaces of all specimens were polished using aluminum oxide discs, and the specimens were then divided into four groups. The specimens in the experimental groups were stored in cola, coffee, or red wine, while the control group was stored in distilled water. Specimen surface roughness was examined after 30 days using an AFM and a profilometer, and the data obtained were subjected to analysis. Results Evaluation of the surface roughness of composite resins using a profilometer revealed no statistically significant difference between the groups, but significant differences were found using the AFM. The mean surface roughness of nanohybrid composites was lower than that of microhybrid composites. Conclusions The surface roughness of the composite resins varies with storage in different solutions, depending on the organic matrix structure and inorganic fillers of the resin.
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    Effect of staining and bleaching on the microhardness, surface roughness and color of different composite resins
    (Wroclaw Medical Univ, 2021) Karataş, Özcan; Gul, Pinar; Akgul, Nilgun; Celik, Neslihan; Gundogdu, Mustafa; Duymus, Zeynep Yesil; Seven, Nilgun
    Background. There are studies that examined the effect of staining on the surface properties of composite resins, using different solutions and bleaching applications. However, the effect of both staining and bleaching on the same composite specimens is an issue that needs to be investigated. Objectives. The aim of this study was to investigate the surface microhardness, roughness and color changes (Delta E) of 2 different composite resins after staining and bleaching. Material and methods. A microhybrid and a nanohybrid composite were used in the study. One hundred and fifty specimens were prepared from each composite. The specimens were divided into 5 groups and stained for 30 days with tea, coffee, cola, red wine, or distilled water (control). Subsequently, each group was divided into 3 subgroups. Each subgroup received a 14-day application of Opalescence (TM) Boost, Opalescence PF or VivaStyle (R) Paint On Plus bleaching materials. The color as well as surface microhardness and roughness of all specimens were determined at baseline, after staining and after bleaching. Data was analyzed using the repeated-measures analysis of variance (ANOVA) and the Bonferroni method. Results. A statistically significant decrease was observed in the surface microhardness of the microhybrid composite specimens after bleaching (p < 0.05).The highest Delta E values were observed in the red wine groups for both composite resins. Conclusions. Staining and bleaching may affect surface properties and color, depending on the type, filler and matrix content of the composite resin.
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    Release of mercury from amalgam filling and its relationship with metallothionein and superoxide dismutase
    (Istanbul Univ Press, Istanbul Univ Rectorate, 2023) Gul, Pinar; Karataş, Özcan; Sagsoz, Omer; Askin, Seda; Turkeri, Ozge; Kiziltunc, Ahmet
    Purpose This study aims at determining the amount of mercury released over time from amalgam after treatment in healthy subjects and to examine the relation of mercury with serum MT-1 and SOD-1 levels.Materials and Methods Amalgam filling was applied to the 15 subjects aged 19-22 years and blood samples were collected before treatment and 1 day, 7 days, 21 days and 35 days after treatment. Mercury analysis of serum samples was performed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In addition, MT-1 and SOD-1 levels in serum samples were measured using commercial enzyme-linked immunosorbent assay (ELISA). Friedman test and Spearman's correlation analysis was performed to analyse the data. p value was interpreted in significance level of 0.05.Results As a result of the analysis for MT-1, it was found that the values decreased over time and this decrease was statistically significant after 21 days (p<0.05). In addition, it was found that SOD-1 decreased over time, but this decrease was not statistically significant . In terms of released mercury, there was no statistically significant difference among the values of mercury released over time . According to the results of correlation analysis, no statistically significant relationship was found among the variables.Conclusion The results of the present study indicated that the amount of mercury released from the tested amalgam were found to be tolerable and no significant relationship was found between MT-1 and SOD-1.
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    The Effects of Different Antioxidant Agents on the Microtensile Bond Strength of Composite Resin to Bleached Enamel
    (Univ Costa Rica, Fac Odontologia, 2022) Ilday, Nurcan Ozakar; Karataş, Özcan; Uygun, Latife Altinok; Gul, Pinar
    Objective: The objective of this in vitro study is to examine the effect of antioxidants on the bonding strength of composite resin to bleached enamel. Materials and Methods: One hundred twenty non decay teeth were used in this study. Specimens were cut from the enamel cement junction. Then the specimens were randomly assigned into two groups-office bleaching and home bleaching. Bleaching antioxidants were applied to the first 12 subgroups. The specimens in the remaining 12 groups were kept in artificial saliva for 14 days and antioxidants were applied. Composite resin restoration was applied to all specimens. A cutting device was employed to obtain six specimens (0.9mm) from each tooth, and the microtensile bond strength (mu TBS) test was performed. Data were analyzed using one-way ANOVA, the paired t-test, and Duncan's post hoc test (p=0.05). Results: In office bleaching specimens, immediate antioxidant application increased the pTBS values (p<0.05). Comparisons of the antioxidants individually revealed that bonding values increased after two weeks in specimens subjected to antioxidant application (p<0.05). In office bleaching specimens, immediate antioxidant application increased the mu TBS values (p>0.05). Mean mu TBS values in the groups to which antioxidants were applied two weeks after home bleaching were higher than those in the groups in which antioxidants were applied immediately. Conclusion: The use of antioxidants after bleaching may increase the MTBS value. The clinician should take this into account especially in immediate restoration applications after bleaching.