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Öğe Analysis of Monomer Release from Different Composite Resins after Bleaching by HPLC(Mdpi, 2022) Demirel, Mehmet Gokberkkaan; Gonder, Hakan Yasin; Tuncdemir, Makbule Tugba(1) Background: This study aimed to examine the effect of bleaching agents on the release of triethylenae glycol dimethacrylate, 2-hydroxyethyl methacrylate, bisphenol A, urethane dimethacrylate, and bisphenol A-glycidyl methacrylate monomers, which are released from different composite resins, using the high-performance liquid chromatography (HPLC) method. (2) Methods: Ninety disc-shaped specimens were produced and immersed in artificial saliva. After different bleaching applications [office type bleaching (OB) and home type bleaching (HB)], the specimens were immersed in a 75 wt% ethanol/water solution, and the released monomers were analyzed by HPLC at predefined time intervals: 1, 7, and 28 days. The Kruskal-Wallis and Mann-Whitney U tests were conducted for statistical analysis (p = 0.05). (3) Results: The monomers were released at all times from all composite specimens. The monomer release was increased over time. The highest monomer release was detected on day 28. Bleaching applications affected monomer release. No statistical difference was found between OB and HB applications (p > 0.05). The most released monomer was Bisphenol-A in all composites. (4) Conclusion: Given that a residual monomer release from composite resins has a toxic effect and that bleaching treatments increase this release, a treatment protocol should be made in accordance with the manufacturer's instructions.Öğe Antimicrobial Activity of Glass Ionomer Cements with Chlorhexidine and Propolis: An In Vitro Study(Georg Thieme Verlag Kg, 2019) Tuncdemir, Makbule Tugba; Ugur, Ayse Ruveyda; Ozdemir, BilgenThe aim of this study was to evaluate the antibacterial effect of conventional glass ionomer cement with the addition of antibacterial constituents in its liquid preparation. Two groups of glass ionomers prepared with propolis and chlorhexidine and a third group without any additive used as control were sterilized by low-temperature hydrogen peroxide plasma sterilizer at the sterilization unit. Seven to eight disk-shaped restorative materials of each group were placed on the Mueller Hinton Agar with sheep blood 5% v/v, on which Streptococcus mutans inoculated. The plates were incubated at 37 degrees C in 5% CO (2) for 24 to 48 hours. After 24-hour and 48-hour-incubation, inhibition zone diameters of each restorative materials were measured. No distinct inhibition zone was reported; only a slight zone (6 mm) around the contact surfaces of each material was observed after the 24-hour and 48-hour incubations. No significant difference was observed in the inhibition zone diameters between the two test groups and control. Within the limitations of this study, results revealed that there was no antibacterial difference among glass ionomers prepared with propolis and chlorhexidine.Öğe Comparison of the Stress Distribution in Class I and Class II Amalgam and Bulk-Fill Composite Restorations Using CAD-FEM Modeling(Quintessence Publishing Co Inc, 2021) Tuncdemir, Makbule Tugba; Yesilyurt, Nilgun Gulbahce; Arikan, MahmutThis study compares the mechanical strengths of bulk-fill composite resin and amalgam material to investigate the stress distribution and capacity to mitigate stress of restored Class I and Class II teeth under chewing loads, using finite element analysis. A 3D model of a human mandibular first molar and four Class I (C1) and Class II (C2) caries, including 95-degree cavity-margin angles, were created. Different material combinations were simulated: model C1-A and C2-A, with an amalgam material; and model C1-C and C2-C, with a bulk-fill composite resin. Solid 3D elements with four grid points were employed for modeling the tooth. A vertical occlusal load of 600 N was applied, and nodal displacements on the bottom cutting surfaces were constrained in all directions. All materials were assumed to be isotropic and elastic, and a static linear analysis was performed. The highest maximum principal stress was observed in C2-C, followed by C1-C, C2-A, and C1-A, respectively. The maximum principal stress load on the lingual cusp was recorded at the junction of the lingual margin (C1-C and C2-C), and stress was recorded on the line of restoration and enamel (C1-A and C2-A). Restoration materials and cavity preparations influence the stress distribution at the restoration-tooth interface and, consequently, the measured bond strength.Öğe Effect of whitening mouthrinses on color change, whiteness change, surface roughness, and hardness of stained resin composites(Mosher & Linder, Inc, 2023) Fidan, Muhammet; Tuncdemir, Makbule TugbaPurpose: To evaluate the effect of whitening mouthrinses on the color change, whiteness change, surface roughness, and hardness of stained resin composites after different immersion times. Methods: Three different resin composites (Estelite Sigma Quick, G-Aenial Anterior, Omnichroma) were used to prepare a total of 90 samples (30 samples from each resin composite). The samples were kept in coffee for 12 days, then divided into three subgroups (Control, Crest 3D White, and Listerine Advanced White; n=10 each). Color change (Delta E-00) and whiteness change (Delta WID) were evaluated at time intervals of 0-24 hours (TO-T1), 0-72 hours (TO-T2), and 24-72 hours (T1-T2). Surface roughness and hardness values were evaluated at TO, T1, and T2 after immersion in mouthrinses. Two-way ANOVA (for color and whiteness changes) and generalized linear model (for surface roughness and hardness) were used for data analyses (P< 0.05). Results: Omnichroma had the highest value for color change with Crest 3D White during TO-T1 and TO-T2. Crest 3D White showed better color changes than Listerine Advanced White. In all composites and mouthrinse groups, the highest and lowest values of Delta WID were at TO-T2 and T1-T2, respectively, with the highest value for Omnichroma with Crest 3D White at TO-T2 and the lowest for G-Aenial Anterior with control groups at T1-T2. The highest roughness values were found with the Omnichroma at T2. Whitening mouthrinses significantly increased roughness and decreased hardness compared to baseline.Öğe Urgent Solution for Single Tooth Loss: Fiber-Reinforced Composite Bridges(Aves, 2018) Demirel, Mehmet Gokberkkaan; Tuncdemir, Makbule TugbaRehabilitation in maxillary anterior teeth loss is a serious challenge in the field of dentistry. Some patients may not wish to undergo implant treatment because of economic inconvenience or the tendency to avoid surgery. In such cases, rehabilitation with full crown teeth causes important amounts of loss material. Fiber-reinforced composite (FRC) bridges are a serious alternative to conventional treatments and present considerably more conservative solutions. This article describes the clinical technique and a 6-month follow-up. The patient had lost the maxillary anterior tooth after trauma. The adjacent teeth were periodontally healthy and had no mobility. The main advantage of this FRC bridge treatment was the improvement in oral hygiene with supragingival margins and the loss of minimum tooth structure. In particular, when the patient's teeth are used as a pontic, the esthetic results are very good and patient satisfaction can be achieved.
