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    Development of biomimetic hydroxyapatite containing dental restorative composites
    (Springer, 2022) Aydınoğlu, Aysu; Türkcan, Julide Hazal; Keleşoğlu, Ergün; Yoruç, Afife Binnaz Hazar
    The aim of the study was to evaluate the incorporation effect of biomimetic hydroxyapatite (BHA) particles on the mechanical properties of experimental dental composites. Two experimental composites were produced from the same organic matrix, Si/Zr nanocluster, and SiO2/silane as main inorganic reinforcing fillers. 7wt% BHA was added to one of the groups to evaluate its effect on mechanical properties. The BHA was also modified with 3-MPTMS to improve chemical bonding. Chemical structures and physical properties of the fillers were identified by XRD, FTIR, XPS, TGA, SEM, BET, and Zeta-Sizer. According to ISO 4049 and DIN 50,133 the mechanical properties, and to ISO 10993-5:2009 the biocompatibility was investigated. Analysis of variance (ANOVA) was used for the statistical analysis of acquired data. The BHA was synthesized by the biomimetic method in simulated body media (SBF). The SEM images of BHA/Silane particles demonstrated rod-like shapes and similar dimensions with natural hydroxyapatite present in tooth enamel. The modification by using 3-MPTMS was decreased the mean particle size of the fillers due to a lower agglomeration tendency. Moreover, the addition of small mass fractions of the BHA into the dental resins can substantially meet the ISO 4049 requirements. Consequently, the BHA was not adversely decreasing the mechanical properties of the dental composites. Also, the biocompatibility of the BHA-containing composites was found better than the samples without BHA-containing composites. The incorporation of the BHA can meet the mechanical requirements of dental resins and composites. Additionally, it may show regenerative properties against small lesions.
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    Öğe
    Does intramedullary elastic nail augmentation increase resistance to bending stress in plate fixation of long bones? A biomechanical study on lamb cadaveric femurs
    (2023) Eren, E.; Keleşoğlu, Ergün; Özdemir, Jülide Hazal; Büyükdoğan, Halil; Ertürk, Cemil
    [Özet yok]
  • Küçük Resim
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    Effect of repolishing on the surface roughness and color stability of air-abraded resin composites
    (Original ArticleInternational Dental Research, 2022) Sağır, Kadir; Altaş, Nurcan; Aydınoğlu, Aydın; Çil, Burcu Gözeteci; Keleşoğlu, Ergün; Yoruç, Afife Binnaz Hazar
    Aim:Air powder polishing (APP) can cause roughness on composite surfaces, and consequently the color change that occurs over time affects the aesthetic negatively. Here, we aim to investigate the effect of repolishing on the roughness and discoloration of resin composites after APP to avoid its negative effects for the first time.Methodology:A total of 39 composite discs were randomly allocated into three groups: Group I: Control (n = 13), Group II: Air Powder Polished (n = 13), and Group III: Air Powder Polished + Re-polished (n = 13). Color and surface roughness of the discs were measured before and after immersion in coffee for 1 week. Color was measured using a colorimeter (CR-400, Konica Minolta, Osaka, Japan), and roughness was measured using a surface roughness analyzer (SJ-400, Mitutoyo, Japan).Results:All specimens in the groups, except those in Group III, showed significant changes in roughness, and all materials showed significant color changes after immersion in the coffee relative to the baseline. There was no statistically significant difference between the groups in terms of roughness and color.Conclusion:In this study, we showed that repolishing after APP does not significantly improve the color stability and roughness of the composite restorations.
  • [ X ]
    Öğe
    Effects of different bonding agents on the shear bond strength between monolithic zirconia and indirect composite
    (2023) Mergen, Elif Saracoğlu; Cömert, Zekeriya Yaşar; İşsever, Dilara Şeyma Alpkılıç; Keleşoğlu, Ergün; Değer, Sabire İşler
    Purpose: To investigate the effects of different bonding agents and application of glaze on the shear bond strength (SBS) between monolithic zirconia (MZ) and indirect composite (IC). Materials and Methods: Five different bonding agents (G-Premio Bond [GP]; Tokuyama Universal Bond [TU]; Signum Zirconia bond [SZ]; Clearfil Ceramic Primer Plus [CCP]; Z-Prime Plus [ZP]) were applied to a total of 200 MZ disk-shaped specimens (n = 100 glazed and 100 nonglazed). Half of the specimens then underwent thermocycling and the other half no thermocycling (n = 10 specimens each subgroup). The experimental setup was prepared as two pieces according to the ISO TR 11405 standards. Specimens embedded in acrylic resin were placed into the experimental setup and a universal testing machine at a crosshead speed of 0.5 mm/minute. Mann-Whitney U test and Kruskal-Wallis test were used for statistical analyses. Bonferroni correction was then performed, and test results with P < .05 were accepted as statistically significant. Results: The application of glaze significantly enhanced SBS when ZP or CCP was used; however, it did not have any significant effect when GP, TU, or SZ were used. Thermocycling significantly decreased the SBS in all bonding agent groups except GP specimens with glaze (P = .16). The highest SBS in all conditions was noted when GP and TU were used. Conclusions: These findings suggest that the bonding agents GP and TU may be recommended for better bonding between MZ and IC.
  • Küçük Resim
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    In vitro bioactivity of laser surface-treated Ti6Al4V alloy
    (Springer, 2019) Yoruç, Afife Binnaz Hazar; Keleşoğlu, Ergün; Ekşioğlu Yıldız, Harika
    The effects of lasing parameters on the precipitation of hydroxyapatite (HA) on the commercial Ti6Al4Valloy in simulated body fluid (SBF) were investigated. Ti6Al4V plates were polished and ultrasonically cleaned in acetone and ethyl alcohol, respectively. The specimen surfaces were treated with Er:YAG laser using super short pulse (SSP, 50 ?s) and very short pulse (VSP, 100 ?s) modes. Surface roughness was measured before and after laser treatment. The specimens were immersed in simulated body fluid (SBF) for 1, 3, and 7 days and, then the amount of Ca and P precipitation on specimens was determined using SEM/ EDS analysis. An average roughness varying between 0.19 and 0.81 ?m in surface roughness was detected in all laser-treated specimens depending on the lasing parameters. The highest surface roughness and Ca precipitation were found in VSP group (20 Hz and 5 W). Laser treatment of specimen surfaces has dramatically increased the HA precipitation due to the increasing surface roughness. It is also concluded that the immersion time was effective on the HA precipitation as well.
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    Production of Y2O3 coated AL2O3 reinforced aluminium matrix composites and the coating of interface effects over wettability properties
    (2024) Altuner, Serdar; Keleşoğlu, Ergün
    Usage of Aluminium metal matrix komposites have been increased in automotive and areospace industry due to physical and mechanical properties of these. Requested properties have been obtained depends on particle’s different particle size and amount is added into matris. In this study, 5-10-15 and 20 % Al2O3 particle has been used as reinforcement. The wettability of Al2O3 is weak by molten aluminium. Weak bond force between aluminium and Al2O3 effects final properties of composite and decrease mechanical properties of it. In order to cope with this problem, Al2O3 powder was coated by Y2O3 and then it was added into aluminium. The aim of this study is the improvement of wettability using by Y2O3 coated Al2O3 particle reinforced aluminium matrix composites produced by squeze casting method so that mechanical properties will be enhanced. Produced composite’s density, hardness and wear behaviour is examined and analysed SEM microstructle. It was aware that during increasing reinforced volume, hardness of MMC was increased,coefficient of friction was decreased so wear resistance was improved.
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    The effect of preceramic soldering on fracture resistance of 4-unit zirconia fixed dental prostheses
    (Wiley, 2022) İrem, Diler Özkan; Cömert, Zekeriya Yaşar; Alpkılıç, Dilara Şeyma; Keleşoğlu, Ergün; Değer, Sabire İşler
    Purpose Preceramic soldering of zirconia may deliver better fitting restorations. However, there is not sufficient evidence regarding the influence of preceramic soldering of zirconia restorations on mechanical strength. The aim of this study was to evaluate the effect of preceramic soldering on the fracture load of 4-unit zirconia fixed dental prostheses (FDPs). Materials and methods Eighty samples of 4-unit FDPs between maxillary right first premolar and maxillary right second molar were prepared and two restorative materials were used as a framework (Z) and monolithic restoration (M). The samples were divided into two subgroups as control (C) and study (S). The restorations of study groups (S) were divided into two pieces and soldered with a bonding material (DCM HotBond Zirkon). The groups were divided into two subgroups for thermal cycle (T) application. After soldering and thermal cycling application, 4-point bending test was applied to the samples at a cross-head speed of 1 mm/min in a universal testing machine and the fracture load was recorded. The data was analyzed statistically, and the level of significance was set at alpha = 0.001. Results Statistically significant differences were found among the groups, based on the results of maximum failure loads (p < 0.001). The highest mean failure load was observed in the ZCT(-) group (1094.1 + 139.77 N), while the lowest mean failure load was obtained in the ZST(+) group (627.7 + 82.14 N). No significant difference was found among the groups MC and MS, MC, and ZC groups (p > 0.001). Thermal aging application caused lower fracture resistance in control and soldering groups (p < 0.001). Conclusions The preceramic soldering applications affected zirconia group negatively. However, the values were above the clinically acceptable static load bearing capacity for posterior teeth. Soldering did not cause a statistically significant difference for the fracture strengths of monolithic zirconia groups. Thermal cycling affected the fracture strength of zirconia and monolithic zirconia restorations negatively.