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Öğe Bond Strength Between Root Dentin and Three Glass-Fiber Post Systems(Mosby-Elsevier, 2006) Kalkan, Mustafa; Üşümez, Aslıhan; Öztürk, A. Nilgün; Belli, Sema; Eskitaşcıoğlu, GürcanStatement of problem. Glass-fiber posts were introduced for use after endodontic therapy instead of metal alloy and ceramic posts. There are several new types of glass-fiber post systems available, but little is known about how well these posts bond to the root surface. Purpose. The purpose of this in vitro study was to compare the bond strengths of 3 different types of glass-fiber post systerns-opaque, translucent, and electrical glass-in 3 different locations of prepared post spaces. Material and methods. Sixty human intact single-rooted extracted teeth were used. The root canals were prepared using a step-back technique and obturated with gutta-percha using lateral condensation. The roots were divided into 3 experimental groups and further divided into 2 subgroups according to testing time (n = 10). Roots were restored with 1 of the following post systems according to the manufacturer's instructions: opaque glass-fiber posts (Snowpost), translucent glass-fiber posts (FiberMaster), and electrical glass-fiber posts (Everstick). A self-etching primer (Clearfil Liner Bond) was applied to the walls of the post spaces, allowed to etch for 30 seconds, and gently air dried. A dual-polymerized bonding agent (Clearfil Liner Bond, Bond A and B) was then applied to the same walls. A dual-polymerizing resin luring agent (Panavia F) was mixed for 20 seconds and then placed in the post spaces using a lentulo spiral instrument. The roots were placed in light-protected cylinders; then the light source was placed directly on the flat cervical tooth surfaces and the cement was polymerized. Specimens were stored in light-proof boxes for 24 hours or 1 week after the polymerization procedure. Each root was cut horizontally, and six 1-mm-thick root segments (2 apical, 2 middle, and 2 cervical) were prepared. Using a push-out test, the bond strength between post and dentin was measured after 24 hours or I week using a universal testing machine. Statistical analysis was performed with 3-way ANOVA followed by independent t tests (alpha = .05) to detect differences between groups defined by the specific interacting variables. The different combinations of posts and luting material from the cervical segments were analyzed with SEM. Results. The 3-way ANOVA indicated that push-out test values varied significantly according to the post system used (opaque, electrical, and translucent) (P < .01); the root segments (cervical, middle, and apical) (P < .01), however, did not vary statistically according to the time of testing (24 hours and 1 week). Opaque and electrical glass-fiber posts showed higher bond strength values than translucent posts (P < .01). Push-out bond strength values of cervical segments were significantly higher than the middle and apical segments in translucent and electrical glass-fiber post groups (P < .01). In the opaque glass-fiber post group, there were no significant differences between cervical and middle segments. In SEM analysis, a distinct hybrid zone with long, numerous resin tags located between luting material and dentin was exhibited in all post systems. Conclusion. The opaque and electrical glass-fiber posts exhibited similar bond strengths, and translucent posts exhibited the lowest bond strength. The highest bond strength was observed in the cervical third of the post spaces for translucent and electrical glass-fiber post groups.Öğe Effect of Polymerisation Techniques on Residual Monomer Amount Released From Different Acrylic Resins(MANEY PUBLISHING, 2010) Büyükerkmen, B.; Öztürk, A. NilgünThe purpose of this study was to investigate the influence of different polymerisation methods (heat, auto-, injection moulding and microwave) with curing processes (conventional, short-and long-term terminal boiled heat polymerisation and room temperature polymerisation) in combination with varied water storage periods (24 h, 7 and 30 days) on the residual methyl methacrylate (MMA) contents of different dental acrylic resins. Twelve discs were fabricated for each denture base material. Specimens were immersed immediately in separate light proof glass bottles containing 20 mL 75% ethanol and 25% deionised water. Residual monomer (MMA) which eluted from acrylic resins was analysed with high performance liquid chromatography. Data were analysed by two-way analysis of variance and Tukey honestly significant difference tests. The MMA monomer amount eluted from autopolymerised acrylic resin groups (p < 0.01) was higher than that from the other groups. Microwave polymerised acrylic resin showed the lowest residual monomer amount compared to the other acrylic resins (p < .01).Öğe THE EFFECTS OF DIFFERENT DENTIN HYPERSENSITIVITY TREATMENTS ON THE SHEAR BOND STRENGTH BETWEEN ADHESIVE COMPOSITE RESIN AND DENTIN(2014) Dilber, Erhan; Çevik, Pınar; Akpınar, Yusuf Ziya; Öztürk, A. NilgünAmaç: Bu invitro çalışmanın amacı farklı duyarlılık tedavilerinin, adeziv akışkan kompozit rezinin dentine makaslama bağlanma dayanıklılığı üzerine etkilerini değerlendirmekti. Gereç ve Yöntem: Tüm dentin örnekleri, smear tabakasını uzaklaştırmak ve hassas dentin yüzeylerini taklit edecek şekilde dentin tübüllerini açmak için 0,5 EDTA ( pH 7.4) ile iki dakika pürüzlendirildi: Kırk örnek rastgele dört gruba ayrıldı (n10) (1) Grup C (kontrol); (2) Grup N (Nd:YAG lazer tedavisi); (3) Grup G (Gluma Hassasiyet giderici tedavisi); (4) Grup NG (Gluma hassasiyet giderici uygulamasının ardından Nd:YAG lazer tedavisi). Dentin yüzeyine akışkan kompozit rezin uygulandı ve makaslama bağlanma dayanıklılık testi uygulandı. Ortalama MBD değerleri değerlendirildi, kırılma tipleri belirlendi ve veriler tek-yönlü ANOVA ile analiz edilip Tukey HSD testi ile karşılaştırıldı. Bulgular: Grup G (11,74,6 MPa) ve Grup N (18,52,5 MPa) arasında anlamlı fark bulundu (p0.05). Diğer gruplar arasında anlamlı fark gözlenmedi. SEM değerlendirmesi, Grup Nnin bazı bölgelerde, dentin tübüllerinin periferini modifiye ederek ve eriterek açık dentin tübüllerini tıkadığını gösterdi. Grup Gde etkilenen tübüllerin çapında azalma ve belirgin daralma gözlendi. Grup NG, dentin tübüllerini değişen derecelerde tıkadı. Sonuç: Gluma hassasiyet giderici ardından Nd:YAG lazer uygulaması, dentin hassasiyeti için etkili bir tedavi olabilir ve adeziv kompozit rezinin dentin yüzeyine bağlanma dayanıklılığını olumsuz yönde etkilemez.Öğe Implant-Retained Auricular Prosthesis(Lippincott Williams & Wilkins, 2010) Demir, Necla; Malkoç, Meral Arslan; Öztürk, A. Nilgün; Tosun, ZekeriyaAuricular defects may result from congenital malformations, injuries from motor vehicle crashes, trauma, or tumor resections. An auricular prosthesis was fabricated for a patient who had an injury from a motor vehicle crash. Extraoral implants and bar-and-clip retention for the proper connection of the auricular prosthesis to implant were used. This prosthesis was acceptable to the patient because of excellent support, retentive abilities, and the patient's appearance.
