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    Comparison of the effects of different loading locations on stresses transferred to straight and angled implant-supported zirconia frameworks: a finite element method study
    (Taylor & Francis Ltd, 2015) Guven, Sedat; Atalay, Yusuf; Asutay, Fatih; Ucan, Musa Can; Dundar, Serkan; Karaman, Tahir; Gunes, Nedim
    The paper presents three-dimensional (3D) finite element models of straight and angled implants and their zirconium-based superstructures. The key objective was to compare the influence of different loading conditions on the stress distribution of straight and angled implants and the zirconia frameworks. 3D finite element straight- and angled-implant models of a mandibular section of bone with missing second molars and their zirconium-based superstructures were used. The straight and angled implants were 4.7 x 13-mm screw-type dental implant systems. Total loads of 300 N were applied in a vertical direction and in an oblique (30 degrees to the vertical) direction buccolingually. Maximum and minimum von Mises stress values of the titanium structures (abutment and implant body) and zirconia frameworks were calculated. When the two groups were examined, the highest stress value was in the zirconia framework of the angled implant-supported model with an oblique loading force (731.46 MPa). The lowest stress values were concentrated in the straight implant-supported model. Thus, the stress values in the angled implant-supported crown were higher than those in the straight implant-supported model. Stress values with oblique loading forces were higher than the values with vertical loading forces. The highest stress value in the zirconia framework was similar to the ultimate strength of the zirconia.
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    Effects of Local and Systemic Zoledronic Acid Application on Titanium Implant Osseointegration: An Experimental Study Conducted on Two Surface Types
    (Lippincott Williams & Wilkins, 2017) Dundar, Serkan; Yaman, Ferhan; Gecor, Orhan; Cakmak, Omer; Kirtay, Mustafa; Yildirim, Tuba Talo; Karaman, Tahir
    The aim of this study was to evaluate the effects of local and systemic zoledronic acid (ZA) applications on titaniumoksit ceramic blasted (TiO-CB)- and sandblasted large acid-grit (SLA)-surfaced titanium implant osseointegration. Twelve New Zealand White rabbits were used in the study, divided into 6 groups: the TiO-CB (TiO-CB-CNT) (n = 2) and SLA (SLA-CNT) (n = 2) control groups in which TiO-CB- and SLA-surfaced titanium implants were surgically inserted into rabbit tibias but no treatment was applied; the TiO-CB (TiO-CB-LZA) (n = 2) and SLA (SLA-LZA) (n = 2) local ZA groups in which 1 mL of normal saline solution containing 2 mg of ZA was injected into sockets and after this the implants were integrated; and the TiO-CB (TiO-CB-SZA) (n = 2) and SLA (SLA-SZA) (n = 2) systemic ZA groups in which a single infusion of 0.1 mg/kg of ZA was administered during surgical implant insertion. Following a period of osseointegration, bone implant contact (BIC) was recorded as a proportion of the total implant surface length in direct contact with the bone. Results of this study indicate that BIC was greater in the systemic ZA application groups than in the local ZA application groups, and BIC was greater in the local ZA groups than in the controls. Statistically significant differences in BIC were not detected between the TiO-CB- and SLA-surfaced implants in all the groups. Furthermore, this study did not reveal significant differences between the 2 types of surfaces due to similar average roughness values. Overall, systemic ZA application was found to be more effective in increasing BIC than local ZA application based on the results obtained by testing 2 implant surfaces.
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    The effects of morus nigra on the alveolar bone loss in experimentally-induced periodontitis
    (Istanbul Univ Press, Istanbul Univ Rectorate, 2019) Yildirim, Tuba Talo; Ozan, Gonca; Dundar, Serkan; Bozoglan, Alihan; Karaman, Tahir; Dildes, Neval; Kaya, Can Ayhan
    Purpose The aim of this study is to evalute the anti-inflammatory effects of morus migra on experimentally-induced periodontitis in rats. Materials and Methods Twenty-four Wistar-albino rats were randomly divided into three groups: control group (C, n=8), experimental periodontitis (PER, n=8), experimental periodontitis and treated with Morus nigra (MN+PER, n=8) (50 mg/kg per day for 21 days). After 21 days, the rats were sacrificed, and alveolar bones were evaluated histopathologically and histometrically analyzed to obtain level of alveolar bone loss. The detection of RANKL and OPG were immunohistochemically performed. Serum and tissue levels of MMP-8 and MMP-13 were also analyzed. Results Morus nigra treatment decreased tissue MMP-8 and MMP-13 levels and there were significant differences in the case of tissue levels of MMP-8 and MMP-13 between groups PER and MN+PER (p=0.035, p=0.041). There were no significant differences among all the groups serum levels of MMP-8 and MMP-13 (p=0.067, p=0.082). In the histometric evaluation, alveolar bone loss was greater in the PER group compared to C and MN groups (p=0.035). Immuno-histochemical staining of RANKL activities were found significantly lower (p=0.037) and OPG activities were found significantly higher in MN+PER group when compared to PER group (p=0.021). Conclusion The present study reveals that systemic administration of Morus nigra significantly inhibited the regional alveolar bone resorption and contributes to periodontal healing in the rat experimental-periodontitis models.
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    Evaluation and comparison of the marginal adaptation of two different substructure materials
    (Korean Acad Prosthodontics, 2015) Karaman, Tahir; Ulku, Sabiha Zelal; Zengingul, Ali Ihsan; Guven, Sedat; Eratilla, Veysel; Sumer, Ebru
    PURPOSE. In this study, we aimed to evaluate the amount of marginal gap with two different substructure Materials using identical margin preparations. MATERIALS AND METHODS. Twenty stainless steel models with a chamfer were prepared with a CNC device. Marginal gap measurements of the galvano copings on these stainless steel models and Co-Cr copings obtained by a laser-sintering method were made with a stereomicroscope device before and after the cementation process and surface properties were evaluated by scanning electron microscopy (SEM). A dependent t-test was used to compare the mean of the two groups for normally distributed data, and two-way variance analysis was used for more than two data sets. Pearson's correlation analysis was also performed to assess relationships between variables. REAMS. According to the results obtained, the marginal gap in the galvano copings before cementation was measured as, on average, 24.47 +/- 5.82 mu m before and 35.11 +/- 6.52 mu m after cementation; in the laser-sintered Co-Cr structure, it was, on average, 60.45 +/- 8.87 mu m before and 69.33 +/- 9.03 mu m after cementation. A highly significant difference (P<.001) was found in marginal gap measurements of galvano copings and a significant difference (P<.05) was found in marginal gap measurements of the laser-sintered Co-Cr copings. According to the SEM examination, surface properties of laser sintered Co-Cr copings showed rougher structure than galvano copings. The galvano copings showed a very smooth surface. CONCLUSION. Marginal gaps values of both groups before and after cementation were within the clinically acceptable level. The smallest marginal gaps occurred with the use of galvano copings.
  • Küçük Resim
    Öğe
    Manyetik Rezonans Görüntülemenin diş hekimliğinde kullanımı ve dental materyallere etkileri
    (Atatürk Üniversitesi Diş Hekimliği Fakültesi, 2018) Karaman, Tahir; Eşer, Bekir; Güven, Sedat; Yıldırım, Tuba Talo
    Radyolojik görüntüleme yöntemlerinden biri olan Manyetik Rezonans Görüntüleme, hastalıkların tanısına çok önemli katkıları bulunmasından dolayı yaygın bir şekilde medikal alanda kullanılmaktadır. Bu görüntüleme tekniğinde kuvvetli manyetik alan oluşması ve vücutta bulunan metalik objelerin bu manyetik alandan etkileşimleri hasta açısından potansiyel sağlık riskleri oluşturabilmektedir. Diş hekimliği alanında yaygın bir şekilde kullanılan Dental implantlar, Ortodontik braketler ve teller, Metal destekli sabit ve hareketli restorasyonlar vb. gibi içeriğinde metal bulunan objelerin varlığında Manyetik Rezonans Görüntülemesi esnasında oluşabilecek manyetik alan etkileşimlerinin yeterince bilinmesi gerekir. Görüntüleme esnasında hasta açısından oluşabilecek riskleri en asgari düzeye indirebilmek için vücutta bulunan ve manyetik alandan etkilenen metalik objeler ile ilgili gerekli tedbirlerin alınması gerekir.
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    Termal siklus ve baskı kuvvetine maruz bırakılan galvano kronlarda marjinal bölge uyumunun (stereomikroskop) ve marjinal bölge yüzey özelliklerinin (Sem’de) incelenmesi
    (2016) Karaman, Tahir; Ülkü, S. Zelal
    Galvano kronlar, içeriğindeki altının ağız dokuları ile biyouyumlu olması, altyapı materyallerinde kullanılan alaşımlardan bir kısmının toksik etkilerinin bulunmasından dolayı diş hekimliğinde protetik restorasyonların altyapısında kullanılmaktadırlar. Altının elektroliz yöntemiyle bir yüzey üzerine çökeltilmesiyle elde edilen galvano kopingler, marjinal uyumlarının oldukça iyi olmasının yanısıra estetik üstünlükleri sebebi ile de geleneksel yöntemlerle elde edilen restorasyonlara alternatif olarak tercih edilmektedirler. Yapılan literatür taramalarında genelde iki farklı preparasyon tipine sahip galvano kronların marjinal uyumları değerlendirilmiş olmakla birlikte, farklı basamak preparasyonuna sahip galvano kopingler ile lazer sinterleme yöntemi ile elde edilen Co-Cr kopingler ve lazer sinterleme yöntemi ile elde edilmiş Co-Cr üzerine altın kaplanan kopinglerin marjinal uyumları ile ilgili çalışmaya rastlanmadı. Bu çalışmada; farklı basamak preparasyonuna sahip 90 adet paslanmaz çelik model üzerine yapılan galvano kopinglerin, lazer sinterleme yöntemi ile elde edilmiş olan Co-Cr kopinglerin ve lazer sinterleme yöntemi ile elde edilmiş Co-Cr üzerine altın kaplanan kopinglerin simantasyon öncesi, sonrası ve termal siklus ve basma kuvvetine maruz bırakılması işlemleri sonrası marjinal bölge uyumları ve yüzey özellikleri değerlendirildi. Elde edilen sonuçlara göre simantasyon öncesi yapılan aralık ölçümlerinde en düşük değeri galvano kopinglerden Chamfer tip basamak preparasyonuna sahip galvano kopingler gösterdi (24.468±5.828 ?m ). Lazer sinterleme ile elde edilen Co-Cr kopinglerden en düşük marjinal aralık ölçümleri Derin Chamfer basamak preparasyonuna sahip kopinglerde elde edildi (60,430±10.674 ?m). Lazer sinterleme yöntemi ile elde edilmiş Co-Cr üzerine altın kaplanan kopinglerin simantasyon öncesinde yapılan ölçümlerde ise en düşük marjinal aralık değerleri Derin Chamfer basamak preparasyonuna sahip kopinglerde elde edildi (58,905±6.902 ?m). Simantasyon öncesi yapılan ölçümlerde Bıçak sırtı basamak preparasyonuna sahip kopinglerde marjinal aralık değerleri Chamfer ve Derin Chamfer basamak preparasyonuna sahip kopinglere göre yüksek bulundu. Anahtar Kelimeler: Galvano kronlar, Termal siklus, Marjinal Uyum, Basma kuvveti