Bu çalışmanın amacı; 3 farklı yapısal özellikteki nikel-titanyum (Ni-Ti) aletin döngüsel yorgunluk dirençlerini serum fizyolojik ve sodyum hipoklorit (NaOCl) çözeltileri kullanarak karşılaştırmaktır. Materyal ve Metod: Çalışmada 6 deney grubu (n=15) oluşturuldu ve toplamda 90 adet eğe kullanıldı.

Background: The effective bonding of fiber posts which are recommended in the restoration of endodontically treated teeth with excessive coronal damage is of critical importance for the long-term success. The aim of this study was to investigate the effect of various irrigation activation protocols on the push-out bond strength of fiber posts in different parts of the post space. Methods: Forty-eight endodontically treated mandibular first premolar teeth were divided into 4 groups according to irrigation protocol (n=12): passive irrigation(PI); manual-dynamic irrigation(MDI); sonic irrigation(SI), ultrasonic irrigation(UI). Fiber posts were bonded with a self-adhesive resin cement. The roots were divided transversally into 3 sections as coronal, middle, and apical, in 2 mm each. Push-out bond strengths were calculated in MPa using a universal-testing machine. Each sample was examined under a stereomicroscope and failure types were classified as follows: adhesive failure between cement and dentin-Adhesive(C/D); adhesive failure between cement and fiber post-Adhesive(C/F); the combination of both adhesive failure types-mix. Results: The lowest bond strength was obtained for PI(p<0.05). There was no statistically significant difference between the other groups (p>0.05). Coronal region showed significantly higher bond strength than the apical (p<0.05). While mixed failure was observed dominantly in the MDI, SI and UI groups, PI was the group that showed the adhesive(C/D) failure type in most. Conclusion: After preparing the post space, using one of the irrigation activation protocols increased the bond strength of fiber posts.Regardless of the irrigation method applied, the bond strength of the fiber post was higher in the coronal region than the apical.

Bu çalışmanın amacı aralarında aleksidin dihidroklorürün (ALX) de bulunduğu farklı final irrigasyon solüsyonları kullanımı sonrası rezin esaslı kök kanal patının dentine bağlanma dayanımını değerlendirmektir.Yöntemler: 90 adet insan üst birinci keser dişi kullanıldı. Uygulanan son yıkama solüsyonuna göre gruplar şu şekilde oluşturuldu: Grup 1: 17% EDTA, Grup 2: QMix, Grup 3: %2 CHX, Grup 4: %1 ALX, Grup 5: Distile su (kontrol grubu). Tüm kanallar güta-perka ve AH Plus ile dolduruldu. Bağlanma dayanımı ölçümü için her bir örnekten koronalden apikale doğru 2 mm kalınlıkta üç yatay kesit elde edildi. Bağlantıda kopma oluşana kadar push-out kuvveti uygulandı. Bağlantı başarısızlığı, her bir örnek stereomikroskop ile değerlendirilerek şu şekilde sınıflandı: Adeziv (pat-dentin ya da pat-güta-perka arayüzünde), koheziv (pat ya da dentin arayüzünde), karma (hem pat hem dentinde). Gruplar arası karşılaştırmalar Kruskal-Wallis H testi ile yapıldı (P < .05).Bulgular: En yüksek ortalama bağlanma dayanımı değerleri sırasıyla koronal, orta ve apikal bölgede görüldü (P < .05). En yüksek ortalama bağlanma dayanımı değeri etilendiamin tetra-asetik asit (EDTA), en düşük kontrol grubundaydı (P < .001). Qmix'in, CHX ve ALX'le kıyaslandığında daha yüksek değer gösterdiği koronal bölge dışında, bu üç grup arasında farklılık yoktu. Tüm örneklerde en fazla koheziv başarısızlık görüldü.Sonuç: EDTA kullanıldığında kök kanalının her üç bölümünde de bağlanma dayanımı en yüksekti. ALX, CHX ile benzer bağlanma dayanımları gösterdi.

Purpose:To compare the cyclic fatigue resistance of ProTaper Universal (PTU) and ProTaper Gold (PTG) nickel titanium files at different angles and to examine the fractured surface areas by using scanning electron microscope (SEM). Materials and Methods: A special static test device made of stainless steel with artificial canals at 3 different angles. The files were rotated until they were broken in artificial canals with 45°, 60° and 90° angles and also the time was recorded using a digital stopwatch. The number of cycles to failure was calculated for each instrument. Statistical analyzes were made by using one-way analysis of variance (Anova) for comparison between main groups. Results: PTG files showed higher fatigue resistance (p

Objective: The aim of this study was to evaluate the influence of orientation angle of direct metal laser sintering (DMLS) post cores during manufacturing to the fracture resistance and failure patterns of endodontically treated mandibular premolar teeth.Materials and Methods: 60 intact human mandibular premolars were endodontically treated. The teeth were then randomly divided into four groups (n=15). Co-Cr metal posts were fabricated by traditional casting, and DMLS method. DMLS post cores were printed in 00, 450 and 900 orientations. The posts were luted with a resin cement and subjected to compression test at a crosshead speed of 1 mm/min. The statistical analysis of the data was performed using one-way analysis of variance (ANOVA) and multiple comparison post hoc Tukey tests ( =.05). Specimens were viewed under a stereo microscope with x20 magnification for evaluating the fracture types. Results: The lowest mean fracture resistance was obtained from conventional casting group (Group C) (1067N). DMLS 450, DMLS 00 and DMLS 900 groups were followed, respectively. Statistically no significant differences were found between groups P<.05 Group C and DMLS 00 group exhibited similar repairability pattern. Conclusion: It is possible to produce post-core restorations with the DMLS technique by choosing 00 build orientation and use them clinically. This facilitates not only ease of removing supports, but also provides minimum cement thickness and maximum adaptation into the canal. Clinical relevance: Co-Cr post-cores manufactured by DMSL with 0º build angulation could be an alternative to conventional casting post-cores in terms of repairability.