Farklı kor materyalleri ile restore edilmiş fibersite ile relyx fiber postlarının diş dokusuna bağlanma dayanımlarının incelenmesi

Objective: This study aimed to assess the pull-out bonding resistance of FiberSite and RelyX Fiber posts constructed from core structures using various resin cement. Materials and Methods: Sixty mandibular premolar teeth were horizontally sectioned to create a root canal length of 15 +/- 1 mm. Up to size #40, samples were prepared and obturated with gutta-percha and root canal sealer. Three groups of specimens (n=20) were formed. FiberSite posts were luted and built-up using Clearfil DC Core Plus in Group 1, RelyX Fiber posts were luted and built-up using Clearfil DC Core Plus in Group 2, and RelyX Fiber Posts were luted and built-up using Filtek Bulk Fill Posterior in Group 3. Each specimen was vertically positioned in a universal testing machine and rotated at 0.5 mm/min until it dislodged. Oneway ANOVA and post hoc tests were used to evaluate the data. Results: The bonding strength of FiberSite posts was higher than that of RelyX Fiber posts (p<0.05). Clearfil DC Core Plus-built RelyX Fiber Posts exhibited higher bond strength than Filtek Bulk Fill Posterior-built posts (p<0.05). Conclusion: FiberSite posts provide better root canal dentin retention than RelyX Fiber posts with different core materials.Amaç: Bu çalışmada farklı rezin simanlar ile kor yapıları oluşturulmuş FiberSite ve RelyX Fiber Post sistemlerinin kök kanalına bağlanma kuvvetlerinin incelenmesi amaçlanmıştır. Gereç ve Yöntemler: Altmış adet mandibular premolar diş, 15±1 mm kök kanal uzunluğu elde etmek için yatay olarak kesildi. Örneklerin kök kanalları #40’a kadar prepere edildi ve guta-perka ve kanal patı kullanılarak kök kanal dolguları yapıldı. Örnekler daha sonra 3 gruba ayrıldı (n=20). Grup 1’de FiberSite postları Clearfil DC Core Plus ile simante edildi. Grup 2’de RelyX Fiber postlarının simantasyonu ve kor yapıları, Clearfil DC Core Plus ile yapıldı. Grup 3’te, Clearfil DC Core Plus ile simante edilen RelyX Fiber postlarının kor yapıları Filtek Bulk Fill Posterior ile yapıldı. Tüm örneklere, universal test cihazında kırılma gerçekleşinceye kadar dikey yönde 0,5 mm/dak sabit kuvvet uygulandı. Verilere tek yönlü varyans analizi yapıldı ve post hoc testleri ile analiz edildi. Bulgular: FiberSite postlarının bağlanma dayanımı, RelyX Fiber postlarından anlamlı ölçüde daha yüksek bulunmuştur (p<0,05). Clearfil DC Core Plus ile kor yapıları oluşturulan RelyX Fiber postları, Filtek Bulk Fill Posterior (p<0,05) ile kor yapısı oluşturulan RelyX Fiber postlarından daha fazla bağlanma dayanımı göstermiştir. Sonuç: FiberSite postları, farklı rezin simanlar ile kor yapıları oluşturulan RelyX Fiber postlarından kök kanal dentinine daha yüksek bağlanma kuvvetine sahiptir

COVID-19 pandemisinin endodontistlerin sürekli mesleki gelişimleri üzerine etkisinin etkisi: Kapsamlı bir anket çalışması

Objective: Continuing professional development (CPD) is a lifelong process that continues despite all kinds of obstacles. The aim of this study was to evaluate of endodontists’ attitudes towards CPD during the coronavirus disease-2019 pandemic and online educa tional resources (OERs). Material and Methods: A questionnaire on demographic data and preferred resources before and after the pan demic was sent to 554 potential participants via e-mail. A chi-square test and multivariate logistic regression test were conducted on the ob tained data at a 5% significance level. Results: One hundred seventy five participants responded to the survey. Of all the participants, 67% were women and 45% were academicians. Since the pandemic began, OERs have been preferred over traditional resources, but traditional ones were considered more useful than OERs. Most of the respondents believed that contagion concerns represented the greatest obstacle to CPD. Gender and experience were related to the perception that the pandemic affected the respondents’ CPD activities (p<0.001). Spe cialty/PhD students tended to benefit more than others from OERs (p<0.05). The respondents mostly considered that OERs are comfort able and advantageous in terms of time, cost, professional knowledge and skill. Conclusion: The resources endodontists chose for CPD ac tivities seemed to have changed in favour of OERs during the pandemic despite their lower perceived usefulness as compared with traditional resources.Amaç: Sürekli mesleki gelişim (SMG), her türlü engele rağ men yaşam boyu devam eden bir öğrenme sürecidir. Bu çalışmanın amacı, endodontistlerin koronavirüs hastalığı-2019 pandemisi sırasında SMG’ye ve online eğitim kaynaklarına (OEK) yönelik tutumlarını de ğerlendirmektir. Gereç ve Yöntemler: Beş yüz elli dört katılımcıya pandemi öncesi ve sonrası olmak üzere demografik veriler ve tercih edilen kaynaklar hakkında hazırlanmış bir anket e-posta yoluyla gön derildi. Elde edilen veriler üzerinde %5 anlamlılık düzeyinde ki-kare testi ve çok değişkenli lojistik regresyon analizi yapıldı. Bulgular: Yüz yetmiş beş katılımcı anketi cevaplamıştır. Tüm katılımcıların %67’si kadın ve %45’i akademisyendi. Pandemi başlangıcından itibaren OEK geleneksel kaynaklara tercih edilmiş, ancak geleneksel olanlar OEK’den daha kullanışlı kabul edilmiştir. Ankete katılanların çoğu, bulaş endişesini SMG’nin önündeki en büyük engel olarak görmüştür. Cinsiyet ve deneyim, pandeminin katılımcıların SMG faaliyetlerini et kilediği algısıyla ilişkili bulunmuştur (p<0,001). Uzmanlık/doktora öğ rencileri OEK’den daha fazla yararlanma eğiliminde bulunmuştur (p<0,05). Ankete katılanlar OEK’nin zaman, para, mesleki bilgi ve be ceri düzeyleri açısından rahat ve avantajlı olduğunu düşünmektedirler. Sonuç: Her ne kadar endodontistler pandemi döneminde SMG için OEK tercih etmiş olsalar da geleneksel kaynakları OEK’ye göre daha kullanışlı olduklarını düşünmektedirler

Bending resistance and cyclic fatigue life of Reciproc Blue, WaveOne Gold, and Genius files in a double (S-shaped) curved canal

Background. This study compared the cyclic fatigue resistance, bending resistance and cross-sectional areas of Reciproc Blue (RPC Blue), WaveOne Gold (WOG), and Genius File (GF) NiTi rotary systems. Methods. Forty RPC Blue R25 (25/.08), 40 WOG Primary (25/.07) and 40 GF (25/.04) files were used in the present study. Flexibility of the files was determined by 45° bending test. The instruments were also subjected to cyclic fatigue resistance, calculating the number of cycles to fracture (NCF) in an S-shaped artificial stainless steel canal. Also the cross-sectional areas of the files were measured at D5 level. The length of the fractured file tips was measured. The fracture surface of all the fragments was examined with a scanning electron microscope. Data was statistically analyzed using one-way ANOVA and post hoc Tukey tests. Results. In both the apical and coronal curvatures, the NCF of the GF was significantly higher than that of the RPC Blue and WOG files. There was no significant difference between the GF, WOG and Reciproc Blue files with respect to the lengths of the fractured file fragments in either the apical or coronal curvature. The bending resistance of the GF was signif-icantly higher than that of the RPC Blue and WOG files. The RPC Blue had the largest cross-sectional area, and the GF had the smallest cross-sectional area. Conclusion. Within the limitations of the present study, the GF NiTi system exhibited the highest cyclic and bending re-sistance among the experimental groups

Cyclic fatigue resistance of 2Shape, Twisted File and EndoSequence Xpress nickel-titanium rotary files at intracanal temperature

Background. The aim of this study was to compare the cyclic fatigue resistance of 2Shape, Twisted File (TF) and EndoSequence Xpress (ESX) nickel-titanium rotary files at intracanal temperature (35°C). Methods. Twenty 2Shape TS1 (25/.04), 20 TF (25/.04) and 20 ESX (25/.04) files were tested for cyclic fatigue at intracanal temperature (35°C). All the instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds using a digital chronometer and the number of cycles to fracture (NCF) for each file was calculated. Kruskal-Wallis test with Bonferroni correction was performed to statistically analyze data using SPSS 21.0. Statistical significance was set at P.05). Conclusion. Within the limitations of present study, it was concluded that the cyclic fatigue resistance of 2Shape files at the intracanal temperature is higher than that of TF and ESX files

Rubber dam and application methods in dental practice

Diş hekimliği uygulamalarının çoğunluğunda izolasyon işlemigereklidir. Bu işlem için sıklıkla rubber dam yöntemi tercih edilir.Rubber dam çalışma alanının uygun bir şekilde izolasyonunusağlayarak işlemin başarısını arttırır. Bunun yanı sıra aerasololuşumunu azaltır. Günümüzde özellikle damlacık yoluyla bulaşankoronavirüs gibi enfeksiyöz hastalıklara karşı hasta, hekim vehekim yardımcılarını korur. Çalışma alanını optimal hale getirerekhekimin görüşünü arttırır ve olası ağız içi yumuşak dokuyaralanmalarının önüne geçer. Bu makalede diş hekimliğindesıklıkla kullanılan rubber dam izolasyon yöntemi anlatılmaktadır.Isolation is necessary in most dental practices. Rubber dammethod is often preferred for this process. Rubber dam improvesthe success of the process by providing proper isolation of thestudy area. In addition, it reduces aerosol formation. Today, itprotects of the operator and the dental staff and the patients frominfectious diseases such as coronavirus transmitted by droplets.By optimizing the way it works, it prevents possible soft mouthtissue injuries that you choose from the operator’s view. In thisreview article, rubber dam isolation method which is usedfrequently in dentistry is explained

Influence of endodontic access cavity design on mechanical properties of a first mandibular premolar tooth: a finite element analysis study

Objectives: This study aimed to investigate the influence of access cavity designs on the mechanical properties of a single-rooted mandibular first premolar tooth under various static loads using a finite element analysis. Materials and methods: 3-dimensional FEA designs were modeled according to the access cavity designs: an intact tooth (control), traditional access cavity (TEC-I), traditional access cavity with Class-II mesio-occlusal cavity design (TEC-II), conservative access cavity (CEC), ninja access cavity (NEC), caries-driven access cavity (Cd-EC), buccal access cavity (BEC) and bucco-occlusal access cavity (BOEC). After the simulated access cavity preparations, root canal treatment was simulated and three different static loads which mimicked oblique and vertical mastication forces were applied to the models. The stress distribution and maximum Von Misses stress values were recorded. The maximum stress values were obtained on both enamel and dentin under multi-point vertical loads. Results: The maximum stress values were obtained on both enamel and dentin under multi-point vertical loads. Under all load types, the minimum stress distribution was observed in the control group, followed by CEC, NEC and BEC designs. The highest stress concentration was detected in Cd-EC and TEC-II designs. Under single-point vertical loading, the stress was mostly concentrated in the lingual PCD area, while under multi-point vertical loading, the entire root surface was stress-loaded except for the lingual apical third of the root. Conclusion: Preserving tooth tissue by simulating CEC, NEC and BEC access cavities increased the load capacity of a single-rooted mandibular first premolar following simulated endodontic treatment

Tumor specific cytotoxicity and telomerase down-regulation in prostate cancer by autologous dendritic cells loaded with whole tumor cell antigens

Objectives: We investigated the efficacy of cytotoxic activity of whole tumor cell-antigen loaded dendritic cells in the treatment of hormone refractory prostate cancer. Materials and methods: From 10 patients with HRPC, peripheral blood samples were obtained and cultured with GM-CSF and IL-4 to provide differentiation of peripheral blood mononuclear cells (PBMs) into dendritic cells (DCs). DC phenotype was confirmed by flow cytometry (MHC class II HLA-DR, CD80, CD86, CD83, CD14 expression analysis). Subsequently, whole tumor cell lysates of LNCaP, DU-145, and PC-3 lines were incubated with DCs. Direct antitumoral activity of induced DCs and activation of PBM cells by these DCs was assessed by lactate dehydrogenase (LDH) cytotoxicity assay. Post-treatment changes in the telomerase gene expression of tumor cells were investigated by real time RT-PCR analysis. Results: LDH activity was highest in the PC-3 cell line (9.5%) and lowest in the DU-145 line (3.2%). Co-incubation of PBMs with activated DCs resulted in a significant increase at the levels of cytotoxicity in all cell lines. Likewise, incubation of tumor cells with activated DCs caused significant down-regulation of telomerase gene expression in all cell lines. Most pronounced suppression was in the LNCaP cell line (decrease by 97.1%). The decrease in the level of telomerase gene expression in DU-145 and PC-3 cell lines was 80% and 70%, respectively. Conclusions: Cytotoxic immune response to prostate cancer-associated antigens can be elicited in vitro in patients with HRPC using an allogeneic tumor cell-based strategy. DC-based active immunotherapy appears as an effective treatment method in the pre-clinical setting and further phase I/II trials are warranted. (C) 2010 Elsevier Inc. All rights reserved

Gas6 expression and Tyrosine kinase Axl Sky receptors: Their relation with tumor stage and grade in patients with bladder cancer

Objectives: It has been shown that the dys-regulation of tyrosine kinase Axl receptor and its ligand growth arrest-specific gene (Gas6) are associated with poor prognosis in various types of tumors but there is not enough study about their importance in bladder cancer (BC). We evaluated the relation of Gas6 gene expression and tyrosine-kinase Axl and Sky (Tyro 3) receptors with tumor stage and grade in patients with BC. Material and Methods: The study group consists of 55 patients whose transurethral resection of bladder (TUR-B) has been performed due to RC and the control group consists of 12 patients with normal bladder mucosa. In tissues mRNAs of Gas6, Axl, and Sky receptors were examined by quantitative (Real-Time) PCR (qPCR). Protein expression was measured by immunohistochemistry. Plasma Gas6 protein levels were compared with control group by ELISA method. Results: Patients with BC were grouped as Ta low (n=17), Ta high (n=5), T1 low (n=9), T1 high (n=8) and T2 (n=16) according to their TUR-B pathologies. The qPCR analysis showed that the expression of Gas6 gene and AxI receptor is higher in the tumor-positive group and the immune-histochemical showed that the bladder samples of the tumor-positive group stained significantly positive. When the patients are grouped according to the TUR-B pathologies, a statistical significant difference was observed among groups in the qPCR analysis ratios of Gas6 gene and Axl receptor by (p 0.05). When Gas6 protein levels in plasma samples were compared by ELISA method, a statistical significance was determined among groups (p = 0.001). Conclusions: Our findings indicate that mRNAs of Gas6 and Axl receptor are closely related to tumor stage and grade in patients with BC. Further studies are needed for understanding the role of Gas6 and its receptors on the neoplastic transformation in terms of novel biomarkers and potential therapeutic targets

Cyclic fatigue resistance of reduced-taper nickel-titanium (NiTi) instruments in doubled-curved (S-shaped) canals at body temperature

Background. This study was conducted to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy Prime, HyFlex CM, and 2Shape nickel-titanium (NiTi) rotary instruments in double-curved canals in a simulated clinical environment. Methods. Eighty NiTi files were used for the fatigue testing in stainless steel canals compatible with instrument sizes until fracture occurred (n=20): VDW.ROTATE (04./25#), TruNatomy Prime (04./26#), HyFlex CM (04./25#) and 2Shape TS04./25#( 1). For each instrument, the number of cycles to fracture (NCF) was calculated, and the fractured fragment length (FL) was measured. To verify that the files were fractured due to cyclic fatigue, the fractured surfaces of the files were evaluated under a scanning electron microscope. Data were statistically analyzed using the Kruskal-Wallis and Student's t-tests at the %95 confidence level. Results. The failure of the files due to cyclic fatigue was first seen in the apical curvature before the coronal curvature (P0.05). There was no difference in the fractured lengths of the files between the apical and coronal curvatures (P>0.05). Conclusion. In artificial S-shaped root canals, VDW.ROTATE and HyFlex CM files exhibited higher fatigue resistance compared to 2Shape and TruNatomy files

Comparison of the cyclic fatigue resistance of VDW.ROTATE, TruNatomy, 2Shape, and HyFlex CM nickel-titanium rotary files at body temperature

Objectives: This study aims to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy, 2Shape, and HyFlex CM nickel-titanium (NiTi) rotary files at body temperature.Materials and methods: In total, 80 VDW.ROTATE (25/0.04), TruNatomy (26/0.04), 2Shape (25/0.04), and HyFlex CM (25/0.04) NiTi rotary files (n = 20 in each group) were subjected to static cyclic fatigue testing at body temperature (37°C) in stainless-steel artificial canals prepared according to the size and taper of the instruments until fracture occurred. The number of cycles to fracture (NCF) was calculated, and the lengths of the fractured fragments were measured. The data were statistically analyzed using a 1-way analysis of variance and post hoc Tamhane tests at the 5% significance level (p < 0.05).Results: There were significant differences in the cyclic fatigue resistance among the groups (p < 0.05), with the highest to lowest NCF values of the files as follows: VDW.ROTATE, HyFlex CM, 2Shape, and TruNatomy. There was no significant difference in the lengths of the fractured fragments among the groups. The scanning electron microscope images of the files revealed typical characteristics of fracture due to cyclic fatigue.Conclusions: The VDW.ROTATE files had the highest cyclic fatigue resistance, and the TruNatomy and 2Shape files had the lowest cyclic fatigue resistance in artificial canals at body temperature