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

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

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

Effect of EDDY and manual dynamic activation techniques on postoperative pain in non-surgical retreatment: a randomized controlled trial

BACKGROUND: During non-surgical retreatment process, the products such as dentin debris, root canal fillings, irrigation solutions, microorganisms and remaining pulp tissues can extrude to the apical area and can cause the postoperative pain and flare-up. Thus, the aim of this study was to evaluatethe effect of EDDY and manual dynamic activation (MDA) techniques on postoperative pain (PP) associated with retreatment. METHODS: Ninety patients scheduled for retreatment were treated at a single visit. Non-vital mandibular premolar teeth diagnosed with asymptomatic apical periodontitis were included in this study. The patients were divided into two groups (n = 45) on the basis of the need for additional irrigation activation procedures (EDDY and MDA). The patients' post-treatment pain levels were asked to rate the intensity of their pain on a 10-point numerical rating scale (NRS) at the 12th, 24th, 48th, and 72nd h and 7 days.The data were analyzed using the chi-square and Wilcoxon signed-rank test was used for within-group comparisons and Mann Whitney U test was used to compare the groups by time period. RESULTS: The difference in postoperative pain intensity between two groups was statistically significant at 12, 24, 48, and 72 h (p  0.05). Pain intensity after the treatment was lesser in the MDA groupthanin the EDDY group at 12, 24, 48, and 72 h. CONCLUSION: This study could lead us to conclude that the two activation systems can be used during endodontic retreatment with no difference at PP 7 days later. However, a comparison of the groups indicated that the EDDY resulted in significantly more PP at 12, 24, 48, and 72 h. Trial registration ClinicalTrials.gov Identifier: NCT04726670.Open Access funding provided by the Qatar National Library

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

Manufacturing Duplex Steel by Using Induction Furnaces and Characterization

Duplex steels are materials that contain ferrite and austenite phases in their structure, have high resistance to corrosion, and also show improved mechanical values. While the austenite in its structure provides general corrosion resistance and ductility, ferrite provides resistance to stress corrosion cracking and mechanical strength. Duplex steels have widespread use, especially in shipping and petrochemistry. The current production method of duplex steels, which are in demand with a wide usage area, is generally argon oxygen decarburization furnaces (AOD). In addition to the production method of duplex steels, which contain elements with critical values in their chemical composition, the heat treatment process also has an important place. The ferrite and austenite phases in its structure are expected to be at 50&#37; values, so that the desired mechanical strength can be achieved while providing corrosion resistance and ductility. In this study, the production of duplex steels, whose current production method is argon oxygen decarburization furnaces, was achieved using induction furnaces. Accordingly, it is aimed to provide new markets, reduce existing costs and reduce carbon emissions. After the duplex steels were produced in the induction furnace, heat treatment was applied to the produced parts. The obtained parts were examined structurally and morphologically, and ferrite and austenite phases were detected at a rate of 50&#37; in the structure. Additionally, the mechanical properties of duplex steels produced in the induction furnace were evaluated

Effect of CDP-choline on distrupted prepulse inhibition (PPI) which is one of the biological markers of schizophrenia

Şizofreni hastalarında görülen önemli bir biyolojik belirteç ‘’duysal-motor süzme fonksiyonunda bozulma’’ durumudur. İnsanlarda ve deney hayvanlarında bu belirteci test etmek için ön-uyaran aracılı inhibisyon (ÖUAİ) fenomeni kullanılmaktadır. Son yıllarda kolinerjik sistemin, özellikle α7 nikotinik asetilkolin reseptörlerinin (nAChR) şizofreni etiyolojisindeki rolünün anlaşılması üzerine bu reseptörler üzerinden yeni tedavi stratejileri geliştirilmektedir. Bu çalışma ile α7 nAChR’lerine agonistik etkisi bulunan CDP-kolinin ÖUAİ fenomeni üzerine olan etkisinin araştırılması amaçlanmıştır. Çalışmada Sprague-Dawley erkek sıçanlar kullanıldı. Çalışma öncesinde bazal ÖUAİ değerleri ölçülerek homejen gruplar oluşturuldu. İlaçlar, tuzlu su içinde hazırlanarak intraperitonel, subkutan ve merkezi yol ile enjekte edildi. İlk aşamada; CDP-kolin’in dört değişik dozu enjekte edilerek ÖUAİ etkisi incelendi. Daha sonra muskarinik antagonist olan skopolamin ve dopamin agonisti olan amfetamin subkutan olarak enjekte edilerek şizofreni hayvan modeli oluşturuldu ve arkasından CDP-kolin’in etkisi bu modeller üzerinde test edildi. Çalışmanın son bölümünde CDP-kolinin etki mekanizmasının araştırılması için nAChR antagonistleri mekamilamin ve metillikakonitin kullanılarak CDP-kolin’in düzeltici etkisine aracılık eden mekanizmalar araştırıldı. CDP-kolin naiv sıçanlarda ÖUAİ üzerinde etki göstermedi. Skopolamin ve amfetaminin ÖUAİ üzerinde yaptığı bozulmayı CDP-kolin’in 250 mg/kg dozu geri çevirdi. CDP-kolin’in bu model üzerindeki etkisi mekamilamin’in 3 mg/kg dozu ile önlenirken periferik verilen metillikakonitin’in 2 ve 5 mg/kg dozları etkiyi değiştirmedi. Fakat merkezi yoldan verilen metillikakonitin, CDP-kolin’in düzeltici etkisini bloke etti. CDP-kolin şizofreni hastalığının biyolojik belirteçlerinden biri olan bozulmuş ÖUAİ fenomenini düzeltmektedir. Sonuçlar bu etkiden nikotinik reseptörlerin α7 alt tipinin sorumlu olduğunu göstermektedir. CDP-kolin’in başta şizofreni olmak üzere ÖUAİ bozukluğu ile seyreden hastalıkların tedavisinde faydalı olabileceğini düşündürmektedir.Disruption of sensory motor gating has been shown the important biological phenomenon in patients with schizophrenia. The disruption of prepulse inhibition (PPI), a well characterized model for identifying sensory-motor gating deficits in schizophrenia and this phenomenon have been extremely used both experimental animals and humans. In recent years, therapeutic strategies have focused on enhancing the function of the cholinergic system especially α7 nicotinic acetylcholine receptors to developing new treatments for schizophrenia. The purpose of this study is to test whether CDP-choline, α7 nicotinic acetylcholine receptor agonist has any effect on PPI. In this study Spraque-Dawley male rats were used. Before the actual experiment, we measured baseline PPI values and rats assigned statistically same groups. All drugs were prepared in saline and administered subcutaneously, intraperitoneally and intracerebroventriculary. In the first experiment we tested four different doses of CDPcholine on PPI. Therefore, a muscarinic antagonist scopolamine and a dopamine agonist amphetamine were injected to make animal model of schizophrenia and effect of CDPcholine on these models were tested. At the end of the study we investigated the mechanism underlying to CDP-choline’s effect and tested nicotinic antagonists’ mecamylamine and methylicaconitine. CDP-choline has no significant effect on PPI in naive rats. CDP-choline at the dose of 250 mg/kg inhibited disrupting effects of scopolamine and amphetamine on PPI. Administration 3 mg/kg dose of mecamylamine reversed the treating effect of CDP-choline on PPI. In cholinergic model, 2 and 5 mg/kg MLA did not change the effect of CDP-choline. However, administration of MLA intracerebroventricularly blocked the effect of CDP-choline on PPI. CDP-choline improved disrupted PPI which is one of the biological markers of schizophrenia. Subunit of α7 nAChR is responsible from the effect. CDP-choline can be potential candidates not only for the treatment of schizophrenia but also several diseases linked with disrupted PPI

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

Cyclic fatigue resistance of HyFlex EDM, Reciproc Blue, WaveOne gold, and twisted file adaptive rotary files under different temperatures and ambient conditions

Background. This study examined the effects of changes in temperature and environmental conditions on the cyclic fatigue resistance of Reciproc Blue, HyFlex EDM, WaveOne Gold, and Twisted File Adaptive. Methods. Forty-five Reciproc Blue (25/.08), 45 HyFlex EDM (25/.08), 45 WaveOne Gold (25/.07), and 45 Twisted File Adaptive (25/.08) files were tested for cyclic fatigue at room temperature (20°C) in air and water and at body temperature (35°C) in water. All the instruments were rotated in artificial canals made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius of curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds, using a digital chronometer. Mann-Whitney U test was used for the statistical analysis of data, with SPSS 21.0. Results. Cyclic fatigue resistance was significantly higher in all the groups in water at an ambient temperature of 20°C compared with air and water at temperatures of 20°C and 35°C, respectively (P0.05). Conclusion. Within the limitations of the present study, an increase in the ambient temperature significantly decreased the cyclic fatigue resistance of the tested NiTi files