Gülşah Uslu

Effect of adaptive motion on cyclic fatigue resistance of a nickel titanium instrument designed for retreatment

Objectives The aim of this study was to evaluate the cyclic fatigue resistance of the ProTaper Universal D1 file (Dentsply Maillefer) under continuous and adaptive motion. Materials and Methods Forty ProTaper Universal D1 files were included in this study. The cyclic fatigue tests were performed using a dynamic cyclic fatigue testing device, which had an artificial stainless steel canal with a 60° angle of curvature and a 5 mm radius of curvature. The files were randomly divided into two groups (Group 1, Rotary motion; Group 2, Adaptive motion). The time to failure of the files were recorded in seconds. The number of cycles to failure (NCF) was calculated for each group. The data were statistically analyzed using Students t-test. The statistical significant level was set at p < 0.05. Results The cyclic fatigue resistance of the adaptive motion group was significantly higher than the rotary motion group (p < 0.05). Conclusion Within the limitations of the present study, the ‘Adaptive motion’ significantly increased the resistance of the ProTaper Universal D1 file to cyclic facture.

The effects of autoclave sterilization on the cyclic fatigue resistance of ProTaper Universal, ProTaper Next, and ProTaper Gold nickel-titanium instruments

Objectives It was aimed to compare the cyclic fatigue resistances of ProTaper Universal (PTU), ProTaper Next (PTN), and ProTaper Gold (PTG) and the effects of sterilization by autoclave on the cyclic fatigue life of nickel-titanium (NiTi) instruments. Materials and Methods Eighty PTU, 80 PTN, and 80 PTG were included to the present study. Files were tested in a simulated canal. Each brand of the NiTi files were divided into 4 subgroups: group 1, as received condition; group 2, pre-sterilized instruments exposed to 10 times sterilization by autoclave; group 3, instruments tested were sterilized after being exposed to 25%, 50%, and 75% of the mean cycles to failure, then cycled fatigue test was performed; group 4, instruments exposed to the same experiment with group 3 without sterilization. The number of cycles to failure (NCF) was calculated. The data was statistically analyzed by using one-way analysis of variance and post hoc Tukey tests. Results PTG showed significantly higher NCF than PTU and PTN in group 1 (p < 0.05). Sterilization significantly increased the NCF of PTN and PTG (p < 0.05) in group 2. PTN in group 3 had significantly higher cyclic fatigue resistance than PTN group 4 (p < 0.05). Also, significantly higher NCF was observed for PTG in group 2 than in groups 3 and 4 (p < 0.05). Conclusions PTG instrument made of new gold alloy was more resistant to fatigue failure than PTN and PTU. Autoclaving increased the cyclic fatigue resistances of PTN and PTG.

The effect of root canal preparation on the surface roughness of WaveOne and WaveOne Gold files: atomic force microscopy study

Objectives To examine the surface topography of intact WaveOne (WO; Dentsply Sirona Endodontics) and WaveOne Gold (WOG; Dentsply Sirona Endodontics) nickel-titanium rotary files and to evaluate the presence of alterations to the surface topography after root canal preparations of severely curved root canals in molar teeth. Materials and Methods Forty-eight severely curved canals of extracted molar teeth were divided into 2 groups (n = 24/each group). In group 1, the canals were prepared using WO and in group 2, the canals were prepared using WOG files. After the preparation of 3 root canals, instruments were subjected to atomic force microscopy analysis. Average roughness and root mean square values were chosen to investigate the surface features of endodontic files. The data was analyzed using one-way analysis of variance and post hoc Tamhanes tests at 5% significant level. Results The surface roughness values of WO and WOG files significantly changed after use in root canals (p < 0.05). The used WOG files exhibited higher surface roughness change when compared with the used WO files (p < 0.05). Conclusions Using WO and WOG Primary files in 3 root canals affected the surface topography of the files. After being used in root canals, the WOG files showed a higher level of surface porosity value than the WO files.

Effect of Sodium Hypochlorite and EDTA on Surface Roughness of HyFlex CM and HyFlex EDM Files

The aim of the present study was to compare the effect of exposure to sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on the surface topography and roughness of HyFlex controlled memory (CM) and HyFlex electrical discharge machining (EDM) using atomic force microscopy (AFM). Twenty HyFlex EDM (25/.08) and 20 HyFlex CM (25/.06) files were divided into five groups (n = 4). One group served as a negative control group. The files in the other groups were exposed to 5.25% NaOCl and 17% EDTA solutions at 37°C for 5 and 10 min, respectively, and examined using AFM after each exposure. The data were analyzed using one‐way ANOVA test. The lowest values were observed in the control group of HyFlex EDM files (p < .05). The highest values were observed in the HyFlex EDM and HyFlex CM files immersed in EDTA for 10 min (p < .05). In conclusion, the tested irrigants had a significant negative effect on the surface porosity of NiTi files.

Push-out bond strength of intra-orifice barriermaterials: Bulk-fill composite versus calcium silicate cement

Background. The aim of this study was to compare the push-out bond strengths of calcium silicate-based ProRoot MTA and Biodentine cements and SureFil SDR and EverX Posterior bulk-fill composite resins. Methods. Twenty-four single-rooted maxillary central incisors were sectioned below the cementoenamel junction, and the root canals were instrumented using rotary files. Thereafter, a parallel post drill was used to obtain a standardized root canal dimension. The roots were randomly assigned to one of the following groups with respect to the intra-orifice barrier used: ProRoot MTA; Biodentine; SureFil SDR; EverX Posterior. Five 1-mm-thick sections were obtained from the coronal aspect of each root. Push-out bond strength testing was performed and data were analyzed with Kruskal-Wallis and post hoc Dunn tests (P<0.05). Results. SureFil SDR and EverX Posterior bulk-fill composite resins’ bond strengths were significantly higher than ProRoot MTA and Biodentine calcium silicate cements. However, no statistically significant differences were observed between bulk-fill composite resins values and calcium silicate cement values. Conclusion. Within the limitations of present study, calcium silicate-based ProRoot MTA cement’s push-out bond strength was lower than those of Biodentine, SureFil SDR and EverX Posterior materials.

Apically Extruded Debris during Root Canal Instrumentation with Reciproc Blue, HyFlex EDM, and XP-endo Shaper Nickel-titanium Files

Introduction: The purpose of this study was to investigate the amount of apically extruded debris by Reciproc Blue (REC Blue; VDW, Munich, Germany), HyFlex EDM (HEDM; Coltene/Whaledent, Altstätten, Switzerland), and XP‐endo Shaper (XPS; FKG Dentaire SA, La Chaux‐de‐Fonds, Switzerland) files during root canal preparation at body temperature. Methods: Sixty extracted single‐rooted mandibular premolar human teeth were randomly assigned to 3 groups (n = 20). The canals were instrumented using 1 of the following instruments: REC Blue, HEDM, or XPS. Apically extruded debris during instrumentation was collected into preweighed Eppendorf tubes. All the procedures were performed at 35°C. The amount of extruded debris was calculated by subtracting the weight value of the tooth‐free apparatus from the postpreparation weight value. The data were analyzed using the Kruskal‐Wallis test at a 5% significance level. Results: All the instruments tested caused extrusion of some debris from the apical foramen. XPS extruded significantly less debris from the apex than REC Blue (P < .05). The difference among the HEDM group and the other groups was not significant (P > .05). Conclusions: Within the limitations of this in vitro study, the amount of apically extruded debris registered for the different files tested was REC Blue > HEDM > XPS, with a statistical difference only between XPS and REC Blue. HIGHLIGHTSWe compared the amounts of debris extruded from the apex during root canal treatment with Reciproc Blue, HyFlex EDM, and XP‐endo Shaper files.All the instruments tested caused extrusion of some debris from the apical foramen.XP‐endo Shaper files extruded significantly less debris from the apex than Reciproc Blue files (P < .05).The difference between the HyFlex EDM group and the other groups was not significant (P > .05).

Effect of Dynamic Immersion in Sodium Hypochlorite and EDTA Solutions on Cyclic Fatigue Resistance of WaveOne and WaveOne Gold Reciprocating Nickel-titanium Files

Introduction: The purpose of this study was to evaluate the effect of sodium hypochlorite (NaOCl) and EDTA solutions on the cyclic fatigue resistance of WaveOne (WO) and WaveOne Gold (WOG) nickel‐titanium reciprocating files. Methods: A hundred WO (25/.08), and 100 WOG (25/.07) were randomly divided into 5 groups: group 1, no immersion; group 2, immersion in 5.25% NaOCl at 37°C ± 1°C for 5 minutes; group 3, immersion in 5.25% NaOCl at 37°C ± 1°C for 10 minutes; group 4, immersion in 17% EDTA at 37°C ± 1°C for 5 minutes; and group 5, immersion in 17 % EDTA at 37°C ± 1°C for 10 minutes. Then, the instruments were reciprocated in an artificial canal until fracture occurred, and the time to fracture was recorded. The data were statistically analyzed using 1‐way analysis of variance and the Student t test via SPSS 21.0 software (IBM Corp, Armonk, NY) with the significance level set at P < .05. Results: The cyclic fatigue resistance of the WOG was statistically higher than the WO in all the conditions tested (P < .05). There was no statistically significant difference among the different conditions tested in terms of cyclic fatigue resistance for both WO and WOG files (P > .05). Among the groups, there was no significant difference in the fracture lengths (P > .05). Conclusions: Within the limitations of the present study, it was determined that NaOCl and EDTA solutions did not have any effect on the cyclic fatigue resistance of WO and WOG files. HIGHLIGHTSIn the present study, the effect of sodium hypochlorite (NaOCl) and EDTA solutions on the cyclic fatigue resistance of WaveOne and WaveOne Gold nickel‐titanium reciprocating files was evaluated.There was no significant difference between the cyclic fatigue resistance of the WaveOne and WaveOne Gold files.It was determined that NaOCl and EDTA solutions did not have any effect on the cyclic fatigue resistance of WaveOne and WaveOne Gold files.

Effect of Glide Path Creating on Cyclic Fatigue Resistance of Reciproc and Reciproc Blue Nickel-titanium Files: A Laboratory Study

Introduction: The purpose of this article was to compare the cyclic fatigue resistance of Reciproc and Reciproc Blue files (VDW GmbH, Munich, Germany) that were used to prepare root canals of mandibular molar teeth with or without a glide path. Methods: Sixty Reciproc R25 and 60 Reciproc Blue R25 files were used. The Reciproc and Reciproc Blue groups were divided into 3 subgroups (ie, as received condition, used without a glide path, and used with a glide path). All the instruments were rotated in a stainless steel artificial canal with an inner diameter of 1.5 mm, a 60° angle of curvature, and a radius of curvature of 5 mm until fracture occurred. The number of cycle to fracture was calculated, and the length of the fractured segments was measured. The Kruskal‐Wallis test was performed to statistically analyze the data using SPSS 21.0 software (IBM Corp, Armonk, NY) at a 5% significance level. Results: The cyclic fatigue resistance of as received condition Reciproc Blue files was found to be higher than as received condition Reciproc files (P < .05). Reciproc Blue files used for root canal preparation showed higher cyclic fatigue resistance than Reciproc files used for root canal preparation (P < .05). There was no statistically significant difference between Reciproc and Reciproc Blue files used with a glide path and without a glide path (P > .05). There was no statistically significant difference in the mean length of the fractured fragments of the instruments (P > .05). Conclusions: Within the limitations of this in vitro study, it was concluded that creating a glide path using ProGlider files had no effect on the cyclic fatigue resistance of RPC and RPC Blue files. HIGHLIGHTSWe compared the cyclic fatigue resistance of Reciproc and Reciproc Blue files that were used to prepare root canals of mandibular molar teeth with or without a glide path.The cyclic fatigue resistance of as received condition Reciproc Blue files was found to be higher than as received condition Reciproc files (P < .05).There was no statistically significant difference between Reciproc and Reciproc Blue files used with and without a glide path (P > .05).In vivo studies are needed in order to determine the clinical performance of Reciproc Blue files.

REHBER YOLU OLUŞTURULMASINDA FARKLI EĞE SİSTEMLERİNİN ETKİNLİKLERİNİN KARŞILAŞTIRILMASI

Amac: Farkli nikel-titanyum doner rehber yol egelerinin sekillendirme etkinliklerinin J sekilli yapay kanallarda degerlendirilmesi Gerec ve Yontem: Otuz adet J sekilli kanallara sahip rezin blok PathFile, ProGlider ve manuel egeler (n: 10 kanal/grup) kullanilarak sekillendirildi. Şekillendirme oncesi ve sonrasi elde edilen fotograflar dijital ortamda ust uste getirilerek cakistirilmis goruntuler elde edildi. Egeler tarafindan uzaklastirilan rezin miktari dijital olcum kalibi ve fotograf analiz programi kullanilarak olculdu. Kanal duzensizlikleri de kayit edildi. Elde edilen veriler tek yonlu varyans analizi ve post hoc Tukey testi kullanilarak istatistiksel olarak analiz edildi. Bulgular: Egelerin uzaklastirdigi rezin miktarlari arasinda gruplar arasinda istatistiksel fark bulunmadi ( P > 0,05). Kanal sekillendirmesi sirasinda manuel ege grubunda 1 ornekte basamak olusumu gozlendi. Sonuc: Calismamizin sinirlari dahilinde test edilen PathFile, ProGlider ve manuel egelerin 5 farkli olcum noktasinda gostermis oldugu sapmalar arasinda fark bulunamamistir. Anahtar Kelimeler: Endodonti, Nikel-Titanyum, PathFile, ProGlider, Rehber Yol

Influence of different movement kinematics on cyclic fatigue resistance of nickel-titanium instruments designed for retreatment

Aim: The objective of this study was to investigate the effect of different types of movement kinematics on the resistance of the ProTaper D3 retreatment file to cyclic fatigue. Materials and Methods: Eighty ProTaper Universal D3 (20.07) files were utilized in this study. The cyclic fatigue tests were performed using a specially manufactured dynamic cyclic fatigue testing device, which has an artificial stainless steel canal having 60° of curvature angle and 5 mm of curvature radius. The files were randomly divided into four groups (Group 1: Rotary motion [RM]; Group 2: Adaptive motion [AM]; Group 3: Reciprocating motion [RCM]; Group 4: WaveOne motion [WM]). The movements of files until the files broke were recorded in “MOV” format using a device employing a slow-motion camera. The number of cycles to failure was calculated for each group. The data were analyzed statistically using one-way ANOVA and Tukeys honestly significant difference test (P < 0.05). Results: The cyclic fatigue resistance of the AM group (3357.9 ± 88.5) was significantly higher than that of the other groups (P < 0.001). The lowest cyclic fatigue resistance was observed in the RM (1850.4 ± 93.0) group (P < 0.001). Conclusion: Within the limitations of the present study, resistance of ProTaper Universal D3 file to the cyclic fatigue significantly increased in the AM group when compared to the RCM and WM groups.