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Background Dentistry has undergone an evolution in endodontics practice caused by the advancement of rotary techniques for root canal preparation and their subsequent incorporation into the teaching of dentistry undergraduates. This research aimed to evaluate the shaping ability of third-year dental students as their first experience in rotary instrumentation using ProTaper Universal (PTU) and ProTaper Next (PTN) (Dentsply Maillefer) rotary instruments in simulated curved canals. Methods Forty students instrumented 200 simulated canals with a 40° curvature in resin blocks according to the manufacturer’s instructions with PTU and 39 students and 195 canals with PTN files. The canals were prepared at a speed of 300 rpm using a 16:1 reduction hand-piece powered by an electric motor (Xsmart; Dentsply Maillefer). The final apical preparation was set to F2 for the PTU and X2 for the PTN group. The change in canal curvature was evaluated based on Schneider technique using the AutoCAD 2007 software on post-digital photographs. The incidence of instrument fracture and deformation, the incidence of ledge, the change in working length (WL), and the working time were noted. The data were analyzed with Student’s t-test and Chi-Square test at a significance level of 0.05 using SPSS. Results PTN maintained the original canal curvature better, resulting in fewer fractures and ledges, and shaped the canals faster than the PTU (P 0.05). The change in WL after instrumentation was 0.97 mm ± 0.95 mm in PTU and 0.96 mm ± 0.80 mm in PTN (p

The purpose of this study was to evaluate and compare the centering ability and canal transportation of the ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland) and Self-adjusting File (SAF; ReDent-Nova, Ra'anana, Israel) systems in long oval root canals using cone-beam computed tomography imaging. Fifty-six fully formed single-rooted mandibular premolars were selected with a buccolingual canal size 2 to 2.5 times the mesiodistal size at 5 mm from the apex, ranging from a 0°–10° canal curvature with a 5- to 6-mm radius. The teeth were divided into 2 groups (n = 28) and prepared with PTN or SAF according to the manufacturers' instructions. Cone-beam computed tomographic images were taken in the same position before and after instrumentation using modeling wax. The centering ability and canal transportation were calculated at 3, 6, and 9 mm from the apex in both mesiodistal and buccolingual directions. The mean and standard deviation were calculated, and the Student t test was used for comparative analysis. significant difference for canal transportation was observed mesiodistally at 9 mm from the apex (P <.05) where the PTN shaved more dentin in 1 direction. A significant difference for the centering ability was observed at 6 mm buccolingually from the apex (P <.05) where the PTN was less centered in the canal compared with the SAF. Both SAF and PTN were shown to be safe for being used in long oval canals. SAF resulted in less transportation at the coronal third in the mesiodistal direction and more centered at the middle third in the buccolingual direction compared with PTN. [ABSTRACT FROM AUTHOR]

Background. Dentistry has undergone an evolution in endodontics practice caused by the advancement of rotary techniques for root canal preparation and their subsequent incorporation into the teaching of dentistry undergraduates. This research aimed to evaluate the shaping ability of third-year dental students as their first experience in rotary instrumentation using ProTaper Universal (PTU) and ProTaper Next (PTN) (Dentsply Maillefer) rotary instruments in simulated curved canals. Methods. Forty students instrumented 200 simulated canals with a 40° curvature in resin blocks according to the manufacturer's instructions with PTU and 39 students and 195 canals with PTN files. The canals were prepared at a speed of 300 rpm using a 16:1 reduction hand-piece powered by an electric motor (Xsmart; Dentsply Maillefer). The final apical preparation was set to F2 for the PTU and X2 for the PTN group. The change in canal curvature was evaluated based on Schneider technique using the AutoCAD 2007 software on post-digital photographs. The incidence of instrument fracture and deformation, the incidence of ledge, the change in working length (WL), and the working time were noted. The data were analyzed with Student's t -test and Chi-Square test at a significance level of 0.05 using SPSS. Results. PTN maintained the original canal curvature better, resulting in fewer fractures and ledges, and shaped the canals faster than the PTU (P <0:05). The mean curves of the resin canals after the instrumentation for the PTU and PTN groups were 24.03° ± 3.14° and 25.64° ± 2.72°, respectively. Thirty-three (17.4%) PTU and 18 (9.3%) PTN files fractured (p<0:05). Nine (4.5%) PTU and 2 (2.6%) PTN deformed (p>0:05). The change in WL after instrumentation was 0.97 mm ± 0.95 mm in PTU and 0.96 mm ± 0.80 mm in PTN (p<0:05). The mean times were 627 s ± 18 s for PTU and 379 s ± 18 s for PTN (p<0:000). Discussion. PTN can be recommended in severely curved root canals in terms of maintenance of the original canal curvature, superior instrument fracture and fewer ledges. Even if training before preparation provides an acceptable level of canal shaping for preclinical students, the use of NiTi rotary instruments should be included in the undergraduate dental curriculum, contributing to an increase in the quality of root canal shaping and, consequently, to an improvement of the clinical experience of students. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the shaping ability of 4 different nickel-titanium systems, considering their variation in alloy treatment, kinematics, and design, used to prepare canals with severe curvature using micro–computed tomographic analysis. Thirty-two mesial roots of mandibular molars with severe curvature were matched based on similar morphologic dimensions and assigned to 4 experimental groups (n = 8) according to the canal preparation: ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (RC; VDW GmbH, Munich, Germany), Reciproc Blue (RCB, VDW GmbH), and TRUShape (TRU; Dentsply Tulsa Dental Specialties, Tulsa, OK) systems. Changes in 2-dimensional (area and perimeter) and 3-dimensional (volume, surface area, and structure model index) morphologic parameters as well as canal transportation were compared among groups using the analysis of variance post hoc Tukey tests with the significance level set at 5%. Preparation significantly increased all analyzed parameters. No statistically significant differences (P >.05) were observed between RC and RCB or between PTN and TRS in any of the analyzed parameters. In the cervical third, RC and RCB presented higher mean increases than PTN and TRU. In the apical third, there were no statistically significant differences (P >.05) among the systems. The instruments of greater taper may promote greater morphologic changes. However, regardless of the number of instruments (multiple or single), the type of movement (rotation or reciprocating), the type of heat treatment of alloys, and the particular characteristics of each instrument (taper and design), the evaluated systems did not result in different dimensional changes and canal transportation in the critical apical area. • There is a lack of studies in the literature regarding root canal anatomy and new generation of instruments with different designs and nickel-titanium alloy heat treatments. • No geometric changes and canal transportation in the apical third were observed in curved canals regardless of the number of instruments, type of movement, type of heat treatment of alloys, and the particular characteristics of each evaluated instrument. [ABSTRACT FROM AUTHOR]

Context: The presence of smear layer and debris can prevent the irrigant and sealer from penetrating the dentinal tubules thereby compromising the seal of the root canal filling.Aim: This study aims to evaluate the efficacy of XP-endo Finisher with ProTaper Next and HyFlex in smear layer and debris removal.Materials and Methods: : Thirty-two extracted mandibular premolar teeth were selected and sectioned at the cementoenamel junction. The roots were then randomly divided into 4 groups. In group 1 and 2, canals were instrumented with X2 ProTaper Next (25 0.06 taper). In group 3 and 4, canals were instrumented with HyFlex system (25 0.06 taper). The canals in group 2 and 4 were further finished with XP-endo Finisher. Irrigation was carried out using 3% sodium hypochlorite during instrumentation, and 17% ethylenediaminetetraacetic acid was used as the final rinse. The roots were then split longitudinally. The canal wall was observed under the scanning electron microscope in coronal, middle, and apical thirds at a magnification of ×400 and ×1000 for evaluation of debris and smear layer, respectively. Photomicrographs were taken, and qualitative assessment for debris and smear layer removal was done.Statistical Analysis Used: The results were analyzed using Kruskal-Wallis test and Mann-Whitney U-test.Results: Lower debris and smear layer scores were seen in canal thirds instrumented with ProTaper Next and XP-endo Finisher (P < 0.01).Conclusion: The use of XP-endo Finisher as an adjuvant during shaping and cleaning produced cleaner root canal walls. [ABSTRACT FROM AUTHOR]

Root canal preparation is an important process in endodontic therapy. Root canals can be shaped in continuous motion by rotary instruments using a crown-down technique and a single lenght technique (simultaneous technique) as well. Most rotary systems require a crown-down approach to minimize torsional loads and to reduce the risk of instrument fracture. The most known of these are ProTaper Universal and ProTaper Gold (Dentsply Sirona). On the other hand, there are also on the market rotary systems that shape the canal in a single lenght technique. These are ProTaper Next (Dentsply Sirona) and Mtwo (VDW). These instruments are used without early coronal enlargement and are lead up to the working length without apical pressure. This work has the aim to compare the ability of two techniques to prepare uniform tapered the root canals and to maintain the original shape of curved canals during preparation. [ABSTRACT FROM AUTHOR]

Abstract Introduction The aim of this study was to evaluate the root canal shaping effect of instruments manufactured from nickel titanium, M-Wire, and Gold wire with different glide path preparation techniques. Methods One hundred thirty-five mesiobuccal canals of extracted human maxillary molars were randomly divided into 3 equal groups (N = 45) for glide path preparation with K-files (KF) (Dentsply Sirona, Ballaigues, Switzerland), One G (OG) files (Micro-Mega, Besançon, France), and ProGlider (PG) files (Dentsply Sirona). Specimens of each glide path group were further divided equally into 3 groups for instrumentation with ProTaper Next (PTN, Dentsply Sirona), One Shape (OS, Micro-Mega), and WaveOne Gold (WOG, Dentsply Sirona) systems (n = 15). Micro–computed tomographic imaging was used to scan teeth before instrumentation and after shaping to compare centering ratio and canal transportation values at the apical, midroot, and coronal levels and the overall changes in canal volume. Data sets were statistically analyzed (analysis of variance and Kruskal-Wallis H tests). Results The centering ratios for all groups were statistically similar at all levels. Apical canal transportation was significantly high for K/OS and K/PTN (P =.003). Midroot canal transportation was significantly high for K/PTN, K/OS, and OG/OS (P =.0003). Coronal canal transportation was significantly high for K/PTN and K/OS (P =.011). The highest change in canal volume was observed with all PTN groups and the lowest with PG/WOG (P =.06). Conclusions WOG manufactured from Gold wire combined with PG showed better root canal shaping ability and removed less dentin from the canal walls. The nickel-titanium (OS) and M-Wire (PTN) instruments used in combination with KF significantly transported more canals. PTN removed the most dentin from the canal walls regardless of the GPP technique. Highlights • This study compared canal shaping with the rotary One Shape (nickel titanium), rotary ProTaper NEXT (M-Wire), and reciprocating Primary WaveOne Gold (Gold wire) after glide path preparation with K-Files, One G, and ProGlider. • No statistically significant difference in the mean centering ratios at the apical, midroot, and coronal levels of the various glide path groups in combination with the shaping instruments. • WaveOne Gold exhibited the lowest transportation values at all levels with ProGlider. • ProTaper NEXT exhibited the highest volume of dentin removed regardless of the glide path preparation technique used. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of the present study is to assess the rate of newly formed microcracks comparatively during root canal instrumentation by using ProTaper Next, Reciproc, and Self-Adjusting File systems using micro-computed tomography. Subjects and Methods: Thirty mesial roots of mandibular molars were randomly assigned to 3 experimental groups (n = 10) as follows, ProTaper Next, Reciproc and Self-Adjusting File system. Preoperative and postoperative scans were obtained at the isotropic resolution of 13.68 µm. Cross-section images were examined to identify the presence of newly formed dentinal microcracks. Results: The Self-Adjusting File and Reciproc systems caused a higher rate of new microcrack formation than the ProTaper Next group (p < 0.001). There were also significant differences in the new microcrack formation between Reciproc and Self-Adjusting File groups (p < 0.001). Conclusion: Reciproc and Self-Adjusting File systems caused a higher rate of newly formed microcraks compared to ProTaper Next system. [ABSTRACT FROM AUTHOR]

Aim: In this study, we compared the occurrence of dentinal micro-cracks after use of the ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Next (Dentsply Maillefer), and Reciproc (VDW, Munich, Germany) nickel-titanium rotary file systems in root canal preparation. Methodology: One hundred mandibular anterior teeth were divided into five groups of 20 specimens each. Group 1 served as a control, with no intervention. In group 2, preparation was performed using the step-back technique and K files. In groups 3-5, root canal preparation was performed using the ProTaper Universal, ProTaper Next, and Reciproc file systems, respectively. Following preparation, specimens were sectioned at 3, 6, and 9 mm using a Minitom precision cut-off machine. The sections were evaluated under a stereomicroscope. The following scoring system was used to rate specimens: 1, no micro-crack; 2, incomplete micro-crack; and 3, vertical root fracture. The results were statistically assessed (p=0.05). Results: No micro-crack formation was observed in groups 1 and 2. The highest rate of micro-crack formation was observed in specimens prepared with the ProTaper Universal file system (20%), followed by those prepared with the Reciproc (11.7%) and ProTaper Next (6.7%) file systems. However, no significant difference was detected among groups (p>0.05). In the groups ProTaper Universal and Reciproc files were used, 1 vertical root fracture was found in 9 mm sections for each. Conclusions: Considering the limitations of in vitro studies, we can conclude that all rotary file systems used in this study led to dentinal micro-crack formation in roots. The ProTaper Universal file system caused more dentinal micro-cracking than did the ProTaper Next and Reciproc file systems. [ABSTRACT FROM AUTHOR]

Amaç: Tek köklü dişlerden farklı eğe sistemlerini kullanarak kanal içi ilaç olan kalsiyum hidroksit’in (KH) uzaklaştırılmasının değerlendirilmesidir. Gereç ve Yöntemler: Bu çalışmada 30 adet tek köklü çekilmiş insan dişi kullanıldı. Kök kanalları ProTaper F4 eğesine kadar genişletildi. KH patı kök kanallarına çalışma uzunluklarında yerleştirildi. Köklerin koronal kısımlarına pamuk pelet ve geçici bir dolgu maddesi konularak kapatıldı. Daha sonra dişler distile su içinde 37oC’de 7 gün boyunca bekletildi. Sonrasında geçici dolgular kaldırıldı. Kök kanallarındaki KH’ın uzaklaştırılmasında kullanılan yönteme göre örnekler rastgele dört deney grubu (ProTaper Universal F4, ProTaper Next X4, Reciproc 40, WaveOne Large) ve kontrol grubu olmak üzere toplam 5 gruba (n=12) ayrıldı. Kökler bukko-lingual olarak ikiye ayrıldı ve kanal içerisinde kalan artık KH miktarı x 15 büyütmede stereomikroskop altında değerlendirildi. Veriler SPSS programında Cronbach alpha yöntemi ile istatistiksel olarak değerlendirildi. Bulgular: KH’in kök kanallarından tamamen uzaklaştırılamadığı görüldü. Reciproc eğe sistemi ile istatistiksel olarak diğer gruplardan daha fazla KH’i uzaklaştırıldığı belirlendi (P < 0.05). Kontrol grubunda diğer gruplardan daha az KH uzaklaştırılmasına rağmen ProTaper Universal, ProTaper Next ve WaveOne eğe sistemleriyle aralarında istatistiksel olarak anlamlı bir fark görülmedi (P > 0.05). Sonuç: Reciproc eğe sisteminin NaOCl ile birlikte kullanımı kök kanallarından KH’i uzaklaştırmada yalnızca NaOCl kullanımından veya ProTaper Universal, ProTaper Next ve WaveOne eğe sistemlerinden daha etkili olduğu görülmüştür. Ancak, kullanılan tekniklerin hiçbiri kök kanallarından KH’i tamamen uzaklaştıramamaktadır.

Objectives: This study aims to evaluate the efficacy of the rotary instrument XP-endo Finisher for the removal of Ca(OH)2 aided by different irrigation regimens. Methods: Sixteen double-rooted upper premolar human teeth were selected for the study. Thirty-two canals were prepared using a ProTaper Next rotary system up to X3. Then, the canals were filled with Ca(OH)2. The volume of Ca(OH)2 inside the canals was measured by microcomputed tomography (micro-CT). After that, the teeth were randomly allocated into two experimental groups, i.e., A and B (n = 16 canals). In group A, Ca(OH)2 was removed using the master apical file (X3). In group B, Ca(OH)2 was removed using a XP-endo finisher. In half of both groups (n = 8), syringe irrigation (SI) was used, while passive ultrasonic irrigation (PUI) was used for the other half. After removal, the remaining volume of Ca(OH)2 was measured. All data were statistically analyzed using two-way ANOVA with Tukey’s post hoc test. Results: The percentages of remaining Ca(OH)2 in the apical thirds of all canals were significantly higher as compared with the middle and coronal thirds in all groups (p < 0.05). There was no significant difference between different files and techniques (p > 0.05). Clinical Significance: This study presents a new method for the removal of Ca(OH)2 from root canals.

This study investigated the cyclic fatigue resistance of three brands of nickel-titanium rotary files—Unicone (size 25 0.06; Medin), Navigator Evo (W-4; size 25 0.06; Medin) and Protaper Next (X2; size 25 0.06 Dentsply Tulsa Dental)—in reciprocating and continuous motion, during artificial canal instrumentation. Seventy-two samples—Unicone (n = 24), Navigator Evo (n = 24), and Protaper Next (n = 24)—each measuring 25 mm in length, were allocated to reciprocating (n = 36) and continuous motion (n = 36) experimental subgroups, and rotated in a simulated steel curved canal until fracture occurred. Fracture times and fragment lengths of samples in the experimental subgroups were recorded. One of the Unicone, Navigator Evo and Protaper Next fractured samples was randomly selected and analyzed for topographic characteristics by using scanning electron microscopy. Times to fracture and fragment lengths of samples were evaluated by analysis of variance and Tukey’s tests. Independent sample t test was used to compare mean values between the different groups. Protaper Next samples displayed significantly higher resistance to cyclic fatigue in reciprocating motion than Unicone and Navigator Evo samples (p < 0.001). Unicone samples exhibited the least fracture-resistant in continuous and reciprocating motion.

Introduction: Flare-ups in endodontics are multifactorial and may cause severe discomfort to the patient. Apical extrusion while preparing root canal space in any form such as debris, bacteria or irrigants has been found to be associated with many flare-up events and may even lead to treatment failure. Aim: To quantitatively evaluate apically extruded debris with five rotary instrumentation systems in mesiobuccal root of maxillary molars. Materials and Methods: A total of 120 human maxillary first molars extracted between January and March of 2017 in oral and maxillofacial surgery department at Drs. Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Gannavaram, Andhra Pradesh, India, were included in the current study. Only the Molars with a three rooted pattern were selected and mesiobuccal root was used to evaluate apical extrusion. An experimental apparatus for evaluation of extruded debris as previously described by Myers and Montgomery was fabricated. All samples were divided into six groups (n=20 each) and instrumentation was done with five rotary file systems (K3XF, ProTaper NEXT, HyFlex CM, Revo-S, and FLEXICON) and HAND K FILES which served as control. The weight of the micro tubes in the apparatus before and after the instrumentation was calculated using an electronic weighing balance with a minimum sensitivity of 10-4 and weights were compared to quantify the apical extrusion. Statistical analysis was analysed with the ANOVA and multiple comparison (Posthoc-Dunnett and Tukey) tests. Results: It was found that all the instrumentation systems showed a considerable amount of apical debris extrusion. HAND K FILES were associated with most debris extrusion compared to all rotary files (p

مقدمه: تغییر زاویه خمیدگی کانال خصوصا در کانال‏های خمیده جزء اتفاقات مرحله آماده‏سازی می‏باشد. فایل‏های چرخشی نیکل- تیتانیوم که برای آماده‏سازی کانال طراحی و عرضه شده اند، می‏توانند این مشکلات را کمتر کنند. همچنین مساله زمان در درمان ریشه بسیار اهمیت دارد. هدف از مطالعه حاضر مقایسه سه سیستم چرخشی Reciproc، ProTaper و ProTaper Next از لحاظ میزان تغییر زاویه خمیدگی و مدت زمان آماده‏سازی کانال ریشه دندان بود. مواد و روش‏ها: در این مطالعه از 45 بلوک رزینی با انحنای کانال بین 25 تا 35 درجه و طول 15 میلی‏متر استفاده شد. ابتدا از مسیر کانال در تمامی بلوک‏ها با استریو میکروسکوپ تصویر تهیه شد. سپس بلوک‏ها به سه گروه تقسیم شدند و هر گروه با یکی از سیستم‏های Reciproc، ProTaper و ProTaper next آماده‏سازی شدند. سپس تصاویر بعد از آماده‏سازی از تمامی بلوک‏ها تهیه شد و تصاویر قبل و بعد از آماده‏سازی تطابق داده شدند و با استفاده از نرم افزار فتوشاپ میزان تغییر زاویه خمیدگی محاسبه گردید. همچنین زمان فعال آماده‏سازی هر یک از گروه‏ها نیز محاسبه شده و داده‏ها، تست‏های آماری آنالیز واریانس و تعقیبی توکی در سطح معنی‏دار 5 درصد مورد انالیز قرار گرفت. یافته‏ ها: زمان آماده‏سازی با فایل‏های Reciproc با اختلاف معنی‏داری کمتر از دو گروه دیگر بود (034/0=P، 001/0>P). تغییرات زاویه کانال پس از آماده‏سازی در بین سه گروه تفاوت معنی‏داری نداشت. نتیجه گیری: مطابق یافته‏های این مطالعه، هر سه گروه فایل‏های چرخشی نیکل-تیتانیوم زاویه انحنای کانال را به میزان کمی تغییر می‏دهند و وسایل مطمئنی برای آماده‏سازی کانال‏های خمیده هستند. همچنین سیستم Reciproc زمان کمتری از دو گروه دیگر برای آماده‏سازی نیاز دارد که می‏تواند پروسه آماده‏سازی را تسریع کند.

Background : Endodontic success depends on the complete cleaning and shaping of the root canal. In order to achieve this goal, debris removal is essential. Even with improvements in instrument design, apical debris extrusion continues to be a cause of periradicular inflammation. The current study aimed to compare the amount of apically extruded debris throughout the canal instrumentation with TruNatomy, ProTaper Next, 2Shape rotary systems. Methods : A total of 60 freshly extracted single‑rooted mandibular premolars were used. An access opening was made, and a working length was estimated. The samples were arbitrarily allocated into three groups i.e. Group I: TruNatomy (n = 20), Group II: ProTaper Next (n = 20), Group III: 2Shape (n = 20). During the canal instrumentation, the extruded debris were collected in preweighed Eppendorf tubes. Post-instrumentation, the tubes were placed in a hot air oven at 140°C for five hours. For calculating the dry debris weight, the tube's pre-instrumentation weight was deducted from the post-instrumentation weight. The data was analysed using one‑way analysis of variance and post hoc Tukey's test. Results : Extrusion of debris was noted in all the specimens. TruNatomy rotary system showed least debris extrusion in comparison to ProTaper Next and 2Shape (P < 0.05). However, the results were statistically non-significant between ProTaper Next and 2Shape (P > 0.05). Conclusions : It was noted that all instruments apically extruded debris, with TruNatomy system being related to minimum extrusion., Competing Interests: No competing interests were disclosed., (Copyright: © 2023 Rajnekar R et al.)

Background: Apically extruded debris produced during root canal preparation can induce postoperative inflammation and subsequent failure of root canal treatment. Therefore, debris production must be reduced to improve the outcome of root canal treatment. Aim: This study aimed to provide a theoretical basis for the improvement of root canal treatment by comparing the difference in the amount of apically extruded debris produced during the root canal preparation of extracted human teeth with ProTaper Universal (PTU), ProTaper Next (PTN), and WaveOne (WO). Materials and Methods: On March 30, 2017, three researchers searched five electronic databases (PubMed/Medline, Cochrane, Science Direct Online, Embase, and Web of Science) with no time limitations. Only articles written in English were retrieved, and 150 articles were obtained. Then, the three researchers independently selected articles in accordance with previously established inclusion and exclusion criteria, and inconsistent results were discussed. Data were analyzed through meta-analysis for standardized mean difference (SMD). Results: Eight studies met the inclusion criteria and were subjected to qualitative analysis. Four articles showed that PTU produced higher amounts of apical debris than WO; two articles showed that PTU produced lower amounts of apical debris than WO; and three articles showed that PTN produced lower amounts of apical debris than WO. Moreover, one article demonstrated that PTU produced higher amounts of apical debris than PTN. A meta-analysis showed that PTU and WO did not produce significantly different amounts of apically extruded debris: SMD -0.26, Z = 0.50 (P > 0.05). PTU produced lower amounts of apically extruded debris than WO: SMD =-4.98, Z = 2.79 (P < 0.05). However, results were significantly heterogeneous among all the included studies (I2 = 97%). No significant difference was found between PTU and WO in the amounts of apically extruded debris: SMD = 0.47, Z = 1.06 (P > 0.05). Conclusion: Currently available evidence shows that PTN can produce lower amounts of apical debris than WO (P < 0.05). Moreover, the amounts of apically extruded debris produced by PTU and WO are not significantly different (P > 0.05). Nevertheless, given the limited number of studies reviewed, a definitive conclusion cannot be reached. [ABSTRACT FROM AUTHOR]

The curved and dilacerated roots in the posterior teeth often present the major challenge to the clinicians during the endodontic treatments. The efficient biomechanical preparation is also affected by improper instrumentation in the curved or the constricted canals. The use of conventional instruments and techniques in the dilacerated roots may develop ledges, fractured instruments, and canal blockages which further complicate the endodontic treatments. The introduction of ProTaper Universal rotary instruments has made a significant impact in the biomechanical preparation of root canals systems. However, the fracture rate of these files and inconvenience to treat the posterior teeth in reduced mouth opening conditions limits their successful usage in endodontic treatments. The ProTaper Next rotary instruments have noted advantages such as increased flexibility, higher strength, and wear resistance over the conventional rotary endodontic systems. The current case series discusses the endodontic treatment of three severely curved root canal systems successfully treated with ProTaper Next rotary endodontic system. [ABSTRACT FROM AUTHOR]

Aim: To compare the incidence of apical root crack formation after root canal preparation at different instrumentation lengths using ProTaper Universal (PTU), ProTaper Next (PTN) and ProTaper Gold (PTG) file systems. Subjects and Methods: Eighty-four mandibular first premolars with single and straight root canal were mounted in resin block after simulating periodontal ligaments. 1–2 mm of root apex was exposed followed by sectioning of 1 mm of root tip for better stereomicroscopic visualization. While the Control group was left unprepared, experimental groups were instrumented up to root canal length (RCL) and (RCL-1 mm) respectively using PTU, PTN and PTG. After staining the root apex with 1% methylene blue dye, stereomicroscopic images were obtained for evaluating apical root cracks. The data were analyzed using Chi-square, phi and Cramer test. The significance level was set at P < 0.05. Results: Significantly less dentinal defects were seen between PTG and PTU while there was no significant difference between PTU-PTN and PTN-PTG. Furthermore, samples instrumented up to RCL-1 mm showed lesser cracks as compared with samples instrumented up to RCL. Conclusion: PTG produced least number of cracks followed by PTN and PTU. Furthermore, instrumenting short of RCL reduced the crack formation risk. [ABSTRACT FROM AUTHOR]

Introduction: Flare-ups in endodontics are multifactorial and may cause severe discomfort to the patient. Apical extrusion while preparing root canal space in any form such as debris, bacteria or irrigants has been found to be associated with many flare-up events and may even lead to treatment failure. Aim: To quantitatively evaluate apically extruded debris with five rotary instrumentation systems in mesiobuccal root of maxillary molars. Materials and Methods: A total of 120 human maxillary first molars extracted between January and March of 2017 in oral and maxillofacial surgery department at Drs. Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Gannavaram, Andhra Pradesh, India, were included in the current study. Only the Molars with a three rooted pattern were selected and mesiobuccal root was used to evaluate apical extrusion. An experimental apparatus for evaluation of extruded debris as previously described by Myers and Montgomery was fabricated. All samples were divided into six groups (n=20 each) and instrumentation was done with five rotary file systems (K3XF, ProTaper NEXT, HyFlex CM, Revo-S, and FLEXICON) and HAND K FILES which served as control. The weight of the micro tubes in the apparatus before and after the instrumentation was calculated using an electronic weighing balance with a minimum sensitivity of 10-4 and weights were compared to quantify the apical extrusion. Statistical analysis was analysed with the ANOVA and multiple comparison (Posthoc- Dunnett and Tukey) tests. Results: It was found that all the instrumentation systems showed a considerable amount of apical debris extrusion. HAND K FILES were associated with most debris extrusion compared to all rotary files (p<0.01). FLEXICON file system showed lowest debris extrusion among all experimental groups. However, there was no statistically significant difference between K3XF and FLEXICON file systems (p=0.312). Conclusion: The rotary systems extruded less debris compared to HAND K FILES. However, it was observed that there was no statistically significant difference between apical extrusion of K3XF and HyFlex CM, K3XF and FLEXICON X7, HYFLEX CM and Revo-S file systems. Among all the rotary groups, FLEXICON X7 and ProTaper NEXT files showed lowest and highest apical extrusion respectively. Design of rotary endodontic instruments may have a greater impact on their innate apical extrusion potentials. [ABSTRACT FROM AUTHOR]

Introduction The aim of this study was to evaluate the root canal shaping effect of 2 nickel-titanium rotary instruments with offset mass of rotation compared with an instrument with a conventional centered mass of rotation. Methods Thirty-six extracted human mandibular first molars with 2 independent mesial canals and 1 oval distal canal were selected and divided equally into 3 groups for instrumentation with ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Revo-S (RS; Micro-Mega, Besançon, France), and ProTaper Universal (PTU, Dentsply Maillefer) systems ( n = 12). For apical preparation, PTN X2 (#25/0.06), RS SU (#25/0.06), and PTU F2 (#25/0.08) were used in the mesial canals and PTN X3 (#30/0.07), RS AS30 (#30/0.06), and PTU F3 (#30/0.09) were used in the distal canals. Specimens were scanned before and after instrumentation using a SkyScan 1272 scanner (Bruker micro-CT, Kontich, Belgium) at 10-μm isotropic resolution. Changes in the canal area, volume, structure model index (SMI), and untouched canal area were evaluated. Canal transportation and centering ratio were measured at 1, 3, 5, and 7 mm from the apical foramen. Data were statistically analyzed using 1-way analysis of variance with the Tukey post hoc test. Results The PTN and RS systems showed significantly less transportation and better centering ability compared with the PTU system at 1 mm from the apical foramen ( P < .05). All instrumentation increased the canal area, volume, and SMI values without significant differences among the 3 groups ( P > .05). Conclusions Regardless of the differences in the cross-sectional design, alloy type, and taper variation, instruments with offset mass of rotation showed better root canal shaping ability compared with an instrument with a centered mass of rotation. [ABSTRACT FROM AUTHOR]

Background/purpose Reciprocating single-file systems are the latest nickel-titanium instruments and little information is available concerning the shaping ability of these new systems. Comparison of these single-file systems with well-known rotary multi-file systems is necessary. The purpose of this study was to compare the shaping ability of single-file system (WaveOne, WO) versus multiple-file system (ProTaper Next, PTN) in severely curved canals. Materials and methods A total of 20 severely curved canals were prepared with WO or PTN. Micro-computed tomography was used to scan the specimens before and after instrumentation. Differences between two groups in canal surface area, volume, Structure Model Index (SMI), thickness, straightening, the ratio of uninstrumented surface area and canal transportation were evaluated. Results The outline of the canals after preparation showed smooth taper in both groups. Canal surface area, volume, SMI, Thickness and canal curvature were significantly increased after preparation in both groups, and no significant difference was found between groups. At apical third, canals prepared with WO showed larger values of transportation compared with those in PTN group in the direction of main curvature. Approximately 29–34% of the root canal surface remained uninstrumented after preparation and no significant difference was noticed between groups. Conclusion Both of the two instrument systems maintained the original outline of the canals well. The canals prepared with PTN had less transportation and were better centered in the apical region. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to compare the incidence of dentinal crack formation after root canal preparation using ProTaper Next, OneShape and Hyflex electrodischarge machining (HEDM). Materials and Methods: A total of 75 extracted mandibular premolars were selected. The root canals were instrumented using ProTaper Next, OneShape and HEDM rotary files. All roots were horizontally sectioned at 3, 6 and 9 mm from apex with slow-speed saw under water cooling. The sections were observed under a stereomicroscope at x25 to determine the absence or presence of crack. Data were analyzed using post hoc test and one-way ANOVA. Results: ProTaper Next and HEDM produced significantly less cracks than OneShape. Conclusion: Within the limitation of this in vitro study, it can be concluded that nickel-titanium instruments may cause cracks on the root surface. ProTaper Next and HEDM tend to produce less number of cracks as compared to OneShape. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To determine the effect of photon‐initiated photoacoustic streaming (PIPS) on the extrusion of debris using multiple‐file (ProTaper Next‐PTN) and single‐file (One Shape‐OS) continuous rotary systems in curved canals in human molar teeth. Methodology: Sixty extracted maxillary first molar teeth with curved mesial roots, mature apices and of similar lengths were selected. Teeth having canals with apical diameters larger than size 15 were discarded. The teeth were randomly divided into four experimental groups (n = 15 teeth per group) according to the file used and irrigation systems: (i) OS with PIPS with a 2940 nm Er:YAG laser (0.3 W, 15 Hz, and 20 mJ), (ii) OS with conventional needle irrigation (CNI) with a 27‐G needle, (iii) PTN with PIPS and (iv) PTN with CNI. The PIPS and CNI was applied during each file change for 20 s. Total irrigation and activation time was 1 min, and a total volume of 7.5 mL of bidistilled water was used as the irrigant. The apically extruded debris was collected into pre‐weighed Eppendorf tubes. The tubes were then stored in an incubator at 70 °C for 5 days. The weight of dry extruded debris was assessed by subtracting the initial weight of the tube from the final weight. The results were analysed statistically using one‐way analysis of variance and Tukey's post hoc tests. Bonferroni correction was used to compare the groups. Results: The PIPS irrigation technique was associated with significantly more debris extrusion than the CNI system (P < 0.05). The single‐file (One Shape‐OS) rotary system was associated with more debris than the multiple‐file (ProTaper Next‐PTN) rotary systems when the same irrigation system was used (P > 0.05). The total amount of debris extruded apically by PIPS activation was significantly greater than that by CNI (P < 0.05). Conclusions: All file and irrigation systems extruded debris apically. PIPS activation was associated with significantly more extrusion debris in curved canals compared with no activation. [ABSTRACT FROM AUTHOR]

Aim This study compared the efficacy of ProFile Vortex (PV) with that of ProTaper Next (PTN) for the removal of root canal filling material. Materials and methods Twenty-six mesial canals of extracted mandibular first molars were instrumented, obturated with gutta-percha and sealant, and randomly allocated to a PTN (X3, X2, or X1) or PV group. The percentage of remaining material, amount of dentin removed, and extent of transportation were assessed using micro-computed tomography. The total time required for removal of material was calculated. Results Both systems were effective for material removal ( p  ≤ 0.001). Less time was required to remove material using PV (256.43 ± 108.95 s) than using PTN (333.31 ± 81.63 s; p  ≤ 0.05). PV and PTN files removed approximately 84% and 78% of the filling material, respectively ( p  > .05). There was no significant canal transportation in either group. PV and PTN files removed 1.32 ± 0.48 mm 3 and 1.63 ± 0.67 mm 3 of the dentin, respectively ( p  = .18). Conclusion Our findings suggest that PV is as effective as PTN for removal of root canal filling material. Therefore, PV can be considered for use in endodontic retreatment, although more effective files or techniques are still required. [ABSTRACT FROM AUTHOR]

Aim: The current study compared the fracture resistance of samples instrumented by two rotary files and a reciprocating file, obturated with gutta-percha and AH Plus. Materials and Methods: A total of 60 freshly extracted mandibular premolar teeth with single roots and single canals were acquired and decoronated at or below the cementoenamel junction. The samples were randomly divided into four groups (n = 15). Group 1 control (noninstrumented/obturated), and for Groups 2–4 root canal instrumentation was done by EndoStar E5 (EE5), ProTaper NEXT (PTN), and WaveOne, respectively. Following instrumentation, the samples were obturated using gutta-percha cones and AH Plus sealer using lateral compaction. A week later, vertical load was applied to the specimen's canal in each group until fracture. The loads required for fracture were recorded and statistically analyzed. Results: The mean loads required to fracture (Newton; N) for the four groups were; 388.54 (±29.93), 310.35 (±26.05), 328.40 (±20.67), and 278.54 (±34.16). The loads exhibited highly significant difference (P < 0.0001; analysis variance). The following Tukey's post hoc test confirmed, both samples in Groups 2 and 3 required similar loads for fracture (P > 0.05) and significantly higher than Group 4 (P < 0.01). Conclusion: The samples instrumented by EE5 and PTN exhibit similar fracture resistance. [ABSTRACT FROM AUTHOR]

Comparison of the ability of newly designed rotary files to eliminate viable Enterococcus faecalis populations from long oval root canals of extracted human teeth to that of the self-adjusting file ( SAF). One hundred caries-free, single-rooted, long oval teeth were contaminated with E. faecalis. The teeth were randomly distributed into four groups ( n = 25) as follows: G.1, manual; G.2, SAF; G.3, ProTaper Next; and G.4, BT-Race. Two microbial samples were obtained from each tooth with sterile paper points, (s1) before and (s2) after instrumentation. The relative reduction in colony-forming units ( CFUs) from s1 to s2 measurements was calculated and compared among the groups using parametric Kruskal-Wallis one-way anova on ranks and Dunn's method ( a = 0.05). The results indicated a descending order of the groups with regard to efficacy as follows: BT-Race, Next, SAF and manual. The statistical analysis showed that the relative percentage reduction ( RR) of CFUs was lower in the manual group than in the other groups, while the SAF group showed a significantly lower RR than the BT-Race group ( P < 0.05). The efficacy in reduction of the microbiological load of viable E. faecalis from long oval root canals was different between the tested endodontic systems. [ABSTRACT FROM AUTHOR]

Introduction: Maintenance of original canal anatomy with proper disinfection is our primary goal to achieve during root canal instrumentation. Surfactants are added to irrigating solution to promote deeper penetration into dentinal tubules. Aim: The aim of this study was to evaluate the influence of addition of surfactants to Sodium Hypochlorite (NaOCl) and Ethylenediaminetetraacetic Acid (EDTA) on transportation of root canal. Materials and Methods: Fifty human mandibular molars with mesial root curvatures of 10° – 40° were selected and embedded in silicone impression material to simulate mandibular arch form to facilitate imaging process and maintain reproducibility of images. Before instrumentation, root canals were scanned by using Cone Beam Computed Tomography (CBCT) imaging (Carestream, India). The canals were then prepared with the ProTaper Next (PTN) system (Dentsply Maillefer, Ballaigues, Switzerland), using one of the following irrigation regimens during the instrumentation and were divided into five groups based on irrigation regimens followed: G1 (n=10)-irrigation with saline solution(control); G2 (n=10)-irrigation with 2.5% NaOCl; G3 (n=10)-irrigation with 2.5% NaOCl added with surfactant; G4 (n=10)-irrigation with 17% EDTA; G5 (n=10)-irrigation with 17% EDTA added with surfactant. Post-instrumentation scans were obtained with similar parameters and position as preinstrumentation scans by CBCT imaging. Transportation of the root canals were then analysed at three cross-sectional planes of pre-instrumentation and post-instrumentation images at 2 mm, 5 mm, 8 mm from the apical end of the root. The data was statistically analyzed using Analysis of Variance (ANOVA) and Tukey post hoc test (p

Introduction: To evaluate the incidence of microcrack formation canal preparation with two rotary nickel'titanium systems Mtwo and ProTaper Next along with the self-adjusting file system. Materials and Methods: One hundred and twenty mandibular premolar teeth were selected. Standardized access cavities were prepared and the canals were manually prepared up to size 20 after coronal preflaring. The teeth were divided into three experimental groups and one control group (n = 30). Group 1: The canals were prepared using Mtwo rotary files. Group 2: The canals were prepared with ProTaper Next files. Group 3: The canals were prepared with self-adjusting files. Group 4: The canals were unprepared and used as a control. The roots were sectioned horizontally 3, 6, and 9 mm from the apex and examined under a scanning electron microscope to check for the presence of microcracks. The Pearson's Chi-square test was applied. Results: The highest incidence of microcracks were associated with the ProTaper Next group, 80% (P = 0.00), followed by the Mtwo group, 70% (P = 0.000), and the least number of microcracks was noted in the self-adjusting file group, 10% (P = 0.068). No significant difference was found between the ProTaper Next and Mtwo groups (P = 0.368) while a significant difference was observed between the ProTaper Next and self-adjusting file groups (P = 0.000) as well as the Mtwo and self-adjusting file groups (P = 0.000). Conclusion: All nickel'titanium rotary instrument systems were associated with microcracks. However, the self-adjusting file system had significantly fewer microcracks when compared with the Mtwo and ProTaper Next. [ABSTRACT FROM AUTHOR]

Aim: This study was intended to evaluate the amount of apically extruded debris following root canal preparation with three different instrumentation systems. Materials and Methods: Sixty mandibular incisor teeth were selected and randomly divided into three groups (n = 20/group) according to the instrumentation system used: the ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), the Twisted File Adaptive (TFA; SybronEndo, Orange, CA, USA), and the WaveOne Gold (WOG; Dentsply Maillefer, Ballaigues, Switzerland). All apically extruded debris was collected and dried in preweighed glass vials. The mean weight of the apically extruded debris was obtained using a microbalance. The time for root canal preparation was also recorded. The data were analyzed using a one-way analysis of variance. Results: The mean weights of apically extruded debris were 0.00035 ± 0.00014 g (PTN); 0.00023 ± 0.0001 g (TFA); and 0.00019 ± 0.0001 g (WOG) (P ˂ 0.01). The mean preparation time value was 301,13 ± 62.14 s (PTN); 234.27 ± 34.88 s (TFA); and 239.8 ± 58.6 s (WOG) (P ˂ 0.05). Conclusions: The PTN system extruded more debris than the TFA and WOG systems. The TFA and WOG systems were faster than the PTN system. [ABSTRACT FROM AUTHOR]

Introduction: Maintenance of original canal anatomy with proper disinfection is our primary goal to achieve during root canal instrumentation. Surfactants are added to irrigating solution to promote deeper penetration into dentinal tubules. Aim: The aim of this study was to evaluate the influence of addition of surfactants to Sodium Hypochlorite (NaOCl) and Ethylenediaminetetraacetic Acid (EDTA) on transportation of root canal. Materials and Methods: Fifty human mandibular molars with mesial root curvatures of 10° - 40° were selected and embedded in silicone impression material to simulate mandibular arch form to facilitate imaging process and maintain reproducibility of images. Before instrumentation, root canals were scanned by using Cone Beam Computed Tomography (CBCT) imaging (Carestream, India). The canals were then prepared with the ProTaper Next (PTN) system (Dentsply Maillefer, Ballaigues, Switzerland), using one of the following irrigation regimens during the instrumentation and were divided into five groups based on irrigation regimens followed: G1 (n=10)-irrigation with saline solution(control); G2 (n=10)-irrigation with 2.5% NaOCl; G3 (n=10)-irrigation with 2.5% NaOCl added with surfactant; G4 (n=10)-irrigation with 17% EDTA; G5 (n=10)-irrigation with 17% EDTA added with surfactant. Post-instrumentation scans were obtained with similar parameters and position as preinstrumentation scans by CBCT imaging. Transportation of the root canals were then analysed at three cross-sectional planes of pre-instrumentation and post-instrumentation images at 2 mm, 5 mm, 8 mm from the apical end of the root. The data was statistically analyzed using Analysis of Variance (ANOVA) and Tukey post hoc test (p<0.05). Results: The mean transportation values were higher in G5. Transportation in G3 and G5 was not significantly different compared to G2 and G4 respectively (p<0.05). Conclusion: Instrumentation using irrigating solutions added with surfactant like 1% cetrimide maintained the canal curvature well. [ABSTRACT FROM AUTHOR]

Aim To assess and compare the mechanical properties of TRUShape ( TRS) with several nickel-titanium rotary instruments. Methodology Cyclic fatigue, torsional resistance, flexibility and surface microhardness of TRS (size 25, 0.06v taper), ProTaper Next X2 ( PTN X2, size 25, 0.06 taper), ProTaper Gold ( PTG F2; size 25, 0.08 taper) and ProTaper Universal ( PTU F2; size 25, 0.08 taper) instruments were evaluated. The topographical structures of the fracture surfaces of instruments were assessed using a scanning electron microscope. The cyclic fatigue resistance, torsional resistance and microhardness data were analysed using one-way analysis of variance ( anova) and Tukey's post hoc tests. The fragment length and bending resistance data were analysed statistically with the Kruskal-Wallis H-test and Mann-Whitney U-tests. The statistical significance level was set at P < 0.05. Results PTN and PTG instruments revealed significantly higher resistance to cyclic fatigue than TRS and PTU instruments ( P < 0.001). PTN instruments revealed significantly higher torsional resistance compared with the other instruments ( P < 0.001). PTG instrument had significantly higher flexibility than the other tested brands ( P < 0.05). However, for microhardness, the PTU had significantly higher surface microhardness values compared with other tested brands ( P < 0.05). Conclusions TRS instruments had lower resistance to cyclic fatigue and lower flexibility compared with PTG and PTN instruments. TRS, PTG and PTU instruments had lower resistance to torsional stress than PTN instruments. TRS and PTG instruments had comparable surface microhardness. [ABSTRACT FROM AUTHOR]

Introduction The purpose of this study was to determine whether final-year undergraduate dental students achieved better shaping outcomes using the new ProTaper Next (PTN; Dentsply Sirona, Ballaigues, Switzerland) system to prepare root canals for the first time compared with the existing ProTaper Universal (PTU, Dentsply Sirona) system on which they had trained. A secondary aim was to explore the attitudes and preferences of the students toward both systems. Methods Forty students prepared 1 simulated S-shaped canal using PTN and another with PTU. Images of the canals were saved before and after preparation, and the outcomes assessed included the formation of aberrations and the amount of resin removed at specific points along the canal length. Student opinions relating to PTN and PTU were collected via a questionnaire completed immediately after using the systems. For statistical analysis, the McNemar test was used to compare the incidence of aberrations, and a paired t test was used to analyze the width measurements. Responses to the questionnaire were analyzed using frequencies. Thus, the McNemar test was used for paired binary data and the marginal homogeneity test for categoric data when more than 2 categories were used. Finally, the overall preferences (either PTN or PTU) were analyzed using the sign/binomial test, which is a standard statistical test that allows us to determine if the proportion preferring one or the other is equal or not. Results Canal ledges were formed in 30% of the canals prepared with PTU, whereas no ledges were formed with PTN ( P < .001). A middle constriction, a form of canal aberration, was created by both systems although it occurred significantly ( P = .006) more often with PTN. The “number of files” was judged by students to be significantly higher ( P < .001) for PTU compared with PTN. Even though using PTN for the first time, students were more likely to recommend the system to other students for preparing S-shaped canals than PTU ( P = .018) and preferred to use PTN in the future ( P < .001). Conclusions The students who had previous experience with the use of PTU were able to produce comparable shaping outcomes when they used PTN for the first time. For the preparation of S-shaped canals, the students preferred PTN over PTU in terms of the number of files and would prefer to use it in the future. [ABSTRACT FROM AUTHOR]

Aim To compare the centring ability and transportation of ProTaper Next (PTN), ProTaper Universal (PTU), Race 123 and RevoS using micro-computed tomography (μCT). Methodology Sixty mesial root canals of thirty mandibular molars were divided virtually into coronal, middle and apical thirds, and two reproducible reference points were marked on the external surface of the roots creating 360 measurement points. Samples were randomly allocated to four NiTi instrumentation techniques. Group 1: PTU up to F2 ( n = 16), group 2: PTN up to X2 ( n = 18), group 3: Race 123 up to T2 ( n = 12) and group 4: RevoS up to SU ( n = 14). To reproduce a clinical situation, samples were prepared on a phantom head using a surgical operating microscope. Samples were scanned pre- and postoperatively using μCT to compare and calculate the transportation and centring ratio. The data were analysed using parametric statistics. Results In the coronal and middle third of the root canals, there were significant differences in centring between PTN and PTU (coronal P < 0.001), PTN and RevoS (coronal P < 0.001), Race and PTU (coronal P < 0.01), Race and RevoS (coronal P < 0.01), PTN and RevoS (middle P < 0.01) and Race and RevoS ( P < 0.05). Furthermore, there were significant differences in centring between PTN root canal preparations and other instruments in the apical third (PTN and PTU P < 0.01, PTN and Race P < 0.001, PTN and RevoS P < 0.001). In terms of transportation, in the coronal third, there was a significant difference between PTN and PTU ( P < 0.05). However, there were no significant differences between the other instruments. In the middle third, significant differences were observed between PTN and PTU ( P < 0.05), PTN and RevoS ( P < 0.05), Race and PTU ( P < 0.05) and Race and RevoS ( P < 0.05). However, there were no significant differences between other systems. There was no significant difference in terms of transportation between the four systems in the apical third. Conclusions ProTaper Next prepared more centred root canal shapes when compared with Race, PTU and RevoS. In the coronal and middle third of the root canals, the differences in centring between PTN and PTU/RevoS were significant. PTN root canal preparations were more centred than those achieved with all other instruments in the apical third. [ABSTRACT FROM AUTHOR]

Introduction The aim of this study was to evaluate and compare, by means of micro–computed tomography imaging, the shaping ability of ProTaper Next (PTN) and the novel HyFlex EDM (HFEDM) instruments. Methods Forty teeth were randomly divided into 2 groups and prepared with PTN or HFEDM. Root canal transportation and centering ratio were evaluated in mesiodistal and buccolingual directions at 5 levels (at the midpoint of the apical, middle, and coronal thirds and at the boundaries between them). Variations in volume, surface, and cross-sectional shape were measured for the apical, middle, and coronal thirds. The null hypotheses were that no differences existed between the 2 groups. The D'Agostino-Pearson test (α = .05) was conducted to assess the normality of the data sets. The distributions were compared by using the Mann-Whitney test (α = .05). Results Statistically significant differences ( P < .005) were recorded only for buccolingual canal transportation and centering ratio at the section between the middle and coronal thirds, where HFEDM files were superior. Conclusions HFEDM and PTN files were similarly effective, and both safely prepared the root canals, respecting their original anatomies. HFEDM files performed better in terms of buccolingual canal transportation and centering ratio at the section between the middle and coronal thirds. [ABSTRACT FROM AUTHOR]

Introduction The aim of this study was to compare the amount of debris extruded from the apex during retreatment procedures with ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (RCP; VDW, Munich, Germany), and Twisted File Adaptive (TFA; SybronEndo, Orange, CA) files and the duration of these retreatment procedures. Methods Ninety upper central incisor teeth were prepared and filled with gutta-percha and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany) using the vertical compaction technique. The teeth were randomly divided into 3 groups of 30 for removal of the root filling material with PTN, RCP, and TFA files. The apically extruded debris was collected in preweighed Eppendorf tubes. The time for gutta-percha removal was recorded. Data were statistically analyzed using Kruskal-Wallis and 1-way analysis of variance tests. Results The amount of debris extruded was RPC > TFA > PTN, respectively. Compared with the PTN group, the amount of debris extruded in the RPC group was statistically significantly higher ( P < .001). There was no statistically significant difference among the RCP, TFA, and PTN groups regarding the time for retreatment ( P > .05). Conclusions Within the limitations of this in vitro study, all groups were associated with debris extrusion from the apex. The RCP file system led to higher levels of apical extrusion in proportion to the PTN file system. In addition, there was no significant difference among groups in the duration of the retreatment procedures. [ABSTRACT FROM AUTHOR]

Background. The aim of this study was to compare the dentinal defects caused by Reciproc, TF Adaptive and ProTaper Next NiTi rotary file systems during the retreatment procedure. Methods. A total of 150 mandibular incisors with straight and single root canals were included in the present study. All the root canals were prepared up to an apical diameter 0.40 mm using stainless steel files. Thirty teeth were randomly stored as the negative control group. A total of 120 specimens were obturated with gutta-percha and AH Plus sealer using vertical compaction technique. Thirty specimens with root canal filling were randomly separated for the only-filled group. Then the teeth were randomly divided into 3 groups; Reciproc, TF Adaptive and ProTaper Next. The retreatment procedure was performed with these NiTi files. Then 150 specimens were cut perpendicular to tooth axis at 3-, 6-, and 9-mm distances from the apex, and examined to determine the presence of any cracks at x25 under a stereomicroscope. Chi-squared test was used at 5% significance level. Results. All the tested NiTi file systems were found to cause significantly more dentinal defects compared to unprepared and only-filled groups (P<0.05). No statistically significant differences were found between the groups in terms of dentinal defects (P>0.05). No correlation was found between the slice levels and the dentinal defect distribution (P>0.05). Conclusion. Within the limitations of present study, all the tested NiTi file systems were found to cause significantly more dentinal defects compared to unprepared and only-filled groups. [ABSTRACT FROM AUTHOR]

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Objective To evaluate the shaping ability of ProTaper Universal (PU), ProTaper Next (PN) and M3 in preparation of curved root canals by CBCT (cone-beam computed tomography). Methods Sixty extracted maxillary first premolars were divided into two groups according to the canal curvature:10°-25° group and 26°-75°group. Then, each group was divided into PU group, PN group and M3 group and prepared with three instruments respectively. Canals were scanned by CBCT scanner before and after preparation. The efficacy of canal preparation was analyzed. The width of dentine removed was measured at three points (2 mm, 5 mm and 8 mm to root tip). The apical transportation indexes and the centring ratio values were recorded. Results PN group and M3 group needed less time in preparation and showed more efficiency than those of PU group in 26°-75° groups. One of root canals in PU group appeared deformation, neither PN group nor M3 group appeared deformation after 5 root canal preparations in average. None instrument was broken in three groups. PU group removed more materials at internal walls than PN group and M3 group at internal walls of root canals in 5 mm from the apex. There was no difference in the offset of the external walls of root canals. Compared with the offset of the internal and external walls of root canals in 2 mm from the apex, the apical transportations prepared by the PN group were less than those of M3 group and PU group in 26°-75° groups. Compared with the offset of the internal and external walls of root canals in 5 mm from the apex, the apical transportations prepared by the PN group and M3 group were less than those of PU group, and their centring ratio values were greater than those of PU group in 26°-75°groups. Conclusion ProTaper Next and M3 tested in this study are effective and time-saving in shaping curved root canals. The results indicate that both ProTaper Next and M3 are comparable to optimally enlarge root canal. [ABSTRACT FROM AUTHOR]

Aims: The aim of this study was to quantify the debris extruded apically from teeth using rotary and reciprocation instrumentation systems. Subjects and Methods: Eighty extracted human mandibular premolars with single canals and similar lengths were instrumented using ProTaper Universal (40, 06; Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Next (40, 06; Dentsply Maillefer, Ballaigues, Switzerland), WaveOne (40, 06; Dentsply Maillefer, Ballaigues, Switzerland), and Reciproc (R40; VDW GmbH, Munich, Germany). Debris extruded during instrumentation was collected into preweighed Eppendorf tubes, which were then stored in an incubator at 70°C for 5 days. The final weight of the Eppendorf tubes with the extruded debris was calculated after obtaining the mean of three consecutive weights obtained for each tube. Statistical Analysis Used: Statistical analysis was performed using SPSS version 16.0 software. The groups were compared using the Kruskal-Wallis test for all variables. Results: There was no statistically significant difference between the groups (P = 0.1114). However, the ProTaper Universal group produced more extrusion and ProTaper Next produced least debris extrusion among the instrument groups (P > 0.05). Conclusions: All instrumentation techniques were associated with extruded debris. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to compare the canal transportation and canal centering ability in the preparation of curved root canals after instrumentation with V-Taper 2H, ProTaper Next (PN), and Hyflex CM files using cone-beam computed tomography (CBCT).Materials and Methods: Thirty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20 to 40 were divided according to the instrument used in canal preparation into three groups of ten samples each: V-Taper 2H (Group 1), PN (Group 2), and Hyflex CM (Group 3). The teeth were instrumented according to manufacturer's guidelines up to 30 no. apical preparation. Canals were scanned using a CBCT scanner before and after preparation to evaluate the transportation and centering ratio at 3 mm, 6 mm, and 9 mm from the apex. The amount of transportation and centering ability was assessed. The three groups were statistically compared with analysis of variance and post hoc Tukey test.Results: All instruments maintained the original canal curvature with significant differences between the different files. Data suggested that V-Taper 2H files presented the best outcomes for both the variables evaluated. V-Taper 2H files caused lesser transportation and remained better centered in the canal than PN and Hyflex CM files. However, it was seen that PN caused less transportation in apical level than Hyflex CM.Conclusion: The canal preparation with V-Taper 2H showed lesser transportation and better centering ability than PN and Hyflex CM. [ABSTRACT FROM AUTHOR]

Aim To investigate the influence of interrupted rotation on cyclic fatigue of two nickel-titanium rotary instruments. Methodology Cyclic fatigue of 300 new ProTaper Next size X1; X2 and Mtwo size 10, .04 taper; size 15, .05 taper; size 20, .06 taper and size 25, .06 taper instruments was tested in continuous or interrupted rotation. Fifty files of the same brand and size were randomly assigned to five groups ( n = 10). Group 1 instruments were tested in continuous rotation; groups 2 and 3 in paused rotation for 1 s every 10 or 20 s, respectively; groups 4 and 5 in interrupted rotation for 5 s every 10 or 20 s, respectively. Cyclic fatigue was expressed in time to fracture (TtF) in an artificial canal with 60° angle and 5 mm radius of curvature. The fracture surface was examined with a scanning electron microscope ( SEM). Data were evaluated by two-way analysis of variance. Results Cyclic fatigue of groups 2 and 4 of ProTaper Next X2 and Mtwo size 25, .06 taper was significantly lower than that of group 1 of the same instruments ( P < 0.01). ProTaper Next X2 had significantly reduced cyclic fatigue in groups 3 and 5 ( P < 0.05). No differences were found by interrupting the rotation for 1 or 5 s in all instruments ( P > 0.05). Fatigue of other instruments was not affected by interrupted rotation ( P > 0.05). Conclusions Interrupted rotation reduced cyclic fatigue resistance of ProTaper Next X2 and Mtwo size 25, .06 taper, especially when a higher number of interruptions was performed. [ABSTRACT FROM AUTHOR]

Aim: This study aims to evaluate and compare the incidence of dentinal defects induced by Hand Files, HyFlex CM, ProTaper Next (PTN), and One Shape during canal preparation. Materials and Methods: One hundred and fifty extracted mandibular premolar teeth with single root canal were selected. Specimens were then divided into five groups with thirty specimens each. Group I: Specimens were prepared with hand instruments. Group II: Specimens were prepared with HyFlex CM rotary files (Coltene) using a crown-down technique according to the manufacturer's instructions. Group III: Specimens were prepared with PTN rotary files (Dentsply) using a crown-down technique according to the manufacturer's instructions. Group IV: Specimens were prepared with One Shape Single file rotary system (MicroMega) using a crown-down technique according to the manufacturer's instructions. Group V: Specimens were used as a control and left unprepared. All roots were cut horizontally at 3, 6, and 9 mm from the apex. Sections were then viewed under stereomicroscope and dentinal defects were registered as "no defect," "fracture," and "other defects." Statistical Analysis: Results of the study were subjected to Chi-square test. Results: Results were expressed as the number and percentage of defected, partially defected and roots with no defects in each groups. Conclusion: Hand files and One Shape file system caused less root defects compared to PTN and HyFlex file systems. [ABSTRACT FROM AUTHOR]

Background: Cleaning and shaping represent a vital step in the endodontic procedure. In routine endodontic therapy, the fracture of nickel-titanium (NiTi) instruments is a procedural problem creating a major obstacle to therapy., Aim: This study examines the life span of one Neoendo Flex and ProTaper Next (PTN) rotary file using reciprocating motion and compares the time required by both file systems for canal preparation., Materials and Methods: One hundred maxillary permanent central incisors were selected. In that, fifty teeth are utilized in a reciprocating motion (RM) with the PTN file ( n = 25) and Neoendo Flex file ( n = 25). To check fractured resistance and the overall root canal preparation time, fifty more teeth are employed in continuous motion (CM) with canals prepared using PTN ( n = 25) and Neoendo Flex ( n = 25). All canals are prepared following the sequence of respective files. Later, the fracture mechanism of the files was inspected using a scanning electron microscope., Results: In an RM motion, both PTN and Neoendo Flex files can be used in a minimum of 25 canals in single-rooted teeth. Statistical analysis using the Mann-Whitney U -test showed no significant difference in total time taken by PTN and Neoendo Flex in both motions., Conclusion: Within the limitation of this study, the RM was found to be better than CM with less incidence of instrument fracture., Competing Interests: There are no conflicts of interest., (Copyright: © 2023 Journal of Conservative Dentistry and Endodontics.)

Background: The extrusion of apical debris is related to various factors, and may be affected by variations in technique or instrumentation system. Although the extrusion cannot be completely prevented, it is crucial to minimize the amount of extruded material., Objectives: The present study aimed to compare apical debris extrusion by the novel TruNatomy (TRN), OneCurve (OC) and ProTaper Next (PTN) instruments in curved root canals., Material and Methods: A total of 60 multi-rooted human mandibular molar teeth with moderate and severe curvature were selected and randomly divided into 3 groups. The root canals were prepared with the OC, TRN and PTN files. For collecting the debris extruded through the apical foramen, Eppendorf tubes were used. After the vaporizing period, the tubes were re-weighed, and the amount of the extruded debris was calculated by subtracting the initial weight from the final weight. Statistical analysis was performed with the Shapiro-Wilk and Kruskal-Wallis tests. The statistical significance level was set at p < 0.05., Results: The least amount of debris was extruded with TRN and the greatest with PTN, but the difference between the groups was not significant (p = 0.257)., Conclusions: All instrumentation systems were associated with debris extrusion. The tested file systems presented similar results in terms of apical debris extrusion in curved canals. The novel TRN system demonstrated promising results, comparable to OC and PTN.