Single-file Systems Research Articles

Apically Extruded Debris in Curved Root Canals Using the WaveOne Gold Reciprocating and Twisted File Adaptive Systems

IntroductionThe purpose of this study was to evaluate apical debris extrusion associated with different kinematics in curved root canals. MethodsForty-five extracted mandibular molars with root curvature angles ranging between 20° and 40° and curvature radii <10 mm were randomly assigned to 3 groups (n = 15) according to the kinematics used for root canal preparation: reciprocating motion with the WaveOne Gold system (Dentsply Tulsa Dental, Tulsa, OK), rotary/reciprocating motion with the Twisted File Adaptive system (SybronEndo, Orange, CA), and the manual technique. The debris apically extruded during preparation was collected into preweighed Eppendorf tubes. The tubes were then stored in an incubator at 70°C for 5 days. The extruded debris was quantified by subtracting the preinstrumentation from the postinstrumentation weight of the Eppendorf tubes. The time required for each instrumentation procedure was recorded. Data were analyzed using 1-way analysis of variance Tukey post hoc tests (∝ = 0.05). ResultsThe WaveOne Gold reciprocating single-file system was associated with less extrusion of debris compared with hand files (P < .05) and the Twisted File Adaptive system (P > .05). The preparation time required by hand files was significantly longer than that required by the other techniques (P < .05). ConclusionsUnder the conditions of this study, all of the instrumentation systems caused apical debris extrusion to some degree. The WaveOne Gold reciprocating system was associated with less debris extrusion in curved root canals compared with the manual technique and the Twisted File Adaptive system although the difference between the WaveOne Gold and Twisted File Adaptive systems was not significant.

Evaluation of Effects of Glide Path on the Centering Ability and Preparation Time of two Reciprocating Single File Systems in Root Canals of Mandibular Molars: An In-Vitro Study

Evaluation of Effects of Glide Path on the Centering Ability and Preparation Time of two Reciprocating Single File Systems in Root Canals of Mandibular Molars: An In-Vitro Study

Comparative Evaluation of Shaping Ability of Different Rotary Nickel Titanium Single File Systems in Root Canals of Mandibular Molars: An In-Vitro Study

Comparative Evaluation of Shaping Ability of Different Rotary Nickel Titanium Single File Systems in Root Canals of Mandibular Molars: An In-Vitro Study

Unbinding Transition of Probes in Single-File Systems.

Single-file transport, arising in quasi-one-dimensional geometries where particles cannot pass each other, is characterized by the anomalous dynamics of a probe, notably its response to an external force. In these systems, the motion of several probes submitted to different external forces, although relevant to mixtures of charged and neutral or active and passive objects, remains unexplored. Here, we determine how several probes respond to external forces. We rely on a hydrodynamic description of the symmetric exclusion process to obtain exact analytical results at long times. We show that the probes can either move as a whole, or separate into two groups moving away from each other. In between the two regimes, they separate with a different dynamical exponent, as t^{1/4}. This unbinding transition also occurs in several continuous single-file systems and is expected to be observable.

Comparative evaluation of the shaping ability of single-file system versus multi-file system in severely curved root canals

Background/purposeReciprocating 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 methodsA 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. ResultsThe 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. ConclusionBoth 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.

Comparative Evaluation of Apical Debris Extrusion with Single File Systems Used under Different Kinematics

Comparative Evaluation of Apical Debris Extrusion with Single File Systems Used under Different Kinematics

Comparative analysis of canal-centering ratio, apical transportation, and remaining dentin thickness between single-file systems, i.e., OneShape and WaveOne reciprocation: An in vitro study.

Aim:This study aimed to compare the canal-centering ability, apical transportation, and remaining dentin thickness (RDT) of OneShape and WaveOne (WO) systems using cone-beam computed tomography.Objective:The objective of this study was to evaluate the efficiency of two rotary systems in maintaining original root canal anatomy.Materials and Methods:Forty extracted human single-rooted mandibular premolars were used in the present study. Preinstrumentation scans of all teeth were taken, canal curvatures were calculated, and the samples were randomly divided into two groups with twenty samples in each group: Group 1 – OneShape (OS) rotary system and Group 2 – WO reciprocation system. Postinstrumentation scans were performed using DICOM software and the two scans were compared to determine the canal-centering ability, canal transportation, and RDT at 1, 3, and 5 mm from the root apex.Results:Using Student's unpaired t-test, results were as follows: for canal-centering ability and RDT, Group 1 showed nonstatistically significant difference at 1 and 5 mm, while statistically significant difference (P < 0.05) at 3 mm was obtained. For canal transportation, Group 1 showed statistically significant difference (P < 0.05) at 1 and 3 mm and nonsignificant difference was obtained at 5 mm, but for Group 2, nonstatistically significant difference (P > 0.05) was obtained at 1, 3, and 5 mm. When comparing the RDT between both the groups, the difference was not statistically significant (P > 0.05).Conclusion:WO single reciprocation file has better canal-centering ability, maintains original canal curvature, causes lesser canal transportation, and preserves more dentine as compared to OS.

The Effect of Canal Preparation with Four Different Rotary Systems on Formation of Dentinal Cracks: An In Vitro Evaluation.

Introduction:Endodontic rotary systems may result in dentinal cracks. They may propagate to vertical root fracture that compromises the outcome of endodontic treatment. This study aimed to compare Neolix and Reciproc (single-file systems), Mtwo and ProTaper (conventional rotary systems) in terms of dentinal crack formation in root canal walls. Methods and Materials:This in vitro study was conducted on 110 extracted human single-rooted teeth. The teeth were randomly divided into four experimental groups (n=25) for root canal preparation with Neolix, Reciproc, Mtwo and ProTaper systems and two control groups (n=5). The first control group underwent root canal instrumentation with hand files while the second control group received no preparation and was only irrigated. After instrumentation, root canals were horizontally sectioned at 3, 6 and 9 mm from the apex and inspected under a stereomicroscope under 12× magnification for detection of cracks. The data were analyzed using Chi-square, GEE test and Bonferroni tests (P<0.05). Results:No crack was found in the control groups. All rotary systems caused dentinal cracks. ProTaper, Reciproc, Mtwo and Neolix caused cracks in 92%, 80%, 68% and 48% of samples. ProTaper caused significantly more cracks than Neolix and Mtwo (P<0.05). No significant differences were noted between other groups (P>0.05). Conclusion:All rotary systems cause dentinal cracks and it is significantly different in apical, middle and coronal third of the root. Neolix appears to be a suitable alternative to other rotary systems since use of this single-file system saves time and cost and minimizes trauma to dentinal walls.

Mechanical root canal preparation using the WaveOne gold® system-Case series

Aim of Study: To describe the endodontic treatment of 4 cases of differing anatomical complexity using the novel WaveOne Gold® reciprocating single-file system. Case Series: 4 patients were referred for endodontic treatment of teeth 17, 37, 47 and 46. The root canals were cleaned and shaped using mechanized Pathfile instruments with continuous rotary movement and then reciprocating movement using the WaveOne Gold single-file system. The irrigants used were a solution of 5% sodium hypochlorite (NaOCl) and 17% Ethylenediaminetetraacetic acid (EDTA). Conclusion: WaveOne Gold reciprocating single-file system represents an advance in root canal preparation. Their flexibility and cutting capacity make the mechanical preparation of curved canals safer, faster and easier than other instruments. In the cases we describe, the instrument was able to maintain the original shape of the root canal and did not present fractures in any of the cases.

Comparative Evaluation of Root Canal Transportation by Three NiTi Single-File Systems in Curved Canals: A Cone Beam Computed Tomography Study.

Introduction This study is aimed at evaluating root canal transportation in the mesiobuccal canal of mandibular first molars prepared with One Shape, Reciproc, and M-One nickel titanium (NiTi) single-file rotary systems using cone beam computed tomography (CBCT). Materials and Methods In this ex vivo study, CBCT scans of 45 extracted human mandibular first molars with 20–40° curvature were obtained. The teeth were randomly divided into three groups (n=15) for preparation of the mesiobuccal canal with One Shape, Reciproc, and M-One rotary systems according to the manufacturers' instructions. CBCT scans were obtained again after canal preparation. Changes caused by preparation in the coronal, middle, and apical thirds were determined on CBCT scans and analyzed using the Kruskal–Wallis test at P ≤ 0.05 level of significance. Results No significant difference was noted in the amount of canal transportation among the three groups (P > 0.05). M-One caused greater transportation in the apical third compared with Reciproc and One Shape, and One Shape caused greater transportation in the coronal third compared with other groups, although its magnitude was less than 0.3 mm. Conclusion Reciproc, One Shape, and M-One are not significantly different in terms of canal transportation.

Comparative evaluation of cleaning ability of reciproc and waveonegold reciprocating file systems – A scanning electron microscopic study

Objective: The aim of this study was to evaluate the canal cleaning ability of two reciprocating single file systems: Reciproc (VDW, Munich, Germany) and WaveOne gold (Dentsply Maillefer, Ballaigues, Switzerland) using scanning electron microscopy (SEM). Materials and Methods: Forty freshly extracted human mandibular premolar teeth with single root and canal were selected. The samples were randomly divided into two experimental groups (n = 15 each). Control group (n = 10) has non-instrumented teeth. Working length was determined using #10/15 K files. All the teeth were prepared to a # 25 final apical size following the manufacturer's instructions using crown-down technique. Teeth were sectioned buccolingually and examined under SEM at 20.0 kV and ×700 magnification. SEM images of the coronal, middle and apical third of the canal were taken and then analyzed using a five-score index. Results: The WaveOne Gold group presented a larger amount of debris than the Reciproc Group, however, without a statistically significant difference (P > 0.05). A larger amount of debris in the control group was observed, with the statistically significant difference between Reciproc and WaveOne Gold groups (P

Efficacy of rotary and reciprocating single-file systems on different access outlines for gutta-percha removal in retreatment: An in vitro study.

Introduction:The aim of this study is to compare the effectiveness of reciprocating and continuous rotary nickel-titanium instruments during retreatment performed through two different access outlines.Methodology:A total of 48 freshly extracted mandibular first and second premolars with single root and canal were selected. Initial root canal treatment was completed through a contracted endodontic cavity (CEC) design. Canals were instrumented with F2 ProTaper instrument, obturated with warm lateral condensation of gutta-percha with AH Plus sealer, and allowed to set for 30 days at 37°C and 100% humidity. For retreatment, specimens were divided into two groups (n = 24) on the basis of access outline, CEC or traditional endodontic cavity. Retreatment was initiated using ProTaper Retreatment instruments (D1–D3). Specimens were further divided (n = 12) and reinstrumented up to Neoniti 25/0.08 or WaveOne 25/0.08. Irrigation was performed using 3% sodium hypochlorite and 17% ethylene diamine tetraacetic acid. Retreatment time was recorded. Teeth were sectioned and photographed, and the percentage of remaining obturation material was measured.Results:Data were collected, and statistical analysis was performed using one-way analysis of variance and Tukey honestly significant difference multiple post hoc procedures (P < 0.05).Conclusion:None of the systems completely removed the root filling material from root canals. However, ProTaper/Neoniti instruments removed more GP when compared to Protaper/WaveOne instruments with both the access outlines. Both the instruments with traditional access outline required less time for removal of obturating material when compared to CEC.

Comparison of Multi- and Single-File System of Ni-Ti Rotary File on Shaping Ability

Comparison of Multi- and Single-File System of Ni-Ti Rotary File on Shaping Ability

Nickel-Titanium Rotary Instruments: Development of the Single-File Systems.

Over the past two decades, the nickel–titanium (NiTi) rotary instruments have highly improved the quality of the cleaning and shaping of the root canals. The superelasticity and shape memory of these instruments reduce the possibility of the canal transportation along with saving the time for both the patients and the clinicians. Several commercial types of these instruments, produced by different manufacturers, have currently become available by modifying the characteristics of the wonder NiTi alloy and also the cross-sectional shapes, cutting edges, tapering and numbers and distances of the flutes of the instruments. Up to this date, five generations for NiTi rotary instruments have been described according to the time of introduction, properties, and method of application. The aim of this article is to review the evolution of these five generations of NiTi rotary instruments since their inception.

Cyclic fatigue and torsional strength of three different thermally treated reciprocating nickel-titanium instruments.

The aim of this study was to evaluate the cyclic and torsional fatigue resistance of the reciprocating single-file systems Reciproc Blue 25.08 (VDW GmbH, Munich, Germany), Prodesign R 25.06 (Easy Dental Equipment, Belo Horizonte, Brazil), and WaveOne Gold 25.07 (Dentsply/Tulsa Dental Specialties, Tulsa, OK, USA). Sixty reciprocating instruments of the systems Reciproc Blue R25 (RB #25 .08 taper), Prodesign R (PDR #25 .06 taper), and WaveOne Gold (WOG #25 .07 taper) (n = 20) were used. Cyclic fatigue resistance testing was performed by measuring the time to failure in an artificial stainless steel canal with a 60° angle of curvature and a 5-mm radius located 5mm from the tip (n = 10). The torsional test (ISO 3630-1) evaluated the torque and angle of rotation at failure of new instruments (n = 10) in the portion 3mm from the tip. The fractured surface of each fragment was also observed using scanning electron microscopy (SEM). In addition, a supplementary examination was performed to measure the cross-sectional area of each instrument 3 and 5mm from the tip. The data were analyzed using one-way ANOVA and Tukey's test, and the level of significance was set at 5%. The cyclic fatigue resistance values of PDR 25.06 were significantly higher (P < 0.05). RB 25.08 showed higher fatigue resistance than WOG 25.07 (P < 0.05). The torsional test showed that PDR 25.06 had lower torsional strength (P < 0.05). No differences were observed between RB 25.08 and WOG 25.07 (P > 0.05). PDR 25.06 showed higher angular rotation values than RB 25.08 and WOG 25.07 (P < 0.05). RB 25.08 presented higher angular rotation than WOG 25.07 (P < 0.05). The cross-sectional area analysis showed that PDR 25.06 presented the smallest cross-sectional areas at 3 and 5mm from the tip (P < 0.05). PDR 25.06 presented the highest cyclic fatigue resistance and angular rotation until fracture compared to RB 25.08 and WOG 25.07. In addition, RB 25.08 and WOG 25.07 had higher torsional strength than PDR 25.06. In endodontic practice, thermally treated reciprocating instruments have been used for the root canal preparation of curved and constricted canals; therefore, these instruments should present high flexibility and suitable torsional strength to minimize the risk of instrument fracture.

Influence of Cervical Preflaring on the Incidence of Root Dentin Defects

IntroductionThis study evaluated the influence of cervical preflaring on the incidence of root dentin defects after root canal preparation. MethodsExtracted human maxillary central incisors were selected and allocated to 1 control group and 12 experimental groups (n = 15). Teeth in the control group were left unprepared, whereas the others were prepared using 2 reciprocating single-file systems (Reciproc and WaveOne [WO]), 3 full-sequence rotary systems (ProTaper Universal, ProTaper Next [PTN], and ProFile), and K-files driven by an oscillatory system, with and without cervical preflaring. Roots were then horizontally sectioned at 4, 8, and 12 mm from the apex, stained with 1% methylene blue, and viewed through a stereomicroscope at ×25 magnification. Slices were inspected and the absence/presence of defects (fractures, partial cracks, and craze lines) recorded. Data were analyzed using Kolmogorov-Smirnov and Levene tests followed by the Tukey post hoc test at a significance level of P < .05. ResultsNo root dentin defects were observed in the control group. WO was associated with a significantly higher number of defects than K-files, ProFile, and PTN (P < .05), but was not significantly different from Reciproc or ProTaper Universal (P > .05). Cervical preflaring significantly reduced the incidence of fractures and other defects in the WO and PTN groups (P < .05). ConclusionsAll instruments caused root dentin defects, regardless of the enlargement or not of the cervical portion. Cervical preflaring was associated with a lower incidence of defects, mainly in root canals prepared with WO and PTN.

A micro-computed tomographic evaluation of dentinal microcrack alterations during root canal preparation using single-file Ni-Ti systems.

The aim of the present study was to evaluate the length of dentinal microcracks observed prior to and following root canal preparation with different single-file nickel-titanium (Ni-Ti) systems using micro-computed tomography (micro-CT) analysis. A total of 80 mesial roots of mandibular first molars presenting with type II Vertucci canal configurations were scanned at an isotropic resolution of 7.4 µm. The samples were randomly assigned into four groups (n=20 per group) according to the system used for root canal preparation, including the WaveOne (WO), OneShape (OS), Reciproc (RE) and control groups. A second micro-CT scan was conducted after the root canals were prepared with size 25 instruments. Pre- and postoperative cross-section images of the roots (n=237,760) were then screened to identify the lengths of the microcracks. The results indicated that the microcrack lengths were notably increased following root canal preparation (P<0.05). The alterations in microcrack length in the OS group were more significant compared with those in the WO, RE and control groups (P<0.05). In conclusion, the formation and development of dentinal microcracks may be associated with the movement caused by preparation rather than the taper of the files. Among the single-file Ni-Ti systems, WO and RE were not observed to cause notable microcracks, while the OS system resulted in evident microcracks.

Efficacy of photon-initiated photoacoustic streaming on apically extruded debris with different preparation systems in curved canals.

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. 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 2940nm Er:YAG laser (0.3W, 15Hz, and 20mJ), (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 20s. Total irrigation and activation time was 1min, and a total volume of 7.5mL 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 5days. 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. 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). All file and irrigation systems extruded debris apically. PIPS activation was associated with significantly more extrusion debris in curved canals compared with no activation.

Toward a more biologically accurate model of diffusion: adhesion and collisions

In single-file dynamics, Brownian particles (referred to as tracer or tagged particles) diffuse and collide with each other in one-dimensional domains. If the average particle density is kept fixed during the diffusion, the collisions between the tracer particles result in their famous anomalous sub-diffusion behavior with time to the one half dependence. Many systems in nature are found to obey single-file dynamics, such as ion transport processes, and inter-particle adhesion plays a crucial role, either structurally or functionally, in the diffusion of such systems; however, the exact effect of adhesion on the diffusion has not been studied so far. We have examined the effect of adhesion on the collective diffusion of single-file systems. Here, we extend previous work where we perform large-scale numerical simulations that utilize Monte Carlo techniques and high-performance computing resources to examine the effect of adhesion on the diffusion of the tracer particles in systems that obey single-file dynamics. We show that if all the tracer particles experience the same adhesion coefficient, adhesion only slows down the diffusion by reducing the magnitude of the tracer diffusion coefficient; however, both the anomalous sub-diffusion behavior and time to the one half dependence of the tracer particles remain almost intact, independent of the adhesion.

Anomalous and nonanomalous behaviors of single-file dynamics

We study the dynamics of a tagged particle that undergoes single-file diffusion in an environment of point Brownian particles. Specifically, we examine the effect of the particle density on the well-known anomalous sub-diffusion behavior of the tagged particle. We compare two single-file systems; the first maintains a fixed average particle density and the second experiences a dilution with time. Both our analytical predictions and computational results, that study the time evolution of the mean square displacement per particle for both systems, show that the behavior of the tagged particle transforms from anomalous sub-diffusive (if the average particle density is kept fixed) to normal if a reduction in the average particle density takes place during the diffusion. Our computational results are based on a discrete Monte-Carlo technique that captures perfectly the dynamics of the continuum formulation of single-file systems.