WaveOne Gold Instruments Research Articles

Comparative Analysis of Surface Roughness and Plastic Deformation of Reciprocating Instruments after Clinical Use.

This study assessed the surface topography and plastic deformation (PD) of new and used contemporary reciprocating instruments. Twenty-six WaveOne Gold (WOG) and EdgeOne Fire (EO) instruments were photographed under magnification. The instruments were randomly assigned to a control group of new instruments preserved for surface roughness analysis (n = 6 each), or to an experimental group to shape the root canal system of a single molar (n = 20 each), making a total of four groups (WOGnew, EOnew, WOGused, EOused). Used instruments were also photographed after instrumentation. The presence of fractures was registered. Preoperative and postoperative images were randomly ordered for evaluation. Two blinded calibrated examiners evaluated the presence of PD. Inter-observer agreement was calculated with the Kappa coefficient (K = 0.89). 3D profilometry was also used for the surface roughness analysis of six randomly selected instruments from the WOGused and EOused groups. Chi-square and two-way ANOVA tests were used to, respectively, compare PD and changes in surface roughness among the groups. No instruments fractured; however, a significantly greater percentage of EO instruments suffered plastic deformation than WOG instruments (p < 0.001), (OR = 11.09 (CI 95% 2.6-56.3)). The overall surface roughness was higher for most parameters in the EO instruments (p < 0.05). Single uses of EO instruments produced significantly higher chances of PD and increased surface roughness values compared to WOG.

Comparative evaluation of cleaning efficiency of single file NiTi rotary system during root canal treatment procedure - A scanning electron microscope study.

Optimal biomechanical preparation, thorough irrigation, proper disinfection, and finally, well-sealed obturation is a must to attain definitive success in root canal procedure. Proper preparation of the root canal is all the more imperative to establish a hermetic apical seal with adequately placed filling materials. The present study was conducted for comparing the Cleaning Efficiency of F360 system and the WaveOne Gold (WOG) system of rotary NiTi instrumentation for a root canal. One hundred freshly extracted noncarious mandibular canines were obtained. Access cavity of standard size was made followed by the establishment of working length. Afterward, random division of all the specimens was done into two study groups: group A: the group in which F360 system was used for instrumentation and group B: the group in which the WOG system was used for instrumentation. Irrigations of all the specimens of both the study groups were done followed by root canal shaping by the instrument system of their respective study groups. Scanning electron microscope (SEM) was used for assessment after specimens were cut buccolingually. Debris score and residual smear layer score were used for assessment. Among group A specimens, the mean smear layer score at the coronal third, middle third, and apical third was 1.76, 2.39, and 2.65, respectively. Among group B specimens, the mean smear layer score at the coronal third, middle third, and apical third was 1.34, 1.59, and 1.92, respectively. While analyzing statistically, it was seen that the mean smear layer score was significantly higher among specimens of group A in comparison to group B. While analyzing statistically, it was seen that the mean debris score was significantly higher among specimens of group A in comparison to group B. The cleaning effectiveness of WOG instruments was significantly enhanced in comparison to F360 equipment.

The effect of two different root canal sealers on treatment outcome and post-obturation pain in single-visit root canal treatment: A prospective randomized clinical trial.

This randomized clinical trial aimed to evaluate and compare the effect of mineral trioxide aggregate (MTA)-based bioceramic- and resin-based sealers on the incidence and intensity of post-obturation pain and treatment outcome in asymptomatic vital molar teeth in single-visit root canal treatment. One hundred asymptomatic mandibular molar teeth with vital pulp were randomly assigned into two groups according to the sealer used: MTA Fillapex or AH Plus sealer. WaveOne Gold instruments were used for root canal preparations. Root canals were obturated with WaveOne Gold gutta-percha cones corresponding in size and taper to the last instrument used. MTA Fillapex was used in the first group and AH Plus was used in the second group as the root canal sealer. The effects of age, gender, tooth types and the level of root canal filling on the treatment outcome were evaluated after 1 and 2 years. Postoperative pain at 6, 12, 24, 48, 72 h, 4, 5, 6, 7 and 30 days after root canal treatment was measured with the Numerical Rating Scale. Chi-square test was used for the treatment outcome and Mann-Whitney U, chi-Square and Spearman correlation analyses were used for postoperative pain. α=.05 was the level of significance. Twelve patients did not complete the 2-year follow-up and the study finished with 88 patients. In the MTA Fillapex group 41 correct, one short, two extruded, and in the AH Plus group 40 correct, one short and three extruded root canal fillings were detected. No significant differences were observed between the first- and second-year treatment outcomes between the groups (p > .05).There was no association between age, gender, tooth number, root canal filling length and the treatment success in all evaluated teeth (p > .05). The differences between the groups in terms of postoperative pain incidence and intensity at all time-points were not significant (p > .05). There was no correlation between the age and postoperative pain (p > .05), but pain was statistically higher in women (p < .05). Mineral trioxide aggregate Fillapex showed similar success rate and post-obturation pain incidence and intensity as AH Plus sealer and can be used as a root canal sealer in asymptomatic mandibular molars with irreversible pulpitis.

Quantitative evaluation of apically extruded debris using TRUShape, TruNatomy, and WaveOne Gold in curved canals

ObjectiveThis study compared the quantity of extruded debris after instrumentation with TRUShape 3D Conforming files, TruNatomy files, and the WaveOne Gold reciprocating system.Materials and methodsFifty-one mesiobuccal canals with severe curvatures (25–40°) were assigned to three equal groups according to the rotary system used for preparation, either TRUShape, TruNatomy, or WaveOne Gold files. The extruded debris was collected in pre-weighed glass vials. The data were statistically analyzed using a one-way ANOVA test and Tukey’s post hoc test.ResultsThe least extruded debris was obtained with the WaveOne Gold instruments compared to the TRUShape and TruNatomy files (p < 0.001).ConclusionsDebris extrusion occurs independently of the motion or design of the instrument. The WaveOne Gold system outperformed TRUShape and TruNatomy files in this study.

Comparison of Cleaning Efficiency of Root Canal Using Different Rotary NiTi Instrumentation System: A Scanning Electron Microscopic Study.

Background: To ensure that endodontic treatment is as effective as possible, it is important to remove any smear layer that forms as part of the instrumentation procedure. This layer might reduce the overall effectiveness of endodontic therapy.Aim of the study: For this research, two distinct types of rotary NiTi files were compared: WaveOne Gold (WOG) (Dentsply Maillefer, Ballaigues, Switzerland) and F360 (Komet Brasseler GmbH & Co., Lemgo, Germany) for its capacity to eliminate trash and the smear layer.Materials and methods: Two groups (n=20 each) of 40 mandibular second premolar teeth were employed in this investigation, with each group receiving a random allocation of teeth. The F360 system and the WaveOne Gold system are two sets of instruments. The samples were irrigated with a mixture of sodium hypochlorite (NaOCl) (5.25%) and citric acid (40%). Finally, all samples in the centre of the coronal, middle, and apical thirds were examined by scanning electron microscopy (SEM). Mann-Whitney U tests were used to analyse the data.Results: F360 instrument showed a statistically significant difference for smear layer removal among all thirds of the root canal whereas WOG resulted in a significant difference when the apical third was compared to the middle and coronal third. Significant differences were found in the middle and apical third in terms of smear layer removal between the two groups.Both F360 and WOG instruments showed statistically significant differences for debris removal among all thirds of the root canal. No significant differences were found in the coronal, middle, and apical third in terms of debris removal between the two groups.Conclusion: WOG resulted in cleaner canals compared to the F360 file system at coronal, middle, and apical third.

Effect of A Clinical-Replicable Cooling Protocol on the Cyclic Fatigue Resistance of Heat-Treated Nickel-Titanium Instruments.

The aim of this study was to evaluate the bending and cyclic fatigue resistance of Wave One Gold (WOG) and X1 Blue (X1B) instruments when tested at body temperature (36°C ± 1°C) with and without subjected to an alloy cooling protocol. A total of sixty instruments (n=30) were tested. Forty instruments (n=20) were randomly selected and divided into two groups: body temperature (BT; n=20) and body temperature with cooling protocol (CP; n=20). Cyclic fatigue test was performed until fracture in a conventional stainless-steel device with water bath equipment to simulate body temperature. CP group instruments were subjected to 5 seconds of spray cooling every 30 seconds. Time to fracture was recorded in seconds. Resistance to bending at an angle of 45 degrees was evaluated using twenty instruments (n=10). Fractured surfaces were examined under scanning electron microscopy (SEM). Statistical analysis was performed at a 5% significance level. Results: There was no difference in the cyclic fatigue resistance between instruments in BT groups (P>0.05). Cooling protocol significantly increased the cyclic fatigue resistance of X1B instruments (P=0.0003) and WOG instruments (P=0.0003). WOG instruments had a significantly lower cyclic fatigue resistance compared to X1B instruments in CP group (P=0.0001). There were no significant differences between the values of resistance increase presented by the instruments after cooling (P>0.05). Bending test presented no statistically significant differences between the tested instruments (P>0.05). Both instruments in both groups showed typical features of cyclic fatigue behavior under SEM. X1 Blue #25.06 and WaveOne Gold #25.07 instruments presented similar cyclic fatigue resistance. The investigated clinical-replicable cooling protocol improved the cyclic fatigue resistance of the tested instruments, with X1 Blue #25.06 presenting a greater cyclic fatigue resistance after cooling. Both instruments presented a similar bending capacity.

Shaping ability of four single-file systems in the instrumentation of second mesiobuccal canals of three-dimensional printed maxillary first molars.

BackgroundThis study evaluated and compared the shaping ability of four advanced single-file nickel-titanium (NiTi) systems during the preparation of curved second mesiobuccal (MB2) canals in maxillary first molar replicas fabricated by three-dimensional (3D) printing via micro-computed tomography (Micro-CT) imaging.MethodsA total of 60 3D-printed maxillary first molar replicas were constructed from one extracted tooth, with an angle of curvature ranging from 15° to 25°. The MB2 canals from these 60 replicas were divided into 4 groups of 15 replicas according to the canal instrumentation system used, namely, Waveone gold (WOG), Reciproc blue (RCB), XP-endo shaper (XPS) and M3-L. The specimens were scanned before and after preparation using Micro-CT. The pre- and post-instrumentation images of each specimen were superimposed, and the amount of resin removed, the change in surface area, the canal transportation, and centering ability were assessed using the Mimics software. Instrumentation time was also recorded. One-way analysis of variance and least significant difference (LSD) tests were used to statistically compare the groups. The significance level was set at 5%.ResultsInstrumentation time with M3-L was significantly longer than the other systems (P<0.05). The amount of resin removed and the change in surface area generated by the 4 systems were different at the apical, middle, and coronal thirds, and the total canal (P<0.05). Overall, WOG and XPS resulted in the less change than RCB and M3-L. There was no significant difference among the groups at the middle third regarding canal transportation and centering ability (P>0.05). However, a significant difference was found at the apical level (P<0.05), where RCB showed the poorest centering ability and the highest canal transportation (P<0.05). In addition, XPS resulted in the least canal transportation (P<0.05) at the coronal level, while there was no significant difference between the four groups in terms of centering ability.ConclusionsThe M3-L instrument required more time to prepare the curved MB2 canals compared with the other systems. Overall, WOG and XPS showed the least resin removal and surface area change. M3-L, XPS, and WOG instruments respected the original canal curvature better than RCB files.

Comparison of Postobturation Pain Experience after Apical Extrusion of Calcium Silicate– and Resin–Based Root Canal Sealers

IntroductionThis study compared the intensity of postobturation pain after unintentional apical extrusion of calcium silicate–based root canal sealers (EndoSequence BC Sealer [Brasseler USA, Savannah, GA] and Bio-C Sealer [Angelus, Londrina, PR, Brazil]) with a resin-based sealer (AH Plus; Dentsply Sirona, York, PA). MethodsA total of 330 patients referred for root canal treatment on molar teeth with asymptomatic irreversible pulpitis were recruited. Root canals were prepared using WaveOne Gold instruments (Dentsply Sirona) in a crown-down technique and irrigated with 2% chlorhexidine gel and saline solution. Next, patients were randomly distributed into 3 groups according to the root canal sealer used (n = 110): AH Plus, BC Sealer, and Bio-C Sealer. Root canal filling was then accomplished with a vertical compaction technique. Patients presenting with an unintentional extrusion of sealers (n = 13/group) were assessed for postobturation pain experience using a visual descriptor scale ranging from 0–10 at 6-, 12-, 24-, and 48-hour and 1-week intervals after treatment. Mixed analysis of variance repeated measures were used to assess the results (α = 0.05). ResultsThe extrusion rate was similar for all sealers (~12%). There was no significant difference in the postobturation pain results between the root canal sealers evaluated (P > .05). However, after the time interval of 12 hours, AH Plus (P = .04073) and Bio-C Sealer (P = .04327) demonstrated a significant reduction in pain, whereas BC Sealer did not show differences in pain intensity, even in the maximum period evaluated of 1 week (P > .05). ConclusionsThe occurrence of unintentional apical extrusion of calcium silicate–based root canal sealers presents similar postoperative pain results compared with resin-based sealers with low-intensity pain.

Effect of Root Canal Preparation on Propagation of Dentinal Microcracks.

This study evaluated the propagation of dentinal microcracks and the root canal volume increase after being prepared with two endodontic instruments: ProTaper Next (PTN) and WaveOne Gold (WOG) by micro-computed tomography analysis. We selected 48 maxillary molars randomly distributed in two groups: PTN and WOG. The samples were scanned before and after instrumentation, and then the image analysis was performed to detect the propagation of pre-existing dentinal micro-cracks and calculate the pre- and post-instrumentation volume. The statistical analysis was performed using Student's t-test, Fisher's exact test, and ANCOVA (P<0.05). Dentinal microcracks were observed in 95.8% of the samples, both PTN and WOG instruments propagated microcracks after instrumentation, but there was no significant difference between the instruments (P=0.538). In relation to the root canal volume there was no statistic difference between PTN and WOG systems for the mesiobuccal (P=0.426) and distobuccal root canals (P=0.523). We can conclude that both ProTaper Next and WOG systems propagate dentinal microcracks after root canal preparation in this in vitro study, without statistical significance. The root canal volume prepared also showed no statistically significant difference between the two groups. This in vitro study requires further studies for more concrete conclusions.

Fracture incidence of WaveOne Gold files: a prospective clinical study.

This prospective clinical study evaluated the incidence of instrument fracture observed after single-file root canal treatment of molars using WaveOne Gold instruments. Three standardized, experienced and calibrated specialists treated 750 maxillary and mandibular molars with curvatures less than 45° (2691 root canals) over a 12-month period. All the treatments were performed in a single session. A total of 1104 WaveOne Gold instruments were used, including 38 small, 750 primary, 228 medium and 88 large instruments. Intracanal procedures were performed according to the manufacturer's recommendations, and each instrument was used in a single clinical case. The instruments were examined after their removal from the canal, under an operating microscope at 8× magnification. No fractures were observed in any of the 1104 instruments used. No fractures of WaveOne Gold reciprocating instruments occurred during root canal preparations performed in maxillary and mandibular molars with curvatures less than 45° when used strictly according to the manufacturer's recommendations and applied in a single clinical case.

Cyclic Fatigue and Torsional Resistance of Four Martensite-Based Nickel Titanium Reciprocating Instruments.

Objective:To evaluate cyclic fatigue and torsional resistance of Reciproc Blue R25 (VDW, Munich, Germany), WaveOne Gold Primary (Dentsply Maillefer, Ballaigues, Switzerland), ProDesign R (Easy Equipamentos Odontológicos, Belo Horizonte, Brazil), and X1 Blue File (MK Life, Porto Alegre, Brazil) nickel titanium (NiTi) martensite reciprocating instruments.Methods:In each group, ten instruments were tested for cyclic fatigue resistance using a stainless-steel artificial canal (curvature angle of 80° and radius of 3 mm) and ten instruments for torsional failure according to ISO 3630-1 standard. The surface of the fractured instruments was examined under scanning electron microscopy (SEM) at ×250 magnification. The results were compared statistically with one-way ANOVA and post hoc Tukey tests and the alpha-type error was set at 5%.Results:X1 blue file and ProDesign Rinstruments showed highest time to fracture than Reciproc Blue and Wave One Gold (P<0.05). However, no differences were found between X1 Blue File and ProDesign R (P>0.05). In addition, Reciproc Blue demonstrated highest time to fracture than WaveOne Gold (P<0.05). The lowest torsional resistance (1.0±0.2 N.cm) and angle of rotation (412º±46) was observed in the ProDesign R group (P<0.05). SEM analyses of fractured surfaces showed a crack initiation area and overload fast fracture zone after cyclic fatigue test, and concentric abrasion marks with microvoids at the centre of rotation after torsional failure experiment.Conclusion:Overall, X1 Blue File and ProDesign R showed higher cyclic fatigue resistance than Reciproc Blue and WaveOne Gold instruments, while ProDesign R had the lowest torsional resistance and angular rotation values to fracture. SEM analysis of all instruments demonstrated typical failures features in both cyclic fatigue and torsional failure tests.

Structural Characteristics and Torsional Resistance Evaluation of WaveOne and WaveOne Gold Instruments after Simulated Clinical Use

IntroductionThe aim of this study was to compare 2 reciprocating nickel-titanium systems with different manufacturing characteristics and to evaluate the influence of simulated clinical use on their torsional resistance. MethodsNew 25/.08 WaveOne Primary (WO; Dentsply Sirona, York, PA) and 25/.07 WaveOne Gold Primary (Dentsply Sirona) files were used in this study. The diameter and cross-sectional area at 3 mm from the tip were measured using image analyses. The alloy microstructure was evaluated by X-ray diffraction and the phase transformation temperatures by differential scanning calorimetry analyses. Forty files were divided into 4 groups: control group 1 and control group 2, which were submitted to torsion tests until rupture, and experimental group 1 and experimental group 2, in which instruments were used to shape 2 mesial canals of an extracted mandibular molar and then submitted to torsion tests until rupture. ResultsWO had higher values of diameter and area at 3 mm from the tip. X-ray diffraction analysis presented R-phase and austenite for both systems. Austenite finish temperatures, determined by differential scanning calorimetry, were above room temperature. WO showed higher values of torque until rupture, and WaveOne Gold showed higher values of angular deflexion (P > .05). No differences were found between the same type of instrument in the control and experimental groups. ConclusionsThe higher torsional resistance of WO can be attributed to geometric characteristics. The use in 1 tooth with curved canals is safe and does not affect the torsional resistance of the instruments analyzed.

Efficacy of 3 Supplementary Irrigation Protocols in the Removal of Hard Tissue Debris from the Mesial Root Canal System of Mandibular Molars

IntroductionInstrumentation of the mesial root canal system of mandibular molars may hinder disinfection by packing hard tissue debris within the isthmuses. The removal of accumulated hard tissue debris (AHTD) by 3 supplemental irrigation systems, 2 ultrasonically activated and 1 multisonic, was assessed with micro–computed tomographic imaging. MethodsTwenty-four extracted mandibular molars with 2 mesial canals connected by an isthmus and converging to a single foramen were selected. After preparation of the mesial canals with WaveOne Gold instruments (Dentsply Maillefer, Ballaigues, Switzerland), anatomically matched specimens were assigned to 3 final irrigation protocols (n = 8): intermittent ultrasonic (IU) with an ultrasonically energized 200-μm wire (Irrisafe; Satelec, Bordeaux, France), continuous ultrasonic (CU) with an ultrasonic irrigation needle (ProUltra PiezoFlow, Dentsply Maillefer), and GentleWave (GW) system (Sonendo Inc, Laguna Hills, CA). Specimens were scanned (SkyScan 1176; Bruker-microCT, Kontich, Belgium) at 17.18-μm pixel size before and after preparation and irrigation protocols. Data sets were coregistered, and the percentage reduction of AHTD calculated within the canals and isthmus for each specimen was statistically compared using 1-way analysis of variance and post hoc Tukey tests with a 5% significance level. ResultsThe mean percentage reduction of AHTD in canals and isthmuses was significantly higher for GW (96.4% and 97.9%, respectively) than for CU (80.0% and 88.9%, respectively) (P < .05). AHTD reduction for IU (91.2% and 93.5%, respectively) did not differ significantly from GW and CU (P > .05). ConclusionsGW achieved greater efficacy in the removal of AHTD from the mesial root canal system of mandibular molars compared with CU but not IU. The efficacy of CU and IU was comparable.

Surface nanoscale profile of WaveOne, WaveOne Gold, Reciproc, and Reciproc blue, before and after root canal preparation.

This study aimed to compare the surface topographies and nanoscale profiles of intact and used WaveOne, WaveOne Gold, Reciproc, and Reciproc blue nickel-titanium (NiTi) instruments. Sixteen NiTi instruments were evaluated; four from each one of WaveOne (25/0.08), WaveOne Gold (25/0.07), Reciproc (25/0.08), and Reciproc blue (25/0.08) files. Each instrument was used to prepare four curved canals. A three-dimensional nanoscale surface profiler was used to assess instrument surfaces before and after root canal instrumentation. The data were analyzed with one-way analysis of variance using SPSS 21.0 software and set significance at P < 0.05. There were significant differences in surface topography between NiTi instruments. Intact WaveOne and WaveOne Gold instruments had the highest values, followed by the Reciproc and Reciproc blue instruments (P < 0.05). Used WaveOne and WaveOne Gold instruments had the highest values, followed by Reciproc and Reciproc blue instruments (P < 0.05). Some indications of microcracks in qualitatively intact Reciproc blue files were observed, and minor surface cracks in used WaveOne Gold instruments were also observed. Used WaveOne, Reciproc, and Reciproc blue instruments exhibited cracks and microcavities. WaveOne Gold and Reciproc blue instruments had significantly higher levels of surface distortion after root canal instrumentation, and WaveOne exhibited the lowest level of surface deformation. Each of the Reciprocating instruments was safely used to prepare four canals without incident. The three-dimensional stylus profiler provided valuable assessments of the surface topographies of NiTi instruments.

Atomic force microscopy and energy dispersive X-ray spectrophotometry analysis of reciprocating and continuous rotary nickel-titanium instruments following root canal retreatment.

The aim was to examine the effect of retreatment process on the surface roughness and nickel titanium (NiTi) composition of ProTaper Universal Retreatment (PTUR; consists of 3 files; D1, D2, D3) and WaveOne Gold (WOG) (primary) instruments. Twenty extracted mandibular molar teeth with severe curved (30-40°) mesial roots were selected and divided into two groups (n = 10) based on the instrument used for the removal of the root canal filling. Before and after using the instruments in two canals, they were subjected to atomic force microscopy (AFM) and energy dispersive X-ray spectrophotometry (EDX) analysis. The EDX analysis data and roughness average (Ra) and root mean square (RMS) values were analyzed statistically using a one-way analysis of variance and post hoc Tukey's test at the 5% significant level. There was no significant difference between the new and used D1 and D2 PTUR and WOG instruments in terms of the Ni composition (p > .05). The Ti contents of the used D2 and D3 PTUR instruments were lower those of the new instruments (p < .05). In both new and used instruments, PTUR and WOG have no difference in terms of Ra and RMS values. (p > .05). The Ra and RMS values of the PTUR and WOG systems significantly increased after removal of the root canal filling (p < .05). The use of PTUR and WOG instruments for removal of root canal filling in severely curved root canals affected the surface topography of the files. The NiTi composition of the WOG instruments was unaffected by the retreatment process.

Effect of Reciproc blue, XP-endo shaper, and WaveOne gold instruments on dentinal microcrack formation: A micro-computed tomographic evaluation.

The purpose of this study was to evaluate and compare the effect of Reciproc Blue (RPCB), XP-endo Shaper (XPS), and WaveOne Gold (WOG) single-files on dentinal microcrack formation using micro-computed tomography (micro-CT). Twenty-four mesial roots (24 mesio-buccal and 24 mesio-lingual canals) of mandibular molar teeth were prepared using RPCB, XPS, and WOG files (n = 8/each group). The samples were scanned with micro-CT in the pre- and post-preparation. Then, before preparation and after preparation cross-sectional images of the teeth were evaluated to detect the presence of microcracks. For each group, the number of microcracks was calculated as a percentage rate. The data were statistically analyzed using McNemar at 5% significance level (p < .05). Dentinal microcracks were observed in 25.99% (2,103 of 7,813), 31.99% (2,482 of 7,758), and 36.66% (2,836 of 7,731) of cross-sectional images of the XPS, WOG, and RPCB groups, respectively. In all the groups, all the dentinal microcracks seen in the post-treatment cross-sectional images were present in the corresponding pre-treatment images. Within the limitations of this study, the XPS, WOG, and RPCB files did not cause new dentinal microcrack formation or propagation of existing dentinal microcracks.

A comparative study of mechanical resistance of two reciprocating files.

BackgroundTo evaluate the cyclic fatigue resistance of two different Nickel-Titanium instruments, Reziflow (Komet, Brasseler GmbH & Co., Lemgo, Germany) and WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland).Material and MethodsTwo groups of 20 different NiTi endodontic instruments of identical tip size of 0.25 mm were tested; Reziflow and Wave-One Gold primary. Cyclic fatigue testing was performed in a stainless steel simulated root canal manufactured by reproducing the instrument’s size and taper. A simulated root canal with a 90 degrees angle of curvature and 5 mm radius of curvature was constructed for the instruments tested. The centre of the curvature was 5 mm from the tip of the instrument and the curved segment of the canal was approximately 5 mm in length. Both the instruments were used in the same preset program specific for the WaveOne instruments. Each instrument was rotated until fracture occurred and the time to fracture (TtF) and the length of the fractured fragment were recorded. Means and standard deviations of TtF and fragment length were calculated and data were subjected to statical analysis (P<0.05).ResultsStatistically significant differences (P<0.05) were noted between Reziflow and WaveOne Gold instruments. There were no significant differences (P>0.05) in the mean length of the fractured fragments between the instruments.ConclusionsRezifllow instruments were associated with a significantly higher cyclic fatigue resistance than WaveOne Gold instruments. Key words:Endodontic instruments, NiTi alloy, Reciprocating motion, Cyclic Fatigue, Heat treatment.

Root Canal Shaping Using Nickel Titanium, M-Wire, and Gold Wire: A Micro–computed Tomographic Comparative Study of One Shape, ProTaper Next, and WaveOne Gold Instruments in Maxillary First Molars

IntroductionThe 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. MethodsOne 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). ResultsThe 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). ConclusionsWOG 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.

DEBRIS EXTRUSION FROM SEVERELY CURVED ROOT CANALS AFTER INSTRUMENTATION WITH WAVEONE GOLD OR ONESHAPE SINGLE FILES

Aim: The aim of this study was to assess the effect of degree of curvature on extrusion of debris from root canals; and to compare the amount of extruded debris after instrumentation with WaveOne Gold reciprocating (WOG; Dentsply Maillefer, Ballaigues, Switzerland) and OneShape rotating (OS; MicroMega, Besancon, France) single file systems.Materials and methods: Sixty mesiobuccal canals were assigned to 2 equal groups according to the degree of curvature, whether severe (25-40°) or moderate (10-15°) as measured using Schneider method. The canals in each group were further subdivided into 2 subgroups (n=15) according to the instrument used for preparation; WaveOne Gold (WOG) or OneShape (OS) files. The extruded debris was collected in preweighed glass vials. Data were statistically analyzed using One-way ANOVA and Tukey’s post-hoc tests.Results: The least amounts of debris were obtained with WaveOne Gold instruments in both curvatures, with no significant difference between them (P > 0.05). Larger amounts of debris occurred with OneShape instruments in severely curved canals; but this difference was of no statistical significance. Statistically significant differences were recorded only when OneShape instruments were used in moderately curved canals. Conclusions: Debris extrusion occurs independent of the motion or design of the instrument. However, moderate root canal curvatures allowed more extrusion of debris than severe curves. WaveOne Gold results were not affected by the degree of canal curvature; and outperformed OneShape instruments in both types of curves.

Effect of sodium hypochlorite and saline on cyclic fatigue resistance of WaveOne Gold and Reciproc reciprocating instruments.

To compare the cyclic fatigue resistance of WaveOne Gold (Dentsply Tulsa Dental Specialties, Tulsa, OK, USA) and Reciproc (VDW, Munich, Germany) reciprocating instruments during immersion in sodium hypochlorite (NaOCl) and saline solutions at body temperature. A total of 180 new WaveOne Gold primary size 25, .07 taper, and Reciproc size 25, .08 taper were randomly divided into three groups: group 1: no immersion (control, air); group 2: immersion in saline at 37±1°C; and group 3: immersion in 5% NaOCl at 37±1°C. The instruments were reciprocated in the test solution until fracture, and the number of cycles to failure was recorded. The data were analysed statistically using t-tests and one-way analysis of variance (anova) with the significance level set at P<0.05. A Weibull analysis was performed on number of cycles to failure data. WaveOne Gold instruments had significantly greater number of cycles to failure than Reciproc instruments in all groups (P<0.001). Fatigue resistance for both instruments tested in air was significantly higher than that in saline and NaOCl solutions (P<0.001). For both instruments, there was no significant difference in the fatigue resistance between saline and NaOCl solutions (P>0.05). The Weibull analysis showed that the predicted cycles of WaveOne Gold in air was 1027 cycles for 99% survival. However, Reciproc instruments tested in NaOCl solution had the lowest predicted cycles (613 cycles) among the groups. Immersion of WaveOne Gold and Reciproc reciprocating instruments in saline and NaOCl solutions decreased considerably their cyclic fatigue resistance. The fatigue resistance of WaveOne Gold instruments was higher than that of Reciproc instruments.