WaveOne Instruments Research Articles

A Comparative Study on the Shaping Ability and Cleaning Efficiency of Two Different Single-File Systems, Reciprocating Wave One Versus Continuous Rotation F360, Evaluated by Scanning Electron Microscope: An In Vitro Study.

Background: In endodontics, the three processes of biomechanical preparation, disinfection, and obturation are each essential. The electron microprobe and scanning electron microscope (SEM) allowed for the detection and identification of the smear layer and debris. The purpose of the current investigation was to use a scanning electron microscope to evaluate the relative merits of two single-file systems, the reciprocating WaveOne and the continuous motion F360 files, in the cleaning and contouring of root canals in removed teeth. Materials and method: The 50 central maxillary permanent teeth Data was gathered from the Oral and Maxillofacial Surgery Division at Sri Ganganagar's Maharaja Ganga Singh Dental College and Research Centre for a number of reasons. Group A followed the manufacturer's guidelines for using the WaveOne instrument, whereas Group B utilised the F360. Reciprocating motion WaveOne system (group A) and continuous motion F360 system (group B) root canals were scored at three levels: coronal third, middle third, and apical third (group B). SPSS version 22 was used for the data analysis. The data were examined using the chi-square test and the one-way analysis of variance. Results: A greater quantity of smear layer was found in the apical third, whereas better results were achieved in the coronal and middle thirds. When compared to the F360 file system, the WaveOne file system is subpar when it comes to clearing the canal of debris. While both groups showed a large amount of debris in the apical third, outcomes were somewhat better in the coronal and middle thirds. Conclusion: The WaveOne and F360 file systems were both more effective in removing trash from the coronal and middle thirds of the disc than they were from the apical thirds. In comparison to the continuous motion F360 file system, WaveOne files demonstrated a statistically significant reduction in the amount of debris cleared from root canals in all three root zone thirds (coronal, middle, and apical). The reciprocating action of the WaveOne file system, in contrast to the continuous motion of the F360 file system, resulted in more extensive cleaning of the root canal smear layer in the coronal and middle thirds and less thorough cleaning in the apical thirds of the canal.

Finite Element Analysis of Stress Distribution in Root Canals When Using a Variety of Post Systems Instrumented with Different Rotary Systems.

It is very important for clinicians to provide restorative treatments that provide durability for endodontically treated teeth. Trauma, occlusal premature contact, and features of teeth are some of the issues that can cause vertical root fractures (VRFs) in root canal-treated teeth. The aim of this 3-D study was to compare stress distribution on mandibular premolar teeth when using a variety of post designs instrumented with different rotary systems. Six mandibular premolar teeth were instrumented with the following tools: ProTaper Next, WaveOne (WO), Reciproc (R), ReciprocBlue (RB), F6-Skytaper, and TF-Adaptive. Teeth were scanned using cone beam computed tomography (CBCT) and the images were transferred to the Catia V5R25 software. Data were recorded in a stereolithography (STL) format. Four different post systems were used, fabricated from metal, fiber, zirconia, and titanium, respectively. Dentin, gutta, post, core, and crown models were added to the solid model. ANSYS V17.2 finite element analysis (FEA) software was used to determine stress distribution on each assembly. Finite analysis models were created that allowed for the calculation of stress distribution of 250-N loading at a 45° angle and vertical in relation to the roots. The maximum principal stress and von Mises values were higher under oblique loading on the roots. The F6-Skytaper and WO systems showed lower stress than other systems. The TF-Adaptive instrument showed higher stress distribution than the other models. Fiber and titanium posts showed lower stress than others. The F6-Skytaper, R, and RB instruments were found to be most effective in terms of displacement of the crown, resulting in the lowest stress values. Fiber and titanium posts showed better results than other post systems, while root canals instrumented with the F6-Skytaper and WO instruments were less likely to result in root fractures.

Quality of root canal treatment performed by undergraduate students using nickel-titanium reciprocating versus hand instruments.

To compare the technical quality of root canal treatment (RCT) depending on the incidence of procedural errors performed by undergraduate students using nickel-titanium reciprocating and conventional hand instrumentation techniques, and to assess the impact of case difficulty and localization of the teeth (maxillary or mandibular molars). Dental records and periapical radiographs of molars that were treated with either hand or reciprocating WaveOne (WO) instruments were evaluated retrospectively. The technical quality of RCTs, the incidence of ledge formation, perforation, instrument fracture, overinstrumentation, underfilling, overfilling, inadequate root canal filling, and the effects of case difficulty and tooth localization were compared using the chi-square test with a significance of 5% (α=0.05). While overinstrumentation was more frequent in the WO group (247 teeth), the incidence of inadequate root canal fillings was higher in the hand instrumentation group (245 teeth) (p<0.01). No significant difference was observed in the incidence of other procedural errors (p>0.05). The number of teeth with acceptable technical quality in preparation and obturation was 172 (69.6%) in the WO group, whereas it was 142 (58%) in the hand instrumentation group, presenting a significant difference between the instrumentation techniques (p<0.01). Higher technical quality rates were observed with WO instrumentation in the high difficulty category and in maxillary teeth (p<0.01). Higher technical quality in preparation and obturation can be achieved with WO reciprocating instruments and file-matched greater tapered gutta-percha cones. No significant difference was observed between the groups in the incidence of procedural errors except for overinstrumentation and insufficient root canal filling. WO instrumentation and obturation with file-matched greater tapered gutta-percha cones provided better technical quality in the high difficulty category and in maxillary teeth.

Major clinical findings of endodontic retreatment: a concise systematic review

Introduction: In the endodontic treatment and retreatment scenario, the primary objective is to eliminate necrotic tissue and infectious bacteria, especially cleaning and shaping. Endodontic retraction is a procedure performed on a tooth that has received a previous attempt at a definitive treatment that has resulted in a condition that requires further endodontic treatment to achieve a successful outcome. The main cause of treatment failure is insufficient cleaning and inadequate filling. Objective: The present study carried out a concise systematic review to evaluate the main findings of clinical studies on endodontic retreatments, showing the main techniques, efficacy, and safety. Methods: The rules of the Systematic Review-PRISMA Platform. The research was carried out from December 2021 to March 2022 and developed based on Scopus, PubMed, Science Direct, Scielo, and Google Scholar. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results: A total of 124 articles were found. A total of 74 articles were evaluated in full and 17 were included and evaluated in the present study. Studies have demonstrated the effectiveness of rotational systems in endodontic retreatment but never producing completely obturator-free root canals. Reciproc instruments were associated with significantly higher cyclic fatigue strength than WaveOne instruments. The persistent infection microbiota is polymicrobial with a predominance of E. faecalis and P. gingivalis in all stages of endodontic retreatment, regardless of the method used for microbial identification. A higher bacterial load and lower lipoteichoic acid level were found in the 2-visit group after the retreatment protocol. Postoperative pain was significantly reduced at 48 and 72 hours after the application of nano-silver and nano-calcium hydroxide alone. Conclusion: The results of clinical trials showed that the root canal instrumentation system with rotary files maintains the quality of the root preparation and reduces the number of files needed to obtain a canal, which would consequently reduce the operative time and also considerably reduce the risk of torsion fracture within the root canal, allowing successful endodontic retreatment. Also, a condition for successful endodontic retreatment is the adequate cleaning of the root canals, therefore, special attention must be given to the technique used to remove the filling material.

The effectiveness of rotary and reciprocating techniques in curved root canals retreatment: a micro-CT analysis.

Introduction: Different NiTi rotary systems have been developed to improve efficiency and retreatment success rates. Aim: To evaluate the Protaper Universal retreatment system and WaveOne instrument in removing the filling material from curved canals during retreatment. Materials and Methods: Thirty mesial root canals of extracted human mandibular molar teeth were randomly allocated into 2 groups (n=15). In the PT group, retreatment was performed with ProTaper Universal Retreatment according to the manufacturer’s instructions. In the WO group, was used WaveOne Primary. ProTaper Universal F2 and F3 were used to achieve the apical diameter in both groups. The samples were scanned by micro-computed tomography pre and postoperatively to evaluate the filling material remaining. The percentage of material filling was compared between groups using Student’s T test and in the same group among thirds was compared using Kruskal-Wallis followed by Dunn’s post hoc test. Results: The filling material remaining was not statistically different between the groups (p≥0.05). The apical third presented a greater amount of remaining filling material when compared with the cervical third for both groups (p&lt;0.05). Conclusion: Rotary and reciprocating techniques can effectively, but not completely, remove the filling materials from the root canal system. The apical third presented a more significant amount of remaining filling material.

In Vitro Analysis of the Fatigue Resistance of Four Single File Canal Preparation Instruments.

Instrument separation during root canal therapy is inevitable in endodontics with several unfavorable clinical consequences. Therefore, examining the cyclic flexural fatigue resistance of commonly used rotary endodontic files is crucial. This study aimed to determine the cyclic flexural fatigue resistance of four nickel–titanium (NiTi) rotary files used as a single canal preparation technique: WaveOne, Reciproc, Protaper F2, and Unicone medium instruments. According to the manufacturer’s instructions, each file was rotated freely within a 1.3 mm deep and 1.3 mm wide V-shaped groove in a stainless-steel block with a 40° and 5 mm radius of curvature. Cyclic fatigue resistance was compared between the NiTi files by verifying the time needed to crack. The data were analyzed using one-way analysis of variance (ANOVA) followed by Scheffé post hoc with a significant level set at p < 0.05. Our results demonstrated that the WaveOne instrument had the highest cyclic flexural fatigue resistance among the tested groups (p ≤ 0.05), while Unicone had the lowest cyclic flexural fatigue resistance. This study concluded that WaveOne size 25/0.08 could illustrate a superior cyclic flexural fatigue resistance when instrumenting root canals with the lowest possibility to cause instrument separation.

Surface profile of different heat-treated nickel-titanium files before and after root canal preparation.

The aim of this study was to evaluate surface wear, presence of microcracks and surface irregularities of WaveOne (WO) and WaveOne Gold (WOG) instruments before and after multiple uses. Eight Primary instruments of the WO and WOG systems were evaluated, each one was used to prepare six mesial canals of extracted human mandibular molars. The surface of the instruments was evaluated before use (T0), after instrumentation of three (T1) and six (T2) root canals. Surface wear was analyzed using a three-dimensional optical profiler and the presence of microcracks and surface irregularities were evaluated using a tabletop scanning electron microscopy. The Friedman test was used to assess surface wear and Kruskal-Wallis test to evaluate the presence of microcracks and surface irregularities, with a 5% significance level. There was a significant increase in wear in both groups at T2, compared to T0 (p=0.0003). The surface wear after instrumentation of six canals (T2-T0) was statistically greater in the WOG group, than in the WO group (p=0.02), where the presence of microcracks was significantly greater and increased after multiple uses (p<0.05). The presence of surface irregularities in the cutting blade before and after use was statistically greater in the WOG group than WO group (p<0.05). Wear of the cutting blade, microcracks and surface irregularities were observed on the surface topography of all the instruments after multiple uses. These surface changes may affect the cutting efficiency of WOG files and increase the risk of fracture of WO files.

Shaping Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Hybrid and Reciprocating Nickel Titanium Endodontic Instruments

The aim of this study was to investigate the shaping ability and cyclic fatigue resistance of Genius (GN) and WaveOne (WO) nickel-titanium (NiTi) instruments. Forty mesial root canals of mandibular molars were randomly divided into two groups, according to the instrument system used for root canal preparation (n = 20): GN and WO. Root canals were prepared to the full working length using the crown-down technique, with up to 40.04 instruments for GN group and 40.08 instruments for WO group. Specimens were scanned with a µCT before and after instrumentation. The changes in 3D parameters and degree of canal transportation were evaluated in the apical, middle and coronal thirds of root canals. Size 25, taper 0.04 (GN) and 0.08 (WO) instruments (n = 20) were used in simulated root canals until fracturing, and the number of cycles to failure (NCF) was recorded. The fractured files were investigated under a scanning electron microscope to characterize fractured surfaces. Data were analyzed using ANOVA post hoc Tuckey’s tests with the significance level set at 5%. The GN system was able to prepare the higher percentage of the canal surface with less canal transportation in all root canal thirds and displayed the higher resistance to cyclic fatigue in comparison to WO instruments (p &lt; 0.05). However, the length of the fractured segments was not significantly different among the groups; meanwhile, SEM investigations revealed the typical topographic characteristics of fractured surfaces. Hybrid GN instruments demonstrated superior shaping ability and resistance to cyclic fatigue. However, both NiTi instrument systems prepared the root canals with no significant shaping errors, considerable changes in 3D parameters and no significant differences in the topographic appearances of the instrument surfaces after fractures.

Influence of static and dynamic cyclic fatigue tests on the lifespan of four reciprocating systems at different temperatures.

To compare the cyclic fatigue resistance of four reciprocating single-file systems within artificial stainless-steel canals at two temperatures using different kinematics. A total of 240 instruments, Reciproc Blue, Reciproc, WaveOne Gold and WaveOne, (60 of each), were tested at room and intracanal temperature using both a static and a dynamic model (n=15) in a stainless-steel artificial canal with an inner diameter of 1.5mm, 60° angle of curvature and 5mm radius of curvature until fracture occurred. The time to fracture was measured in seconds using a digital chronometer, and data were analysed using one-way analysis of variance and Bonferroni tests. WaveOne instruments had significantly less fatigue resistance compared to that of other systems in all conditions (P<0.05). Comparison of the results from the static and dynamic models at both temperatures revealed that fatigue resistance was significantly increased in the dynamic model for all the instrument systems (P<0.05). Temperature did not influence the cyclic fatigue resistance results (P>0.05). There were no significant differences in the mean length of the fractured fragments of the various instruments tested (P>0.05). WaveOne files had a shorter cyclic fatigue life. The dynamic axial movement extended the cyclic fatigue life, but it did not have any influence on the comparison among the instruments tested in respect of the static test. Temperature did not significantly affect the cyclic fatigue of these nickel-titanium files.

Apical extrusion of debris following the use of single-file rotary/reciprocating systems, combined with syringe or ultrasonically-facilitated canal irrigation.

Aim:The aim of the study is to quantify the amount of debris extrusion after instrumentation with single-file rotary and reciprocating systems used either with conventional irrigation (CI) or passive ultrasonic irrigation (PUI) systems.Methodology:Sixty extracted human mandibular incisors were randomly assigned to two groups (n = 30); rotary single-file system, One Shape (OS-Group 1) and reciprocating single-file system, WaveOne (WO-Group 2) instruments. The two groups were further subdivided into two subgroups (n = 15); (A) PUI and (B) CI. The apically extruded debris was collected in preweighed glass vials as per the Myers and Montgomery method. After drying, the mean weight of debris was assessed with a microbalance and statistically analyzed using analysis of variance and Student's t-test.Results:The reciprocating file system produced significantly more debris compared to the rotary file system using either of the irrigation systems (P = 0.04). CI produced significantly more (P = 0.02) debris extrusion compared to PUI irrespective of the file system used.Conclusion:Under the conditions of this study, both systems caused apical debris extrusion. Rotary single-file system produced less debris extrusion compared to reciprocating single-file system. Use of PUI may be advocated as an alternative to CI, as it causes lesser apical debris extrusion.

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.

Evaluating the cutting efficiency of NiTi instruments with reciprocating motions

Aim: This study tested a setup for in vitro experimental analysis of axial forces and torque during the preparation of artificial canals using nickel-titanium reciprocating endodontic files. Methods: The cutting efficiency of Reciproc (RC) and WaveOne (WO) reciprocating size 25/.08 instruments (n = 10) was evaluated, taking into account their dimensional and geometrical features. Measurements of the diameter at each millimeter from the tip, pitch length, helical angle, and cross-sectional design and area were assessed. Cutting efficiency tests were carried out on a specific bench device by measuring the torque and axial force required during artificial canal shaping. Statistical analysis was performed using one-way ANOVA (α = 0.05). Results: The WO samples showed larger A3 mean values than did the RC instruments (P &lt;.0001), despite having equal diameters at 3mm from the tip (D3) (P = .521). The mean values of pitch length were higher for RC than for WO instruments (P &lt;.0001), with consequently smaller helical angles (P &lt;.0001). For the cutting efficiency tests, the required torque was lower for the RC group when compared to the WO group, but it was significant only in the first stage of insertion in the artificial canals (P = .008). Regarding the apical force, the RC instruments reached higher values when compared to the WO instruments (P = .04) in the second stage of cutting action. Conclusion: Reciproc instruments demonstrated statistically higher cutting efficiency when compared to WaveOne instruments.Uniterms: cutting efficiency; M-Wire; reciprocating motion; Reciproc; WaveOne

Defect propagation in NiTi rotary instruments: a noncontact optical profilometry analysis.

To evaluate the presence and propagation of defects and their effects on surfaces of nickel-titanium (NiTi) instruments using noncontact, three-dimensional optical profilometry, and to assess the accuracy of this method of investigation. The flute surface areas of instruments from two commercial instrumentation systems, namely Reciproc R25 (n=5) and WaveOne Primary (n=5), were assessed and compared before and after performing two instrumentation cycles in simulated root canals in clear resin blocks. All the analyses were conducted on areas measuring 211×211μm, located 3mm from the tips of the instruments. A quantitative analysis was conducted before and after the first and second instrumentation cycles, using the Sa (average roughness over the measurement field), Sq (root mean square roughness) and Sz (average height over the measurement field) amplitude parameters. All the data were submitted to statistical analysis at a 5% level of significance. There was a significant increase (P=0.007) in wear in both groups, especially between baseline and the second instrumentation cycle, with significantly higher wear values being observed on WaveOne instruments (Sz median values=33.68 and 2.89μm, respectively, for WO and RP groups). A significant increase in surface roughness (P=0.016 and P=0.008, respectively, for Sa and Sq) was observed in both groups from the first to the second instrumentation cycle, mostly in WaveOne specimens. Qualitative analysis revealed a greater number of defects on the flute topography of all the instruments after use. More defects were identified in WaveOne Primary instruments compared to Reciproc R25, irrespective of the evaluation stage. The investigation method provided an accurate, repeatable and reproducible assessment of NiTi instruments at different time-points.

Noncontact three-dimensional evaluation of surface alterations and wear in NiTi endodontic instruments.

The aim of this study was to undertake a qualitative and quantitative assessment of nanoscale alterations and wear on the surfaces of nickel-titanium (NiTi) endodontic instruments, before and after use, through a high-resolution, noncontact, three-dimensional optical profiler, and to verify the accuracy of the evaluation method. Cutting blade surfaces of two different brands of NiTi endodontic instruments, Reciproc R25 (n = 5) and WaveOne Primary (n = 5), were examined and compared before and after two uses in simulated root canals made in clear resin blocks. The analyses were performed on three-dimensional images which were obtained from surface areas measuring 211 × 211 µm, located 3 mm from their tips. The quantitative evaluation of the samples was conducted before and after the first and second usage, by the recordings of three amplitude parameters. The data were subjected to statistical analysis at a 5% level of significance. The results revealed statistically significant increases in the surface wear of both instruments groups after the second use. The presence of irregularities was found on the surface topography of all the instruments, before and after use. Regardless of the evaluation stage, most of the defects were observed in the WaveOne instruments. The three-dimensional technique was suitable and effective for the accurate investigation of the same surfaces of the instruments in different periods of time.

Topographic and Chemical Analysis of Reciprocating and Rotary Instruments Surface after Continuous Use.

This study aimed at evaluating the changes in surface characteristics and NiTi content of reciprocating and rotary instruments after continuous use. Thirty brand-new instruments were assigned to 3 groups (n=10): PNX1 Group - ProTaper Next system - instrument X1; PNX2 Group - ProTaper Next system - instrument X2 and WO Group - WaveOne system - Primary instrument 25.08. The instruments were used to prepare 60 simulated root canals. Analysis of surface characteristics by scanning electron microscopy (SEM) and chemical analysis of Ni and Ti content by energy-dispersive spectroscopy (EDS) were performed before and after the first and third use of the instruments. Only WO Group had significant increase in the quantity of defects and deformations after the third use (p<0.05). PNX1 Group had significant decrease in Ni content after the third use, in comparison with the unused instruments (p<0.05). PNX1 Group had no decrease in Ti content throughout the time of use (p>0.05), however, in PNX2 Group, there was significant decrease in the different time interval of analysis (p<0.05). Continuous use promoted increase in defects and deformations only for WaveOne instruments. Chemical composition presented significant changes according to the time of instruments use.

Fracture Incidence of WaveOne and Reciproc Files during Root Canal Preparation of up to 3 Posterior Teeth: A Prospective Clinical Study

IntroductionReciprocating instruments were developed to improve and simplify the preparation of the root canal system by allowing greater centralization of the canal and requiring a shorter learning curve. Despite the risk of instrument separation, using a reciprocating instrument in more than 1 case is a relatively common clinical practice. The aim of this study was to evaluate the fracture resistance of Reciproc (R25; VDW, Munich, Germany) and WaveOne (Primary; Dentsply Maillefer, Ballaigues, Switzerland) instruments according to the number of uses during the preparation of root canals in up to 3 posterior teeth. MethodsA prospective clinical study was conducted by 3 experienced specialists who performed treatment of 358 posterior teeth (1130 canals) over a period of 12 months using 120 reciprocating instruments, 60 of which were Reciproc R25 and 60 were WaveOne Primary. The motion used during instrumentation followed the recommendations of the respective manufacturers. After each use, the instruments were observed under a dental operating microscope at 8× magnification. In the case of fracture or deformation, the instrument was discarded. ResultsNone of the instruments showed any signs of deformation, but 3 instruments fractured (0.26% of the number of canals and 0.84% of the number of teeth). All fractures occurred in mandibular molars (1 WaveOne Primary file during the third use and 2 Reciproc R25 files, 1 during the first use and the other during the third use). ConclusionsThere was a low incidence of fracture when reciprocating files were used in up to 3 cases of endodontic treatment in posterior teeth.

Bending Resistance and Cyclic Fatigue Life of a new Single-File Reciprocating Instrument Waveone Gold.

Objective:The present study aimed to evaluate the bending resistance and cyclic fatigue fracture resistance of a new single-file reciprocating instrument called WaveOne Gold. Reciproc and WaveOne instruments were used as references for comparison.Methods:Sixty 25-mm NiTi instruments (Reciproc R25, WaveOne Primary and WaveOne Gold Primary) were tested. Flexibility was determined by applying 45° bending tests using a universal testing machine (n=10). A custom-made device was used during cyclic fatigue test (n=10), comprising a stainless steel artificial canal measuring 1.4 mm in diameter, 19 mm in total length with an 86° angle and 6 mm radius of curvature. Possible deformations at the helical shaft and mode of fracture were evaluated using scanning electron microscopy analysis. Statistical analysis was performed using one-way analysis of variance. Post hoc pair-wise comparisons were performed using Tukey’s test for multiple comparisons (P<0.05).Results:WaveOne presented significantly higher bending resistance than the other tested systems (P<0.05), whereas Reciproc presented the lowest bending resistance (P<0.05). Reciproc revealed a significantly longer cyclic fatigue fracture resistance than the other systems (P<0.05).Conclusion:Although WaveOne Gold presented higher flexibility than WaveOne, no differences in the resistance to fatigue were observed between both systems. The Reciproc files were more flexible and resistant to fatigue for the angle of curvature of 86° and 6 mm radius than WaveOne and WaveOne Gold files.

In vitro Comparison of Apical Debris Extrusion Using Rotary and Reciprocating Systems in Severely Curved Root Canals.

Introduction:The aim of this in vitro study was to compare the amount of apically extruded debris after root canal preparation using rotary and reciprocating systems in severely curved root canals. Methods and Materials:Thirty six extracted human mandibular first molars with 25-35° curvature in their mesiobuccal (MB) canal (according to Schneider’s method) were cleaned and shaped with ProTaper and WaveOne systems. The extruded debris was collected and their net weight was calculated. To compare the efficiency of the two systems, the operation time was also measured. The data were analyzed with t-test.Results:The amount of extruded debris in WaveOne group was significantly greater in comparison with ProTaper group (26%). The operating time for ProTaper was however, significantly longer than WaveOne. Conclusion:Both root preparation systems caused some degree of debris extrusion through the apical foramen. However, this amount was greater in WaveOne instruments.

APICAL TRANSPORTATION AND CENTERING RATIO IN S-CURVED CANALS USING NITI FULL ROTATION VERSUS RECIPROCATION SHAPING TECHNIQUES

Objectives: The aim of the present study is to compare apical transportation, centering ratio, changes in working length and canal axis ratio in the S-shaped canals using full rotation versus reciprocation shaping techniques. Methodology: Twenty-five S-curved artificial canals were used. Five canals were used for the pre-instrumentation radiographs and records. The other 20 canals were divided into two groups (10 canals each); G1: One-Shape (OS) and G2: Wave-One (WO) files. Canals were prepared, and obturated. Post-obturation radiographs were taken with the same parameters of the pre-instrumentation records. Pre- and post-instrumentation digital images were evaluated with AutoCAD program analysis. Results: Full rotation using OS files showed significantly far less apical transportation than WO reciprocation (P 0.05). WO produced higher percentage increase in working length than OS files. Both techniques could not maintain the original canal axis ratio. Conclusions: Within the parameters of this study, Single-file shaping technique with full rotation instruments produced significantly less transportation and less violation of the working length than did the reciprocating WO instruments. Both techniques violated the original canal axis ratio and had nearly equal centering ratio, however, none of them was perfectly centered.

Bending Resistance and Cyclic Fatigue Life of Reciproc, Unicone, and WaveOne Reciprocating Instruments

IntroductionThis study evaluated the bending resistance and cyclic fatigue life of a new single-file reciprocating instrument (Unicone; Medin, Nové Město na Moravě, Czech Republic). Reciproc (VDW, Munich, Germany) and WaveOne (Dentsply Maillefer) instruments were used as references for comparison. MethodsFlexibility was determined by 45° bending tests using a universal testing machine. The cyclic fatigue test was performed using a custom-made device. For this test, an artificial canal with a 60° angle and a 5-mm radius of curvature was used. Scanning electron microscopic analysis was performed to determine the mode of fracture and possible deformations at the helical shaft. Statistical analysis for the bending resistance test was performed using parametric methods (ie, 1-way analysis of variance). Post hoc pair-wise comparisons were performed using the Tukey test for multiple comparisons (P < .05). Weibull analysis was used to calculate the mean life, beta, and eta parameters. ResultsReciproc presented significantly lower bending resistance than the other tested systems (P < .05), whereas no differences were observed between WaveOne and Unicone (P > .05). When mean life was compared among the brands, Reciproc lasted longer than WaveOne with a probability of 99.9%, longer than Unicone in the “RECIPROC ALL” mode with a probability of 99.9%, and longer than Unicone in the “WAVEONE ALL” mode with a probability of 99.9% (all statistically significant). Moreover, WaveOne lasted longer than Unicone in the “RECIPROC ALL” mode with a probability of 98.5% and longer than Unicone in the “WAVEONE ALL” mode with a probability of 99.8% (all statistically significant). Finally, Unicone in the “RECIPROC ALL” mode lasted longer than Unicone in the “WAVEONE ALL” mode with a probability of 95.3% (statistically significant). ConclusionsThe new reciprocating instrument Unicone showed lower cyclic fatigue resistance compared with Reciproc R25 and WaveOne Primary files.