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Aim: The aim is to investigate and compare the amount of apically extruded debris after root canal preparation using single rotary and reciprocating file system. Materials and Methods: Forty single-rooted human mandibular premolars with straight canals were randomly assigned to four groups (n = 10). The root canals were instrumented according to the manufacturers' instructions using single-rotary file systems Hyflex EDM (HEDM), One Shape (OS) and single-reciprocating file systems Wave OneGold (WOG) and OneRECI (OR). The apically extruded debris was collected in preweighed glass vials using the Myers and Montgomery method. After drying, the mean weight of the extruded debris was assessed using a microbalance. Results and Conclusions: Multiple comparison between groups demonstrated that the mean weight of apically extruded debris in the HEDM group was significantly less compared to all other study groups, and the differences were statistically significant (P < 0.001). Under the condition of this study, all file systems caused apical debris extrusion. The mean apically extruded debris was significantly least in HEDM, followed by WOG, OneRECI and highest in the OS group. [ABSTRACT FROM AUTHOR]

Objectives: The present randomised clinical study aimed to evaluate the effect of OneShape and ProTaper Next rotary systems on the removal of endotoxins from root canals of teeth with asymptomatic necrotic pulp. Materials and methods: 30 patients were randomly allocated into two groups (n = 15) according to the type of rotary system used in the mechanical preparation: group OneShape (OS) or group ProTaper Next (PN). Samples were collected before and after mechanical preparation and the quantification of endotoxins was conducted using the human enzyme-linked immunosorbent assay (ELISA) kit. Statistical analyses were performed using the Mann-Whitney U test to compare the two groups, and the Wilcoxon signed rank test to study the changes after treatment within each group. The significance level was set at P ≤ 0.05. Results: The group OS showed a statistically significant reduction in the endotoxin levels after treatment (P < 0.001, effect size = 0.880). In the PN group there was a statistically significant reduction in endotoxin levels after treatment (P < 0.001, effect size = 0.931). In the OS group a statistically significant median percentage reduction in endotoxin levels was observed compared with the group PN (P < 0.05). Conclusions: ProTaper Next was more effective than OneShape in reducing endotoxins from root canals of teeth with asymptomatic necrotic pulp. [ABSTRACT FROM AUTHOR]

Abstract Background The ex vivo study is to compare the root canal preparation outcomes achieved by five nickel–titanium single-file instrumentation systems (M3-L, Reciproc Blue, V-Taper 2H, WaveOne Gold, XP-endo Shaper) in severely curved molar root canals. Methods A total of 60 root canals were selected from extracted human molar teeth with curvatures ranging from 25° to 50° and divided into five groups based on the instrumentation system employed (n = 12). Before and after root canal preparation, a Micro-CT scan was taken, and pre- and post-operative data were analyzed to evaluate the following parameters: volume increment of root canals (VI), untouched root canal areas (UTA), and canal transportation (CT). Apically extruded debris (AD) was collected during preparation. After that, all samples were separated into two parts and examined respectively by scanning electron microscope (SEM) to assess cleaning ability. Data were statistically analyzed with ANOVA (UTA, AD, VI) or Kruskal–Wallis test (CT, SEM-score), the level of significance was set at α = 0.05. Results There were no significant differences between the five systems regarding the AD, VI, and UTA parameters (P > 0.05). In terms of CT, no significant difference was noted at the straight section of canal and apical levels, while XP-endo Shaper showed less canal transportation than M3-L at the level of curved vertex (P

Background/purpose: Glide path management (GPM) is a consequential clinical step that serves to influence predictably successful root canal therapy. However, the effect of GPM on the shaping ability of single-file system remains controversial. This study compared the performance of rotary single-file One Curve (OC) and reciprocating single-file Reciproc Blue (RCB) in combination with/without different glide path techniques: no glide path preparation (NG), PathFile (PF), ProGlider (PG) and WaveOne Gold Glider (WOGG), respectively. Materials and methods: 80 simulated curved canals (n = 10 canals/per group) were instrumented to an apical size of 0.25 mm using OC and RCB in combination with/without different glide path techniques, respectively. The amount of resin removal, canal transportation, and the degree of canal straightening were measured in Photoshop CS6 software. Statistical analysis of the data was performed by using Kruskal–Wallis test, followed by Dunn's post hoc test with Bonferroni correction (α = 0.05). Results: Post–glide path analysis found that WOGG and PG produced less canal transportation and curvature straightening than PF (P

Background: The ex vivo study is to compare the root canal preparation outcomes achieved by five nickel–titanium single-file instrumentation systems (M3-L, Reciproc Blue, V-Taper 2H, WaveOne Gold, XP-endo Shaper) in severely curved molar root canals. Methods: A total of 60 root canals were selected from extracted human molar teeth with curvatures ranging from 25° to 50° and divided into five groups based on the instrumentation system employed (n = 12). Before and after root canal preparation, a Micro-CT scan was taken, and pre- and post-operative data were analyzed to evaluate the following parameters: volume increment of root canals (VI), untouched root canal areas (UTA), and canal transportation (CT). Apically extruded debris (AD) was collected during preparation. After that, all samples were separated into two parts and examined respectively by scanning electron microscope (SEM) to assess cleaning ability. Data were statistically analyzed with ANOVA (UTA, AD, VI) or Kruskal–Wallis test (CT, SEM-score), the level of significance was set at α = 0.05. Results: There were no significant differences between the five systems regarding the AD, VI, and UTA parameters (P > 0.05). In terms of CT, no significant difference was noted at the straight section of canal and apical levels, while XP-endo Shaper showed less canal transportation than M3-L at the level of curved vertex (P < 0.05), and the centering ability of V-Taper 2H was significantly better than WaveOne Gold at the initial point of bending (P < 0.05). Debris and smear layers were present on the canal walls of all specimens, the apical thirds of the canal presented higher SEM scores than the coronal thirds in all groups (P < 0.05). Reciproc Blue and XP-endo Shaper showed fewer smear scores than WaveOne Gold in the apical thirds (P < 0.01 and P < 0.05, respectively), and no statistical difference was found between other groups in the middle and coronal thirds. Conclusion: The five single-file systems evaluated performed equally in apically debris extrusion, dentin removal, and untouched root canal areas, while XP-endo Shaper and V-Taper 2H resulted in less canal transportation compared to M3-L and WaveOne Gold. Regarding cleaning ability, Reciproc Blue and XP-endo Shaper were associated with less smear layer than WaveOne Gold in the apical thirds. [ABSTRACT FROM AUTHOR]

Glide path management (GPM) is a consequential clinical step that serves to influence predictably successful root canal therapy. However, the effect of GPM on the shaping ability of single-file system remains controversial. This study compared the performance of rotary single-file One Curve (OC) and reciprocating single-file Reciproc Blue (RCB) in combination with/without different glide path techniques: no glide path preparation (NG), PathFile (PF), ProGlider (PG) and WaveOne Gold Glider (WOGG), respectively. 80 simulated curved canals (n = 10 canals/per group) were instrumented to an apical size of 0.25 mm using OC and RCB in combination with/without different glide path techniques, respectively. The amount of resin removal, canal transportation, and the degree of canal straightening were measured in Photoshop CS6 software. Statistical analysis of the data was performed by using Kruskal–Wallis test, followed by Dunn's post hoc test with Bonferroni correction (α = 0.05). Post–glide path analysis found that WOGG and PG produced less canal transportation and curvature straightening than PF (P < 0.05). Post-shaping analysis showed that OC groups removed significantly less resin than RCB groups (P < 0.05). The PG and WOGG subgroups in both OC groups and RCB groups produced less transportation and curvature straightening than NG and PF subgroups (P < 0.05). OC + PG subgroup and OC + WOGG subgroup yielded the least canal transportation and curvature straightening (P < 0.05). PG and WOGG can improve the shaping ability of OC and RCB instrument. OC, especially when combined with PG and WOGG, has a less aggressive dentin cutting and more centered preparation than the RCB instrument. [ABSTRACT FROM AUTHOR]

The present study compared the effect of the number of pecking motions at the working length (WL) on the shaping ability of single-file systems in long oval-shaped curved root canals. Single-rooted mandibular premolars with long oval-shaped curved canals (25°–35°) were prescanned using micro–computed tomographic imaging, anatomically paired, and randomly divided into 3 groups (n = 15): XP-endo Shaper (XPS; FKG Dentaire, La Chaux-de-Fonds, Switzerland), Reciproc Blue (RB; VDW, Munich, Germany), and WaveOne Gold (WOG; Dentsply Sirona, Ballaigues, Switzerland). After preparation to the WL, each specimen underwent 1, 2, 4, 10, or 20 pecking motions to the WL and was rescanned. Morphologic parameters were measured and analyzed using a 2-factor repeated measures analysis of variance and the Scheirer-Ray-Hare test. The minor apical diameter and percentage increase in canal volume increased with the number of pecking motions, whereas the percentage of unprepared canal surface area decreased (P <.05). The mean minor diameters (in mm) at D0 varied between 0.29 and 0.35 after 4 pecking motions with the RB and WOG systems and between 0.35 and 0.36 after 10 pecking motions with the XPS system. No significant differences in canal transportation or centering ratio were observed among the groups at the levels of canal curvature and canal thirds (P >.05). Increasing the number of pecking motions improves the cutting efficacy of single-file systems without adversely altering the anatomic characteristics of oval-shaped curved canals. No more than 4 pecking motions for the RB and WOG systems and 10 pecking motions for the XPS system appear to be acceptable for the shaping of these difficult to clean root canals. [ABSTRACT FROM AUTHOR]

Objectives: This study compared canal transportation and centering ratio produced after instrumentation with a single heat-treated reciprocating system, WaveOne Gold (WOG; Dentsply Sirona, Tulsa, OK, USA) and a single heat-treated rotary instrument, XP-endo Shaper (XPS; FKG, La Chaux-de-Fonds, Switzerland), using micro-computed tomographic (micro-CT) imaging, and evaluated the ability of double-digital radiography (DDR) to detect canal transportation. Materials and methods: Mesial root canals of mandibular molars with severe curvature (25–70°) were randomly assigned to either WOG or XPS groups for preparation. Centering ratio was measured by micro-CT imaging, while canal transportation was measured by micro-CT and DDR methods at 3, 5, and 7 mm from the apex. Data were statistically compared between groups using the t test (α = 5%). Results: The micro-CT method showed that XPS's shaping ability regarding the centering ability (P = 0.030) and canal transportation (P = 0.028) was significantly better than WOG only at the 7-mm level. The DDR technique detected no difference in canal transportation between groups at any level (P > 0.05); however, a significant difference between evaluation methods was detected at the 5-mm level in the WOG group (P = 0.023). Conclusions: Micro-CT technique revealed a significantly better centering ability and less canal transportation with XPS compared to WOG. The DDR technique was not capable of detecting the significant difference between the tested groups. Clinical relevance: Root canal curvatures may lead to procedural errors during endodontic treatment. Thus, differences on the shaping ability of single heat-treated reciprocating and rotary systems should be known. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate the difference in cyclic fatigue resistance between OneCurve (OC) and OneShape (OS) endodontic single-file NiTi systems in a severely curved artificial canal. After sample size calculation (α = 0.01; β = 0.20; σ = 20.0; δ = 20.0), 25 OC and 25 OS files were used. An artificial canal with 60° angle and 5-mm radius of curvature was milled in a stainless-steel block reproducing the size and taper of the files used. The test device was electrically heated to maintain the environmental temperature at 37 °C. All files were rotated until fracture; the time to failure was recorded and the number of cycles to fracture (NCF) calculated. The length of the fractured fragments was measured too. Fractographic examination and cross-sectional area calculation were performed by scanning electron microscopy analysis (SEM). Data were statistically analyzed using an independent sample t test. The significance level was set at 0.01. Statistical analysis showed that OC files exhibited significantly greater cyclic fatigue resistance than OS (p < 0.001), with 721 ± 89 NCF and 301 ± 38 NCF, respectively. No significant difference was found in the length of the fractured fragments (p > 0.01). SEM fractographic analysis confirmed that all the scanned samples separated due to cyclic fatigue. Within the limitations of the present study, OC endodontic instruments resisted to cyclic fatigue better than OS. The improved mechanical resistance of OC could be related to new NiTi alloy used for their manufacturing. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the bacterial reduction achieved by WaveOne Gold (Dentsply Sirona Endodontics, Ballaigues, Switzerland), Hyflex EDM (Coltene‐Whaledent, Altstätten, Switzerland), and XP‐endo Shaper (FKG Dentaire SA, La Chaux‐de‐Fonds, Switzerland) in canals infected with Enterococcus faecalis. The null hypothesis (H0) was that there would be no difference amongst the NiTi systems in reducing the root canal bacterial load. Methodology: Seventy‐four mandibular premolar teeth with straight and round root canals were selected. Sixty‐two root canals were contaminated with E. faecalis for 4 weeks and subjected to mechanical preparation with one of three single‐file NiTi rotary systems (WaveOne Gold, Hyflex EDM, and XP Endo Shaper). Twelve non‐contaminated root canals were used as negative controls. Bacterial samples were collected with sterile paper points (Dentsply Sirona Endodontics) before and after rotary instrumentation to quantify the bacterial load. Five roots from each instrumentation group were evaluated topographically from the coronal, middle and apical thirds by SEM. The bacterial reduction was calculated and analysed statistically by the Kruskal–Wallis and Dunn post hoc tests, all at 5% significance. Results: The samples taken before instrumentation showed approximately 9.64 log CFU bacterial load. Instrumentation with the Hyflex EDM and XP‐endo Shaper resulted in significantly greater bacterial reduction than those with WaveOne Gold (P = 0.00). All specimens had bacterial growth. SEM images supported the CFU/mL data. Thick and dense debris was observed in WaveOne Gold samples. Instrumentation resulted in the disruption of the biofilm‐like structure, and both areas of clean and open dentinal tubules and areas with thick debris were observed in Hyflex EDM and XP‐endo Shaper samples. Conclusions: Instrumentation in straight and round canals of premolar teeth with the Hyflex EDM and XP‐endo Shaper resulted in significantly greater bacterial reduction than WaveOne Gold. No instrumentation system rendered root canals completely free from bacteria. [ABSTRACT FROM AUTHOR]

Abstract Introduction The aim of this study was to evaluate in vitro the performance of 3 single-file systems: WaveOne Gold Primary (WOG; Dentsply Sirona, Ballaigues, Switzerland), Hyflex EDM "one file" (EDM; Coltene/Whaledent, Alstatten, Switzerland), and XP Shaper (XP; FKG, La Chaux de Fonds, Switzerland), for nonsurgical endodontic retreatment on mandibular anterior teeth in regard to the amount of remaining filling material inside the canal, debris extrusion, and operation time. Methods Sixty extracted standardized mandibular incisors presenting with a single oval canal were prepared to size 30.04 and obturated using warm vertical condensation. After 30 days (37°C, 100% humidity), teeth were randomly divided into 3 groups (n = 20) according to the file used for retreatment (WOG, EDM, or XP operated at 3000 rpm). During the retreatment procedures, preweighed vials were used to collect apically extruded debris, and the time required to remove the filling material was recorded in seconds. Cone-beam computed tomographic scans were taken before and after the retreatment to determine the amount of remaining filling material inside the root canal space. Statistical analysis was performed using the Kruskal-Wallis test, 1-way analysis of variance, and the Pearson test at a 5% significance level. Results There was a statistically significant difference among the groups regarding the instrumentation time (P <.05). XP was the fastest to remove gutta-percha from the canals (40.54 ± 28.03 seconds) followed by EDM (55.77 ± 19.76 seconds) and WOG (105.92 ± 53.92 seconds). The percentage of remaining filling was significantly greater for WOG (26.65% ± 14.63%) (P <.05). No difference was found between EDM (13.51% ± 9.53%) and XP (8.60% ± 7.28%). No difference was found regarding the amount of extruded debris among the 3 groups (P >.05). Conclusions XP was the most efficient in gutta-percha removal from the canals when operated at a higher speed (3000 rpm) followed by EDM and WOG. Highlights • In this study, we investigated the effectiveness of 3 different single-file systems for endodontic retreatment in regard to the remaining root canal filling material, the amount of apically extruded debris, and operation time. • Within the limitations of the study, the XP Shaper was the most efficient in gutta-percha removal from the canals followed by Hyflex EDM and WaveOne Gold. • The percentage of remaining filling was significantly greater for WaveOne Gold compared with the other 2 rotary systems. • No difference was found in regard to the amount of extruded debris among the 3 groups. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to evaluate the cyclic fatigue resistance of two single file engine-driven instruments, Reciproc and NeoNiTi, in simulated root canals. Methods and Materials: Two groups of 15 NiTi endodontic instruments with an identical tip size of 0.25 mm were tested: Reciproc R25 (group A) and NeoNiTi A1 (group B). Cyclic fatigue testing was performed in a stainless steel artificial canal. The simulated canals had a 60° angle and 5- mm radius curvature. The Reciproc instruments were operated using the preset program on torque control electric motor specific for the Reciproc instruments, while the NeoNiTi instruments were operated using the manufacturer recommendation. All instruments were rotated until fracture occurred, and the number of cycles to fracture (NCF) and the length of the fractured tip were recorded and registered. Means and standard deviations of NCF and fragment length were calculated for each system and data were subjected to Student’s t test (P<0.05). Results: A statistically significant difference (P<0.05) was noted between Reciproc and NeoNiTi instruments. NeoNiTi A1 instruments were associated with a significantly higher mean NCF as compared to Reciproc R25 instruments (833±176 vs. 318±87 NCF). There was no significant difference (P>0.05) in the mean length of the fractured fragments between the instruments. Conclusion: NeoNiTi instruments were associated with a significantly higher cyclic fatigue resistance than Reciproc instruments. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to compare the incidence of dentinal crack formation by instrumentation with ProTaper Universal system (rotary, multi-file system), SafeSider (reciprocation movement, multi-file system) and Neolix (rotary, single-file system). Methods and Materials: In this in vitro study, 60 freshly extracted mandibular first molars were randomly divided into three experimental groups (n=15) and a control group containing unprepared teeth (n=15). Instrumentation in different groups was accomplished using either ProTaper, Neolix or SafeSider systems up to 25/0.08. The teeth were then sectioned at 3, 6 and 9 mm from the apex, and observed under a stereomicroscope for presence of dentinal cracks. Data were analyzed with Chi square test, Fisher’s exact test and Bonferroni correction. Results: Micro cracks were seen in all experimental groups (13.3% in ProTaper, 26.7% in SafeSider and 40% in Neolix). There was a significant difference between Neolix and the control groups in microcrack formation (P=0.042). Micro cracks mainly occurred in the coronal section (9 mm). No microcrack occurred in the control group. Conclusion: Neolix rotary single-file system caused more dentinal cracks compared to the unprepared roots. All the instrumentation systems increased the number of micro cracks compared to unprepared teeth. [ABSTRACT FROM AUTHOR]

The field of endodontics has become increasingly successful due to technological advances that allow clinicians to solve clinical cases that would have been problematic a few years ago. Despite such advances, endodontic treatment of teeth with internal root resorption remains challenging. This article presents a clinical case in which a reciprocating single-file system was used for endodontic treatment of a mandibular molar with internal root resorption. Radiographic examination revealed the presence of internal root resorption in the distobuccal root canal of the mandibular right first molar. A reciprocating single-file system was used for root canal instrumentation and final preparation, and filling was obtained through a thermal compaction technique. No painful symptoms or periapical lesions were observed in 12 months of follow-up. The results indicate that a reciprocating single-file system is an adequate alternative for root canal instrumentation, particularly in teeth with internal root resorption. [ABSTRACT FROM AUTHOR]

Introduction The purpose of this study was to compare the formation of microcracks after canal preparation performed with different single-file systems as One Shape (Micro-Mega, Besancon, Cedex, France), F6 SkyTaper (Komet Italia Srl, Milan, Italy), HyFlex EDM (Coltene/Whaledent AG, Altstatten, Switzerland), WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (VDW, Munich, Germany), and WaveOne Gold (Dentsply Maillefer). Methods Eighty-four human extracted mandibular central incisors (40–60 y) were selected and divided into 6 experimental groups ( n = 12 teeth) and a control group (unprepared teeth): One Shape (group 1), F6 SkyTaper (group 2), HyFlex EDM (group 3), WaveOne (group 4), Reciproc (group 5), and WaveOne Gold (group 6). Roots were then sectioned at 3, 6, and 9 mm from the apex, and the surface was observed under a stereomicroscope. Data were analyzed using logistic regression ( P < .05). Results No cracks were observed in the control group. All the systems tested caused cracks, mainly in the apical section (3 mm). HyFlex EDM (33.3%) and WaveOne Gold (58.3%) showed fewer microcracks than other experimental groups ( P < .01); however, no significant difference was found between them in crack formation ( P > .05). There was no difference among the other experimental groups ( P > .05). Conclusions All the instruments tested created dentinal cracks. Within the limitations of this study, the flexibility of nickel-titanium instruments because of heat treatment seems to have a significant influence on dentinal crack formation. HyFlex EDM and WaveOne Gold caused less microcracks than the other instruments tested. [ABSTRACT FROM AUTHOR]

Aim To evaluate the effect of coronal flaring on the amount of debris extruded apically during root canal preparation using the Reciproc, WaveOne ( WO) and OneShape ( OS) single-file systems. Methodology Ninety extracted single-rooted mandibular incisor teeth were randomly assigned to six groups ( n = 15 for each group) for canal instrumentation. Endodontic access cavities were prepared in each tooth. In three of the six groups, coronal flaring was not performed; coronal flaring was performed with Gates-Glidden drills on all teeth in the remaining three groups. The canals were then instrumented with one or other of the following single-file instrument systems: Reciproc, WO and OS. Debris extruded apically during instrumentation was collected into pre-weighed Eppendorf tubes. The tubes were then stored in an incubator at 70 °C for 5 days. The weight of the dry extruded debris was established by subtracting the pre-instrumentation and post-instrumentation weight of the Eppendorf tubes for each group. Data were analysed using one-way analysis of variance ( anova) and Tukey's post hoc tests ( P = 0.05). Results Reciproc and WO files without coronal flaring produced significantly more debris compared with the other groups ( P < 0.05). There was no significant difference in apical extrusion of debris amongst the other groups ( P > 0.05). Conclusions All single-file systems caused apical extrusion of debris. Performing coronal flaring prior to canal preparation reduced the amount of apically extruded debris when using Reciproc or WO systems. [ABSTRACT FROM AUTHOR]

Aim To evaluate the effect of a glide path on the amount of apically extruded debris during canal preparation using single-file systems in curved canals. Methodology Ninety extracted mandibular molar teeth were randomly assigned to six groups ( n = 15 for each group) for canal instrumentation. Endodontic access cavities were prepared in each tooth. In three of the six groups, a glide path was not created whereas a glide path was created using PathFile instruments on the mesial canals of all teeth in the remaining three groups. The mesial canals of the teeth were then instrumented with the following single-file instrument systems: WaveOne, Reciproc and OneShape. Debris extruded apically during instrumentation was collected into pre-weighed Eppendorf tubes. The tubes were then stored in an incubator at 70 °C for 5 days. The weight of the dry extruded debris was established by subtracting the pre-instrumentation and post-instrumentation weight of the Eppendorf tubes for each group. The data obtained were analysed using one-way analysis of variance ( anova) and Tukey's post hoc tests. Results The OneShape file was associated with less debris extrusion than the Reciproc and WaveOne files when canal instrumentation was performed without a glide path ( P < 0.05). However, no significant difference was found between the Reciproc and WaveOne files ( P > 0.05). There was no significant difference amongst the OneShape, Reciproc and WaveOne files when a glide path was created before canal preparation in curved root canals ( P > 0.05). All systems extruded significantly less debris in groups with a glide path than in groups without a glide path ( P < 0.05). Conclusions All instruments were associated with apical extrusion of debris. Creating a glide path prior to canal instrumentation reduced the amount of apically extruded debris in curved canals. [ABSTRACT FROM AUTHOR]

Aim To investigate changes in three-dimensional geometry, in various cross-sectional morphological parameters and in the centring ability of root canals prepared with different preparation systems using microcomputed tomographic imaging technology. Methodology Sixty-four mesial canals of mandibular molars were matched based on similar morphological dimensions using micro-CT evaluation and assigned to four experimental groups ( n = 16), according to the canal preparation technique: Reciproc, WaveOne, Twisted File and HyFlex CM systems. Changes in several 2D (area, perimeter, form factor, roundness, minor and major diameter) and 3D [volume, surface area, structure model index (SMI)] morphological parameters, as well as canal transportation, were compared with preoperative values using Kruskal-Wallis and anova post hoc Tukey's tests with the significance level set at 5%. Results Preparation significantly increased all tested parameters in the experimental groups. No significant differences were observed between groups regarding changes in volume, surface area, SMI, form factor and roundness of the root canal after preparation ( P > 0.05). In the apical third, the Reciproc group had significantly greater changes in canal area, perimeter, major and minor diameters than the other groups ( P < 0.05). Overall, the Twisted File and HyFlex CM systems were associated with significantly less transportation than the reciprocating instruments, Reciproc and WaveOne ( P < 0.05). Conclusions Shaping procedures led to the enlargement of the root canal space with no evidence of significant preparation errors. Changes in 3D parameters were not different between groups whilst, in the apical third, Reciproc was associated with significantly greater changes in several 2D parameters compared to the other groups. Twisted File and HyFlex CM systems were able to maintain the original canal anatomy with less canal transportation than Reciproc and WaveOne; however, these differences are unlikely to be of clinical significance. [ABSTRACT FROM AUTHOR]

In conventional adsorbate–adsorbent systems, for microdynamically indistinguishable species A and B, the total amount adsorbed is unaffected by intrinsic reactionsA→B. Under the conditions of molecular traffic control, i.e. for differing accommodation probabilities of the two species for different adsorbent segments, this simple rule collapses. As an example, mutually intersecting single-file systems are considered, where each of the two sets of parallel files is able to accommodate only one of the two molecular species. The total amount adsorbed as well as the sorbate distribution over the file network under stationary conditions are investigated by means of dynamic Monte Carlo simulations. With respect to a conventional (a “reference”) system, deviations are observed to both smaller and larger concentrations. Both of them may be explained by the peculiarities of intrinsic molecular transport. [Copyright &y& Elsevier]

Abstract: Introduction: The aim of this study was to compare the incidence of root cracks observed at the apical root surface and/or in the canal wall after canal instrumentation with 3 single-file systems and the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland). Methods: One hundred mandibular incisors were selected. Twenty control teeth were coronally flared with Gates-Glidden drills (Dentsply Maillefer). No further preparation was made. The other 80 teeth were mounted in resin blocks with simulated periodontal ligaments, and the apex was exposed. They were divided into 4 experimental groups (n = 20); the root canals were first coronally flared with Gates-Glidden drills and then instrumented to the full working length with the ProTaper, OneShape (Micro-Mega, Besancon, France), Reciproc (VDW, Munich, Germany), or the Self-Adjusting File (ReDent-Nova, Ra'anana, Israel). The apical root surface and horizontal sections 2, 4, and 6 mm from the apex were observed under a microscope. The presence of cracks was noted. The chi-square test was performed to compare the appearance of cracked roots between the experimental groups. Results: No cracks were found in the control teeth and teeth instrumented with the Self-Adjusting File. Cracks were found in 10 of 20 (50%), 7 of 20 (35%), and 1 of 20 (5%) teeth after canal instrumentation with the ProTaper, OneShape, and Reciproc files, respectively. The difference between the experimental groups was statistically significant (P < .001). Conclusions: Nickel-titanium instruments may cause cracks on the apical root surface or in the canal wall; the Self-Adjusting File and Reciproc files caused less cracks than the ProTaper and OneShape files. [Copyright &y& Elsevier]

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., Competing Interests: There are no conflicts of interest., (Copyright: © 2019 Journal of Conservative Dentistry.)

Introduction: This study evaluated the shaping ability of the XP-endo Shaper (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland), iRaCe (FKG Dentaire SA), and EdgeFile (EdgeEndo, Albuquerque, NM) systems using micro-computed tomographic (micro-CT) technology., Methods: Thirty long oval-shaped canals from mandibular incisors were matched anatomically using micro-CT scanning (SkyScan1174v2; Bruker-microCT, Kontich, Belgium) and distributed into 3 groups (n = 10) according to the canal preparation protocol (ie, XP-endo Shaper, iRaCe, and EdgeFile systems). Coregistered images, before and after preparation, were evaluated for morphometric measurements of the volume, surface area, structure model index (SMI), untouched walls, area, perimeter, roundness, and diameter. Data were statistically compared between groups using the 1-way analysis of variance post hoc Tukey test and within groups with the paired sample t test (α = 5%)., Results: Within groups, preparation significantly increased all tested parameters (P < .05). No statistical difference was observed in the mean percentage increase of the volume (〜52%) and surface area (10.8%-14.2%) or the mean percentage of the remaining unprepared canal walls between groups (8.17%-9.83%) (P > .05). The XP-endo Shaper significantly altered the overall geometry of the root canal to a more conical shape (SMI = 2.59) when compared with the other groups (P < .05). After preparation protocols, changes in area, perimeter, roundness, and minor and major diameters of the root canals in the 5 mm of the root apex showed no difference between groups (P > .05)., Conclusions: The XP-endo Shaper, iRaCe, and EdgeFile systems showed a similar shaping ability. Despite the XP-endo Shaper had significantly altered the overall geometry of the root canal to a more conical shape, neither technique was capable of completely preparing the long oval-shaped canals of mandibular incisors., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The field of endodontics has become increasingly successful due to technological advances that allow clinicians to solve clinical cases that would have been problematic a few years ago. Despite such advances, endodontic treatment of teeth with internal root resorption remains challenging. This article presents a clinical case in which a reciprocating single-file system was used for endodontic treatment of a mandibular molar with internal root resorption. Radiographic examination revealed the presence of internal root resorption in the distobuccal root canal of the mandibular right first molar. A reciprocating single-file system was used for root canal instrumentation and final preparation, and filling was obtained through a thermal compaction technique. No painful symptoms or periapical lesions were observed in 12 months of follow-up. The results indicate that a reciprocating single-file system is an adequate alternative for root canal instrumentation, particularly in teeth with internal root resorption., Competing Interests: Disclaimer: The authors have no financial, economic, commercial, and/or professional interests related to topics presented in this article.

Objective: This study aimed to compare the frequency of dentinal microcracks after root canal shaping with 2 reciprocating (Reciproc and WaveOne) and 1 combined continuous reciprocating motion twisted files adaptive (TFA) rotary system., Materials and Methods: Ninety molars were chosen and divided into three groups of 30 each. Root canal preparation was achieved by using Reciproc R25, Primary WaveOne and TFA systems. All the roots were horizontally sectioned at 15, 9, and 3 mm from the apex. The slices were then viewed each under a microscope at × 25 magnification to determine the presence of cracks. The absence/presence of cracks was recorded, and the data were analyzed with a Chi-square test. The significance level was set at P < 0.05., Results: Instrumentation with Reciproc produced significantly more complete cracks than WaveOne and TFA (P = 0.032). The TFA system produced significantly less cracks then the Reciproc and WaveOne systems apically (P = 0.004)., Conclusions: Within the limits of this study, the TFA system caused less cracks then the full reciprocating system (Reciproc and WaveOne). Single-file reciprocating files produced significantly more incomplete dentinal cracks than full-sequence adaptive rotary motion.