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Cyclic Fatigue Resistance of Reciproc Blue, Reciproc, and WaveOne Gold Reciprocating Instruments

Introduction The aim of the present study was to compare the cyclic fatigue resistance of Reciproc Blue R25 (VDW, Munich, Germany) with Reciproc R25 (VDW) and WaveOne Gold Primary (Denstply Maillefer, Ballaigues, Switzerland). Methods Fifteen Reciproc Blue R25, 15 Reciproc R25, and 15 WaveOne Gold Primary instruments were collected and tested in a dynamic cyclic fatigue test device, which has an artificial canal with a 60° angle of curvature and a 5‐mm radius of curvature. All instruments were operated until fracture occurred, and time to fracture (TF) and the lengths of the fractured fragments were recorded. The mean and standard deviations of TF and fragment length were calculated for each reciprocating system. TF data were subjected to Kruskal‐Wallis 1‐way analysis of variance and the Dunn test, whereas fractured fragment length data were subjected to 1‐way analysis of variance (P < .05). Results Reciproc Blue R25 exhibited the highest cyclic fatigue resistance (P < .05). The cyclic fatigue resistance values of WaveOne Gold Primary were significantly higher than those of Reciproc R25 (P < .05). There was no significant difference in the mean length of the fractured fragments among the instruments (P > .05). Conclusions Reciproc Blue R25 instruments had significantly higher cyclic fatigue resistance than WaveOne Gold and Reciproc R25 instruments. HighlightsThe cyclic fatigue (CF) resistance of novel Reciproc Blue was compared with WaveOne Gold and Reciproc.Reciproc Blue R25 exhibited the highest CF resistance.The CF resistance of WaveOne Gold was significantly higher than Reciproc.

Apical Root Canal Morphology of Mesial Roots of Mandibular First Molar Teeth with Vertucci Type II Configuration by Means of Micro–Computed Tomography

Introduction: The aim of this study was to assess the features of the apical root canal anatomy and its relation to the level at which 2 separate root canals merge in the mesial roots of the mandibular first molars with Vertucci type II canal configuration by using micro–computed tomography analysis. Methods: The anatomic features of the apical 3 mm of root canals in 83 mesial roots of mandibular first molar teeth were investigated by micro–computed tomography and software imaging according to the level at which 2 separate root canals merge. The most apical slice where a visible root canal was detectable was recorded as 0 level. The specimens from where 2 root canals rejoin at within 3 mm from the 0 level were then assigned to group 1 (n = 37), whereas the specimens from where root canals rejoin 3–9 mm from the 0 level were assigned to group 2 (n = 46). Data were presented by using descriptive statistics and Mann‐Whitney U tests, with the significance level set at 5%. Results: In all specimens the long oval type of cross‐sectional shape increased from 50.9% at 1 mm to 80.5% at 3 mm. Group 1 presented significantly higher major diameter values compared with group 2 (P < .05). There was no significant difference regarding minor diameter values (P > .05) between groups. Group 2 displayed significantly higher roundness values than group 1 (P < .05). Conclusions: A long oval root cross section of apical root canal anatomy is more prevalent in roots for which 2 root canals merge within apical 3 mm of root canals. HighlightsWe aimed to determine whether the level at which the 2 root canals join influences the cross‐sectional shape and size in the apical 3 mm of the canal.We scanned 269 mesial roots of mandibular first molar teeth and included 83 specimens with Vertucci type II root canal configuration.Major diameter values were significantly higher in the group in which 2 root canals rejoin within 3 mm.When the 2 root canals merged within the apical 3 mm, the major diameter increased, and the canal shape became a longer oval.

Efficacy of XP-endo Finisher File in Removing Calcium Hydroxide from Simulated Internal Resorption Cavity

Introduction: The aim of this study was to evaluate the effect of supplementary use of XP‐endo Finisher file, passive ultrasonic activation (PUI), EndoActivator (EA), and CanalBrush (CB) on the removal of calcium hydroxide (CH) paste from simulated internal resorption cavities. Methods: The root canals of 110 extracted single‐rooted teeth with straight canals were prepared up to size 50. The specimens were split longitudinally, and standardized internal resorption cavities were prepared with burs. The cavities and root canals were filled with CH paste. The specimens were divided into 5 groups as follows: XP‐endo Finisher, EA, PUI, CB, and syringe irrigation (SI). The root canals were irrigated with 5.25% NaOCl and 17% EDTA for 2 minutes, respectively. Apart from the SI group, both solutions were activated by using tested techniques for 1 minute. The quantity of CH remnants on resorption cavities was scored. Data were analyzed by using Kruskal‐Wallis H and Mann‐Whitney U tests. Results: XP‐endo Finisher and PUI removed significantly more CH than SI, EA, and CB (P < .05), showing no significant difference between them (P > .05). Differences among SI, EA, and CB were also non‐significant (P > .05). Conclusions: None of the tested techniques render the simulated internal resorption cavities free of CH debris. XP‐endo Finisher and PUI were superior to SI, CB, and EA. Highlights:XP‐endo Finisher is a novel instrument designed to enhance intracanal medicament removal.To our knowledge, no study has investigated the ability of XP‐endo Finisher to remove calcium hydroxide paste from internal resorption cavities.We compared XP‐endo Finisher with syringe irrigation, passive ultrasonic irrigation, EndoActivator, and CanalBrush.Supplementary use of these techniques was performed to activate NaOCl and EDTA.XP‐endo Finisher file and passive ultrasonic irrigation were superior to conventional irrigation, EndoActivator, and CanalBrush.

Effect of intracanal cryotherapy on pain after single‐visit root canal treatment

The purpose of this study was to evaluate the effect of 2.5°C cold saline irrigation as final irrigant on postoperative pain after single-visit root canal treatment of teeth with vital pulps. One-hundred and seventy patients were assessed as eligible and included to the study. The teeth were randomly divided into two groups (n = 85) (i.e. the control group and the cryotherapy group). In the cryotherapy group, final irrigation with 2.5°C 0.9% physiological saline solution for 5 min was performed following completion of biomechanical preparation, whereas in control group same solution stored at the root temperature was used. Treatments were performed in a single visit. Participants were asked to rate the intensity of their postoperative pain using visual analogue scale at 24 and 48 h. Data were analysed by Mann-Whitney U test and Students t test. In the cryotherapy group level of reported postoperative pain was significantly lower than the control group (P < 0.05, Mann-Whitney U test). The outcome of this investigation indicates that 2.5°C cold saline irrigation as final irrigant can result a significant reduction in postoperative pain levels in comparison to the control group. Cryotherapy is a simple, cost-effective, and non-toxic option for postoperative pain control in single visit root canal treatment.

Pyrosequencing Analysis of Cryogenically Ground Samples from Primary and Secondary/Persistent Endodontic Infections

Introduction This study aimed to characterize the microbial communities of primary and secondary/persistent endodontic infections using high‐throughput pyrosequencing from the pulverized samples. Methods The roots of 20 extracted human teeth with primary endodontic infection and 20 teeth with secondary/persistent endodontic infection were collected. The outer surfaces of the roots were disinfected, and whole roots were cryopulverized. 16S amplicon pyrosequencing data from the DNA extracted from the pulverized root powders were obtained, and microorganism abundance and diversity were calculated. Data were analyzed using statistical and bioinformatic methods. Results Pyrosequencing analysis resulted a total of 2,606,128 sequences from 40 samples. A total of 15 phyla, 160 genera, and 368 species were detected. No significant difference between primary and secondary/persistent endodontic infections was found regarding the diversity and richness of operational taxonomic units at the phyla, genera, and species levels (P > .005). Conclusions The present study revealed that the microbial diversity of secondary/persistent endodontic infections did not differ than those of primary endodontic infections. A new archaeal species, Candidatus Nitrosoarchaeum limnia, was detected in root canals of 1 patient with primary endodontic infection for the first time. HighlightsMicrobial community profiles of endodontic infections were investigated.Cryopulverized samples were used to represent microbial community structure.Microbial diversity was similar in primary and secondary/persistent infections.Candidatus Nitrosoarchaeum limnia was reported for the first time in a root canal sample.

Detectability of Middle Mesial Root Canal Orifices by Troughing Technique in Mandibular Molars: A Micro–computed Tomographic Study

Introduction The objective of the present study was to measure the orifice depth of middle mesial canals (MMCs) and evaluate the detectability of orifices using troughing preparation. Methods For this study, 85 mandibular molar teeth with MMCs were selected from the scanned micro–computed tomographic images. The MMCs were categorized, and the distances between the MMC orifices and the cementoenamel junctions (CEJ) were recorded as the depth of the orifice. Data were evaluated with frequency analysis and a chi‐square test using SPSS (SPSS Inc, Chicago, IL), and the results indicated a 5% significance level. Results It was found that 77.41% of the MMC orifices were at the CEJ level, whereas 5.38% and 9.69% of the MMC orifices were detectable within 1‐mm and 2‐mm depths from the CEJ, respectively. Of the specimens, 7.52% had MMC orifices deeper than 2 mm from the CEJ. Confluent anatomy was the most frequent configuration. No significant relation was detected between the orifice depth and MMC configuration (P > .05). Conclusions It was concluded that 77.41% of the specimens did not require troughing preparation, the remaining 15.07% would require troughing, and 7.52% could not be accessed even with the troughing preparation. HighlightsRoots having middle mesial root canals (MMC) were selected using micro–computed tomographic (micro‐CT) imaging.The distances between MMC orifices and cementoenamel junctions (CEJs) were measured.The majority of MMC orifices were detectable at the CEJ level.15.07% of the specimens would require troughing with 1‐ to 2‐mm depths to be accessed.7.52% of the orifices were deeper than 2 mm so they could not be revealed via troughing.

Cyclic Fatigue Resistance of XP-Endo Shaper, K3XF, and ProTaper Gold Nickel-titanium Instruments

Introduction: The aim of this study was to compare the cyclic fatigue resistance of the ProTaper Gold (PTG; Dentsply Maillefer, Ballaigues, Switzerland), K3XF (SybronEndo, Orange, CA), and XP‐endo Shaper (FKG Dentaire, La Chaux‐de‐Fond, Switzerland) nickel‐titanium rotary instruments at intracanal temperatures. Methods: Eighteen XP‐endo Shaper (30.01), 18 K3XF (30.04), and 18 PTG F3 (30.09v) instruments were used to test the cyclic fatigue resistance at an intracanal temperature of 35° ± 2°C. The instruments were tested in a metal block that simulated a canal curvature angle of 60° and a curvature or radius of 5 mm. All instruments were operated until fracture occurred, and then the number of cycles to failure was calculated. The lengths of fractured fragments were measured with a digital caliper. The data were analyzed statistically using 1‐way analysis of variance and the Tukey post hoc test with significance set at P < .05. Results: The XP‐endo Shaper instruments showed a significantly higher number of cycles to fracture than the K3XF and PTG instruments (P < .05). There was no difference between the PTG and K3XF instruments (P > .05). Conclusions: The XP‐endo Shaper instruments exhibited greater cyclic fatigue resistance compared with the other instruments at the intracanal temperature. Highlights:The cyclic fatigue (CF) resistance of the novel XP‐endo Shaper instrument was compared with the ProTaper Gold F3 and K3XF instruments.The XP‐endo Shaper (30.01) exhibited the highest CF resistance.There was no significant difference between ProTaper Gold (30.09v) and K3XF (30.04) regarding CF resistance.

Scanning electron microscopy with energy dispersive X-ray spectrophotometry analysis of reciprocating and continuous rotary nickel-titanium instruments following root canal retreatment

This study aimed to evaluate superficial defects and the composition of Reciproc R25 and ProTaper Retreatment file systems (Dentsply Maillefer, Ballaigues, Switzerland) used for retreatment. A total of 100 maxillary incisor teeth were randomly divided into the following two groups: Reciproc R25 (n = 25) and ProTaper Retreatment instrument (n = 75) groups. The nickel-titanium (Ni-Ti) compositions of the files before and after use were analyzed using energy dispersive X-ray spectrophotometry (EDX). Chi-square, Mann-Whitney U, and Kruskal-Wallis tests were used to analyze the data. ProTaper Retreatment instrument group showed a significantly higher number of defects than the Reciproc group (P < 0.05). No instrument fracture was detected. The presence of debris was observed in both groups before use, although the level was significantly higher in the ProTaper Retreatment group, which consisted of metals (P < 0.05). There was no significant difference between new and used instruments with regard to Ni-Ti composition (P < 0.05). EDX analysis showed that both the Reciproc and ProTaper Retreatment instruments had a Ni-Ti composition that was within the standards specified by the American Society of Testing and Materials. This study confirmed the use of both the Reciproc R25 file and ProTaper Retreatment file system for root canal filling removal in straight root canals as a safe procedure. (J Oral Sci 58, 401-406, 2016).

The efficacy of laser, ultrasound and self-adjustable file in removing smear layer debris from oval root canals following retreatment: A scanning electron microscopy study.

This study aims to compare the efficacy of different irrigation activation methods to remove smear layer and debris from oval-shaped root canals following retreatment. Ninety mandibular canines with oval-shaped root canals were selected. Retreatment was performed with R-Endo retreatment files. The samples were randomly divided into six groups (n = 15). Groups were assigned according to agitation technique: R-Endo with classic irrigation, with self-adjustable file, with passive ultrasonic irrigation, R-Endo + Er:YAG, R-Endo + PIPS and R-Endo + Nd:YAG. Compared with the classic irrigation (R-Endo + CI) group, all other groups were more successful in reducing smear layer and debris (P < 0.05). The least amount of residual smear layer and debris was detected in the Er:YAG laser group (P < 0.05). Additional use of different agitation methods contributes to removal of debris and smear layer following root canal filling removal with rotary instruments; however, none of the techniques tested render root canal walls completely free of smear layer or debris.

Comparison of the shaping ability of novel thermally treated reciprocating instruments

Objectives The present study aimed to evaluate the shaping ability of 2 thermally treated nickel-titanium reciprocating systems in simulated curved canals. Materials and Methods Forty simulated canals were prepared to apical size 25 using Reciproc Blue R25 (VDW) and WaveOne Gold Primary (Dentsply Sirona) instruments. Standard pre- and post-preparation images were taken and superimposed. The removal of resin material was measured at 5 standard points: the canal orifice, halfway between the canal orifice and the beginning of the curve, the beginning of the curve, the apex of the curve, and the end-point of the simulated canal. The data were analysed using the independent sample t-test with a 5% significance threshold. Results The canals in which Reciproc Blue R25 was used showed a significantly greater widening than those in which WaveOne Gold was used at 4 of the 5 measurement points (p < 0.05). The Reciproc Blue R25 instrument removed significantly more resin from the inner aspect of the curve at 2 of the 5 points and similar amounts at the remaining 3 points. At the 2 apical points, there was no significant difference between the Reciproc Blue R25 and WaveOne Gold Primary instruments. Conclusion Both instruments respected the original canal anatomy; however, WaveOne Gold resulted in a more conservative shape with less transportation.