Influence of File Motion on Shaping, Apical Debris Extrusion and Dentinal Defects: A Critical Review

Influence of two kinematics on canal transportation and centering ability of WaveOne Gold and One Curve files

This research examines canal transportation and centering ability of single-file systems when operated in continuous rotation or reciprocation. Sixty J-shaped resin blocks were used. The specimens were divided into two main groups (n = 30). Then, based on the motion used to operate the instruments, each group was subdivided into two subgroups (n = 15). Group A1: One Curve/rotation, Group A2: One Curve/clockwise reciprocation, Group B1: WaveOne Gold/Reciprocation, Group B2: WaveOne Gold/counter-clockwise rotation. Pre- and post-instrumentation images were obtained using digital microscope. Canal transportation was measured at five levels. A non-significant difference (p > 0.05) resulted between two motions at all levels. However, group A1 showed significantly less transportation at levels 3 and 4 (p ≤ 0.05), also more centered preparation at level 4 (p ≤ 0.05) than group B1. Within the limitations of this study, the apical transportation and centering ability of single-file systems are unaffected by different kinematics.

Influence of endodontic motors on the behaviour of root canal shaping instruments: an in vitro comparative study

AIMS

The endodontic literature reports a lot of comparative study on endodontic instruments, concerning as well their geometry, instrumental dynamics, material, mechanical behavior or heat treatment. However, to our knowledge, no study has focused on the influence of endodontic motors on the shaping abilities of endodontic instruments. Thus, the aim of this study was to analyze the influence of the endodontic motors on root canal shaping instruments.

METHOD

Dual Move (MICRO-MEGA, Besançon, France), Canal Pro CL2i (COLTENE, Alstätten, Suisse), Canal Pro Jeni Motor (COLTENE, Alstätten, Suisse), Ai Motor (WOODPECKER, Guilin, China), Wave One motor (VDW, Postfach, Munich) and Smart A (WOODPECKER, Guilin, China) were pre-clinically compared in continuous rotation and reciprocating motion on a traction/compression bench using resin blocks. Canal shaping in continuous rotation and reciprocating motion were performed with One Curve and One RECI instruments (MICRO-MEGA, Besançon, France), respectively. The penetration/removal forces, making it possible to objectify the cutting effect and screwing effect of the instruments during root canal shaping, were analyzed.

RESULTS

The results showed (i) that endodontic motors influence the mechanical behavior of endodontic instruments, (ii) that the influence of the motors is essentially felt during reciprocating motion and (iii) that the reciprocating angles influence the mechanical behavior of endodontic instruments.

CONCLUSION

Only endodontic instruments are widely studied in literature while endodontic motors have a direct influence on root canal treatment. This study analyzes the influence of the endodontic motors on root canal shaping instruments. This study tends to demonstrate that Jeni Motor could optimize the mechanical behavior of endodontic instruments.

COMPARATIVE EVALUATION OF THE EFFECT OF DIFFERENT ROTARY INSTRUMENT SYSTEMS ON THE AMOUNT OF APICALLY EXTRUDED DEBRIS

Objectives: The purpose of our study is to examine in vitro the amount of debris extrusion from the apical after root canal preparation with different rotary instruments. Materials and Methods: In present study, 60 single root single-canal lower premolar human teeth were used. The teeth were randomly selected and divided into 4 main groups (n=15). Root canals are shaped by using 2Shape, One Curve and XP-3DEndo Shaper working in rotational motion and WaveOne Gold working reciprocal motion. Later, the weight of each eppendorf tube was weighed on a precision scale and the amount of debris extrusion from the apical was determined with 10ˉ4 precision by subtracting the empty weight of the tube. Since the parametric test assumptions were fulfilled in the evaluation of the data obtained regarding the amount of debris extrusion from the apical of file systems by loading them into the SPSS 22.0 program, One-Way Variance analysis was used and the level of error was taken as 0.05. Results: When the amount of debris extrusion from the apical is ordered from high to low, it was seen that there are 2Shape, One Curve, XP-Endo Shaper, WaveOne Gold. However, the difference between study groups was not statistically significant (p> 0.05). Conclusions: Considering the results obtained in terms of debris extrusion from the apical about the new generation files with different metallurgy, kinematics, structural features, designs and different configurations that we used ın present study, it was seen that these systems would not show any difference in terms of the effect of debris on the success of endodontic treatment.

Effect of mode of rotation on apical extrusion of debris with four different single-file endodontic instrumentation systems: Systematic review and meta-analysis

This systematic review and meta-analysis evaluated whether single-file endodontic instrumentation systems with the reciprocating type of motion are responsible for more debris extrusion than single-file endodontic instrumentation systems with the full rotational type of motion. Electronic and manual searches were performed following the recommendations of Preferred Reporting Items for Systematic Reviews and Meta-Analysis - PRISMA. We included studies comparing rotary (Neoniti and/ OneShape) versus reciprocating (WaveOne and/ Reciproc) systems. We evaluated the quality of studies and performed statistical analysis using R-Project software. Eight studies of high quality were included to perform the meta-analysis. Subgroup analysis was also done. The overall risk of bias was too low. In conclusion, single-file reciprocating systems tend to generate more extrusion of debris than single-file rotary systems.

Instrumentation Kinematics Does Not Affect Bacterial Reduction, Post-Operative Pain and flare-ups: A Randomized Clinical Trial

AIM

This randomized clinical trial aimed to assess the effect of instrumentation kinematics (reciprocation or continuous rotation) on bacterial reduction, post-operative pain and incidence of flare-ups after root canal treatment of single-rooted mandibular premolars with asymptomatic apical periodontitis.

METHODOLOGY

Sixty-six patients were included in this prospective, parallel, randomized clinical trial. Patients were randomly allocated into two groups (N=33) according to the kinematics of the shaping instrument: WaveOne Gold (WO) used in reciprocation or One Shape (OS) used in continuous rotation. Under complete asepsis, bacterial samples were taken before (S1) and after (S2) a standard cleaning and shaping protocol. Evaluation of bacterial reduction was done by both culture technique and quantitative real-time polymerase chain reaction (qPCR) analysis. Post-operative pain was evaluated using the visual analog scale (VAS) after 24, 48- and 72-hours following treatment, while flare-ups were recorded as a binary outcome (Yes/No). Independent and paired t-tests were used for inter and intragroup comparisons for bacterial count data respectively. For post-operative pain score, intergroup comparisons were analyzed using Mann-Whitney U test while intragroup comparisons were analyzed using Friedman test followed by pairwise comparisons utilizing Wilcoxon signed rank test with Bonferroni correction. The significance level was set at p≤0.05 within all tests.

RESULTS

All the allocated participants received the intervention and were analyzed. The comparison between culture and qPCR methods showed that qPCR analysis demonstrated significantly higher pre-instrumentation baseline bacterial count (p<0.05). The percentage of bacterial reduction, detected by either method, significantly decreased after instrumentation using either rotation or reciprocation kinematics (p<0.05). However, the difference between the WOG or OS files was statistically non-significant (p>0.05). The intra-group comparisons showed a significant reduction in post-operative pain with time (p<0.05) for both groups. However, the inter-group comparison demonstrated that the difference in post-operative pain after the use of either WOG or OS was statistically non-significant (p>0.05). The incidence of flare-ups between both groups was also not-significant (p=1).

CONCLUSIONS

Shaping kinematics, either rotation or reciprocation motions, had no impact on bacterial reduction and the incidence of post-operative pain and flare-ups after root canal preparation of single-rooted premolars with asymptomatic apical periodontitis.

Effects of different glide path techniques on the amount of extruded debris and preparation times during root canal preparation

Background. This study purposed to compare the effect of new single glide path files on extruded apical debris and total preparation times during root canal preparation with the WaveOne Gold system.

Methods. Thirty-six extracted human lower molar teeth with mesiobuccal canal curvature angles of 25‒35° were randomly splited to three groups. In group 1, the glide path was created with WaveOne Gold Glider (WGG) file at working length (WL); in group 2, the glide path was created with ProGlider file (PG); in group 3, the glide path was not performed. In all the groups, the root canals were shaped with WaveOne Gold Primary (WOG) reciprocating files at WL. Apically extruded debris during instrumentation was picked up into pre-weighed Eppendorf tubes. The weight of the dry extruded debris was calculated by subtracting the pre- and post-instrumentation weights of the tubes in each group. The total time elapsed during the canal preparation was calculated with a chronometer. The data were analyzed using one-way ANOVA and post hoc Tukey tests.

Results. The WGG/WOG group extruded significantly fewer debris than the WOG and PG/WOG groups (P<0.05). There was no significant difference between the WOG and PG/WOG groups (P>0.05). The WGG/WOG and PG/WOG groups were significantly faster than the WOG group.

Conclusion. The amount of debris extruded apically significantly diminished when conventional WGG was implemented before using WOG. The total preparation time significantly diminished when the WOG file was used in combination with reciprocating and rotary glide path preparation techniques.

Apical extrusion of debris with different rotary and reciprocating single-file endodontic instrumentation systems: a systematic review and meta-analysis protocol

INTRODUCTION

Root canal treatment is one of the oldest dental procedures for the treatment of endodontic infection. Extrusion of debris beyond the root apex during root canal instrumentation and subsequent persistence of pain are common complications. A systematic review of the evidence on reciprocating single-file instrumentation systems and their comparison with rotary single-file systems, with apical extrusion of debris as primary outcome, will be done through this study.

METHODS AND ANALYSIS

Published ex vivo and in vitro studies with no language restriction will be included. We will search MEDLINE (Ovid), EMBASE (Ovid), Web of Science, Cochrane and Google Scholar. Strategies will be incorporated to search grey literature also. Thorough evaluation of search results, completion of data abstraction and assessment of quality will be done by two reviewers independent from each other. Assessment of included studies will be done by utilising an evidence model developed on the basis of standards of quality reported in guidelines to document ex vivo and in vitro studies regarding dental materials and pertained for extrusion of debris apically and has been already used in quality assessment of studies involving quantification of debris extrusion apically. We will calculate the standardised mean differences for apically extruded debris, with congruent 95% CIs. We will measure the statistical heterogeneity by applying the Cochrane Q test and quantify using the I² statistic. Existence of covariates and any potential heterogeneity will be explored through prespecified subgroup and sensitivity analyses.

ETHICS AND DISSEMINATION

Approval from an ethical research committee is not required because it will be done using data that have been already published and have no concerns related to the privacy of patients. Extensive dissemination of results from this review will be done through submission to a peer-reviewed journal for publication and conferences.

PROSPERO REGISTRATION NUMBER

CRD42019151804.

Comparison of Shaping Ability of Different Single-File Systems Using Microcomputed Tomography

OBJECTIVES

 To evaluate the shaping ability of four different single-file systems using micro-computed tomography (micro-CT).

MATERIALS AND METHODS

 Eighty mesiobuccal and mesiolingual canals of permanent mandibular molars were randomly assigned to four groups according to the file used; WaveOne Gold, RECIPROC Blue, HyFlex EDM, and One Shape (n = 20). The samples were scanned using micro-CT for the preinstrumentation record; then the canals were instrumented and scanned for the postinstrumentation records.

STATISTICAL ANALYSIS

 The data were then analyzed statistically using one-way analysis of variance (ANOVA) with the level of significance set at α = 0.05.

RESULTS

 The results of canal centering ratio and canal transportation showed that no significant difference was found among the four file groups at the middle and the coronal levels. However, a significant difference was found at the apical level (p < 0.05), where WaveOne Gold showed the best centering ratio and the least amount of canal transportation. The change in the canal volume was significant at the coronal level (p < 0.05), whereas the change in the canal volume was higher for the HyFlex EDM group than the other groups. No significant difference was found between the other groups at the apical level, middle level, or in the total percentage of canal volume.

CONCLUSION

 WaveOne Gold produced a more centralized canal preparation with a lesser amount of transportation at the apical level. HyFlex EDM showed the highest canal volumetric change at the coronal level. The interim design of the endodontic files has a high impact on the behavior of the file inside the root canal.