Effect of glide path preparation on apical extrusion of debris in root canals instrumented with three single-file systems: An ex vivo comparative study

Glide Path in Endodontics: A Literature Review of Current Knowledge

The introduction of nickel-titanium rotary instruments revolutionized shaping procedures as they were able to produce a well-tapered preparation while reducing operator fatigue. The major drawback of rotary instruments was the high risk of fracture due to bending and torsional stress. Thus, the creation of a glide path has been advocated and recommended by most rotary instrument manufacturers. The aim of the present review is to summarize existing knowledge on glide path preparation and identify areas where further research is needed. The primary goal is to provide a comprehensive overview of the techniques and instruments used in glide path preparation, highlighting their advantages and limitations. The secondary goal is to explore the effect of glide path creation on the overall success of endodontic treatment, particularly in terms of reducing procedural errors and improving treatment outcomes. An online search on PubMed, ScienceDirect, UCLA, and Scopus databases was conducted, and 116 articles were identified. Eligible articles were divided into nine categories based on what they researched and compared. The categories included centering ability and/or root canal transportation, cyclic fatigue resistance, glide path and shaping time, tortional stress resistance, apical extrusion of debris and/or bacteria, defects in dentine walls, file separation, postoperative pain assessment, and scouting ability and performance. Establishing a glide path reduces root canal transportation, especially with rotary methods. Reciprocating and heat-treated files offer higher fatigue resistance and shorter preparation time. Instruments with shorter pitch lengths have greater torsional strength. Preparation and coronal preflaring reduce apical debris and bacteria. Glide paths do not affect dentine microcracks, file separation, or defects but reduce immediate postoperative pain and improve cutting ability. Randomized trials are needed to assess their impact on treatment outcomes.

Evaluation of apically extruded debris following glide-path preparation with different file systems

The amount of apically extruded debris following glide-path preparation of mesial root of 120 freshly extracted human mandibular molar teeth using Senseus ProFinder files, PathFile, G-Files, Scout-RaCe files, HyFlex glidepath files and V glide-path two file system is of interest. The Eppendorf tubes were used as test equipment for collecting debris and the average weight of the debris was measured using an electronic micro-balancing system. It was observed that regardless of the file system utilized, debris was expelled from the apex. The G files resulted in a lower quantity of debris being extruded (0.070 ± 0.002 mg). In contrast, the V glide-path two file system exhibited the highest amount of debris extrusion (0.110 ± 0.004 mg) compared to all other file systems.

Evaluation of apical extrusion of debris and centering ability in different nickel-titanium files during curved root canal preparation

BACKGROUND

Curved root canals lead to difficulties in cleaning, shaping and filling the root canal system. Apical extrusion of debris and root canal transportation are important factors causing postoperative complications. In clinical practice, commonly selected instruments include multifile NiTi systems, such as M3-Pro PLUS (M3-PRO), Orodeka Plex 2.0 (ODP), Rotate (ROT), and Protaper Gold (PTG), as well as single-file NiTi systems, such as M3-L Platinum 2019 (M3L), Waveone Gold (WOG), and Reciproc Blue (RCB). This study aimed to comprehensively evaluate the differences in the apical extrusion of debris and centering ability of the above NiTi files.

METHODS

Seventy 3D-printed resin teeth were used (n = 10). The apically extruded debris was collected in a preweighed centrifuge tube. The resin teeth with or without root canal preparation were cut into separate cross sections at 1 mm, 3 mm, 5 mm, and 7 mm away from the root apex, and then the root canal transportation and centering ratio of each cross section were calculated.

RESULTS

Apical extrusion of debris was highest in RCB but lowest in OD-P (P < 0.05). Root call deviation was lowest in ROT at the 3 mm level, in PTG at the 5 mm level, and in PTG and ROT at the 7 mm level (P < 0.05). The centering ratio of NiTi files was highest in the RCB group at the 3 mm level, in the PTG group at the 5 mm level, in the ROT group at the 7 mm level (P < 0.05).

CONCLUSIONS

For NiTi files with the same system, the cross-sectional design is the greatest factor affecting the extrusion of debris, and motion mode is the second. In addition, the multifile system could reduce the degree of root canal transportation.

Microcomputed tomographic analysis of the efficiency of two retreatment techniques in removing root canal filling materials from mandibular incisors

This study aimed to evaluate the removal effect of the ProTaper Next system (PTN) combined with manual nickel-titanium Hedström (MNiTiH) files or chloroform on filling materials of mandibular incisors by microcomputed tomography (micro-CT). Sixty-four extracted human mandibular incisors were finally selected and assigned to two groups (n = 32) based on root canal morphology after instrumentation. Two subgroups (n = 16) were formed based on two retreatment methods. The volume of residual filling materials (RFMs) and the surface area covered by RFMs were analyzed by micro-CT, the apical extrusion and the time taken for removing the filling materials were recorded. A smaller percentage of the volume of RFMs and less surface area covered by RFMs occurred in PTN combined with MNiTiH groups and round-shaped canal incisors (P < 0.05). The time taken for removing the filling materials was not significantly different in all groups (P > 0.05). The apical extrusion was significantly less in PTN combined with MNiTiH groups than in PTN combined with chloroform groups (P < 0.05). Neither of the two methods rendered root canals completely free from filling materials. PTN combined with MNiTiH could reduce the apical extrusion and remove filling materials more efficiently than PTN combined with chloroform.

Comparative Evaluation of Apically Extruded Debris during Pulpectomy Procedure in Primary Molar Teeth Using Two Different Rotary Systems and Hand Files: An In Vitro Study

Background

Successful outcome of endodontic treatment depends on chemomechanical preparation of the tooth. However, during canal preparation, debris may extrude through the apical foramen causing postoperative complications. The aim of this study is to evaluate and compare the amount of apically extruded debris during the pulpectomy procedure in primary molar teeth using two different rotary files and hand files.

Materials and Methods

Distal roots of sixty extracted primary molars were divided into three groups: group A: Prime Pedo™ pediatric rotary files, group B: DXL-Pro Pedo™ pediatric rotary files, and group C: hand files. Myers and Montgomery experimental model was used. Preweighed Eppendorf tubes were used to collect apically extruded debris. The tubes were then placed in an incubator at 70°C for 5 days. The weight of the debris attained was determined. The data were analyzed using ANOVA and post hoc Bonferroni test.

Results

Hand files produced more apical debris extrusion (P < 0.05). Prime Pedo™ pediatric rotary files produced the least debris (P < 0.05).

Conclusion

Prime Pedo™ and DXL-Pro Pedo™ pediatric rotary files extruded significantly lower amount of debris apically during pulpectomy as compared to hand files. Rotary files can be considered an alternative to hand files in pediatric endodontics.

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.

Influence of Negotiation, Glide Path, and Preflaring Procedures on Root Canal Shaping-Terminology, Basic Concepts, and a Systematic Review

INTRODUCTION

Negotiation, glide path, and preflaring are essential steps in root canal shaping procedures. This report aimed to discuss the terminology, basic concepts, and clinical considerations of negotiation, glide path, and preflaring procedures and the influence of these steps on root canal shaping.

METHODS

This systematic review was undertaken following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The protocol has been registered with the International Prospective Register of Systematic Reviews (number CRD42019127021). A comprehensive literature search was performed by 2 independent reviewers using a selected search strategy in 2 electronic databases (PubMed and Scopus) until January 28, 2019. A further search was performed manually in endodontic journals. Studies investigating or comparing at least 1 shaping property resulting from root canal instrumentation with a glide path or preflaring in human extracted teeth or clinical studies were included.

RESULTS

The literature shows that the definition of glide path and preflaring procedures remains controversial, which requires an elaboration in the American Association of Endodontists' Glossary of Endodontic Terms. After the removal of irrelevant and duplicated articles, 98 articles were included. The impact of glide path preparation and preflaring on working length determination, apical file size determination, canal transportation, separation of endodontic files, shaping time, dentinal microcrack formation, and extrusion of debris was discussed. Because of heterogeneity among the included studies, quantitative synthesis was not performed for most of the parameters.

CONCLUSIONS

An evidence-based guideline is needed to define and correlate the basic concepts and current applications of each step of contemporary advancements in root canal instruments. Glide path preparation reduces the risk of debris extrusion, has no influence on the incidence of dentinal crack formation, and improves the preservation of the original canal anatomy. The creation of a glide path may have no impact on Reciproc files (VDW, Munich, Germany) in reaching the full working length. Preflaring increases the accuracy of working length determination. Further randomized clinical trials are required to evaluate the effect of a glide path and preflaring on root canal treatment outcomes.

Extrusion of Debris from Curved Root Canals Instrumented up to Different Working Lengths Using Different Reciprocating Systems

INTRODUCTION

The aim of this study was to evaluate the extrusion of debris associated with the use of the Reciproc (VDW GmbH, Munich, Germany) and WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland) reciprocating systems in curved canals instrumented up to different working lengths (WLs).

METHODS

Sixty mesial roots of extracted mandibular first molars with mesiobuccal canals having curvatures between 10° and 20° and independent foramina were randomly distributed into 4 experimental groups (n = 15) according to WL and the instrumentation system used: RC0, Reciproc and WL at the apical foramen; RC1, Reciproc and WL at 1 mm short of the apical foramen; WOG0, WaveOne Gold and WL at the apical foramen; and WOG1, WaveOne Gold and WL at 1 mm short of the apical foramen. The canals were irrigated with double-distilled water throughout the preparation. Each root was fit into an Eppendorf tube to collect the debris extruded through the foramen during instrumentation. After instrumentation, the roots were removed from the tubes, and the weight of the debris was obtained by subtracting the initial weight of the tubes from their final weight. The data were submitted to the analysis of variance parametric test complemented by the Tukey test.

RESULTS

No statistically significant difference was observed between the 4 experimental groups regarding the amount of debris extruded (P > .05).

CONCLUSIONS

The 2 reciprocating systems tested were associated with similar amounts of apically extruded debris, regardless of the working length used in the instrumentation.