Comparison of air-driven vs electric torque control motors on canal centering ability by ProTaper NiTi rotary instruments

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.

A Critical Review of Methods for Quantitative Evaluation of Root Canal Transportation

INTRODUCTION

A comparison between root canal transportation studies is nearly impossible because of nonstandardized transportation evaluation methods. The aim of the present review was to search, compare, and critically discuss transportation evaluation methods.

METHODS

A search of PubMed, Web of Science, Scopus, ScienceDirect, and reference lists of articles was conducted up to March 2020 using appropriate key words to identify transportation evaluation methods. The methods in the included articles were extracted, compared, and categorized.

RESULTS

Seventy-four articles using original methods were selected. All studies share 3 main steps: image acquisition, image measurements, and calculation of parameters. Images were acquired by photography, radiography, and computed tomographic imaging. Two types of measurements were used: the amount of removed material and the canal center point distance. The parameters were calculated and reported as distance or ratio. Relationships between the different transportation parameters were found and confirmed with mathematical simulation.

CONCLUSIONS

Although methods were proposed as being novel, similarities between them were found, enabling the classification of the methods and identifying correlations. The canal center point distance is the most suitable for the description of canal transportation because it is comprehensible and it relates to the mathematical concept of translation. Removed material-based measurements are double the value of the canal center point distance. Ratio parameters are not suitable for reporting transportation.

A review of instrumentation kinematics of engine-driven nickel-titanium instruments

Over the years, NiTi alloys have become indispensable materials in endodontic treatment. With technological advancements in metallurgy, manufacturers have attempted to produce instruments with enhanced features. In parallel with these developments, endodontic motors have undergone improvements in terms of torque control and kinematics that are adjustable in different directions. This review presents an overview of the advancements in instrumentation kinematics and the effect of instrumentation kinematics on root canal shaping procedures and instrument performance. The literature search for this narrative review was conducted in Google Scholar, Scopus, PubMed and Web of Science using the keywords 'kinematics and endodontics' and 'reciprocation and endodontics'. In addition, historical literature was searched using the keyword 'nickel-titanium and endodontics'. Overall, 143 articles were included up to 2015.

Apical transportation associated with ProTaper Universal F1, F2 and F3 instruments in curved canals prepared by undergraduate students

Objective

This study evaluated apical transportation associated with ProTaper^® Universal Fl, F2 and F3 rotary files in curved canais prepared by undergraduate students.

Material and Methods

Twenty mesial roots of mandibular molars with curvatures ranging between 25° and 35° were selected. Mesiobuccal canals were instrumented by twenty students with the ProTaper^® system (Dentsply-Maillefer, Ballaigues, Switzerland) according to the manufacturer's instructions. Pre-fiaring was performed with Sl and SX files. A #15 K-file was inserted into the root canal up to the working length (WL), and an initial digital radiograph was taken in a buccolingual direction (baseline). Afterwards, the S1, S2, F1, F2, and F3 files were employed up to the WL. Other radiographies were taken in the same orientation of the baseline after the use of the Fl, F2, and F3 files, with each file inserted into the root canal. The radiographic images were overlapped, and the Image J software was used to measure the distance between the rotary files' ends and the #15 K-file's end, characterizing the apical transportation. Data were analyzed by Repeated Measure ANOVA and by the SNK post hoc test (P<0.05).

Results

It was verified that file size affected apical transportation significantly (P<0.001). The F3 file showed higher apical transportation than Fl and F2, while between these last files there was no difference.

Conclusion

The undergraduate students produced lower apical transportation in curved canals when they did not use the F3 rotary file.