NSK reciprocating handpiece: in vitro comparative analysis of dentinal removal during root canal preparation by different operators

Cyclic Fatigue Resistance of Glide Path Rotary Files: A Systematic Review of in Vitro Studies

The aim of the present systematic review was to perform a qualitative synthesis of in vitro studies that assess the cyclic fatigue resistance of rotary glide path (GP) files of endodontic applications. Systematic electronic searches were performed in the Medline, Embase, Scopus, SciELO, and Web of Science databases on 15 February 2022, and were last updated on 1 April In vitro studies that evaluated and compared the cyclic fatigue resistance of at least one rotary GP file system with another rotary GP file system were included. A total of 25 studies were included in the qualitative synthesis. All studies assessing the difference in the cyclic fatigue resistance between continuous and reciprocating rotation in rotary glide path files found that the latter resulted in a significantly higher cyclic fatigue resistance, as evidenced by a higher number of cycles until fracture and/or time until fracture. Within the limitations of this review and the in vitro nature of the included studies, the results indicate that the cyclic fatigue resistance of rotary GP files may be influenced by several intrinsic factors of the files, such as their taper, cross-sectional design, alloy properties, kinematics, and external factors, such as the curvature and radius at which the file is activated, the irrigation or lubricant used, and the temperature.

Comparison of Apical Transportation with the Use of Rotary System and Reciprocating Handpiece with Precurved Hand Files: An In Vitro Study

Introduction:

Success of root canal treatment depends on several factors; among which, maintaining the original canal path during mechanical preparation is extremely important. This in vitro study aimed to compare apical transportation using RaCe NiTi rotary system and precurved stainless steel (SS) hand files in a reciprocating handpiece.

Methods and Materials:

Mesiobuccal canals of 40 extracted human mandibular first and second molars with 20 to 45^° curvatures and 3 to 7 mm curve radius were chosen for this study. After working length determination, the teeth were divided into two groups (n=20). Root canals were prepared with RaCe in group 1 and NSK handpiece and precurved SS hand files in group 2 up to #30 with 2% taper in both groups. Radiographs were taken of teeth before and after instrumentation from buccolingual and mesiodistal directions. The images were superimposed using Adobe Photoshop CS3 software. Degree of straightening and amount of apical transportation at 0, 0.5, 1, 2, 3, 4 and 5 mm levels short of the working length were determined using digital subtraction radiography. The student’s t test was used to compare the degree of straightening and Mann Whitney test was applied to compare apical transportation (millimeters) between the two groups.

Results:

No significant difference was noted between the two groups on buccolingual or mesiodistal views in degree of straightening and apical transportation on buccolingual view (P>0.05). However, on mesiodistal view, NSK reciprocating handpiece caused greater apical transportation at 0. 0.5 and 1 mm levels (P<0.05).

Conclusion:

The RaCe system and precurved SS files in reciprocating handpiece were highly similar in terms of degree of straightening and apical transportation. Thus, engine-driven NSK reciprocating handpiece can be used as an efficient adjunct for root canal preparation.

Glide Path Enlargement of Mandibular Molar Canals by Using K-files, the ProGlider File, and G-Files: A Comparative Study of the Preparation Times

INTRODUCTION

The preparation of a glide path before the introduction of rotary nickel-titanium instruments is a standard adjunct to ensure increased safety during root canal preparation. The aim of this study was to compare the mean preparation time of manual instrumentation with K-files, G-Files, and the ProGlider instrument to prepare a glide path in curved root canals.

METHODS

The mesial canals of 90 mandibular molars (with curvature angles between 25° and 35°) were selected. The specimens were randomly divided into 3 groups with 30 canals each, and canal preparations were performed by an endodontist who used #10-15-20 stainless steel manual K-files (group KF), #10 stainless steel manual K-file followed by #12-17 G-File instruments (group GF), and #10 stainless steel manual K-file followed by #16 ProGlider instrument (group PG). The total time it took to prepare the glide paths was recorded with an electronic stopwatch. New instruments were used for each canal.

RESULTS

Glide path enlargement with the PG group (27.9 ± 8.6 seconds) and GF group (41.9 ± 20.1 seconds) was shown to be statistically significantly faster than stainless steel KF group (74.9 ± 24.1 seconds) by using analysis of variance (P < .05). There was no statistically significant difference observed between the mean preparation times of the PG and GF groups (P < .05).

CONCLUSIONS

Glide path preparation times with the rotary instrument groups were significantly faster than with stainless steel manual K-files.