Comparison of two canal preparation techniques using Mtwo rotary instruments

INTRODUCTION: Root canal preparation is an important process in endodontic therapy. Nickel-titanium (NiTi) rotary file system can be used in single length technique (simultaneous technique) without early coronal enlargement, as well as in crown-down method. The purpose of this in vitro study was to compare single length with crown-down methods’ shaping ability using Mtwo NiTi files.MATERIALS & METHODS: Fifteen acrylic-resin blocks containing simulated canals were divided into two experimental groups. In group A, single length technique was used and in group B root canals were prepared by crown-down technique. Pre- and post-preparation canals were photographed in a standardized manner and were superimposed. The inner and outer walls of canal curvature were evaluated at three points (apical, middle and coronal) to determine the greatest change. The data was statistically analyzed using the Student t-test by Statistical Analysis System (SAS) software. RESULTS: Statistical analysis revealed that in group B, dentine was equally removed within the canal coronal to the curvature, whereas in group A, the inner wall was predominantly removed (P < 0.01). The two groups had no significant difference at the apical and middle points of the canal curvature.CONCLUSION: Our in vitro study revealed no significant difference between the single length method and crown-down technique using Mtwo for preparation of apical and middle portion of canal curvature.

Negotiation, Centering Ability and Transportation of Three Glide Path Files in Second Mesiobuccal Canals of Maxillary Molars: A CBCT Assessment

Introduction: The aim of this study was to compare negotiation, centering ability and transportation of three path finder rotary instruments (ProGlider, ScoutRace and M3 Pro-Gold Path File) to create glide path in second mesiobuccal (MB2) canals of maxillary molars with cone-beam computed tomography (CBCT). Methods and Materials:  In this in vitro study, 66 maxillary molars with separate second MB2 canals were selected with the following criteria: having 18-21 mm root length, without any resorption or calcification in radiography, without previous treatment and 20-40ºcurve according to Schneider’s method. Then MB2 canals were randomly divided into three groups (n=22). CBCT scan before and after root canal negotiation was taken. A #10 K-file for determination of working length was inserted into all canals. In group1; ProGlider file, group2; ScoutRace file and in group 3; M3 Pro-Gold Path file was implemented. The calculated data from CBCT based on reaching full working length (RFWL) or not (NRFWL) were analyzed using the Pearson Chi-square test. Centering ability was calculated by Fisher’s exact test and amount of transportation was determined with the Pearson Chi-square test in SPSS software. Results: ProGlider file had the least RFWL and ScoutRace was the best, but the results were not statistically significant (P&gt;0.05). Regarding the centering ability and transportation, all 3 groups showed no significant differences (P&gt;0.05), except at level of 2 mm from the apex in buccopalatal direction for ProGlider and ScoutRace files (P&lt;0.05). Conclusion: In spite of insignificantly different results, ScoutRace file was better than other groups in negotiating and centering ability in mesiodistal direction of the MB2 canal in maxillary molars. Also, ProGlider file was significantly better than ScoutRace regarding transportation at level of 2 mm from apex in buccopalatal direction.Keywords: Centering Ability; Cone-Beam Computed Tomography; ProGlider; Second Mesiobuccal Canal; Transportation

A Comparison of Mtwo Rotary File with K-File on Negotiation of Second Mesiobuccal Canal in Maxillary First Molar: A Clinical Study

INTRODUCTION: This study was carried out to compare the capability of K-files with Mtwo rotary file in terms of negotiation as well as depth of penetration in second mesiobuccal (MB2) canal of maxillary first molar. MATERIALS AND METHODS: A total of 32 MB2 canal of maxillary first molars having different root curvatures (not more than 30 degree) and root lengths were selected and then detected by K-file #10, #8 and #6. Based upon file penetration the samples were assigned into four groups. Group A: K-file #10 penetrate&gt;2mm into coronal third, group B: K-file #10 could penetrate&lt;2mm into coronal third, continue proceeding with #8 which had&gt;2mm penetration, group C: K-files #10 and 8 could penetrate&lt;2mm, continue proceeding with #6 for deeper penetration, and group D: Mtwo file #10/.04 was applied into all three above groups until resistance was felt. Finally, accurate working lengths at each group after K-file #10 insertions into the canal were determined radiographically. The mean depths of root canal penetration were analyzed statistically using Duncan test by SAS software (version 9.1) in GLM procedure. RESULTS: The mean of initial penetration for #10 Mtwo files was 19.16 mm, whilst it was 7.72 mm for K-File #6, 10.72 mm for K-File #8, and 12 mm for K-File #10. The difference between Mtwo rotary files and hand K-Files was statistically significant (P&lt;0.01). CONCLUSION: Mtwo rotary files could be an efficient substitute for hand files to negotiate MB2 canal both more easily and rapidly. To our knowledge, it is the first time that a NiTi rotary file showed success in negotiation of any canal

An in vitro comparison of root canal transportation by reciproc file with and without glide path.

The aim of ideal canal preparation is to prevent iatrogenic aberrations such as transportation. The aim of this study was to evaluate the root canal transportation by Reciproc file with and without glide path.Thirty acrylic-resin blocks with a curvature of 60° and size#10 (2% taper) were assigned into two groups (n= 15). In group 1, the glide path was performed using stainless steel k-files size#10 and 15 at working length In group 2, canals were prepared with Reciproc file system at working length. By using digital imaging software (AutoCAD 2008), the pre-instrumentation and post-instrumentation digital images were superimposed over, taking the landmarks as reference points. Then the radius of the internal and external curve of the specimens was calculated at three α, β and γ points (1mm to apex as α, 3mm to apex as β, and 5mm to apex as γ). The data were statically analyzed using the independent T-test and Mann-Whitney U test by SPSS version 16.Glide path was found significant for only external curve in the apical third of the canal; that is, 5mm to apex (P=0.005). But in the other third, canal modification was not significant (P> 0.008).Canal transportation in the apical third of the canal seems to be significantly reduced when glide path is performed using reciprocating files