A comparison of dimensional standard of several nickel-titanium rotary files

Diameter and taper variability of gutta-percha cones adapted to TruNatomyTM and RotateTM rotary file systems

Background

Evaluate the discrepancy in diameter and taper between adapted gutta-percha cones for TruNatomyTM 26.04 (TRU04), RotateTM 25.04 (ROT04) and 25.06 (ROT06) systems and their reference files.

Material and Methods

A sample of 60 gutta-percha cones and 15 rotary files was selected and divided into three groups (TRU04, ROT04, ROT06). Each group consisted of 20 cones and 5 corresponding files. They were observed under an optical microscope at x20 magnification and images of all observations were obtained. Diameters were measured with a digital ruler calibrated at 3 levels: D1, D3, D16 (mm from tip). The taper of each system of cones and files was calculated, The percentage of discrepancy between the taper of each file system and its corresponding gutta-percha cone was calculated.

Results

The percentage of discrepancy between the diameter of the tested gutta-percha cones and their corresponding files varied from -7% to 21%. The smallest dimensional discrepancy between gutta-percha cone and corresponding file was found at D16 in TRU04 group. The tapers of the gutta-percha cones vs their respective files were: 2% vs 3% (TRU04), 4% vs 5% (ROT04), and 6% vs 5% (ROT06). The highest discrepancy was observed at D16 in ROT06 group. The global taper discrepancy between gutta-percha cone and its corresponding file was negative in TRU04 and ROT04 groups.

Conclusions

The taper and the diameter at D1, D3, and D16 differed between all of the tested gutta-percha cones and their corresponding files. TruNatomy 26.04 files and its adapted gutta-percha cones exhibited the least discrepancy. Key words:Corresponding gutta-percha, rotary file, taper, TruNatomy, Rotate, standardization.

Diameter and Taper Variability of Single-file Instrumentation Systems and Their Corresponding Gutta-percha Cones

INTRODUCTION

Manufacturers offer single-file instrumentation systems with matching gutta-percha (GP) cones to simplify root canal preparation and obturation. The purpose of this study was to determine whether file diameters and tapers match with corresponding cone diameters and tapers (precision) as well as industry standards (accuracy).

METHODS

Twenty files and corresponding GP cones from each size of F360 (#25, #35, #45, #55 with .04 taper) and Reciproc (#25, #40, #50 with variable tapers) instruments were examined by using optical microscopy (×32) to determine their diameter and taper. Precision was evaluated by using one-way analysis of variance (α = 0.05) with Scheffé post hoc tests and t tests with Bonferroni correction. Accuracy was calculated by subtracting the nominal values from the measured values of all files and GP cones, and mean diameter and taper differences were compared by using one-way analysis of variance (α = 0.05) and Scheffé post hoc test for pairwise comparison.

RESULTS

For F360, the majority of file and cone diameters were within the tolerance levels, but most of the file diameters were significantly larger than GP cone diameters (P < .05), but the majority of all measured values were within the tolerance levels. For Reciproc, file and cone diameters at D1 and D3 mostly approached the nominal values. At the coronal end, file diameters #25 and #50 were significantly smaller than cone diameters (P < .05). For both instrumentation systems, almost all file and cone tapers matched with the preset tolerance ranges. For Reciproc, significant differences between file and GP cone demonstrated either smaller cone or smaller file diameters and tapers, depending on the size. Most of the measured values were within the acceptable range, but diameters at the coronal end exhibited the highest percent difference from the nominal values.

CONCLUSIONS

Despite the call for standardization, variability in diameter and taper dimensions between single-file instrumentation systems and their corresponding GP cones can be expected.

Assessment of consistency in the dimension of gutta-percha cones of ProTaper Next and WaveOne with their corresponding number files

OBJECTIVES

To compare the dimensions of gutta-percha (GP) cones of ProTaper Next (25/0.06) and WaveOne (25/0.08) in relation to their corresponding instruments of the same dimension, respectively.

MATERIALS AND METHODS

Two groups of GP cones were made with 25 cones in each group. Group 1 consisted of 25 GP cones # 25/0.06 (ProTaper Next). Group 2 consisted of 25 GP cones # 25/0.08 (WaveOne). Measurements were done at D1 (1 mm short of the tip), D3 (3 mm short of the tip), and D11 (11 mm short of the tip) for GP cones of both groups and were compared with their corresponding instruments.

RESULTS

Group 1 (ProTaper) 25/.06 GP points showed greater diameters than those of the corresponding instrument, which was statistically significant. Group 2 (WaveOne) 25/0.08 GP points showed greater diameters than those of the corresponding instrument which was statistically significant whereas it was nonsignificant at level D1.

CONCLUSION

Diameters of both ProTaper Next and WaveOne GP cones were greater than their corresponding instruments. Hence, there are chances of under obturation with both systems.