In Vitro Assessment of Force Generated by Different Novel Nickel-Titanium Rotary Systems
A. Eshaq, S. Alsalman, F. Foschi & F. Mannocci
Department of Conservative Dentistry, King’s College London Dental Institute, London
The aim of the present study was to compare in-vitro the force necessary to reach the apical portion of the natural root canals in extracted human teeth of the new PTN files with other files including PTU, Revo-S and RaCe123 by a miniature load-testing machine.
Eighty mesio-buccal canals of extracted human permanent maxillary first and second molars teeth were manually prepared, to the pre-determined working length, up to a size ISO 15 K-flexofile. The teeth were randomly assigned to four groups of 20 samples each (PTN, PTU, RaCe123, and Revo-S). The teeth were mounted on one end of a miniature load-testing machine while the files/handpiece assemblies were mounted on the other. The canal preparation was undertaken at a pre-set velocity towards the apex, while the machine measured the apical force applied on the file. Maximum and average forces were calculated and statistically analysed using Kruskal-Wallis and Mann-Whitney-U test analyses of variance followed by the Bonferroni correction for multiple testing.
Statistically significant differences in the forces applied by the different filing systems were noted in the experimental groups, with the Revo-S and PTN generally scoring the lowest average forces (with the concomitant highest peaks) when reaching the apical third and fourth quarters of the canal length, followed by RaCe123 and PTU.
The results, within the limitations of this study, indicated that the ProTaper Next and Revo-S systems required less apical force during root canal shaping than ProTaper Universal and RaCe 123.