Cutting efficiency of nickel–titanium rotary and reciprocating instruments after prolonged use

Abstract

The aim of the present study was to compare the cutting efficiency of Twisted File instruments used in continuous rotation or TF Adaptive motion and evaluate if prolonged use significantly affected their cutting ability. 20 new NiTi instruments were used in the present study (TF tip size 35, 0.06 taper; Sybron-Endo, Orange, CA, USA), divided into 2 subgroups of 10 instruments each, depending on which movement was selected on the endodontic motor. Group 1: TF instruments were activated using the program TF continuous rotation at 500 rpm and torque set at 2 N; Group 2: TF instruments were activated using the reciprocating TF Adaptive motion. Cutting efficiency was tested in a device developed to test the cutting ability of endodontic instruments. Each instrument cut 10 plastic blocks (10 uses) and the length of the surface cut in a plastic block after 1 min was measured in a computerized program with a precision of 0.1 mm. Maximum penetration depth was calculated after 1 use and after 10 uses, and mean and standard deviation (SD) of each group was calculated. Data were statistically analyzed with a one-way ANOVA test (P < 0.05). TF instruments used in continuous rotation (Group 1) cut a mean depth of 10.4 mm (SD = 0.6 mm) after the first use and 10.1 mm (SD 1.1 mm) after 10 uses, while TF instruments used with the Adaptive motion cut a mean depth of 9.9 mm (SD = 0.7 mm) after the first use and 9.6 mm (SD = 0.9 mm) after 10 uses. There was no statistically significant difference between the two groups investigated (P > 0.05) nor between instruments after 1 or 10 uses. In conclusion, the TFA motion showed a lateral cutting ability similar to continuous rotation and all tested instruments exhibited the same cutting ability after prolonged use.

Cutting efficiency of conventional and heat‐treated nickel–titanium rotary or reciprocating glide path instruments

“…, Gambarini et al . ). However, the hardness of Plexiglass has been reported to be lower than dentine (Haïkel et al .…”

“…, Gambarini et al . ); consequently, in other studies, the cutting efficiency of endodontic NiTi instruments was tested using Plexiglass samples due to their standardized production (Giansiracusa Rubini et al . , Gambarini et al .…”

Infection Control in Retreatment Cases: In Vivo Antibacterial Effects of 2 Instrumentation Systems

“…The instrument uses continuous rotation when it is exposed to a minimal or no applied load and changes to reciprocating motion when it engages dentin and some load is applied. This adaptive technology and the twisted file design that uses R-phase treatment is claimed to reduce the risk of instrument failure and increase flexibility and canal centering ability (20,21).…”

Measurement of torque generated during intracanal instrumentation in vivo

“…It is important to highlight that in these preliminary investigations, only TF instruments, which have high cutting efficiency and flexibility (Gambarini et al . , ) were used. Since it is unclear to which extent the present results could be extended to all the other instruments available on the market, futures studies are needed to evaluate the benefits of the effect of using outward motion with different instruments.…”

“…Most of these improvements in design and manufacturing processes have been evaluated in laboratory settings, using mechanical tests that evaluate a single parameter such as flexibility, cutting efficiency, torsional or cyclic fatigue resistance (Gambarini et al . , Plotino et al . ).…”