DIAMOND Cutting efficiency of new endodontics instruments : an in vitro comparative study

Aim of the present study was to analyze the cutting efficiency of two different NiTi systems in all their four most used sizes as proposed by manufacturer in their clinical sequence: ProTaper Gold (Maillefer, Baillagues, CH) and newly released Diamond Edge File (EdgeEndo, Albuquerque, NM) (n=10 for each size). The testing methodology was designed in order to mimic clinical usage and compare the cutting efficiency defined as easier progression to the working length in plastic blocks, using a custom-designed testing system. The system consisted of a sample holder, a motor dedicated to driving endodontic instruments, and a sensor located under the sample holder. Two parameters were recorded to assess cutting efficiency: axial force and operative torque. Mean values and standard deviations of all tests were then statistically analyzed using 1-way ANOVA followed by the post hoc Tukey test with significance set to a 95% confidence level. Results from the present study shows significant differences between the two instruments and the two sequences. When comparing all instruments Diamond Files require less force (measure by torque values) to cut a block and progress to the working length. These data show that they are more efficient at cutting versus ProTaper Gold. On the other hand, they require more force, so called positive force, in order to progress the instrument apically. These last data may seem contradictory when compared to torque values. Moreover Diamond instruments in all sizes showed a statistically significant lower screw-in effect (less negative force) when compared to ProTaper Gold instruments. All these above-mentioned differences were noted in all the four instruments inside the proposed sequence. Overall, the new Diamond files showed very balanced properties and allowed smoother and safer progression to the desired working length as shown by the proposed methodolog