Comparison of design, metallurgy, mechanical performance and shaping ability of replica‐like and counterfeit instruments of the ProTaper Next system

Abstract

Aim To compare the ProTaper Next (PTN) system with a replica‐like and a counterfeit system regarding design, metallurgy, mechanical performance and shaping ability. Methodology Replica‐like (X‐File) and counterfeit (PTN‐CF) instruments were compared to the PTN system regarding design (microscopy), phase transformation temperatures (differential scanning calorimetry), nickel‐titanium ratio (energy‐dispersive X‐ray spectroscopy), cyclic fatigue, torsional resistance, bending strength, and untouched canal areas in extracted mandibular molars (micro‐CT). anova, post hoc Tukey’s and Kruskal–Wallis tests were used according to normality assessment (Shapiro–Wilk test) with the significance level set at 5%. Results Overall similarities in design and nickel‐titanium (Ni/Ti) ratio were observed amongst instruments with the X‐File having a smoother surface finish. PTN and PTN‐CF had mixed austenite plus R‐phase (R‐phase start approximately at 45 ºC and near 30 ºC, respectively), whilst X‐File instruments were austenitic (R‐phase started at approximately at 17 ºC) at room temperature (20 ºC). PTN‐CF had the greatest inconsistency in the phase transformation temperatures. Time to fracture of PTN‐CF X2 and X3 was significantly shorter than PTN and X‐File instruments (P < 0.05), whilst no difference was noted in maximum torque to fracture amongst the tested systems (P > 0.05). X‐Files and PTN‐CF had a stress‐induced phase change during bending load. Mean unprepared surface areas of root canals were 25.8% (PTN), 31.1% (X‐File) and 32.5% (PTN‐CF) with no significant difference amongst groups (P > 0.05). Conclusion Similarities amongst the systems were noted in the Ni/Ti ratio and maximum torque to fracture, whilst differences were observed in the design, phase transformation temperatures and mechanical behaviour. The ProTaper Next counterfeit instruments could be considered as the less secure system considering its low‐cyclic fatigue resistance. Apart from these differences, the unprepared canal surface areas, obtained with the tested systems, were similar.

Design, metallurgical features, mechanical performance and canal preparation of six reciprocating instruments

“…2013, Martins et al . 2020b, Silva et al . 2020), which allowed a complete and accurate overview of the instruments’ properties.…”

“…Cyclic fatigue tests followed the same protocol reported in previous studies (Martins et al . 2020b, Silva et al . 2020) using a nontapered custom‐made stainless‐steel tube apparatus.…”

“…Considering the large sample size of paired canal that would be required to pair amongst six groups (42 paired canals) and the low clinical impact that this could have on such a large sample, a total of 11 paired canals were defined, as mentioned, following previous studies methodologies (Martins et al . 2020b, Silva et al . 2020).…”

Can Type of Instrumentation and Activation of the Final Irrigant Improve the Obturation Quality in Oval Root Canals? A Push-Out Bond Strength Study

“…Moreover, the SAF lacked areas where debris was left in or vigorously packed into recesses of the canal. The presence of such debris in oval canals instrumented with either rotary or reciprocating files was well-documented by DeDeus et al [ 4 , 11 , 12 ] and more recently by Martins et al [ 19 ]. The presence of such debris most likely reduces the area of the root canal wall that comes into contact with the root canal filling compared with cleaner recesses that result from the SAF instrumentation [ 12 ].…”

“…Two recent investigations revealed the inability of PTN and WO to adhere to the surfaces of canal walls of mandibular molars. The uninstrumented area associated with these files were almost 41% for PTN and almost 29% for WO [ 1 , 19 ]. This could explain the results obtained in the current investigation with the samples instrumented with PTN and WO exhibiting lower values of dislocation resistance of the root canal fillings.…”