Effect of ProTaper Universal, Endoflare, Revo-S, HyFlex Coronal Flaring Instruments, and Gates Glidden Drills on Crack Formation
Coronal flaring during the initial stages of root canal preparation is an accepted technique with many advantages. Historically the use of Gates Glidden drills has been the technique of choice. Unfortunately the design of the instrument, the required spped of rotation and its rigidity have been the cause of many iatrogenic problems. Various manufacturers have sought to overcome the problems associated with the use of these drills by introducing their own versions of coronal flaring instruments to complement their own rotary systems.
In a paper published in the October 2014 issue of the Journal of Endodontics, Arslan et al set out to evaluate crack formation caused by four coronal flaring nickel titanium instruments and gates glidden drills. They concluded that “The use of the Gates Glidden drills resulted in the formation of the most cracks. However, the results for the ProTaper Universal, Endoflare, Revo-S, and HyFlex flaring instruments were similar to those of the control group in terms of crack formation.” The lowest incidence of cracks occurred with the Endoflare (MicroMega, Besançon, France) which is also known as the Z-Flare (ZendoDirect.com).
The use of gates glidden drills have always been a cause for concern with this new paper adding one more reason to caution the practitioners who continue to use them and to recommend that they consider the alternatives that are available in the market.
The published abstract appears below:
The aim of the present study was to evaluate crack formation after flaring root canals with Gates Glidden drills and ProTaper Universal (SX; Dentsply Maillefer, Ballaigues, Switzerland), Endoflare (MicroMega, Besançon, France), Revo-S (MicroMega), and HyFlex (Coltene-Whaledent, Allstetten, Switzerland) flaring instruments.
One-hundred eight mandibular molars were selected. Eighteen teeth were left unprepared to serve as negative controls; the experimental groups consisted of the mesiobuccal and mesiolingual root canals of the remaining 90 teeth, which were instrumented with the following coronal flaring instruments: Gates Glidden drills and ProTaper Universal SX, Endoflare, Revo-S SC1, and HyFlex 25.08 instruments. All roots were then sectioned perpendicular to the long axis at 1, 2, 3, 4, 6, and 8 mm from the cementoenamel junction. The sections were inspected under a stereomicroscope, and any crack formations were recorded. The data were analyzed using the chi-square test (P = .05).
The Gates Glidden drills resulted in a higher rate of crack formation than that noted in the control group (P < .05). Flaring of the root canals using the ProTaper Universal, Endoflare, Revo-S, and HyFlex instruments resulted in crack formation similar to that of the control group (P > .05).
The use of the Gates Glidden drills resulted in the formation of the most cracks. However, the results for the ProTaper Universal, Endoflare, Revo-S, and HyFlex flaring instruments were similar to those of the control group in terms of crack formation.