Negotiability of mesiobuccal canals in maxillary first molars using different path file systems

In endodontics, glide path creation has been extensively considered a mandatory clinical step to improve the safety and efficiency of rotary nickel–titanium instruments. The high anatomic variations in the mesiobuccal (MB) root of the maxillary molars are observed in the form of canal configuration, number, and position.The aim of this study was to evaluate the negotiability of MB canals in maxillary molars using different pathfiling systems (ProGlider, R‑pilot, HyFlex electrical discharge machining [EDM], WaveOne Gold Glider, and C‑Pilot).

This in vitro study included 125 maxillary first molars with closed apex. Before preparation, all teeth were scanned by periapical radiograph for review of the presence of second MB (MB2) canals, without any resorption or calcification, and moderate curve of MB root canal. Subsequently, the access cavity was prepared with a Diamond Fissure Bur. Then, the samples were divided into five groups (ProGlider, R‑pilot, HyFlex EDM, WaveOne Gold Glider, and C‑Pilot). Certain relevant indices were recorded for analysis, such as the negotiability of the glide path file in the MB canals, file fracture rate, and negotiation speed. The level of significance P value was set at 0.05.

In this study, HyFlex EDM was the only path file that could not reach the full working length (WL) in some cases. The highest frequency of file fracture in the MB2 was observed with HyFlex EDM (24%); nevertheless, R‑Pilot presented an intermediate fracture rate (16%), and both ProGlider and WaveOne Gold Glider were the safest files (4%) in this regard. However, there were no significant differences between the groups (P = 0.065). The lowest and the highest average time of reaching full WL was observed with WaveOne Gold Glider and HyFlex EDM; nonetheless, there was no significant difference between the four rotary groups. The average number of pecks in HyFlex EDM was significantly higher in comparison to those reported for WaveOne Gold Glider and ProGlider.

Path files used for glide path preparation in the MB2 canals of maxillary molars should be flexible with low taper. The use of HyFlex EDM in the MB2 canals is not recommended due to its high taper.