Surface Changes of PathFile after Glide Path Preparation: An Ex Vivo and In Vivo Study

The aim of this study was to evaluate the changes in the surface profile of rotary nickel-titanium (NiTi) files designed to prepare a glide path and conventional stainless steel (SS) hand files when used in extremely narrow canals both in clinical and experimental conditions.

This ex vivo/in vivo study used either SS #10 K hand files or the PathFile system (Dentsply Maillefer, Ballaigues, Switzerland) to establish a glide path in maxillary molars with narrow root canals (defined as canals that bound a #8 K-file at the working length). After treatment, all files were cleaned and scanned using a noncontact laser profilometer. Changes to the surface profile (Ra cutting edge waviness = Ra_CEW) and roughness (Ra cutting edge roughness = Ra_CER) of the cutting edges and the surface roughness of the flute area (Sa flute roughness = Sa_FR) were analyzed.

#10 K-files had significant increases in all types of measurements (Ra_CEW, Ra_CEW, and Sa_FR) after the preparation of second mesiobuccal canals compared with the control group (P < .05) in both studies. In the ex vivo study, the PathFile (P1) had no significant changes in the surface profile from baseline but had a significant increase in the surface roughness of the flute (Sa_FR) (P < .05). PathFiles that were used 3 times in vivo had a significant increase in roughness (flute and cutting edge) values across all PathFile sizes compared with control values.

This study showed that PathFiles had significantly less surface defects compared with SS files after the preparation of narrow canals, indicating their possible benefits when establishing a glide path in extremely narrow canals.