Cutting efficiency of conventional and heat‐treated nickel–titanium rotary or reciprocating glide path instruments

Abstract

Aim To compare the cutting efficiency of several glide path files: HyFlex EDM Glidepath File (HEGF), One G (OG), R‐Pilot (RP) and WaveOne Gold Glider (WOGG) at different cutting inclinations. Methodology Cutting efficiency of 120 new HEGF, OG, RP and WOGG was tested at 90°, 70° and 45° inclination in relation to the sample. Depending on manufacturer instructions, instruments were tested in continuous rotation or reciprocating motion against standardized gypsum samples for 120 s using a customized apparatus. Cutting efficiency was determined by measuring the weight loss and the length of the sample cut. Data were analysed using two‐way analysis of variance and Tukey t‐test (P < 0.05). Results RP and WOGG had greater cutting ability than HEGF and OG in all tested angles. RP tested at 45° had significantly greater cutting efficiency than when tested at 90° and 70° (P < 0.05). OG was not significantly different in terms of cutting ability at 90°, 70° and 45° (P > 0.05). HEGF and WOGG had significantly greater cutting efficiency at 45° and 70° compared to 90° (P < 0.05), with no significant difference between 45° and 70° (P > 0.05). RP had the greatest cutting ability at all tested angles. Conclusions Reciprocating glide path instruments had greater cutting efficiency compared to those in continuous rotation. An inclined insertion (45° or 70°) increased the cutting ability of glide path files except for One G conventional NiTi files.

Cutting efficiency of heat‐treated nickel–titanium single‐file systems at different incidence angles

“…This set‐up has ensured standardised conditions and allowed for a direct comparison of the tested instruments cutting ability. Moreover, this new machine, unlike the previous studies, allowed to mimic clinical situation in which file’s cutting blades are inclined respect to dentinal walls (17).…”

“…Special gypsum type IV plates (25 × 50 × 1.5 mm) created from the same original raw material were used (Zeus Dental Stone IV, Zingardi, Italy) to eliminate the variability deriving from the different mechanical characteristics of dentine specimens (17,20). Gypsum plates production was standardised by employing a dental laboratory vacuum mixer (Zhermack Labomix, Badia Polesine, Italy) that guaranteed the same gypsum powder/water ratio for the creation of every sample.…”

“…Cutting efficiency was determined by using a customised testing apparatus (17). Unlike the previously employed testing machines, this device displays some new elements.…”

“…(16) reported the mean angle of file access in a mesial canal of a first mandibular molar was approximately 20° with a traditional endodontic cavity and 20°–30° with a contracted endodontic access cavity. Consequently, as previously reported, cutting efficiency should also be evaluated at different incidence angles (such as 70° and 45°) and not only 90° (17).…”

“…In particular, the complexity of anatomical curvatures and angulated file access induced by contracted endodontic cavities (CECs) generate an inhomogeneous contact between the file blades and the dentinal walls thus influencing the cutting effectiveness (16–18). Alovisi et al .…”