[Glide path management of rotary nickel-titanium instruments in simulated root canals]

To compare the shaping ability of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 with that of PathFile and stainless steel K-file hand instruments in simulated root canals.

A total of 60 simulated resin blocks were divided randomly into five groups (n=12), each group prepared with each instrument, respectively. Preparation time was recorded. Pre- and post-operative images were obtained using a scanner and superimposed using Photoshop. The material removal from the inner and outer canal walls beginning from 0 mm at the end point of the canal were measured using ImageJ. Centering ability was determined, accordingly. The data were analyzed using the One-Way ANOVA at a significance level of P<0.05.

Preparation time for ProGlider was (61.018±5.020) s, significantly the fastest (P < 0.05), that for SS K-file (111.100±6.987) s, the slowest (P<0.05), and the differences among the other 3 groups were not significant (P>0.05). The removal of resin from the outer wall at the apical portion was significantly lower for HyFlex EDM Glidepath File than for ProGlider (P<0.05), both of them were significantly lower than the other 3 groups (P<0.05). For the removal from the inner wall at the curvature portion, ProGlider was the least whilst SS K-file the most (P<0.05). At the straight portion, RaCe ISO 10 removed the most not only from the inner but also the outer wall (P<0.05), HyFlex EDM Glidepath File the second most, and the other 3 groups among the same levels. As far as the centering ability was concerned, at the apical portion, HyFlex EDM Glidepath File was the best, ProGlider the second best, no significant difference identified among the other 3 groups. At the curvature portion, ProGlider and HyFlex EDM Glidepath File were the best, PathFile the second, RaCe ISO 10 the third, the worst was the SS K-file. At the straight portion, the difference amongt the 5 groups was not significant.

The shaping abilities of ProGlider, HyFlex EDM Glidepath File and RaCe ISO 10 were better or comparable to that of PathFile, while the preparation time for ProGlider reduced significantly, and HyFlex EDM Glidepath File and RaCe ISO 10 removed significantly more resin at the straight portion of the canal.