Search

Aim: To investigate whether a minimally invasive basic root canal preparation technique has an influence on root canal cleanliness in extracted mandibular molar teeth. Methodology: A total of 80 root canals (40 mesio‐buccal and 40 mesio‐lingual) from 40 mandibular molars were included. The teeth were divided equally into four different experimental groups depending on the subsequently root canal preparation technique: Group 1: a basic preparation was performed up to size 20,.04 taper; Group 2: a basic preparation was performed up to size 2,.06 taper; Group 3: a basic preparation was performed up to size 25,.04 taper; and Group 4: a basic preparation was performed up to size 25,.06 taper. After the use of each instrument, each root canal was irrigated with 2.5 mL of 6% sodium hypochlorite for 30 s. Then, 1 mL NaOCl was activated for 20 s using an EDDY sonic tip. Final irrigation was performed using a total of 5 mL of 17% EDTA solution. The roots were then split longitudinally and all root canal thirds were observed through scanning electron microscopy (SEM) to evaluate the presence of superficial debris and smear layer using a scoring system. Data were statistically analysed using the Kruskal–Wallis and Bonferroni tests with a level of significance set at P < 0.05. Results: In all groups, there was significantly more residual debris and smear layer in the apical third (P < 0.05), with no differences between the middle and coronal thirds (P > 0.05). For both the parameters analysed, there was no difference amongst the groups in the middle and coronal thirds (P > 0.05), whilst in the apical third significantly less debris and smear layer was found in specimens from groups 3 and 4 than for groups 1 and 2 (P < 0.05). Conclusion: All basic root canal preparation techniques were associated with less debris and smear layer on the canal walls in the middle and coronal thirds, without differences among them. Even though debris and smear layer were always present in the apical third, an apical size of 25 resulted in significantly cleaner canals walls compared to a size 20. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To compare the cyclic fatigue resistance and bending properties of R‐Pilot and WaveOne Gold (WOG) Glider files, at intracanal temperature (35°C). Methodology: Forty R‐Pilot and 40 WOG Glider files were subjected to a cyclic fatigue resistance test (n = 20), calculating the time to fracture (TTF) in an artificial stainless steel canal. The length of the fractured file tips (FL) was also measured. The fracture surface of fragments was examined with a scanning electron microscope, and the cross‐sectional area of the fractured surfaces was measured. Flexibility of the tested files (n = 20) was determined using 45° bending test. Data were analysed statistically using the Mann–Whitney U‐test at 5% significance level. Results: Time to fracture was significantly higher in the R‐Pilot group compared to the WOG Glider (P < 0.05). There was no significant difference between groups for fracture length. The bending resistance of R‐Pilot files was significantly greater than WOG Glider files (P < 0.05). Conclusions: A significant greater cyclic fatigue resistance was observed for R‐Pilot files compared to WOG Glider instruments, although the bending resistance of WOG Glider files was lower. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To compare the cyclic fatigue resistance of the One G, ProGlider, HyFlex EDM and R‐Pilot glide path NiTi files at body temperature. Methodology: Twenty One G (size 14, .03 taper), 20 ProGlider (size 16, .02 taper), 20 HyFlex EDM (size 10, .05 taper) and 20 R‐Pilot (size 12.5, .04 taper) instruments were operated in rotation at 300 rpm (One G, ProGlider and HyFlex) or in reciprocation (R‐Pilot) at 35 °C in artificial canals that were manufactured by reproducing the size and taper of the instrument until fracture occurred. The time to fracture was recorded in seconds using a digital chronometer, and the length of the fractured fragments was registered. Mean data were analysed statistically using the Kruskal–Wallis test and post hoc Tukey tests via SPSS 21.0 software. The statistical significance level was set at 5%. Results: The cyclic fatigue resistance of the R‐Pilot files was significantly greater than the other instruments, and the One G was significantly lower (P < 0.05). There was no difference between the HyFlex EDM and the ProGlider (P > 0.05). No significant difference (P > 0.05) was evident in the mean length of the fractured fragments of the various instruments. Conclusions: The cyclic fatigue resistance of the R‐Pilot reciprocating glide path file was significantly greater than that of the rotary HyFlex EDM, ProGlider and One G glide path files. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To examine the cyclic fatigue resistances of R‐Pilot, HyFlex EDM and PathFile NiTi glide path files in S‐shaped artificial canals. Methodology: Twenty R‐Pilot (12.5/.04), 20 HyFlex EDM (10/.05) and 20 PathFile (19/.02) single‐file glide path files were included. Sixty files (n: 20/each) were subjected to static cyclic fatigue testing using double‐curved canals until fracture occurred (TF). The number of cycles to fracture (NCF) was calculated by multiplying the rpm value by the TF. The length of the fractured fragment (FL) was determined by a digital microcaliper. Six samples of fractured files (n: 2/each) were examined by SEM to determine the fracture mode. The NCF and the FL data were analysed using one‐way anova, post hoc Tamhane and Kruskal–Wallis tests using SPPS 21 software. The significance level was set at 5%. Results: In the double‐curved canal, all the files fractured first in the apical curvature and then in the coronal curvature. The NCF values revealed that the R‐Pilot had the greatest cyclic fatigue resistance, followed by the HyFlex EDM and PathFile in both the apical and coronal curvatures (P < 0.05). Conclusions: R‐Pilot NiTi glide path files, used in a reciprocating motion, had the greatest cyclic fatigue resistance amongst the tested NiTi glide path files in an artificial S‐shaped canal. [ABSTRACT FROM AUTHOR]