Abstract
The aim was to evaluate the canal straightening and the amount of apically extruded debris associated with five rotary nickel-titanium when preparing curved root canals. A total of 100 root canals in extracted human teeth (angles of curvatures 20°–30°; radii 5.9–13.5 mm) were divided into five groups (n = 20/group). The groups were balanced with respect to the angle and the radius of canal curvature. The root canals were prepared using conventional austenite 55-NiTi alloy instruments F360, F6 SkyTaper (both Komet, Lemgo, Germany), and the heat-treated NiTi Jizai, Silk-Complex and Silk-Standard instruments (all Mani, Tochigi, Japan) to an apical size 25. The amount of extruded debris was assessed with a micro balance. Statistical analysis was performed using Kruskal–Wallis test with Bonferroni correction at a significance level of p < 0.05. During canal preparation, neither instrument fractures nor procedural preparation errors were noticed. Regarding canal straightening, the use of Jizai instruments resulted in the significantly lowest straightening (p < 0.05), while no significant differences were obtained between all other groups (p > 0.05). Regarding the amount of apically extruded debris, no significant differences between all groups were obtained (p > 0.05). Within the limitations of this study, all instruments performed well, and especially the Jizai instruments showed an excellent shaping ability.
Highlights
Accepted: 23 February 2021Root canal treatment is indicated in the case of irreversible pulpitis and non-vital teeth with or without associated apical periodontitis
The currently available evidence suggests that maintaining the original canal curvature during root canal preparation has a positive impact on the clinical outcome [2]
Engine-driven nickel-titanium (NiTi) instruments have been shown to cause less canal straightening during preparation of curved root canals than stainless steel hand instruments [3]
Summary
Accepted: 23 February 2021Root canal treatment is indicated in the case of irreversible pulpitis and non-vital teeth with or without associated apical periodontitis. Engine-driven nickel-titanium (NiTi) instruments have been shown to cause less canal straightening during preparation of curved root canals than stainless steel hand instruments [3]. The use of engine-driven NiTi instruments seems to be associated with less apical debris extrusion during preparation than conventional stainless steel hand instruments [3,4]. The latter aspect, apical debris extrusion, is claimed to exert a clinically relevant impact on post-endodontic pain and on quality of life of patients after nonsurgical root canal treatment [5,6,7,8]. In the periradicular tissues, extruded debris may cause expression of Substance P and Calcitonin gene-related peptide, which results
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