Residual dentin thickness at the apical third of mandibular first molar mesial root instrumented by nickel-titanium rotary and manual files with different tapers
Accepted: 8 November 2021
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Aim: The residual root dentin thickness (RDT) in endodontically treated teeth is a major factor affecting their longevity. This study aimed to assess and compare the RDT in teeth instrumented with hand files and also with Dia-PT, Edge Taper Platinum (ETP), and Mani-Silk rotary instruments with different tapers.
Materials and Methods: Sixty-eight extracted human mandibular first molars with separate mesial and distal roots were evaluated. The teeth were mounted in Speedex putty and underwent cone-beam computed tomography (CBCT). The primary thickness of the mesial and distal root canal walls was measured at 1, 2, and 3 mm from the apex. The teeth were divided into four groups (n=17) for instrumentation of the mesiobuccal canal with Dia-PT with 0.09 taper, ETP with 0.08 taper, Mani-Silk with 0.04 taper, and stainless steel K files with 0.02 taper. They were then placed back in the putty in their previous position and underwent CBCT again. The RDT was measured at 1, 2, and 3 mm from the apex in the mesial and distal surfaces, and compared with the baseline values. Data were analyzed by the Kruskal-Wallis and Mann-Whitney tests using SPSS version 20 at P<0.05 level of significance.
Results: In the mesial surface, hand files yielded the maximum RDT. Mani-Silk and Dia-PT showed comparable RDT at all levels from the apex lower than the values yielded by hand files, except at 3 mm from the apex, where Mani-Silk yielded RDT comparable to hand files. In the distal surface, hand files and Mani-Silk yielded maximum RDT at all levels from the apex, except at 1 mm, where Mani-Silk showed significantly lower RDT. RDT in ETP and Dia-PT groups was almost similar, and significantly lower than other groups at all levels, except at 1 mm where RDT in ETP group was similar to that in Mani-Silk and hand file groups.
Conclusions: Use of hand files resulted in maximum RDT at all three levels from the apex. Files with greater taper removed greater amount of dentin from the distal surface.
Copyright (c) 2022 Forough Farahi, Eshaghali Saberi, Shima Bijari
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