Evaluation of Torsional Resistance and Bending Stiffness of Coronal Flaring Nickel-Titanium Instruments

Author(s)

Weissheimer, Theodoro ^[1] ; Alcalde, Murilo Priori ^[2] ; Cortez, Julia Barrionuevo ^[2] ; da Rosa, Ricardo Abreu ^[1] ; Vivan, Rodrigo Ricci ^[3] ; Souza Calefi, Pedro Henrique ^[3] ; Hungaro Duarte, Marco Antonio ^[3] ; Reis So, Marcus Vinicius ^[1]

Affiliation

^[1] Univ Fed Rio Grande do Sul, Dept Conservat Dent, Porto Alegre, RS - Brazil

^[2] Univ Sagrado Coracao, Dept Hlth, Sci Ctr, Bauru, SP - Brazil

^[3] Univ Sao Paulo, Bauru Fac Dent, Endodont & Dent Mat, Dept Operat Dent, Bauru, SP - Brazil

• Document type: Journal article
• Source: EUROPEAN ENDODONTIC JOURNAL; v. 6, n. 3, p. 284-289, 2021.
• Web of Science Citations: 0

Abstract

Objective:The aim of this study was to evaluate the bending and torsional resistance of the following instruments: Mtwo 25/.07 (MT - VDW, Munich, Germany), Navigator W-XN 25.07 (WXN - Wizard Navigator, Medin, Nove Mesto na Morave, Czech Republic), ProTaper Universal SX 19/.04 (PSX - Dentsply Tulsa Dental Specialties, Tulsa, USA), MK Orifice Shapper 17/.08 (OS - MK Life Medical and Dental Products, Porto Alegre, Brazil) and MK Sequence 17.12 (MKS - MK Life Medical and Dental Products, Porto Alegre, Brazil). Methods: One hundred instruments were used (n=20). Resistance to bending (n=10), torque and angular deflection (n=10) at the failure of new instruments were measured according to ISO 3630-1. Metal mass volume at 3 mm from the tip was evaluated using micro-computed tomography (micro-CT). The fractured surface of each fragment was examined by scanning electron microscopy (SEM). Data were analysed using 1-way analysis of variance and Tukey tests. Results: Torsional resistance values of MK Sequence were higher than the other groups (P<0.05). No differences were observed among MT, WXN and OS (P>0.05) and PTS, which presented the lowest values (P<0.05). MT showed the highest angular deflection (P<0.05). WXN and PSX presented no significant difference (P>0.05). PSX and OS also showed no significant differences (P>0.05). MKS instruments had the lowest angular deflection values (P<0.05). There were significant differences among all the groups in bending stiffness test (P<0.05), but PSX had the lowest torque to bend (P<0.05). MKS had the larger metal mass volume at 3 mm from the tip (P<0.05). SEM analysis showed similar and typical features of torsional failure for all instruments tested. Conclusion: In conclusion, MK Sequence 17/.12 had the highest torsional fracture resistance. Mtwo 25/.07 showed higher angular deflection capacity, and ProTaper Universal SX the 19/.04 lower bending stiffness. (AU)

• FAPESP's process: 18/23452-8 - Evaluation of the torsion and flexural strength of nickel-titanium rotary instruments used for the cervical preparation of the root canals
• Grantee: Júlia Barrionuevo Cortez
• Support Opportunities: Scholarships in Brazil - Scientific Initiation