Effect of temperature on the cyclic fatigue resistance of thermally treated reciprocating instruments

Autor(es)

Klymus, Michel Espinosa ^[1] ; Alcalde, Murilo Priori ^[1] ; Vivan, Rodrigo Ricci ^[1] ; Reis So, Marcus Vinicius ^[2] ; de Vasconselos, Bruno Carvalho ^[3] ; Hungaro Duarte, Marco Antonio ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Bauru Sch Dent, Dept Operat Dent Endodont & Dent Mat, Al Octavio Pinheiro Brisolla 9-75, BR-17012901 Bauru, SP - Brazil

^[2] Univ Fed Rio Grande do Sul, Dept Conservat Dent, Porto Alegre, RS - Brazil

^[3] Univ Fed Ceara, Dept Endodont, Sobral, CE - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CLINICAL ORAL INVESTIGATIONS; v. 23, n. 7, p. 3047-3052, JUL 2019.
• Citações Web of Science: 3

Resumo

ObjectivesThe aim of this study was to evaluate the impact of body temperature on the cyclic fatigue resistance of different NiTi alloys used for the manufacturing of Reciproc Blue R25 (RB 25.08; VDW, Munich, Germany), X1 Blue File 25 (X1 25.06; MK Life Medical and Dental Products, Porto Alegre, Brazil) and WaveOne Gold Primary (WOG 25.07; Dentsply Maillefer, Ballaigues, Switzerland).Materials and methodsSixty instruments of the RB 25.08, X1 25.06 and WOG 25.07 systems were used (n=20). Cyclic fatigue tests were performed at room temperature (20 degrees 1 degrees C) and at body temperature (37 degrees 1 degrees C). The instruments were reciprocated until fracture occurred in an artificial stainless steel canal with a 60 degrees angle and a 5-mm radius of curvature. The time to fracture (TTF) was recorded. Also, the number of cycles to fracture (NCF) was calculated. Data were analysed using one-way ANOVA and Tukey's tests for inter-group comparison at both temperatures and for the reduction of cyclic fatigue at body temperature. For intra-group comparison at the different temperatures, the unpaired t test was used.ResultsThe cyclic fatigue test at 20 degrees C showed that RB 25.08 and X1 25.06 presented significantly higher TTF and NCF than WOG 25.07 (P<0.05). At 37 degrees C, all groups presented significant reduction of TTF and NCF (P<0.05). RB 25.08 presented significant higher TTF than WOG 25.07 (P<0.05). Regarding the NCF, there was no significant difference among the groups (P>0.05). The WOG 25.07 presented the lowest percentage reduction of cyclic fatigue (P<0.05).Conclusion The body temperature treatment caused a marked reduction of the cyclic fatigue resistance for all reciprocating instruments tested. The RB 25.08 and X1 25.06 systems presented similar results at both temperatures tested. However, WOG 25.07 presented the lowest percentage reduction in fatigue resistance at body temperature.Clinical relevance The cyclic fatigue resistance of NiTi reciprocating instruments has been evaluated at room temperature. However, the fatigue resistance significantly decreases upon exposure to body temperature, which could affect the mechanical behaviour of the NiTi instruments during root canal preparation. (AU)

• Processo FAPESP: 14/25520-0 - Avaliação das propriedades químicas, resistência torcional e flexural, caracterização geométrica e superficial de instrumentos endodônticos em função do tratamento da liga: análise após 3 vezes simulando uso clínico
• Beneficiário: Rodrigo Ricci Vivan
• Modalidade de apoio: Auxílio à Pesquisa - Regular