Katia R Weber1, Daniel E Meneghetti2, Paula Benetti3, Alvaro Della Bona3, Jason A Griggs4, Márcia Borba5. 1. PhD student, Post-Graduation Program in Dentistry, Dental School, University of Passo Fundo (UPF), Passo Fundo, RS, Brazil. 2. Predoctoral student, Dental School, University of Passo Fundo (UPF), Passo Fundo, RS, Brazil. 3. Professor, Post-Graduation Program in Dentistry, Dental School, University of Passo Fundo (UPF), Passo Fundo, RS, Brazil. 4. Professor, Department of Biomedical Materials Science, University of Mississippi Medical Center, Jackson, Miss. 5. Professor, Post-Graduation Program in Dentistry, University of Passo Fundo, Passo Fundo, RS, Brazil. Electronic address: marcia_borb@hotmail.com.
Abstract
STATEMENT OF PROBLEM: The lack of standardization regarding the loading piston material used in fatigue tests could limit the interpretation of study findings. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the piston material on the fatigue behavior of a lithium disilicate glass-ceramic. MATERIAL AND METHODS: Plate-shaped, 1.2-mm-thick, lithium disilicate glass-ceramic specimens were cemented onto a dentin analog substrate with resin cement. The specimens were divided into 4 groups according to the piston material used in the fatigue test (n=30): metal, glass fiber-reinforced epoxy resin, ceramic, and human tooth. The fatigue test was performed in a mechanical cycling machine by using the boundary technique at 2 Hz in distilled water at 37 °C. The fatigue data were analyzed by using the Weibull distribution and a lifetime-inverse power law relationship. Failures were evaluated with fractography and transillumination. RESULTS: The Weibull modulus (β) was similar among groups. The exponent of crack growth (n) was significantly greater for glass fiber-reinforced epoxy resin and tooth groups than for metal and ceramic; therefore, the probability of failure (Pf) of glass-ceramic specimens loaded by resin and tooth pistons depended more on load amplitude. Specimens tested with tooth showed the highest value of K (characteristic lifetime), which is an indication of greater survival. Radial crack was the only failure mode observed for all experimental groups. CONCLUSIONS: The piston material influenced the fatigue survival of the lithium disilicate glass-ceramic. The glass fiber-reinforced epoxy resin piston closely simulated the fatigue behavior induced by the human tooth on the evaluated glass-ceramic.
STATEMENT OF PROBLEM: The lack of standardization regarding the loading piston material used in fatigue tests could limit the interpretation of study findings. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the piston material on the fatigue behavior of a lithium disilicate glass-ceramic. MATERIAL AND METHODS: Plate-shaped, 1.2-mm-thick, lithium disilicate glass-ceramic specimens were cemented onto a dentin analog substrate with resin cement. The specimens were divided into 4 groups according to the piston material used in the fatigue test (n=30): metal, glass fiber-reinforced epoxy resin, ceramic, and human tooth. The fatigue test was performed in a mechanical cycling machine by using the boundary technique at 2 Hz in distilled water at 37 °C. The fatigue data were analyzed by using the Weibull distribution and a lifetime-inverse power law relationship. Failures were evaluated with fractography and transillumination. RESULTS: The Weibull modulus (β) was similar among groups. The exponent of crack growth (n) was significantly greater for glass fiber-reinforced epoxy resin and tooth groups than for metal and ceramic; therefore, the probability of failure (Pf) of glass-ceramic specimens loaded by resin and tooth pistons depended more on load amplitude. Specimens tested with tooth showed the highest value of K (characteristic lifetime), which is an indication of greater survival. Radial crack was the only failure mode observed for all experimental groups. CONCLUSIONS: The piston material influenced the fatigue survival of the lithium disilicate glass-ceramic. The glass fiber-reinforced epoxy resin piston closely simulated the fatigue behavior induced by the human tooth on the evaluated glass-ceramic.
Authors: Carline Rg van den Breemer; Carolien Vinkenborg; Hans van Pelt; Daniel Edelhoff; Marco S Cune Journal: Int J Prosthodont Date: 2017 Jan/Feb Impact factor: 1.681
Authors: Ediléia Lodi; Kátia R Weber; Paula Benetti; Pedro H Corazza; Álvaro Della Bona; Márcia Borba Journal: J Prosthet Dent Date: 2017-09-18 Impact factor: 3.426