IADR Abstract Archives
Influence of Antagonist Piston Material on Glass-Ceramic Fatigue Behavior
Objectives: The objective of the study was to assess the influence of antagonist piston material on the fatigue behavior of a glass-ceramic.
Methods: Plate-shaped specimens of lithium disilicate-based glass-ceramic (1.2-mm thick) were adhesively cemented onto a dentin analogue substrate. The specimens were divided into three groups according to the piston material (n=30): (M) metal (stainless steel), (R) fiber-reinforced epoxy resin (NEMA-G10,), (C) ceramic (lithium disilicate-based glass-ceramic). Fatigue testing was performed using a mechanical cycling machine with 2Hz in 370C distilled water. Load was applied in axial compression perpendicular to the ceramic surface. Two lifetimes were evaluated (100,000 and 500,000 cycles), and the load amplitude was defined according to the boundary technique (63-90N). Fatigue data were analyzed using Weibull distribution and an inverse power law lifetime relation (ALTA PRO, Reliasoft). Failure was analyzed using transillumination and classified as either radial or cone cracks.
Results: Group R had a significant higher value of crack growth exponent (n) than groups M and C, meaning that the failure probability (Pf) of specimens tested with R piston was more dependent on the load amplitude. Therefore, when the Pf (%) was estimated for lower loads, such as 30N and 60N (100,000 and 500,000 cycles), specimens tested with R piston showed lower Pf (%) than the ones tested with M and C pistons. Yet, when estimations were performed at a higher load (90N) there was no difference among groups. Radial cracking was the predominant failure mode found for all groups.
Conclusions: The antagonist piston material affected the fatigue behavior of the glass-ceramic. The probability of failure of specimens tested with the fiber-reinforced epoxy resin piston was more sensitive to the load level applied.
Methods: Plate-shaped specimens of lithium disilicate-based glass-ceramic (1.2-mm thick) were adhesively cemented onto a dentin analogue substrate. The specimens were divided into three groups according to the piston material (n=30): (M) metal (stainless steel), (R) fiber-reinforced epoxy resin (NEMA-G10,), (C) ceramic (lithium disilicate-based glass-ceramic). Fatigue testing was performed using a mechanical cycling machine with 2Hz in 370C distilled water. Load was applied in axial compression perpendicular to the ceramic surface. Two lifetimes were evaluated (100,000 and 500,000 cycles), and the load amplitude was defined according to the boundary technique (63-90N). Fatigue data were analyzed using Weibull distribution and an inverse power law lifetime relation (ALTA PRO, Reliasoft). Failure was analyzed using transillumination and classified as either radial or cone cracks.
Results: Group R had a significant higher value of crack growth exponent (n) than groups M and C, meaning that the failure probability (Pf) of specimens tested with R piston was more dependent on the load amplitude. Therefore, when the Pf (%) was estimated for lower loads, such as 30N and 60N (100,000 and 500,000 cycles), specimens tested with R piston showed lower Pf (%) than the ones tested with M and C pistons. Yet, when estimations were performed at a higher load (90N) there was no difference among groups. Radial cracking was the predominant failure mode found for all groups.
Conclusions: The antagonist piston material affected the fatigue behavior of the glass-ceramic. The probability of failure of specimens tested with the fiber-reinforced epoxy resin piston was more sensitive to the load level applied.