IADR Abstract Archives
Wear and Fracture Resistance of Multilayer Zirconia
Objectives: To improve the optical properties of high strength 3 mol% yttria partially stabilized tetragonal zirconia (3Y-TZP), a multilayer material with different contents of yttria stabilizer has been developed. The objective of this study is to characterize the wear and fracture resistance of a multilayer translucent zirconia in relation to its multi-transition zones. The wear behavior of restorative materials can affect the longevity of both antagonist and restoration.
Methods: Two types of zirconia ceramics were evaluated, a multilayer translucent zirconia (IPS e.max ZirCAD-MT(MULTI) and a control 3Y-TZP (IPS e.max ZirCAD-LT). Pre-sintered CAD-CAM zirconia blocks were cut, grinded, sintered and polished to 1 µm finish. For the wear test (n = 12), square-shaped specimens (16x16x1mm) were adhesively bonded to a dentin analog (G10). The sliding wear test was performed using a zirconia ball (r = 3.15mm) as antagonist, with 30 N load at 1.5 Hz for 500,000 cycles, in distilled water. Optical microscope and 3-D laser scanner were used for quantitative and qualitative wear analysis. For flexural strength test (n = 10), bar-shaped specimens (16x2x1.5mm) were obtained from MULTI (enamel, dentin, cross-section) and 3Y-TZP. Specimens were tested in four-point flexure using a universal testing machine (1.0 mm/min). Data was analyzed using one-way ANOVA and Tukey’s tests (a=0.05).
Results: A significant amount of wear damage was observed on specimens when tested from 10,000 to 100,000 cycles, until it reached a plateau stage (up to 500,000). Wear rate was similar for both ceramics. There were significant differences among mean flexural strength within groups (p<0.001). 3Y-TZP had the highest strength (851.1±96.8MPa), followed by dentin group (744.2±103.8MPa).Enamel(386.7±59.8MPa)and cross-section(429.8±54.0MPa) groups showed lower but statistically similar mean flexural strength.
Conclusions: Multilayer translucent zirconia and 3Y-TZP had similar wear rate, although 3Y-TZP showed superior strength. Different layers within the multilayer material showed different flexural strength.
Methods: Two types of zirconia ceramics were evaluated, a multilayer translucent zirconia (IPS e.max ZirCAD-MT(MULTI) and a control 3Y-TZP (IPS e.max ZirCAD-LT). Pre-sintered CAD-CAM zirconia blocks were cut, grinded, sintered and polished to 1 µm finish. For the wear test (n = 12), square-shaped specimens (16x16x1mm) were adhesively bonded to a dentin analog (G10). The sliding wear test was performed using a zirconia ball (r = 3.15mm) as antagonist, with 30 N load at 1.5 Hz for 500,000 cycles, in distilled water. Optical microscope and 3-D laser scanner were used for quantitative and qualitative wear analysis. For flexural strength test (n = 10), bar-shaped specimens (16x2x1.5mm) were obtained from MULTI (enamel, dentin, cross-section) and 3Y-TZP. Specimens were tested in four-point flexure using a universal testing machine (1.0 mm/min). Data was analyzed using one-way ANOVA and Tukey’s tests (a=0.05).
Results: A significant amount of wear damage was observed on specimens when tested from 10,000 to 100,000 cycles, until it reached a plateau stage (up to 500,000). Wear rate was similar for both ceramics. There were significant differences among mean flexural strength within groups (p<0.001). 3Y-TZP had the highest strength (851.1±96.8MPa), followed by dentin group (744.2±103.8MPa).Enamel(386.7±59.8MPa)and cross-section(429.8±54.0MPa) groups showed lower but statistically similar mean flexural strength.
Conclusions: Multilayer translucent zirconia and 3Y-TZP had similar wear rate, although 3Y-TZP showed superior strength. Different layers within the multilayer material showed different flexural strength.