IADR Abstract Archives
Physical and Mechanical Properties of Novel Multilayered Zirconia Materials
Objectives: To determine the flexural strength of individual layers of multilayered zirconia materials using gradations in translucency by varying yttria content. These gradients are designed to give the material unique physical and mechanical properties at various locations throughout the restoration.
Methods: Multilayered zirconia discs were sectioned to produce 3-point bend bars for each individual translucency layer. These materials were LayZir All Indication (Smart Dentistry) and IPS e.max ZirCAD Prime (Ivoclar). The specimens were sectioned using a Buehler precision saw to yield bars for each individual translucency layer. Sectioned bars were polished with a Buehler EcoMet 250 Grinder-Polisher using 600-grit wet/dry sandpaper and dried overnight. All bars were sintered with a Zircar Hot Spot 110 furnace according to the manufacturer’s recommendations. Final polishing on top and bottom surfaces was performed using diamond grinding disc to a 15 μm and 0.5 μm finish, respectively. Final bar dimensions were approximately 3 mm x 4 mm x 25 mm. Bars were annealed with a Sirona inFire HTC speed furnace at 1000 °C for 15 min. Three-point flexural strength was performed with an Instron using a 20 mm support span at a speed of 0.5 mm/min. The 15 μm finish was under compression, and the 0.5 μm finish was under tension. For the transition layer of each specimen, the incisal portion was the top and the cervical portion was the bottom. Two-way ANOVA with HSD Tukey test was used to compare the difference of the flexural strength with α = 0.05.
Results: The mean and standard deviation of flexural strength values are shown in Table 1.
Conclusions: Flexural strength values for layered discs decreased from cervical to incisal. Incisal layers had a significantly lower flexural strength than that of cervical layers.
Methods: Multilayered zirconia discs were sectioned to produce 3-point bend bars for each individual translucency layer. These materials were LayZir All Indication (Smart Dentistry) and IPS e.max ZirCAD Prime (Ivoclar). The specimens were sectioned using a Buehler precision saw to yield bars for each individual translucency layer. Sectioned bars were polished with a Buehler EcoMet 250 Grinder-Polisher using 600-grit wet/dry sandpaper and dried overnight. All bars were sintered with a Zircar Hot Spot 110 furnace according to the manufacturer’s recommendations. Final polishing on top and bottom surfaces was performed using diamond grinding disc to a 15 μm and 0.5 μm finish, respectively. Final bar dimensions were approximately 3 mm x 4 mm x 25 mm. Bars were annealed with a Sirona inFire HTC speed furnace at 1000 °C for 15 min. Three-point flexural strength was performed with an Instron using a 20 mm support span at a speed of 0.5 mm/min. The 15 μm finish was under compression, and the 0.5 μm finish was under tension. For the transition layer of each specimen, the incisal portion was the top and the cervical portion was the bottom. Two-way ANOVA with HSD Tukey test was used to compare the difference of the flexural strength with α = 0.05.
Results: The mean and standard deviation of flexural strength values are shown in Table 1.
Conclusions: Flexural strength values for layered discs decreased from cervical to incisal. Incisal layers had a significantly lower flexural strength than that of cervical layers.