Optical Properties and Flexural Strength of Zirconia Ceramic Matrix Composites

Objectives: Determine the effects of additives and sintering temperature on the optical and mechanical properties of zirconia ceramic matrix composites.
Methods: Groups consisted of zirconia powder as received and zirconia powder with glass and/or porogens to form the porous ceramic matrix. For the pure zirconia group, TZ3YSB-E (Tosoh Co., Japan) was used to fabricate blocks by dry pressing and isostatic pressing methods and then were sintered at 1000 and 1150°C and sectioned into discs (n=10/group). For the glass and porogens added zirconia groups, glass and zirconia powders were ball-milled, mixed with a porogen, and pressed to fabricate blocks. The blocks were divided into 4 groups for sintering at 1000, 1150, 1200 and 1300°C (n=10/group). All of the porous discs were silaned and dried in a vacuum oven for 24 hours. Triethylene glycol dimethacrylate (TEGDMA) with Urethane dimethacrylate (UDMA) resin monomers were used for infiltration into the discs and then cured under pressure. Biaxial flexural strength of the 1.5mm-thick polished discs was determined using an Instron at a crosshead speed of 0.5 mm/min. Optical properties were determined for each group using an X-Rite spectrophotometer. JMP Version 14 software was used to analyze the data by performing a student T-test and analysis of variance (ANOVA) followed by Tukey’s multiple-comparison test (p < 0.05).
Results: (please see Table1.)
Conclusions: 1.Increasing sintering temperature significantly increases translucency parameter, light transmission, and biaxial flexural strength.
2.Resin-infiltrated pure zirconia has higher biaxial flexural strength than the porcelain and porogens added resin-infiltrated zirconia at the same sintering temperatures.