[Bi-axial flexure strength and fracture mode of alumina glass-infiltrated core/veneer ceramic composites].

PURPOSE

To determine the bi-axial flexural strength and fracture mode of bilayered alumina glass-infiltrated core and the veneering porcelain.

METHODS

Forty disk specimens were made from alumina glass-infiltrated core (HSDC-A) and veneer porcelain (Vintage AL), and equally divided into four groups as follows: monolithic specimens of veneer(MV),monolithic specimens of core material(MC),bilayered specimens with the veneer on top (BC) and bilayered specimens with core material on top(BV). Mean flexure strength, standard deviation and associated Weibull modulus were determined using bi-axial flexure (ball-on-ring) for each group. The results were analyzed with one-way ANOVA and the Weibull distribution with SPSS 13.0 software package. Both optical and scanning electron microscopy were employed for identification of the fracture mode and origin.

RESULTS

The strength in the group MC and BC were significantly stronger than that in the group MV and BV. The frequency of specimen delamination, Hertzian cone formation and sub-critical radial cracking in the bilayered discs were dependent on the surface loaded in tension.

CONCLUSION

Material which lies on the bottom surface dictates the strength and fracture mode of the specimens. Supported by Shenzhen Municipal Technological Project (Grant No.200903082).