Effect of specimen preparation method on the microtensile bond strength of veneering ceramic to zirconia / 대한치과보철학회지

ABSTRACT

PURPOSE: The aim of this study was to investigate effect of specimen preparation method on the microtensile bond strength of veneering ceramic to zirconia core. MATERIALS AND METHODS: Cylindrical Lava zirconia block (3M ESPE, Seefeld, Germany) was cut into discs using a diamond disc. After sintering, the core specimens were placed in an adjustable mold and veneered with Lava ceram (3M ESPE, Seefeld, Germany). The disc shaped specimen of group 1 was cut into microbars (1x1x7 mm3) using a low speed diamond disc under water cooling (n = 15). The specimen of group 2 was cut into microbars (1.2x1.2x7 mm3) in the same way. Whereafter the microbars were trimmed (1x1x7 mm3) using a thick diamond disc under water cooling (n = 15). The microtensile bond strength was tested in a microtensile tester (Instron 8848, Instro(R) Co., Norwood, USA). Fractured microtensile specimens were analyzed under a stereomicroscope (MZ6, Leica Microsystems GmbH, Wetzlar, Germany) at magnification x30. RESULTS: The microtensile bond strength of group 1 (28.8 +/- 7.0 MPa) was significantly higher than group 2 (11.0 +/- 3.3 MPa) (P=.00). CONCLUSION: It appears advisable to avoid the trimming action, especially high strength ceramic specimens.