A study of compressive strength between zirconia framework and veneering ceramic as a function of thermal expansion coefficient using Shell–Nielsen test method

Abstract

This study investigated the bond strength between a zirconia framework and four veneering ceramic materials with varying coefficients of thermal expansions (CTE) using the Shell Nielsen bond strength test. Zirconia rods (N=40) (ICE Zirkon) (diameter: 4 mm, height: 20 mm) were milled in green state and sintered. After firing, the zirconia rods were air-abraded, ultrasonically and steam cleaned. They were randomly assigned to receive four veneering ceramic materials (n=10/group), namely a) Vita VM9 (VZ; 9-9.2x10 -6 K -1 ), b) Cerabien ZR (CZ; 9.1x10 -6 K -1 ), c) Matchmaker ZR (MM; 9.4x10 -6 K -1 ) and d) IceZirconia Ceramic (IZ; 9.6x10 -6 K -1 ). The veneering ceramics were then fired onto zirconia discs (height: 2 mm, thickness: 2 mm) circumferentially and were thermocycled for 6.000 times (5/55 0 C, dwell time: 30 s).Specimens were loaded from the top of the zirconia rods (crosshead speed: 0.5 mm/min) in a universal failure type between the framework and veneering ceramic followed by mixed failures. Veneering ceramics with a greater mismatch of CTE with the zirconia framework exhibited similar Shell Nielsen bond strength to those with fewer mismatches. Shell Nielsen bond strength test used in this study subjecting the zirconia framework-veneering ceramic assemblies to circumferential shear forces did not show the effect of CTE mismatch between the veneering ceramics accept those between CZ (9.1x10 -6 K -1 ) and IZ (9.6x10 -6 K -1 ).

Mechanical Analysis of Ceramic/Polymer Composite with Mesh-Type Lightweight Design Using Binder-Jet 3D Printing

“…Our lightweight-designed samples are evaluated using a universal testing machine (KDMT-156, Kyung Do Precision Co., Ltd., in Kyungi-do, Republic of Korea). The compression test was carried out at a rate of 1.2 mm/min under a load of 10 tons [ 25 , 26 , 27 ]. Each test was conducted twice for data accuracy.…”