Bond strength of metal–ceramic systems in three‐point flexure bond test

Abstract

This study deals with a three-point flexure test for the metal-ceramic bond involving geometrically simple specimens (alloy strips partly coated with ceramic) that can be fabricated with reasonable expenditure and sufficient reproducibility. The calculation of the stress distribution in such specimens with the aid of the finite-element method (FEM) is presented. The aim of this numerical analysis is: to investigate the stress distribution in a ceramometallic specimen with dimensions that, in a large number of experiments, have proven to lead to debonding at one end of the ceramic veneer instead of a crack in the middle of the veneer; and to assign a bond strength to the measured critical bending force that takes into account the influence of the Young's modulus of the alloy as well as a possible deviation of the thickness of the metal substrate from the standard value. Bond strength values of a variety of metal-ceramic combinations are demonstrated. These experimental results demonstrate the reproducibility of the test method as well as its sensitivity to diverse parameters. The presented method is proposed as an alternative to another flexure bond test nominated for international standard. In this test ceramometallic strips are bent over a rod to a 90 degrees angle of the specimen ends, subsequently flattened, and the fracture surface visually inspected for adherence of the ceramic to the alloy substrate along the predominant part of the middle third of the specimen. It is clear that such a test can at most deliver qualitative results.

A comparison of debonding strengths of four metal-ceramic systems with and without opaque porcelain

“…However, cracks forming on one end of the porcelain layer indicate that the combined shear and normal stresses at the metal-ceramic junction were responsible for debonding. 67 In this study, the latter mode constituted a valid test. Therefore, following testing each specimen was observed using light microscopy (Wild M8, Heerbrugg, SWitzerland) at x20 to x80 magnification to determine whether or not a satisfactory test Table IV.…”

Influence of surface treatment on bond strength of veneering ceramics fused to zirconia

“…Bond strength between the TZP and the veneering ceramics was determined by assessing debonding/crackinitiation strength with the Schwickerath crack initiation test (SCT) 23) as specified in ISO9693:1999. The sample was set in the jig with a inter-support distance of 20.0 mm and punch radius of 1.0 mm ( Fig.…”

Surface characterization and bond strengths between Ti-20Cr-1X alloys and low-fusing porcelain

“…In addition, alloying additions could change the CTE of titanium 13) either through dissolution in solid state, or the formation of new phases, with some effects on metal-ceramic bond strength 14,15) . A number of test methods are used for measuring bond strength, which can be classified as shear tests, flexure tests, and tensile tests 16,17) . The International Organization for Standardization has recommended a three-point flexure bond test 17) , which is described in the revision of the standard ISO 9693 18) .…”

“…A number of test methods are used for measuring bond strength, which can be classified as shear tests, flexure tests, and tensile tests 16,17) . The International Organization for Standardization has recommended a three-point flexure bond test 17) , which is described in the revision of the standard ISO 9693 18) . The purpose of this study was to evaluate the bond strength of experimental ternary Ti-20Cr-1X alloys to dental porcelain, and its potential application as a superior dental restoration material.…”