Bond strength of porcelain on cast vs. wrought titanium

Abstract

The bond strength of porcelain fused to cast and wrought titanium surfaces was calculated from fracture loads in a 4‐point bending test. Two different porcelain were applied (O'Hara and Duceratin). The surface of Ti‐cast specimens was treated in two different ways to produce variations in the impurity level before porcelain veneering. Microhardness measurements as well as scanning electron microscopy with EDX analysis were conducted. The results showed no significant difference in bond strength between the two porcelains. Nor was any difference in bond capacity found between thoroughly blasted castings and wrought titanium. Significantly lower bond strengths were observed for lightly blasted specimens and for specimens treated with Gold bonding agent. Impurities in the surface region of the castings were found to be due to contact with the investment during solidification. This indicates that a thin surface layer (50–100 μm) of the casting should be removed before firing of the porcelain.

Effect of sandblasting conditions on alumina retention in representative dental alloys

“…For all materials tested (except for cp Ti), the selection of 250 µm grit size and up to 0.30 MPa application pressure provided the lowest retention of alumina fragments, in agreement with results of previous studies in which fragment retention decreased with increasing grit size 11,14,16,24) . Previous studies have reported significantly higher metal-ceramic bond strengths 13,25) for surfaces sandblasted with 250 µm-grit alumina particles, a finding that might be explained by decreased alumina fragment retention under these conditions. Some manufacturers suggest that a 45° incidence angle of airborne particles facilitates their deflection from the surface, an assertion supported by some limited evidence 20) , but not yet fully documented.…”

“…The presence of such embedded fragments adversely affects the bond strength of metal-ceramic 8,11) and metal-resin 12) systems, decreasing the mechanical interlocking and inhibiting the chemical bonding of porcelain with metallic oxides [13][14][15] . In implant technology, sandblasting with alumina grains is also used for surface roughening in combination with acid-etching to enhance osseointegration 16) , but concerns have been raised regarding the impact of alumina fragments embedded in these surfaces on their eventual osseointegration 17) .…”

Effects of sandblasting media and steam cleaning on bond strength of titanium-porcelain

“…Sandblasting with alumina (Al2O3) is one of the methods that are recommended for creating surface irregularities and providing mechanical interlocking force for porcelain. Derand et al 16) and Lautenschlager et al 17) found significant amounts of alumina particles embedded in the titanium-porcelain interface, which is attributed to the sandblasting surface treatment. The presence of such particulates may have an adverse effect on weakening the mechanical interlocking of porcelain to metal by introducing stress concentration points 16,17) .…”

“…Derand et al 16) and Lautenschlager et al 17) found significant amounts of alumina particles embedded in the titanium-porcelain interface, which is attributed to the sandblasting surface treatment. The presence of such particulates may have an adverse effect on weakening the mechanical interlocking of porcelain to metal by introducing stress concentration points 16,17) . Improving the bond strength of porcelain to titanium is important for enhancing its clinical usability.…”

“…It is known that the alumina particles are embedded into titanium by the process of sandblasting 16,17,24) . The existence of these particles may sometimes have a favorable effect 24) or an adverse effect 16,17) on the bond strength probably depending on their fixation in the matrix metal. If the particles are loosely embedded in titanium, the porcelain will be peeled off from titanium surface by accompanying the particles.…”