Maximum Bond Strength of Dental Luting Cement to Amalgam Alloy

Abstract

Although dental amalgam is used frequently under artificial crowns for restoration of severely damaged teeth, there is little information available on the bond between luting cements and this alloy. This study was designed for determination of the strength of the bond between a dental amalgam alloy and three crown-luting cements. Cylinders of dental amalgam were joined in pairs, with use of a zinc-phosphate, a glass-ionomer, and an acrylic-adhesive resin cement. The tensile-fracture stress of 45 samples of each cement was measured with a universal testing machine, and subjected to a Weibull analysis. The fractured surfaces were examined under low magnification with use of a light microscope, and at low and high magnifications with use of a scanning electron microscope, for evaluation of the appearance of the fractured joints. The Weibull analysis demonstrated that the adhesive resin cement provided a stronger and more predictable bond than either the zinc-phosphate or the glass-ionomer cement. The appearance of the fractured surfaces gave no indication of the strength of the joints, a feature that is common to brittle materials. The results suggest that crowns placed on teeth offering a large amalgam-alloy surface could be retained more predictably with an adhesive resin cement.

Evaluation of the bond strength of different bracket-bonding systems to bovine enamel

“…Outliers have to be expected at the low end of the stress range. To gain more reliable predictions, the 10 per cent probability of failure was calculated instead of the 1 per cent probability of failure used by McCabe and Carrick (1986), McCabe and Walls (1986) and Mojon et al (1989).…”

“…Orthodontic bonding resins are brittle materials and produce a wide scattering of the bond strength data (Mojon et al, 1989). The Weibull analysis helps to handle these characteristics of the orthodontic adhesives.…”