Abstract
An apparatus was constructed for measuring adhesive strength under compression shear stress, and adhesion tests were done on the basis of the measured strength of adhesion between dental adhesives and SUS 304. Two dental adhesives, Superbond C&B (SB C&B) and PANAVIA EX (PEX), were examined. The Ni-Cr-Co-Mo quarternary alloy, which was chosen as a potential material for an adhesion bridge, was fused and cast to obtain samples, and their mechanical properties and resistance to tarnishing were determined. Alloy samples with good properties were selected and their respective adhesive strengths to SB C&B were measured under compression shear stress. The adhesive strength of SB C&B to SUS 304 varied with aging temperature, and was about 550 kgf/cm2 when the samples were left to stand at 60℃. For the samples aged at 20℃ and 37℃, adhesive strength further increased when they were subjected to 30 thermal cycles of 120 s in the water adjusted to 4℃ and 60℃, respectively, whereas it decreased in samples aged at 60℃. When applied to SUS 304, the adhesive strength of PEX was less affected by aging temperature than SB C&B, though the measured values themselves were smaller with a larger coefficient of variation.
Tests were made on 24 samples of the Ni-Cr-Co-Mo alloy with a molybdenum content fixed at 15 wt%, cobalt and chromium contents ranging from 5 to 30 wt% and from 10 to 25 wt% respectively, and a nickel content accounting for the rest. The results suggested that an alloy with a composition in the range of 45±10Ni-20±2Cr-20±8Co-15Mo (wt%) has excellent mechanical properties and resistance to tarnishing. Being capable of bonding strongly to SB C&B, Alloys 15, 16 and 17, which stay in the above range, were found to have excellent potential as practical materials for an adhesion bridge.
