Characterization of cast-to implant components from five manufacturers.

Statement Of Problem: Cast-to components are commonly used in screw-retained implant-supported restorations to produce precise fit. There is little information in the literature about the compositions and microstructures of commercially available products.

Purpose: The purpose of this study was to characterize as-received cast-to components from 5 manufacturers (Dentsply Friadent CeraMed, Lifecore Biomedical, Inc, Nobel Biocare AB, Institut Straumann AG, and Zimmer Dental).

Material And Methods: Two components from each manufacturer were mounted in metallographic resin, sectioned into quarters, remounted, wet polished with alumina abrasives, cleaned by ultrasonic agitation in distilled water, etched with aqua regia solutions, and carbon coated for scanning electron microscope (SEM) observation. Secondary (SE) and backscattered electron (BSE) images were collected to investigate the variations in surface topography and composition, respectively. Elemental analyses (EDS) were performed using an energy-dispersive x-ray spectrometer coupled to the SEM. Overall Vickers hardness (500-g load) and Vickers hardness of the 2 primary microstructural constituents (10-g load) were measured. Mean values and standard deviations were determined for the composition and Vickers hardness data.

Results: All implant components were composed of 2 distinctive parallel-band constituents containing gold, palladium, and platinum. Trace concentrations of iridium were also found. Elemental compositions of the darker bands observed by BSE differed by up to 20% for Au and Pt in the 5 products, whereas there was a minimal difference in Pd content. The lighter bands observed by BSE had nearly the same compositions in all 5 products, and contained much more Au and much less Pt than the darker bands. The gold-rich bands in each product were found to have much lower Vickers hardness. At high magnifications, each of the 2 bands appeared to contain 2 phases.

Conclusions: The elemental compositions, microstructures, and Vickers hardness of the 5 as-received cast-to implant components were similar. Because both microstructural bands principally contain gold, palladium, and platinum, these noble cast-to implant components should be metallurgically compatible with noble metal casting alloys.