Use of ferrofluids to obtain magnetic domain images in AFM.
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Iron↗
Biomedical subjects
I R Harris
Publications and source records attributed to I R Harris.
Investigations into the failure of dental magnets.
PURPOSE: The aim of this study was to determine the mechanisms of failure of magnets used for denture retention. MATERIALS AND METHODS: Magnets were retrieved from dentures that had failed after 4 to 18 months of clinical use. The magnets were sectioned and the failure modes were evaluated using optical or scanning electron microscopy. RESULTS: The magnetic retention system investigated consists of a neodymium-iron-boron magnet sandwiched in a stainless steel keeper, capped with a titanium dome, and sealed with epoxy resin. The diffusion of moisture through the epoxy seal and the breakdown of the encapsulating material led to corrosion of the magnet. In both cases, a loss in retention occurred as the corrosion products weakened the overall magnetic attraction. CONCLUSION: The failure of magnets may occur by either breakdown of the epoxy seal or breakdown of the encapsulating material. Both problems need to be addressed to prolong the life span of these magnets.
Corrosion↗
A comparison of the fit of spark-eroded titanium copings and cast gold alloy copings.
The fit of spark-eroded titanium and cast gold alloy copings was compared by assessment of retrieved cement film analogues. This technique was chosen for its simplicity, nondestructive nature, and for the information it provided on overall fit. The present study showed that the overall fit of titanium copings was comparable to that of gold copings. In marginal areas, the space between die and coping was found to be larger for spark-eroded than cast copings.
Crowns↗