Affiliations: [a] University of Edinburgh, Postgraduate Dental Institute, Edinburgh, UK | [b] Heriot-Watt University, School of Engineering and Physical Sciences, Edinburgh, UK | [x] Mechanical Engineering Faculty, Laboratory for Materials Technology, University of Applied Science, Regensburg, Germany | [y] University Clinic, Department of Traumatology, Regensburg, Germany
Correspondence:
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Address for correspondence: Salim Badre Asbia, University of Edinburgh, Postgraduate Dental Institute-Lauriston Building, Lauriston Place, Edinburgh EH3 9HA, Scotland, UK. E-mail: [email protected].
Abstract: This work is concerned with the performance, under dynamic compression, of the adhesives used to simulate cementation of gold crowns onto nickel chromium dies. A measurement system, based on the mounting of strain gauges onto the outer surface of the crowns, has been developed, which allows a semi-quantitative estimate of the state of adhesion. A preliminary study was carried out where miniature gauges were bonded onto the buccal, lingual, mesial and distal surfaces of gold crowns cast to fit onto a chromium-cobalt die, as a precursor to the final design of the instrumented crown. The crowns were then loaded in compression periodically measuring the strain at all four gauges. The results showed the load-strain relationship in fully, partially and uncemented crowns, along with repeated load-unload behaviour to close to the ultimate strength of the bond. The load-strain relationship is linear and repeatable and the slope varies over a factor of about 30 between the un-cemented and fully cemented crown, demonstrating that there is significant sensitivity to bond integrity. These results were used to determine the parameters for a systematic study of S-N relationships in restorative dentistry crowns.
