An innovative method for in-situ composition analysis of fixed metallic dental restorations

Abstract

Dental restorations made from alloys corrode during their service time. In cases of suspected toxic or allergic reactions to the corrosion products, the composition of the intraoral dental restorations has to be determined. The sample materials can be obtained intra-orally in a non-destructive manner using the chipping test. Metallic shavings are extracted with the aid of a dental stone and graphite carrier platelet, which is then transferred to an electron microscope for electro dispersive X-ray (EDX) analysis. The chipping test suffers from a rather complicated and error-prone procedure of obtaining and transferring the samples. ObjectiveThe objective of the present study was the validation of a simplified method for non-destructive in-situ extraction of dental alloy samples, using a newly developed dental bur made from carbon fiber reinforced polyether ether ketone (PEEK), which at the same time serves as an electrically conductive sample carrier for EDX analysis. MethodsFifteen burs for dental hand pieces were manufactured from carbon fiber reinforced PEEK, using two formulations. The burs were passed over precious and non-precious dental alloys with different rotation speeds. The alloy samples embedded in the burs were analyzed using EDX and compared to a control. ResultsThe burs manufactured from PEEK containing 30% short carbon fibers proved sufficiently robust for sample extraction even from the harder non-precious metals. The results of EDX analysis were in accordance with the control,no statistical significant differences, free of contamination, and were not affected by rotation speed,higher as 20%. SignificanceThe proposed method is valid, practical and constitutes an improvement over the traditional chipping test.