In situ microsampling technique for identification of elements of a restoration with exposed metal to identify potential allergens.

STATEMENT OF PROBLEM: For clinical investigations of allergic reactions to dental materials, it is necessary to know the type of metal used in restorations in the mouth of the patient. However, an intraoral method of sampling the dental alloy without removing the metal restoration has not yet been established. PURPOSE: This study attempted to establish a clinically serviceable method for microsampling dental alloy. MATERIAL AND METHODS: A piece of silicone sampling tube is held on the surface of the metal restoration. This surface was ground with a carbide bur through the sampling tube, and the ground metal particles were then recovered from the inner surface of the tube. The recovered sample was subjected to energy-dispersive x-ray microanalysis. The percentage recovery of ground alloy by this microsampling method, which was the ratio of the recovered weight of metal to the total weight of the metal ground, was evaluated using 3 mm diameter x 1 mm thick disk-shaped specimens of Ag-Au-Pd and Ni-Cr alloys. RESULTS: Elemental analysis of the retrieved alloys identified the component elements in the alloy compositions. The percentage recovery by this microsampling method was 75.0% for Ag-Au-Pd alloy and 69.9% for Ni-Cr alloy, respectively. CONCLUSIONS: The microsampling method demonstrated a relatively high percentage recovery of the ground alloy particles. This microsampling method would be of great benefit clinically to patients who have allergic reactions to dental materials.