The relationship of metals to the general health of the patient, the dentist and office staff.

Recently a few dental practitioners have asserted that some of the metallic dental restorative materials can be toxic to patients. In particular, nickel from base-metal casting alloys and mercury from silver amalgam have been implicated. Nickel is a strong allergen and a weak carcinogen. However, current evidence does not support the view that the making and use of base-metal cast restorations causes an increased incidence of either of these problems in dental personnel or in patients. Mercury rarely causes allergy but the possibility of such an event must be remembered. Mercury has a strong potential for causing chronic toxicity. Dental personnel must use caution in the handling of free mercury in the process of making amalgam restorations. There is evidence that mercury can be released from dental amalgam restorations, but only in very small quantities. Except for the claims of those practitioners who decry the use of dental amalgam, there is no evidence to support the view that there is a toxic hazard to patients who have amalgam restorations.