DENTINAL AND PULPAL UPTAKE OF MERCURY FROM LINED AND UNLINED AMALGAM RESTORATIONS IN MINIPIGS

The aim of the present investigation was to examine dentin and pulp in amalgam-restored teeth in minipigs with respect to presence of mercur y, and to evaluate whether lining of restored cavities with a resin-mo dified glass ionomer cement had any effect on the penetration of mercu ry. Class I and V cavities were cut in 49 posterior and canine teeth o f 4 minipigs. 35 cavities were restored with amalgam and 14 with compo site material. 26 of the amalgam cavities were lined with a resin-modi fied glass ionomer cement. Following observation periods of 17-28 mont hs, the pigs were killed and the jaws sectioned. After decalcification , the teeth were processed for light or electron microscopy examinatio ns. Mercury was visualized by autometallography. Silver-enhanced mercu ry was found in all teeth with amalgam, whereas teeth with composites were devoid of mercury. Mercury could be traced in the odontoblast pro cesses, in the body of odontoblasts, and on rare occasions in the nerv e tissue of the pulp from lined and from unlined amalgam restorations. The present study thus demonstrates transport of mercury through dent inal tubules to the pulp, and that lining of cavities with a resin-mod ified glass ionomer cement does not prevent penetration of mercury.