Autometallographic demonstration of mercury in rat molars.

Male, adult Wistar rats were exposed to 500 micrograms/m3 mercury vapor 6 h per day, 5 days a week for 4 wk. They were subsequently killed by transcardial perfusion. The molars were extracted, demineralized, and embedded in resin before sectioning. Autometallographic development was performed according to the method of Danscher & Möller-Madsen. Mercury deposits were found in small amounts in several areas of the pulp, but with larger accumulations of grains in relation to odontoblasts. Mercury also could be seen in odontoblastic processes in the dentin and predentin. Our conclusion is therefore that systemic uptake of mercury vapor leads to accumulation of mercury in the odontoblasts and that the mercury may be transported into the dentin tubules in the odontoblastic process.