A study of 118 professional commercial divers, using an inquiry form, revealed that 55% of the divers complained about a metallic taste in the mouth when working with electrical equipment under water. A nationwide clinical examination of 40 divers was performed to see if the metallic taste during work reflected any alteration in the oral cavity. The clinical appearance of the dental amalgam restorations differed significantly between divers who had been working with electrical equipment and divers who had not. A number of other dental indexes were assessed and showed no differences between the two groups. These included salivary secretion rate, buffering capacity, secondary caries, plaque index, bleeding index, and cultures of S. mutans and Lactobacillus. Relatively high levels of the two organisms were noted, indicating that the group of divers examined should be considered as a caries risk groups.