Oral changes in divers working with electrical welding/cutting underwater.

Divers performing electrical welding/cutting underwater often complain about a metallic taste in the mouth, strictly related to their work. In a nationwide clinical investigation, professional commercial divers were examined orally. The majority of the divers complained about a metallic taste. An increased surface deterioration of dental amalgam was detected in those divers who had performed electrical welding/cutting during the previous two years. In addition, after clinical and bacteriological examination, divers were found to belong to a caries risk group. In order to study the intraoral electrical activity, several actual dives were performed. When they were welding or cutting, the electrical activity registered intraorally in dental amalgam test samples was too low in magnitude to explain the metallic taste and the clinical appearance of the amalgam. The divers were dressed in a dry-suit and full-face mask. When leakage occurred or when a hot-water heated suit was used higher electrical activity was registered. This activity was still not of a magnitude, which could explain the symptoms theoretically, although a metallic taste and a subjective change in the divers dental amalgam were provoked. No increased levels of Hg and Cu could be detected in saliva, blood or urine. The flux density of the intraoral magnetic field created by a current of 650 ADC was calculated and measured to be 1.15 mT, which is approximately 25 times stronger than that of the earth. When exposing divers in-vivo to a field generated by a 200 ADC current, no symptoms other than magnetophosphenes were reported, such as metallic taste. The divers helmets offered almost no shielding effect towards the magnetic field. In-vitro exposure of dental amalgams to a magnetic field (1.15 mT; 50 Hz) increased the mobility of cupper and especially mercurity in the superficial layers of the amalgam after 24 h exposure, and gave rise to slight morphological changes within the amalgam.