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Galvanic currents within the oral cavity may have harmful effects on biological tissues. In the present work 16 patients with different kinds of oral and other discomfort and pain which they attributed to oral galvanism were investigated. The potential and polarization of each metal restoration within reach of a platinum probe were measured versus a reference electrode. A recording of these measured values permits a calculation of the currents which may pass between the teeth. A control group of patients with no subjective symptoms of galvanism in the oral cavity was also investigated. The results of the electrochemical measurements showed that conditions for oral galvanism existed within the individuals of the patient group as well as within the control group. One remarkable observation was that the metallic restorations often consisted of different electrically isolated areas with different electrochemical properties. This and other factors influencing oral galvanism are discussed.

Galvanism or galvanic action is a well known phenomenon in dentistry. Small galvanic currents are generated from the presence of dissimilar metals in most mouths and consequently cause corrosion of fillings.

A method is described for the measurement of currents generated between dissimilar alloys in die oral cavity. Tests were performed using amalgam fillings versus specimens consisting of a gold alloy, a chromium-cobalt alloy and a stainless sleel alloy. Currents of 0.1-0.3I1Ncm2 of specimen area were measured.

Due to the difference in open circuit potential (OCP) versus SCE for Aristaloy amalgam (-969 mV) and Dispersalloy amalgam (-549 mV) in Ringer’s solution at 25 degrees C, a galvanic cell was created with Dispersalloy amalgam as cathode and Aristaloy amalgam as anode. The galvanic corrosion current was studied as a function of time for the above cell as well as for a cell of type III dental gold (OCP is +0-5 mV) versus Aristaloy amalgam. The initial corrosion current of the latter cell (105 micronA) is about twice that for the cell of Aristaloy amalgam versus Dispersalloy amalgam (54 micronA), however, their passivating behaviour is quite similar. Also, an interrupted galvanic corrosion test simulating the oral ‘make and break’ situation was performed. A much higher corrosion current than the steady state was found when the two electrodes resumed contact.

An unreported spillage of mercury in a dental surgery resulting in four non-fatal cases of mercury intoxication by inhalation of mercury vapour is described and clinical symptoms in relation to urine mercury levels noted and discussed. The method of detection and decontamination of the mercury vapour source is reported, and suggestions for preventing spillage of mercury and for reducing the risk of intoxication from such accidental spillage are made.  Continued vigilance by all persons handling mercury is stressed.

A metal worker had repeated episodes of contact dermatitis over a period of years. Patch tests with 5% ammoniated mercury were strongly positive but occupational contact could not be proved. Recurrence of the dermatitis one day after amalgam dental fillings had been made and again one year later, this time without new fillings, raised the possibility that it was due to the old amalgam fillings. Removal of all the amalgam fillings resulted in a new outbreak of severe dermatitis; during the 5 years ensuing there has been no recurrence. This case history suggests that contact dermatitis may be caused by not only the mercury in new fillings but also by that in old fillings.