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Thirteen patients with symptomatic oral lichen planus had been shown by patch testing to be allergic to ammoniated mercuric chloride. Replacement of amalgam restorations in these patients effected an improvement in all but one case. In some cases the resolution of symptoms was dramatic following the replacement of one or two fillings. The authors feel that the removal of all amalgam fillings need not be necessary except in the most intractable case.

The corresponding systemic uptake of Hg was estimated to 12 µg/d based on external data relating air Hg°-exposures to urinary Hg-excretions. The worst case individual showed a gross mass balance of 200 µg Hg/d connected to a systemic uptake of 70 µg Hg/d. These values were compared to the average intake of to al-Hg by a Swedish diet (2 µg/d) and to the WHO’s tolerable value for intake of total-Hg by food (45 µg/d). Upscaled to the entire Swedish population (8 mill.), the data suggests a fecal/urinary emission to the environment of 100 kg Hg yearly originating from a population load of amalgam fillings containing 90,000 kg of Hg.

This paper investigates the hypothesis that mercury from silver dental fillings (amalgam) may be related to multiple sclerosis (MS). It compares blood findings between MS subjects who had their amalgams removed to MS subjects with amalgams. MS subjects with amalgams were found to have significantly lower levels of red blood cells, hemoglobin and hematocrit compared to MS subjects with amalgam removal. Thyroxine levels were also significantly lower in the MS amalgam group and they had significantly lower levels of total T Lymphocytes and T-8 (CD8) suppressor cells. The MS amalgam group had significantly higher blood urea nitrogen and lower serum IgG. Hair mercury was significantly higher in the MS subjects compared to the non-MS control group. A health questionnaire found that MS subjects with amalgams had significantly more (33.7%) exacerbations during the past 12 months compared to the MS volunteers with amalgam removal. The paper also examines epidemiological correlations between dental caries and MS; as well as how mercury could be causing the pathological and physiological changes found in multiple sclerosis.

The threshold limit value (TLV) for occupational exposure to mercury can be exceeded in the dental operatory after a contamination event or during certain dental procedures. The objective of this study was to determine the time required for the mercury vapor levels to return to baseline in both non-ventilated and ventilated operatories after they had been contaminated with mercury to the TLV of 0.050 mg/m3; and to evaluate the efficiency of an activated charcoal filtering device for removing mercury vapor. The results showed that even in a poorly ventilated operatory, the mercury vapor level returned to background within 20-30 minutes after a contamination, and within 10-20 minutes when the operatory was ventilated. The filtering device reduced the level of mercury vapor by approximately 25% during a continuous contamination event, but did not clear the operatory faster than normal settling after a limited source contamination. The filter caused a significant reduction in mercury in the breathing zones of the patient and dentist during and after amalgam removal, but did not eliminate the exposure. This study demonstrated the difficulty in contaminating an operatory with mercury vapor and confirmed the limited time mercury remains airborne, presumably due to its density and affinity for surfaces.