The societal costs of AD are very high, especially for patients with moderate and severe AD. This implies that treatments with the ability to delay progression of the disease into more severe stages have the potential to save large costs for society.

Possible adverse effects of mercury exposure in dentistry have been discussed in several studies. The objective of the present study was to carry out detailed measurements of mercury exposure in the dental profession in Sweden, and to search for adverse health effects from such exposure. We examined 22 dentists and 22 dental nurses, working in teams, at six Swedish dental clinics. Measurements of air mercury, performed with personal, active air samplers, showed a median air Hg of 1.8 micrograms/m3 for the dentists, and 2.1 micrograms/m3 for the dental nurses. Spot measurements with a direct reading instrument displayed temporarily elevated air Hg, especially during the preparation and application of amalgam. The average concentration of mercury in whole blood (B-Hg) was 18 nmol/L, in plasma (P-Hg) 5.1 nmol/L, and in urine (U-Hg) 3.0 nmol/mmol creatinine. Possible effects on the central nervous system (CNS) were registered with three questionnaires: Q16, Eysenck Personality Inventory (EPI), and the Profile of Mood Scales (POMS). In the Q16, the number of symptoms was statistically significantly higher in the dentistry group compared with an age- and gender-matched control group (n = 44). The urinary excretion of albumin and urinary activity of the tubular enzyme N-acetyl-beta-glucose-aminidase (NAG) did not differ between the two groups. The results confirm that exposure to mercury in the dental profession in Sweden is low. The air Hg levels were mainly influenced by the method of amalgam preparation and inserting, and by the method of air evacuation during drilling and polishing.

Possible effects of mercury on the central nervous system (CNS) were examined in a group of chloralkali workers exposed to mercury (n = 89) and compared with a control group (n = 75), by registration of subjective symptoms, personality changes, forearm tremor, and performance on six computerised psychometric tests in the two groups. The groups were similar in age, education, verbal comprehension, and work tasks. In the chloralkali group, median blood mercury concentration (B-Hg) was 55 nmol/l, serum mercury concentration (S-Hg) 45 nmol/l, and urine mercury concentration (U-Hg) 14-3 nmol/ mmol creatinine (25-4 pg/g creatinine). Corresponding concentrations in the control group were 15 nmol/l, 4 nmol/l, and 1P1 nmol/mmol creatinine (19 pg/g creatinine) respectively.The number of self reported symptoms, the scores for tiredness and confusion in the profile of mood states (POMS), and the degree of neuroticism in the Eysenck personality inventory (EPI), were significantly higher in the mercury exposed group compared with the controls. Performance on the psychometric tests and tremor frequency spectra did not differ significantly between the two groups. Dose-response calculations showed weak but statistically significant relations between symptom prevalence and current mercury concentrations in both blood and urine. Psychomotor performance, attention, and short term memory were tested using six computerised tests, which were selected and adapted from the neurobehavioural evaluation system.4 17 A personal computer equipped with a joystick and a special button panel was used. All test sessions were performed in a quiet room under guidance of the same test leader (OA). The test conditions were standardised as much as possible. Exposed subjects and controls were tested in a randomised order, and could not be identified by the test leader. In all tests the first trial was a practice run. The six tests are:(1) Hand-eye coordination (HEC) -This is a visual motor coordination test executed with a joystick. The task was to move a cursor as close as possible to a curved line on the screen. The average deviation from the line (mean absolute error based on a graphic measure) during five tests was used as test parameter.(2) Finger tapping-Motor speed function was tested by finger tapping with (a) dominant hand, (b) non-dominant hand, and (c) alternating hands. The subjects were instructed to tap a button with the index finger as fast as possible for 10 seconds. The average number of taps during five trials for each condition was used as test parameter.(3) Simple reaction time-In this attention test the subjects were required to press a button with the index finger of the preferred hand as quickly as possible when a symbol (a large "0") appeared on the display. Twelve stimuli were presented per minute with randomised time intervals between 2-5 and five seconds. The average reaction time (ms) and standard deviation (SD) during six minutes were calculated and used as test parameters.(4) Symbol-digit-In this test of perceptual...

The results do not support the hypothesis that release of mercury from amalgam fillings is the cause of 'amalgam disease', but suggest that there may be various explanations for the patient's complaints.

Dental amalgam is the major source of inorganic mercury (Hg) exposure in the general population. The objective of the present study was to obtain data on changes in Hg levels in blood, plasma, and urine following removal of all amalgam fillings during one dental session in 12 healthy subjects. The mean number of amalgam surfaces was 18 (range, 13 to 34). Frequent blood sampling and 24-hour urine collections were performed up to 115 days after amalgam removal, and in eight subjects additional samples of plasma and urine were collected up to three years after amalgam removal. A transient increase of Hg concentrations in blood and plasma was observed within 48 hours after amalgam removal. In plasma, the peak concentrations significantly exceeded the pre-removal plasma Hg levels by, on average, 32% (1.3 nmol/L; range, 0.1 to 4.2). No increase in the urinary Hg excretion rate was apparent after amalgam removal. An exponential decline of Hg was seen in all media. Sixty days after the amalgam removal, the Hg levels in blood, plasma, and urine had declined to approximately 60% of the pre-removal levels. In seven subjects, who were followed for up to three years, the half-lives of Hg in plasma and urine were calculated. In plasma, a bi-exponential model was applied, and the half-life was estimated at median 88 days (range, 21 to 121). The kinetics of Hg in urine (nmol/24 hrs) fit a mono-exponential model with a median half-life of 46 days (range, 35 to 67). It is concluded that the process of removing amalgam fillings can have a considerable impact on Hg levels in biological fluids. After removal, there was a considerable decline in the Hg levels of blood, plasma, and urine, which slowly approached those of subjects without any history of amalgam fillings.