January 1993. p.5
We have recently come across a very fascinating study titled "Silver Amalgam - An Unstable Material" that was published in the October 1989 issue of the Danish Dental Journal "Tidsskr. f. Tandlaeger".
The authors were Christer Malmström and Magnus Nylander.
Mats Hansson Ph.D. of Sweden was kind enough to translate the study for us.
Previous studies measuring the release of mercury vapor from amalgam dental fillings have either measured the concentration of mercury in intra - oral air or in exhaled air.
This study was designed to measure "local" concentrations of mercury vapor directly over the amalgam dental fillings.
A single - beam atomic absorption spectrometer developed at the Centre for Dental Technology and Biomaterials in Huddinge, Sweden was the instruments used for all measurements.
The measurements were made with the air intake of the instrument 0,5 - 1 mm over the occlusal surface and maximum values were registered.
Four measurements were made, one in each quadrant for unstimulated teeth.
The release of mercury vapor from amalgam dental fillings.
In order to obtain accurate values, measurements were done close to the tooth reducing losses though absorbation by mucous membranes, lungs etc.
Usual method for measuring the release of mercury vapor.
Stimulated values were only recorded in the quadrant where stimulation took place (e.g. by polishing).
Seventy-eight (78) patients took part in the investigation.
No patient had received any new amalgam fillings in the two years prior to participating in the study.
401 measurements were made during 4 months.
Figure 3 of the study depicts the results of measuring mercury vapor emission from the amalgam fillings under various conditions.
Unstimulated measurements were performed even in areas where there were no amalgam fillings and immediately before any type of stimulation (the researchers found that blowing air on the amalgam filling increased mercury release).
Stimulated values were
- chewing food, no tooth brushing before measuring.
- after chewing gum.
- tooth brushing for 15-30 seconds with the paste preferred by the patient, and then rinsing the mouth with 20 centigrade water.
- prophylactic polishing with rubber and polishing paste (Depurdent) and rinsing as in 3.
- wet polishing with rubber disk, grinding paper or fine burr under water spray for 20 - 30 seconds.
dry polishing with rubber disk, grinding paper or fine burr - no water spray - for 20 - 30 seconds.
- Malmström, C.: Infraktioner og cuspfrakturer på tænder med amalgamfyldninger: Tidskr. f. Tandl. 1986:6:65-68.
- Malmström, C.: Oral miljø forurening. Tidskr. f. Tandl. 1988:8:53-59.
- Oden, A. " Tullberg, M.: Cracks in gold crowns cemented on amalgam restorations. Acta Odontol. Scand. 1985:43:15-17.
- Svara, C. W., Peterson, L. C., et al: The effect of dental amalgams on mercury levels in expired air: J.Dent. Res.1981:60:1668-1671.
- Vimy, M. J & Lorscheider, F. L.: Intra - oral air mercury released from dental amalgam. J. Dent. Res. 1985: 64: 1069-1071.
- Vimy, M. J. & Lorscheider, F. L.: Serial measurements of intar- oral air mercury: estimation of daily dose from dental amalgam. J. Dent. Res. 1985:64:1072-1075.
- Patterson, J. E., Weissberg, B. G. & Dennison, P. J.: Mercury in human breath from dental amalgams. Bull. Environ. Contam. Toxicol. 1985:34:459-468.
- Takaku, S.: Mercury dissolution from dental amalgam into saliva. Bull. Tokyo. Dental. Coll. 1985: 26:137-152.
- Nylander, M., Friberg, L. & Lind, B.: Mercury concentrations in the human brain and kidneys in relation to exposure from dental amalgam fillings. Swed. Dent. J. 1987:11:179-187.
- Eggleston, D. & Nylander, M.: Correlation of dental amalgam with mercury in brain tissue. J. Prosthet. Dent. 1987:58:704-707.
- Nylander, M.: Mercury in pituitary glands of dentists. Lancet, I 1986: 442.
- Nylander, M., Friberg, L., Eggleston, D. & Björkman, L.: Mercury accumulation in tissues from dental staff and controls in relation to exposure. 1989, to be published.
- Langworth, S., Köhlbeck, K.-G. & Åkesson, A.: Mecury exposure from dental fillings. Release and absorption. Swed.Dent.J. 1988:12:71-72.
- Berglund, A,. Pohl, L., Olsson, S. & Bergman, M.: Determination of the rate of release of intra-oral mercury vapor from amalgam. J. Dent. Res. 1988:67:1235-1242.
- Aronsson, A.-M., Release of Hg- vapor from amalgam fillings. Toxicology education. Karolinska Institutet, Stockholm, Sweden.
- Aronsson, A.-M., Lind, B. Nylander, M. & Nordberg, M.: Dental amalgam and mercury. 1989, to be published.