Author: Takaku S.

Source: Bull Tokyo Dent Coll

Year: 1985

Comment:

Abstract / Excerpt:

The safety of dental amalgam use in patients needing dental fillings is well established, based on the relatively rapid decline in urinary mercury concentration following filling. Only a small number of studies, however, have attempted to describe the method of transfer of the mercury in the amalgam to the saliva. Atomic absorption spectrophotometry was utilized to study reduction and vaporization and showed excellent sensitivity in quantification. Using this method, the release of mercury from the amalgam to the saliva was studied. To begin with, in experiments in vitro, the release of mercury from the test amalgam to fresh saliva was shown to be approximately 10 times as great as the amount released to an inorganic test solution. The mercury concentration in the mixed sa liva sample obtained from 198 test subjects under ordinary conditions was then measured. The concentration of mercury in the mixed saliva obtained from 65 test subjects with either amalgam-filled teeth nor exposure to exogenous mercury was 1.48± 1.73 ppb using the a rithma tic mean, and 0.88?; 2.71 ppb using the geometric mean. These values were felt to represent the normal mercury concentration in mixed saliva. In test subj ects with amalgam-filled teeth, on the other hand, a significant correlation was noted between the mercury concentration in the mixed saliva and the number of teeth filled with amalgam, with a correlation coefficient of y=0.44. Measurement of the release of mercury from an amalgam·filled tooth to the saliva gave a mean of 12.3 ng/ml per filled tooth in the molar region as measured immediately after filling. Since the mercury concentration in the saliva showed a rapid decrease within 24 hours, it is not likely that this amount of mercury is ingested continuously. Test subjects with amalgam-filled teeth thus ingest an amount of mercury larger by approximately 2.1 p.g than those without such fillings, through the swallowing of saliva. Since this amount of mercury corresponds to less than 1/ 10 the amount contained in the food of a normal daily diet, the safety of the amalgam-filling of the teeth is thought to be confirmed.

Citation: Takaku S. Mercury dissolution from dental amalgam into saliva. Bull Tokyo Dent Coll. 1985;26(3):137-52.