Fluoride and magnesium concentrations in human dental calculus obtained from Japanese and Chinese patients

Calculus deposited on a total of 68 permanent teeth from patients 30-60 yea rs old from Nagoya in Japan and Beijing in China was investigated. An abras ive microsampling method was used to examine the fluoride (F) and magnesium (Mg) distribution, using a fluoride ion-specific electrode and atomic abso rption spectrophotometry, respectively. F concentrations decreased from the surface towards the interior of the calculus. Mg concentrations, however, gradually rose towards the innermost surface adjacent to the tooth, In all parts of the depth profiles, the average concentrations of both magnesium a nd fluoride were higher in the Japanese than in the Chinese calculus. Towar ds the inner surface of the calculus, F and Mg concentrations were also muc h higher in the Japanese than in the Chinese group, A greater intake of sea foods and greater use of fluoride dentifrices are possible reasons for the higher F and Mg concentrations in the Japanese individuals. (C) 2000 Elsev ier Science Ltd, All rights reserved.