FLUORIDE PROFILES IN DENTAL CALCULUS FROM JAPANESE, CHINESE AND BRITISH RESIDENTS

Whether the fluoride concentrations and profiles differ in human denta l calculus obtained from different countries was investigated. A total of 203 dental calculus deposits on 203 permanent teeth from residents (mean age, 52.1 years) of Nagoya (Japan). Shanghai (China), Leeds (Gr eat Britain) and the Wuhan mountainous area (China, fluoridated area) were analysed. An abrasive microsampling procedure was used to examine fluoride distribution. There were five types of fluoride profiles in dental calculus in each area/country (designated types L. J, U, T, W). In supragingival calculus, type L (highest in the outermost layers) a nd type J (highest In the innermost layers) both had significantly hig her values than type U (high in the surface and innermost layers) but were relatively identical. In subgingival calculus, type W (high in th e outermost, mid and innermost layers) was characteristic. Calculus fr om the Wuhan mountainous area (fluoridated) had the highest fluoride c oncentration, followed by Leeds (non-fluoridated), and Nagoya and Shan ghai (non-fluoridated) calculus had the lowest. Fluoride concentration s in supragingival calculus were higher in teeth extracted because of periodontal diseases than dental caries. It is concluded that fluoride concentrations and distribution in dental calculus differ from countr y to country, probably due to different fluoride environments. (C) 199 7 Elsevier Science Ltd.