FLUORIDE DISTRIBUTION IN SOUND AND CARIOUS ROOT TISSUES OF HUMAN TEETH

Proton probe analysis has been used to provide for the first time quan titative F concentration data in carious root tissues from subjects co nsuming water containing 1 ppm F. In small lesions at the neck of the tooth with minimal tissue loss the F concentration was significantly h igher at the outer lesion edge than at the outer edge of adjacent soun d root tissue. In one sample with high F values the lesion edge had 19 ,000 ppm F and the adjacent sound root surface 5,400 ppm F (mu g F/g a patite). In large lesions with extensive cavitation F was again concen trated in the outer edge of the lesion and was significantly higher (1 ,800-4,100 ppm) than in adjacent sound inner dentine (190-290 ppm). Fl uoride concentrations varied markedly along the outer edge of both nor mal and carious root tissues. Fluoride increase at the lesion edge is not an effect of tissue shrinkage but probably a result of remineralis ation events during caries. This additional F may be expected to incre ase tissue resistance to further acid attacks.