Individual samples of urine, fingernails, head-hair, saliva, plaque and enamel were collected from three groups of Hungarian children, aged 14 years, who were exposed to contrasting water fluoride levels (less than or equal to 0.11 ppm; 0.5-1.1 ppm; 1.6-3.1 ppm). The mean fluoride concentration of the samples increased consistently and significantly, but mostly non-proportionately, with increasing water fluoride level. With the exception of plaque, the materials examined are considered suitable indicators of exposure to or systemic utilization of fluoride for population groups. Caries experience decreased with increasing fluoride exposure. Dental fluorosis constituted no clinical or aesthetic problem.

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A pilot survey of oral health included 83 adolescent and adult Aborigines (41 M, 42 F, range 16--70 years, mean age 37.3 years), resident in fringe settlements around the far western New South Wales towns of Brewarrina and Walgett (fluoride in water less than or equal to 0.02--0.26 parts/10(6)). Dental caries prevalence (mean DIMFT per person) increased from 17.1 at 20 years to 10.7 at 35 years and declined to 14.6 by the age of 50 years and over. Oral hygiene (OHI) was poor overall and deteriorated with age. Periodontal status (PI) was significantly correlated with the presence of debris (DI) and calculus (CI). The mean PI increased from 1.7 at 20 years to 4.8 at 43 years and over. Tooth mortality reached 75% by the age of 43 years. Prosthetic needs were correspondingly high, but 95% of denture requirements were unmet. No evidence of effective or sustained oral health care was seen; 38% of subjects needed emergency treatment.

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Double-layer superimposed biopsies were used for sampling sound labial enamel of upper permanent central incisor teeth of 189 children (mean age 8.4 years, SD = 0.36), comprising five groups, representing life-long exposure to contrasting concentrations of F in the water (range less than or equal to 0.12 ppm to 2.8 ppm) and to supplements of 200 or 350 mg F/kg domestic salt. The mean F concentrations of enamel ranged through the groups from 924 ppm to 2401 ppm in the surface layer (average central depth = 0.49 micron) and from 450 ppm to 1428 ppm in the subsurface layer (average central depth = 2.62 microns). The differences between the mean F concentrations of the groups were significant in each instance and the values consistently reflected the extent of F exposure. It was concluded that the F content of enamel is a reliable indicator of environmental exposure to F for populations, but not for every individual.

Oral health parameters were compared for 6--8 and 10--11-year-old children living in neighbouring. N. S. W. towns, where the community water supplies consisted of artesian and river were respectively. The demographic characteristics, living pattern and dietary carbohydrate challenge were similar in the two areas and effective oral hygiene practices were uniformly lacking. Children in the artesian water area had 40% lower caries prevalence (DIMFT), 50% less severe carious lesions (SR) and significantly better oral hygiene (OHI) and gingival condition (PI) and correspondingly lesser treatment needs than those supplied by river water. The findings were examined in relation to the concentrations of 10 elements in roof catchment, river and artesian water. Apart from a contribution by fluoride to better oral health, the results implicate lithium as a possible beneficial element.

Twenty-two children aged 13 to 14 years rinsed for 3 X 1 min periods with a supersaturated calcium phosphate solution containing urea and monofluorophosphate. Plaque sampled one min after the last rinse showed a marked increase in water-extractable F and a smaller increase in Ca but no increase in water-extractable P. Water-insoluble forms of all three ions were elevated, however. The mean plaque pH was 8.28. Plaque sampled 24 hr after the last rinse showed significant increases in water-insoluble F and Ca only, and no increase in pH. The prompt pH rise and disappearance of water-soluble P suggest that, on exposure to the mineralizing solution, urea and monofluorophosphate are rapidly hydrolyzed by plaque enzymes to provide catabolites which cause the immediate precipitation of fluoridated calcium phosphate.

The F concentrations in plaque and in underlying enamel were determined in a sample of 99 schoolchildren aged 8.4 years (S.D. = 0.37), comprising four groups, exposed life-long to contrasting concentrations of F in the water (range less than or equal to 0.12 ppm to 2.8 ppm) and to supplements of 350 mg F/kg domestic salt. The mean total F concentrations in plaque (dry wt) increased consistently with increasing exposure to F, but the absolute differences were small and the individual variation was high within each group. Significant inverse associations were demonstrated between individual plaque and surface enamel values within two groups, supported by consistent inverse trends (ns) in the remaining groups. These associations and trends are considered to reflect transfer of F from plaque to underlying surface enamel and concommitant reduction in plaque F concentration.