If results of cross-sectional studies must be used as a basis for setting up models of development of caries in permanent teeth, then the average rather than individual posteruptive age of teeth has to be resorted to. Data available for this purpose had been obtained from a total of 54,000 children living in two G.D.R. cities, namely, Plauen and Karl-Marx-Stadt, as well as from two surveys made in 1959 and 1971, respectively. Calculation of the average posteruptive age of teeth assumes good knowledge of the distribution of dates of eruption in a population. Of the three types of distribution considered, namely, normal, lognormal, and log-logistic distribution, the log-logistic model proved to be superior to others because of better adaptation to the data available. The method of calculating the posteruptive age of teeth is described and illustrated by use of a number of examples. Since one of the two surveys (namely that which was made in Karl-Marx-Stadt in 1971) was made after twelve years' drinking water fluoridation, it was possible to study the effect of fluoridation upon the eruptive behavior of permanent teeth. The results of this study confirmed those obtained during previous investigations.

Adolescent↗

PubMed1978

[Effect of sodium fluoride on the metabolism of the rat kidney cortex and medulla].

Tissue sections of cortex and outer and inner medulla of rat kidneys were examined in the Warburg apparatus with and without addition of NaF. It was shown that the O2 consumption was not significantly reduced in the presence of 0.05 mM F (=0.95 ppm F!) or smaller amounts. The respiratory quotient was not changed by NaF. Lactate formation in sections from the inner medulla was reduced to the same degree as O2 consumption. Maximal concentrations of plasma fluoride which are met in doses of fluoride used for the prophylaxis of caries, do not impair renal metabolism.

Animals↗

PubMed1977

[Cancer mortality in Austrian locations with high and low natural fluoride content in drinking water].

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Austria↗

PubMed1976

Distribution of caries among tooth types in fluoride and non-fluoride areas.

A method is described for estimating the preferential caries protective action of fluoride on certain morphological types of permanent teeth. The results of an analysis by this method, applied to data for 1164 Austrian school-children aged 6--14 years, are reported. There was no indication that fluoride would exert its caries inhibitory effect selectively on certain types of teeth. Tentative explanations are put forward for the only inconsistency within the general results observed in 11--14-year-old children having a total of 3 carious teeth.

Adolescent↗

PubMed1976