Study of physiopathological phenomena in dental enamel by neutron activation analysis.

An epithermal neutron activation method is used to determine the concentration of mineral elements in human dental enamel. A large number (252) of samples from ancient and modern origins are analyzed. The analytical results are mathematically processed using a statistical multivariant method. This allows to differentiate deciduous from permanent teeth and decayed from sound enamel. It is also possible to distinguish the teeth coming from two different necropoles. The origin and the localization of determined elements in the mineralized part, or in the aqueous-organic part, of enamel is suggested. Their role, as witnessed in the physiopathological phenomena of dental enamel, is discussed.

Characterization of human dental enamel by epithermal neutron activation analysis.

Dental enamel is considered to be a biological interface depending on two phenomena the surroundings and the individual's general metabolism. The analysis of its chemical composition is becoming more and more developed. A neutron activation method has been elaborated and applied to these analyses. The results obtained and their statistical interpretation emphasize the fundamental importance of trace elements as a result of their role in the main physiopathological phenomenon peculiar to dental enamel.

Quantification of free water in human dental enamel.

The amount of free water in 50 samples of air-dried enamel from permanent and deciduous teeth was measured by the Karl Fischer method. Samples included both contemporary and burial specimens. The mean values obtained showed that free water constituted about 1% of enamel mass. However, the range of individual values varied considerably, from 0.56 to 1.48%. The proportion of free water did not seem to depend on the patient's age, the type of tooth, or the relationship between the tooth and its oral environment. On the other hand, the deciduous enamel tested displayed a mean free water content that was three times the mean for the permanent teeth (3.01 vs. 1.00%) and the five burial teeth, a mean content of 1.68%.

[Use of dysprosium considered as an activable tracer in the study of tooth structures]. / Utilisation du dysprosium en tant que traceur activable dans l'étude des structures dentaires.

After 32 days of administration to rats of dysprosium in drinking water, this element has been studied by neutron activation analysis in the intra-oral part of the incisors as well as in the molar crowns. This element was absent in the intra-osseous parts of the incisors, the femurs and the liver. After intravenous injection of 13 mg or 26 mg of Dy in several doses over 32 days, this element was found in the incisor formation and maturation zones as well as in the part having erupted in the oral cavity. It was also found in the molars, the femurs and the liver. The structural study has shown that no cytotoxic effect was observed with the dysprosium doses used. Dentinogenesis and amelogenesis were not disturbed. The final structures were homogeneous. By comparing the two administration ways of dysprosium we have at our disposal a study model using an inducible tracer of the incorporation of adsorption of a mineral element in dental structures during early or late maturations.