Electron probe microanalysis of human teeth for the determination of individual age.

The calcium and phosphorus weight concentrations as well as the calcium/phosphorus weight ratio were determined by electron probe microanalysis both peritubularly and intertubularly in the dentine of 25 adults of varying age and sex, originating from our autopsy material. The studies were performed with a TESLA BS-300 scanning electron microscope coupled with an EDAX-149-10 X-ray detector and a BMG-38100 X-ray analyser with an accelerating potential of 15 kV, a sample current of 100 pA and a measurement time of 20 s. Peritubularly the Ca/P weight ratio of the hypermineralized part of the dentine decreases with age and is in close correlation with it (r = -0.9052) and this tendency is significant even at the level of 95% (P less than 0.05). The equation of the regression line is: Y = 37.17 x +139.37 where x is the age and y is the Ca/P weight ratio. The weight concentration of phosphorus is in an even closer correlation with age (r = 0.9712) and this correlation is also significant (P less than 0.01). The equation of the regression line is the following: y = 625.0 x -42.06 The close correlation of both the Ca/P weight ratio of the teeth and of the phosphorus weight concentration with the age allows individual age determination to be performed in the course of forensic medical and palaeoanthropological studies.

[Demineralization behavior, enamel permeability and the morphological characteristics in relationship to the stage of eruption of the permanent teeth]. / Demineralisationsverhalten, Schmelzpermeabilität und morphologische Besonderheiten in Abhängigkeit vom Durchbruchsstadium permanenter Zähne.

The posteruptive maturation of enamel is an important factor in caries disposition. In an experimental study the demineralization of enamel as well as its permeability and its morphological features in dependence of eruption stage were examined on extracted premolars. Chemical analysis showed variations in the Ca/P molar ratio. It is possible, that the instability of Ca-ions in crystalline configuration decreased during the time of eruption. The permeability of enamel decreased between 5 and 11.8%. It appears to be useful to concentrate preventive measure on this phase of dentition development.

[Levels of internal irradiation of the population of the RSFSR by natural alpha emitters]. / Ob urovniakh vnutrennego oblucheniia zhitelei RSFSR alphaizluchateliami estestvennogo proiskhozhdeniia.

The values of regional mean concentrations of natural radionuclides in the teeth samples of the RSFSR residents vary within 130-203 mBk/kg for 238U, 174-490 mBk/kg for 226Ra, 1.8-3.4 Bk/kg for 210Pb, 26-56 mBk/kg for 232Th, 50-150 mBk/kg for 228Th. The mean values of 238U in osseous tissue and teeth are similar and equal 120 +/- 35 and 112 +/- 38 mBk/kg, respectively. Radioactive balance between 228Th and 232Th in osseous tissue is absent. The ratio of the concentration of 228Th/232Th is on the average equal to 2.4 +/- 0.9 and of 220Th/832Th doesn't exceed 1.3. The distribution of regional mean concentrations of radionuclides of uranium and thorium series complies with standard distribution. An annual effective equivalent internal dose obtained because of natural alpha-emitters has been calculated for the population of the RSFSR.

[Age and content of certain mineral components in permanent teeth]. / Wiek a zawartosc niektórych skladników mineralnych w zebach stalych.

The chemical composition of the teeth is determined during its development, however, in the postdevelopmental period changes of inorganic components are possible, which have an important effect on the morphology, structure and chemical composition of teeth. Using the method of X-ray fluorescence the levels of Ca, P, Cl, S, K and Zn were determined in hard tissues of 218 permanent non-carietic teeth from all dental groups. The correlation between these various elements in the teeth and the age of the subjects, whose teeth were taken for the investigations, was expressed with the correlation coefficient r of Pearson. The significance of the correlation was analysed using Students t test. In case of significant correlation equations of regression were determined for predicting the expected value of the level of a given element in teeth for a given age. No significant differences were noted in the levels of Ca and P in relation to age. The levels of S, K and Zn rose with age, while the chloride content was decreasing.

A scanning electron microscopy and electron probe X-ray microanalysis (SEM-EPMA) of pink teeth.

Samples of postmortem pink teeth were investigated by scanning electron microscopy and electron probe X-ray microanalysis. Fracture surfaces of the dentin in pink teeth were noticeably rough and revealed many more smaller dentinal tubules than those of the control white teeth. Electron probe X-ray microanalysis showed that the pink teeth contained iron which seemed to be derived from blood hemoglobin. The present study confirms that under the same circumstance red coloration of teeth may occur more easily in the teeth in which the dentin is less compact and contains more dentinal tubules.

Structural and microanalytical changes in dentition after radiotherapy applied in cases of tumour in the oral cavity region.

Morphological observations by means of the scanning electron and optical microscopes as well as microanalytical qualitative and quantitative tests concerning content and distribution of calcium, phosphorus and magnesium in the teeth being in irradiation field were made in patients treated for larynx cancer by methods of radiotherapy. The teeth enamel was in some places thinner and in some others it was lacking. The characteristic defects took place in the form of notches, cracks and of superficial destruction. In X-ray microanalyser the enamel showed some features of demineralization. In dentine, features of demineralization and on the other hand features of remineralization were seen. The root dentin, in which destructive processes but also reparation processes developed by root cement could be seen, was rather characteristic. Clear structural changes and disturbances of mineralization in hard tooth tissues being under therapeutic X-ray irradiation were observed.

Effect of aluminium on mineralization of rat third molar in vitro.

Crl: COBS rat third-molar explants were cultured for 12 days in either 0.6 X 10(-2), 4 X 10(-2) or 6 X 10(-2) mM aluminium, or for 12 days with exposure to 13 X 10(-2) mM Al at different 6-day intervals. Total protein, alkaline phosphatase, calcium and phosphorous were measured to evaluate cell viability and the degree of mineralization. Al in concentrations above 4 X 10(-2) mM significantly reduced the Ca and P content of explants cultured for 12 days. Explants exposed to 13 X 10(-2) mM Al for the first 6 days had less Ca and P than those exposed for the last 6 days of culture. Haematoxylin and eosin-stained sections of explants showed no gross abnormalities.

Morphology and microanalysis of teeth in scleroderma.

The studies were carried out on teeth extracted for stomatological reasons in the persons with generalized scleroderma. The studies included: morphologic examination of the longitudinal and cross-ground sections in the light and scanning microscope, and microanalytic examination of the longitudinal halves of the teeth in the X-ray microprobe. In the course of scleroderma morphological changes of the mesenchymal origin occurred in the teeth hard tissues. The deviation in the calcium and phosphorus contents was relatively significant and an absence of magnesium in the dentine and distinct decrease in the calcium-phosphorus ratio were observed.

Measurement of enkephalin peptides in canine brain regions, teeth, and cerebrospinal fluid with high-performance liquid chromatography and mass spectrometry.

Endogenous enkephalin pentapeptides are measured with unambiguous molecular specificity in canine and human tissue and fluid extracts. Both field desorption and fast atom bombardment mass spectrometry have been used to produce a protonated molecular ion of the peptide high-performance liquid chromatography fraction. The protonated molecular ion is subjected to collision-activated dissociation processes and a linked-field scan (B/E) selects a unique amino acid sequence-determining ion for monitoring and measurement. Stable isotope-incorporated peptide internal standards are used for quantification. Endogenous enkephalins are measured in hypothalamus, cerebrospinal fluid, pituitary, caudate nucleus, and tooth pulp extracts. Part-per-billion levels of endogenous peptide are measured.

The tooth-amalgam interaction.

The interaction between tooth and amalgam during in vitro corrosion of dental amalgams has been studied in this investigation. Extracted teeth have been restored with five commercial amalgams, one of which was gamma 2 -free and the others contained the gamma 2-phase. The restored teeth were immersed in a 1% NaC1 solution for 9 months. Post corrosion restorations have been examined by optical microscopy, scanning electron microscopy, and X-ray microanalysis. The results are: (1) gamma 2-containing amalgam surfaces were covered with Ca-Sn-P-rich corrosion products of various morphology which occasionally contained relatively low concentrations of C1 and/or Zn; (2) the corrosion products on the gamma 2-free amalgam surface indicated relatively high concentrations of Hg in addition to Ca, p, Sn, Cu, and Zn. These results agree with the past observations that corrosion of amalgam restorations is not an isolated process. Rather it may involve reactions of the restoration and the surrounding oral environment including tooth and oral fluids in which interactions of Sn, Zn, Hg, Ca and P take place.

Ultrastructural analysis and quantitative distribution of Macro-and microelements in young teeth hard tissues by the use of an X-ray microanalyser.

Determination of quantity, distribution and topography of calcium, phosphorus, magnesium and copper in transverse and longitudinal sections of deciduous and early erupted permanent human teeth were made by the use of an x-ray microanalyser and simultaneous analysis of the microstructure of the examined surface by the use of an electron scanning microscope. The examinations demonstrated the higher content of calcium and phosphorus, greater density and more homogenous distribution of these elements in the deciduous teeth. In the permanent teeth characteristic conglomerations of mineral granules were visible in the area corresponding to the dentine tubuli.

[Comparative study of the effect of weightlessness and artificial gravity on the density, ash, calcium, and phosphorus content of calcified tissues]. / Sravnitel'noe izuchenie vliianiia nevesemosti i iskusstvennoi sily tiazhesti na plotnost' soderzhanie zoly, kal'tsiia i fosfora v obyzvestvlennykh tkaniakh.

The studies were carried out on 30 rats flow for about 19 days aboard the biosatellite Cosmos-936 (5 centrifuged rats including) and 25 ground-based control rats. Postflight the centrifuged rats did not show significant differences in the density, mineral saturation, distribution of vascular channels in bones, ash, calcium and phosphorus content in skeletal bones and teeth as compared with the parameters in synchronous and vivarium controls. In the weightless rats these values were significantly lowered.

Ca and P concentrations of the urodele tooth as revealed by electron microprobe analysis.

The electron microprobe analysis has been used to determine the concentrations of Ca and P in different regions of functional teeth in adult Salamandra salamandra (Amphibia, Urodela). Ca and P levels were found to be more elevated in the dentine shaft below the apex than in its basal part and in the pedicel. The concentrations are similar to those measured in teeth of higher vertebrates.