Elemental composition of normal primary tooth enamel analyzed with XRMA and SIMS.

There is an interest to analyze the chemical composition of enamel in teeth from patients with different developmental disorders or syndromes and evaluate possible differences compared to normal composition. For this purpose, it is essential to have reference material. The aim of this study was to, by means of X-ray micro analyses (XRMA) and secondary ion mass spectrometry (SIMS), present concentration gradients for C, O, P and Ca and F, Na, Mg, Cl, K and Sr in normal enamel of primary teeth from healthy individuals. 36 exfoliated primary teeth from 36 healthy children were collected, sectioned, and analyzed in the enamel and dentin with X-ray micro analyses for the content of C, O, P and Ca and F, Na MgCl, K and Sr. This study has supplied reference data for C, O, P and Ca in enamel in primary teeth from healthy subjects. No statistically significant differences in the elemental composition were found between incisors and molars.The ratio Ca/P is in concordance with other studies. Some elements have shown statistically significant differences between different levels of measurement. These results may be used as reference values for research on the chemical composition of enamel and dentin in primary teeth from patients with different conditions and/or syndromes.

Analysis of some elements in primary enamel during postnatal mineralization.

The primary teeth start to mineralize in utero and continue development and maturation during the first year of life.The aim of this study was to investigate the concentrations of some elements, C, F, Na, Mg, Cl, K and Sr, by secondary ion mass spectrometry (SIMS) in human primary incisors at different stages of mineralization.The teeth derived from an autopsy material from children who had died in sudden infant death.The buccal enamel of specimens from the ages 1, 2, 3, 4, 6 and 19 months, respectively, was analyzed. It was evident that posteruptive effects play an important role in composition of the outermost parts of the enamel. Before the tooth erupts, the concentrations of the elements vary with the maturation grade of the mineralization in the enamel. Sodium was the element with the highest concentration of the measured elements and chlorine was the element of lowest concentration.The 19 month old specimen, considered as the only mature and erupted tooth, showed to differ from the other specimens.The concentration of fluorine, in the 19 month old specimen's outermost surface, is readily seen higher compared with the other specimens at this depth zone. In the 19 month old specimen the concentration of carbon is lower. Potassium, sodium and chlorine have higher concentrations, in general, in the 19 month old specimen compared with the immature specimens. The thickness of the enamel during mineralization was calculated from data from SIMS.The thickness of the buccal enamel of primary incisors seemed to be fully developed between 3-4 months after birth, reaching a thickness of 350-400 microm.

Chemical composition of enamel and dentine in primary teeth in children from Thailand exposed to lead.

Enamel and dentine in teeth of children with high blood levels of lead were analyzed by means of secondary ion mass spectrometry (SIMS) and X-ray micro-analyses (XRMA) and compare with teeth from children with low blood levels of lead. The SIMS analysis revealed detectable levels of Pb in dentine close to the pulp. The XRMA analyses could not detect any lead. There were no differences found in lead level in enamel of high lead level exposed teeth from low level exposed. The results confirm that children with high blood levels of lead have an uptake of lead in dentine close to the pulp.

Morphological appearance and chemical composition of enamel in primary teeth from patients with 22q11 deletion syndrome.

Patients with 22q11 deletion syndrome have many and complex medical problems, including hypocalcemia and/or hypoparathyroidism. Odontological findings include enamel aberrations in both dentitions. In order to describe enamel morphology, chemical composition in primary teeth, and to investigate the relationship between medical history and morphological appearance, dental enamel was investigated in 38 exfoliated primary teeth from 15 children and adolescents. Morphology was studied by the use of a polarized light microscope, microradiography, scanning electron microscopy, X-ray microanalysis, and secondary ion mass spectrometry. The morphological findings were compared with medical history. The teeth showed, in principle, a normal morphological appearance with regard to prism structure. A high frequency of aberrations, such as hypomineralization, hypoplasia and extra incremental lines, were found. The majority of the aberrations were found around the neonatal line. There was a relationship between high numbers of medical problems in the patients and enamel deviations. The result supports the hypothesis of under-reporting of both hypocalcemia and hypoparathyroidism in patients with 22q11 deletion syndrome.

Titanium release from implants prepared with different surface roughness.

OBJECTIVES: There may be a risk of greater ion release for surface-enlarged implants than conventionally turned components. The major aim of the present paper was to investigate whether a correlation exists between ion release and a surface roughness relevant for today's commercial implants. Other aims were to compare ion release after two insertion times and concentration in bone tissue as a function of distance from the implant surface. MATERIAL AND METHODS: Lactic acid aqueous solution (pH=2.3) and phosphate-buffered saline were used for the in vitro investigation. For the in vivo investigation, synchrotron radiation X-ray fluorescence (SRXRF) spectroscopy and secondary ion mass spectroscopy (SIMS) were performed 12 weeks and 1 year after implantation in rabbit tibiae. RESULTS: The average height deviation (S(a)) was 0.7, 1.27, 1.43 and 2.21 microm, respectively, for the four surfaces investigated. No difference in ion release was found in vitro. In vivo, SRXRF demonstrated slightly higher values for the roughest surface up to a distance of 400 microm from the implant surface; thereafter no difference was found. SIMS demonstrated no difference in ion release for the roughest and smoothest surfaces, but slightly more titanium in bone tissue after 1 year than after 12 weeks. Titanium rapidly decreased with distance from the implant surface. CONCLUSION: At a level relevant for commercial oral implants, no correlation was found between increasing roughness and ion release, neither in vitro nor in vivo.