Localised enamel hypoplasia of human primary canines (LHPC) in the Necropolis of Great Moravia in Znojmo-Hradiste (the so called Stronghold of Znojmo, 9th-10th century CE, Czech Republic) and analysis of chemical elements on surface enamel and hypoplastic defect via EDX method

摘要

The present study aimed to evaluate the frequency and time of the development of enamel hypoplasia of the primary canine of the Slavic population from the 9th to the first half of the 10th century CE in the South Moravian burial ground of Znojmo-Hradiste, to establish the association with incidence of dental caries, and to analyse the chemical element content of the enamel. The frequency and time of the development of enamel hypoplasia of the primary canine were established macroscopically. The chemical element content of the enamel was analysed via the EDX method. The incidence of LHPC is very high in this analysed collection in comparison with other Slavic populations. 45.59% individuals (n = 31) displayed at least one hypoplastic defect on their canines. Most individuals were 2-5 years old and more than a quarter of them had multiple hypoplasia. The most frequent shape of enamel defect is irregular. The difference between the defects originating in the perinatal period and those originating in the postnatal or prenatal period is statistically significant. Individuals with LHPC (localised hypoplasia of primary canines) have a higher presence of dental caries in primary teeth than individuals without LHPC, but without statistical significance. Individuals with LHPC have other hypoplasia on the primary teeth more often than individuals without LHPC. The EDX analysis shows the average value of the Ca/P ratio in Spectrum 1 to be highest in teeth with unsolid enamel (LHPC), decreasing to Spectrum 2 and subsequently to Spectrum 3. The concentration of phosphor is increasing from Spectrum 1 to Spectrum 3. Magnesium was most commonly present in Spectrum 1, and less often in Spectrum 2 and Spectrum 3 in mean concentration 0.27 and 0.39 at.%. Values of Mg content rise to on average 0.63 at.% on the base of hypoplastic defects. In agreement with the findings of Robinson et al. (1981), this might mean a lower density of enamel in the place of a hypoplastic defect. However, this cannot be argued clearly, because the difference in concentration could have been caused by diagenetic processes over the time that the samples lay deposited in soil. Sodium is found in our collection of teeth about as often in all three spectra in an almost identical mean concentration (0.51, 0.46 and 0.56 at.%, respectively).