Dental pulp calcifications in prehistoric and historical skeletal remains

A comparison of dietary isotopes in pulp stones and incremental dentine from Early Neolithic individuals of the Whitwell Long Cairn, England

Objectives

This study investigates if palaeodietary information can be obtained from pulp stones through stable isotope analysis, presents a method for their extraction from tooth samples, and assesses their utility as a source of paleodietary information when coupled with the incremental dentine method.

Materials and Methods

Six tooth samples (2 per individual), four of which contained pulp stones, were selected from three Early Neolithic (3720–3650 cal BC) individuals from the Whitwell Long Cairn in Derbyshire, England. After demineralization, each tooth was divided into 1 mm increments. Stable isotope analysis of collagen was conducted on each dentine increment and a portion of each pulp stone.

Results

All samples met the quality control criteria for well‐preserved collagen. Excluding the pulp stones, the mean δ¹³C value of the teeth sampled was −21.5 ± 0.2‰ and the mean δ¹⁵N value was 9.9 ± 0.5‰, suggesting these individuals had a terrestrial‐based diet. The pulp stones produced similar δ¹³C values between −21.6 and −21.4‰ and δ¹⁵N values between 9.1 and 9.8‰.

Discussion

The results demonstrate that paleodietary information can be obtained from pulp stones through stable isotope analysis. There are, however, significant challenges in interpreting this data, particularly as to inferring the timing and duration of their formation. The pulp stone results were compared with the incremental dentine profiles for each person to further investigate when they might have formed. For two individuals, the pulp stones appear to reflect diet from a time period after childhood and adolescence. For the third individual, it could not be determined if the pulp stones reflect a contemporary or later time period than the incremental dentine series. All teeth with pulp stones have moderate to severe wear on the occlusal surface, which could have been a contributing factor to their development.

Incremental lines in human acellular tooth cementum - new insights by SEM analysis

BACKGROUND

Tooth cementum covers the surface of the root dentine and is produced and laid down in thin layers continuously throughout life. Functionally, different types of tooth cementum can be distinguished, which can be roughly divided into acellular (primary cementum) and cellular (secondary cementum) forms. One main type is acellular extrinsic fibre cementum (AEFC), which covers the cervical and middle third of the root. Light microscopic examinations of transverse sections of AEFC show lamellar patterns of alternating light and dark lines called growth or incremental lines. Following mammalian research, a seasonal rhythm of incremental line formation is also assumed in humans. Previous attempts at visualising incremental lines in the AEFC by scanning electron microscopy (SEM) were not particularly successful. The aim of the present study was to detect incremental lines in the AEFC and to analyse their underlying structure by SEM.

METHODS

For this purpose, non-embedded and resin-embedded transverse and longitudinal sections of three single-rooted teeth obtained from different patients were investigated. The thin sections were not pre-treated (e.g. by etching, grinding or coating).

RESULTS

Lamellar structures, which could be identified as incremental lines, were detectable in both transverse and longitudinal sections, with transverse orientation in the cross-section and longitudinal orientation in the longitudinal section. The lamellar pattern was created by broad fibre-rich layers alternating with narrow fibre-poor layers. The orientation of the collagen fibres changed from layer to layer from transverse to radial direction. The visibility of the layered structure discovered varied significantly.

CONCLUSIONS

The study demonstrate that it is possible, in principle, to detect incremental lines in AEFC and to identify their basic structure using SEM. Our results suggest that the density and orientation of the fibres play an essential role in the formation of incremental lines. Functional aspects seem to be of particular importance.

Nutritional reconstruction in an early modern population: Searching for a relationship between dental microwear and bone element composition

BACKGROUND

Observing the microwear patterns of the dental crowns enamel surface can provide information on the ingredients and structure of the food consumed, but also on eating habits and lifestyle. Major role in reconstructing the diet and lifestyle of past populations is played by the analysis of alkaline earth metals, such as strontium, barium, zinc and calcium. Ba and Sr are indicators of the consumption of vegetables, plants (cereals and legumes) and marine organisms. This study aims to assess dietary diversity and identify its components based on microscopic techniques and chemical analyses of material from early modern archaeological sites in Wrocław, Poland.

METHODS

The material consisted of 36 permanent molars and the intrasternal parts of 122 first ribs, collected from 6 Wroclaw early modern cemeteries. Tooth microwear was evaluated on Scanning electron microscopy images, with Microwear 4.02 software. Bone chemical composition (Ca, P, Ba, Sr content) was evaluated with mass spectrometry.

RESULTS

Most lines were present on the teeth from St. Mary Magdalene Cemetery, with the lowest average number of lines observed on the teeth from St. Barbara Cemetery. The Ca/P ratios calculated for different sites formed two clusters that allows to distinguish two groups of archaeological sites with different bone preservation status. Number of differences in Ba/Sr, Sr/Ca, Ba/Ca ratios was found between disctinct archaeological sites. A number of correlations were found between the concentration of the chemical elements, but no statistically significant correlation was found between the microwear characteristics and the proportion of the elements studied. Some strong correlations were found between microwear features and the Ca/P ratio.

CONCLUSIONS

the different values of Sr/Ca, Ba/Ca and Ba/Sr ratios indicate different diets in the different communities. The data obtained indicate a mixed diet, with a relatively high proportion of animal products throughout Wrocław. Conclusions should be treated with caution due to secondary diagenesis. The lack of interdependence between microwear and chemical composition characteristics suggests that the two methods should be considered complementary and not overlapping, as they provide different insights into the diets of past populations. The comparison of microwear between different sites should always take into account secondary diagenesis and the burial environment, as these influence the characteristics of microwear.

Adoption of Biomedical Ceramic iRoot BP in the Treatment of Localized Pulpitis in Children

To explore the clinical efficacy of biomedical ceramic iRoot BP in the treatment of localized acute pulpitis in children, and the effect of iRoot BP on proliferation and osteogenic differentiation of human dental pulp stem cells (hDPSCs), 72 localized acute pulpitis children admitted to our hospital from September 2018 to September 2019 were selected and divided into group A (treated with MTA pulp capping material) and group B (treated with iRoot BP material), and the clinical effect, pain degree, and adverse reactions (ADR) rate were compared. The effects of iRoot BP on hDPSCs proliferation and osteogenic differentiation were analyzed; the proliferative activity of cells in iRoot BP group, MTA group, and control group (C group) were measured by cholecystokinin-8 (CCK-8) assay, the ability of cell mineralized nodular formation was observed via alizarin red staining; and quantitative reverse transcription PCR (qRT-PCR) andWestern blot were adopted to determine the expression of osteogenic related genes of hDPSCs and key proteins of mitogen-activated protein kinase (MAPK) signaling pathway. After 1 week of treatment, the clinical efficacy of group B was more favorable in contrast with group A (P < 0.05); the pain of children in group B was notably better in contrast with group A, and incidence of ADR was notably lower in contrast with group A (P < 0.05). 5.0 mg/mL, 10.0 mg/mL, and 30 mg/mL iRoot BP or MTA could improve cell proliferation activity (P < 0.01); the effect of iRoot BP on proliferation of hDPSCs was greater in contrast with MTA (P < 0.05); and the integral optical density (IOD) value of iRoot BP group was notably higher in contrast with MTA group (P < 0.01). The mRNA expression levels of collagen-I (COL-I), bone sialoprotein (BSP), and osteocalcin (OC) in MTA group and iRoot BP group were notably higher in contrast with C group (P < 0.01); the COL-I mRNA expression level of iRoot BP group was notably higher in contrast with MTA group (P < 0.01); the mRNA expression level of BSP in MTA group was notably higher in contrast with iRoot BP group (P < 0.01); the relative protein expression levels of phosphorylated ERK (p-ERK) and phospho-Jun N-terminal kinase (p-JNK) in MTA group and iRoot BP group were notably higher in contrast with C group (P < 0.01); and the relative expression level of p-ERK protein in iRoot BP group was higher in contrast with MTA group (P < 0.05). These results indicated that the clinical efficacy of biomedical ceramic iRoot BP was better than MTA in the preservation of live pulpitis in children, and the patients treated with iRoot BP had better pain recovery effect and lower risk of ADR. The effect of iRoot BP on the proliferation and mineralization of hDPSCs was better than that of MTA, and it may promote the osteogenic differentiation of hDPSCs by activating MAPK signaling pathway and regulating gene expression of COL-I, BSP, and OC.