Impressions

Chewed Birch Tar Reveals Oral Health and Lifestyle of Mesolithic Scandinavians

A new study revealed the oral health conditions of southwestern Scandinavian hunter-gatherers who lived around 10,000 years ago. The study, published in Scientific Reports, analyzed the DNA sequences of chewed birch tar from the Huseby Klev area of Sweden. The study intended to identify the plant, microbial and animal DNA on the tar. It compared these findings against ancient and modern human samples to determine the tar’s chewers and their oral health. The research revealed that the microbial profiles of the birch tar featured a close match with those traditionally found in a human’s mouth (ancient and modern). This suggests that the pieces were human-chewed.

The researchers found an elevated level of bacteria associated with tooth decay and gum disease such as Streptococcus sobrinus and Treponema denticola. This indicates that the people studied in this hunter-gatherer group probably had poor oral health, with a 70–80% estimated probability that they suffered from gum disease based on the relative abundance of the microbial species.

Additionally, the study showed the lifestyle implications of these hunter-gatherers in terms of their oral health. More specifically, the parafunctional use of teeth, such as cutting, tearing and gripping materials, could have increased exposure to microbial species that were harmful. This may have contributed to more instances of gum disease. Parafunctional use, as well as microbial evidence, suggests more detail about the challenges these people faced in keeping up with their oral hygiene.

DNA from various animal and plant species such as apple, hazelnut and red fox was discovered in the birch tar that was chewed. This suggests the range of food sources and diversity of materials used by the hunter-gatherers, further providing information about their diet, lifestyle and natural resources.

The study was led by researchers Emrah Kırdök, PhD, and Anders Götherström, PhD, of Stockholm University in Sweden. Kırdök has served as a post-doctoral researcher at Stockholm University since 2018. He is an assistant professor, and his current research is focused on understanding the history of humans via ancient DNA. Götherström is a professor of molecular genetics at Stockholm University and his research has largely focused on archaeogenetics in Anatolia and Northern Europe. Their research provides interesting insights into the dental ailments, environmental adaptations and daily lives of ancient people.

Study Finds No Significant Link Between Vitamin D Levels and Childhood Dental Caries

A recent study showed mixed results from prior research on the link between childhood dental caries and vitamin D. The research set out to analyze if there is a connection between serum vitamin D status and the severity and prevalence of molar incisor hypomineralisation (MIH) and dental caries in kids between the ages of 7 and 9 in Norway. Interestingly, even though it is known that vitamin D is important for bone mineralization and calcium absorption and the potential role it has in oral health, the study did not find significant connections between the levels of vitamin D and the number of teeth experiencing dental caries.

The study highlights a scarcity in the number of studies on the effects of MIH. Previous research has utilized dichotomous outcomes for oral health, which may have oversimplified the connection of vitamin D and oral health. This study addresses those limits by using continuous variables in regression analyses and using tandem mass spectrometry and liquid chromatography for accurate measurements of serum 25-hydroxyvitamin D levels.

The study analyzed data from 101 children who participated in the TRaining In Pregnancy study (TRIP-study), which began as a randomized controlled trial (RCT) examining the impact of an exercise program for pregnant women on gestational diabetes. The research team measured the children’s vitamin D levels with LC-MS/MS and assessed their oral health through examinations by calibrated dentists who used specific indices for caries and MIH. The researchers considered confounding factors such as body mass, gender, age, maternal education level and season of blood draw. Odds and rate ratios were implemented through logistic and negative binomial regression models.

The study found 27% of the children had insufficient vitamin D levels and higher rates of dental caries, but it also revealed no statistically significant connection between the oral outcomes and vitamin status. Research suggest that the lack of significant findings might be attributed to the low prevalence of caries and caries experienced in the study population, among other things such as small sample size and cross-sectional design. The study, conducted by researchers at the Center for Oral Health Services and Research, Mid-Norway (TkMidt), Norwegian University of Science and Technology, and the Netherlands Organization for Applied Scientific Research, among others, suggests that larger, more prospective research efforts should be carried out to explore the relationship further.

Maternal Oral Hygiene Identified as Key to Reducing Candida Transmission to Infants

Mothers should strive to maintain good oral hygiene to keep from transmitting Candida albicans to their infant children, according to a new study. The research revealed that mothers who have high levels of dental plaque are eight times more likely to pass this pathogenic fungus to their child. This finding highlights the need for mothers to maintain dental cleanliness to prevent and safeguard the oral health of their kids.

Ambiguity around the extent of a mothers’ role in transmitting Candida albicans to their children prompted the study. The research utilized a prospective infant-mother cohort. To compile the data, the researchers collected oral samples from 160 mother-child dyads from pregnancy through the child’s second year of life. They used the whole-genome sequencing for Candida albicans isolates and multilocus sequence typing. To analyze genetic relatedness, the study attempted to find out the maternal contribution to oral colonization early in a child’s life.

The results showed 227 Candida albicans oral isolates gathered from 93 child-mother pairs. Further analysis through eBURST, a novel clustering algorithm designed for use on microbial MLST data, found 16 clonal complexes and UPGMA (unweighted pair group method) analysis showed six clades. A significant majority of isolates belonged to a single predominant clade. More specifically, 94% of the child-mother combinations with Candida albicans shared highly genetically related strains. The various factors considered included the oral hygiene of the mother, measured by the level of dental plaque. A higher level of dental plaque was identified as a major factor in the vertical transmission of Candida albicans.

The study, which was published in PLoS ONE and conducted by researchers at Kuwait University and University of Rochester, suggests that screening should take place for maternal fungal oral carriage, as well as more oral health education during the perinatal period, to help reduce the risk to the infants.

Groundbreaking Study Maps Dental Stem Cells, Unveils Key Differences

Research from the ADA Forsyth Institute and the University of North Carolina at Chapel Hill has revealed key differences that may exist between periodontal ligament stem cells (PDLSC) and dental pulp stem cells (DPSC). Published in the Journal of Dental Research, this investigation serves as the most detailed study of these stem cells to date, cataloging their genomic signatures and diving into their various differentiation potentials.

UNC biostatistician, Di Wu, PhD, and Alpdogan Kantarci, DDS, MSc, PhD, led the study, which set out to determine the variances between PDLSCs and DPSCs, specifically in their ability to morph into other cell variations. The researchers used stem cells directly from extracted teeth and analyzed them without previous culturing – an approach that delivers a fresh perspective on stem cell capabilities. Through bulk RNA sequencing and advanced bioinformatics, the study challenged previous notions about stem cell uniformity and validated the unique differentiation potentials of PDLSCs and DPSCs.

The study pin-pointed seven unique gene clusters within both stem cell types, corresponding to different differentiation stages. Four of the clusters were common to both stem cell category, but three showed specific differences. PDLSCs shared characteristics with fibroblasts, illustrating an enhanced proportion of certain clusters. This indicated a predisposition toward forming connective tissue. On the other hand, DPSCs showed a greater capacity for differentiation, specifically into bone cells because of their distinct genetic profiles.

The study results illustrate the potential to revolutionize regenerative therapies by harnessing the distinct characteristics of oral stem cells, which will offer targeted and more effective solutions for tissue regeneration and repair, according to the authors.

Migration Patterns of Ancient Populations in the Americas Using Dental Morphology Analysis

Anthropologists have made big strides in understanding migration patterns of ancient populations throughout and into the Americas. The findings, published in Wiley Online Library, reveal that Southeast Asian groups showed a complex ancestry with minimal classifications aligning with Native American or American Arctic groups. Additionally, East Asian groups often were classified within their own region, though a good amount of them also had classifications within Native American groups. The research also showed that people from North & South America and the American Arctic were mainly assigned to their regions, with a small amount showing affiliations with East Asian areas. The complex genetic relationships show how intertwined the history of the populations were and delivers insights into the people of the Americas.

This is all thanks to the new research that used biodistance analyses related to dental morphology. The researchers employed the rASUDAS2 method, a tool intended to determine the ancestry of unidentified individuals through analysis of their tooth root and crown characteristics, based on a naïve Bayes’ algorithm, a widely used supervised machine learning algorithm for categorization tasks, including text classification. This has shifted the focus toward individual-based analysis instead of depending on aggregate sample frequencies. This allows for a nuanced exploration of genetic relationships and human movement across various regions.

The research used the C.G. Turner II database, an extensive repository of data concerning the shape and variability of human teeth, to analyze the probability of assigning an individual to one biogeographic group. The groups were from various areas across North & South America, American Arctic, Sub-Saharan Africa, Western Eurasia, Australo-Melanesia, Southeast Asia & Polynesia and East Asia. The research included 1,418 individuals and attempted to understand the frequency of classifications for the individual biogeographic groups. This would then help reveal patterns of human migration among ancient people.

The study, conducted by researchers at University of Nevada Reno, University of Coimbra, University of Kansas, CENIEH and University of Colorado, also opens the door for further research. The analysis, which is planned to be augmented by a searchable database of global dental morphology, represents a big advancement in anthropological science. This may be able to further unlock more secrets of migration and human ancestry.