The Vikings, famous as raiders who terrorised many parts of Europe, may have been quite ruthless, but their society seems to have had access to surprisingly advanced dental care for the era. A University of Gothenburg analysis of Viking Age teeth showed that although caries and toothache were widespread, there was also evidence of dental practices not too dissimilar from modern ones.
The study examined 3293 teeth from 171 individuals among the Viking Age population of Varnhem in Västergötland, Sweden.
The site is known for extensive excavations of Viking and medieval environments, including tombs where skeletons and teeth have been preserved well in favourable soil conditions.
The research team from the University of Gothenburg’s Institute of Odontology worked with an osteologist from Västergötland’s Museum. The skulls and teeth underwent clinical examinations at Gothenburg using standard dentistry tools under bright light.
A number of X-ray examinations were also performed using the same technique used in dentistry, where the patient bites down on a small square imaging plate in the mouth.
Caries and tooth loss
The results, which have been published in the journal PLOS ONE, show that 49% of the Viking population had one or more caries lesions.
Of the adults’ teeth, 13% were affected by caries – often at the roots. Children with milk teeth or a mix of milk and adult teeth, were entirely caries-free however. (Presumably sweets for the kids were not high on the Viking raiders’ lists.)
Tooth loss was also common among adults. The studied adults had lost an average of 6% of their teeth, excluding wisdom teeth, over their lifetimes. The risk of tooth loss increased with age.
The findings suggest that caries, tooth infections, and toothache were common among the Viking population in Varnhem – but the study also reveals examples of tooth care.
“There were several signs that the Vikings had modified their teeth, including evidence of using toothpicks, filing front teeth, and even dental treatment of teeth with infections,” says Carolina Bertilsson, a dentist and Associate Researcher, and the study’s first-named and corresponding author.
Not unlike today’s treatments
One sign of more sophisticated procedures was molars with filed holes, from the crown of the tooth and into the pulp, probably in order to relieve pressure and alleviate severe toothache due to infection.
“This is very exciting to see, and not unlike the dental treatments we carry out today when we drill into infected teeth. The Vikings seem to have had knowledge about teeth, but we don’t know whether they did these procedures themselves or had help.”
The filed front teeth may have been a form of identity marker. In both this and previous studies, the cases found were male.
Carolina Bertilsson continues: “This study provides new insights into Viking oral health, and indicates that teeth were important in Varnhem’s Viking culture. It also suggests that dentistry in the Viking Age was probably more sophisticated than previously thought.”
In one of every 10 people, and in one third of children with celiac disease, the enamel coating of the teeth appears defective, failing to protect the teeth properly. As a result, teeth become more sensitive to heat, cold and sour food, and they may decay faster. In most cases, the cause of the faulty enamel production is unknown.
Now, a study by Prof Jakub Abramson and his team at the Weizmann Institute of Science, published recently in Nature, may shed light on this problem by revealing a new children’s autoimmune disorder that hinders proper tooth enamel development. The disorder is common in people with a rare genetic syndrome and in children with celiac disease. These findings could help develop strategies for early detection and prevention of the disorder.
Tooth enamel is made up primarily of mineral crystals that are gradually deposited on protein scaffolds during enamel development. Once the crystals are in place, the protein scaffold is dismantled, leaving behind a thin, exceptionally hard layer of enamel. A strange phenomenon was identified in people with a rare genetic disorder known as APS-1: although the enamel layer of their milk teeth forms perfectly normally, something causes its faulty development in their permanent teeth. Since people with APS-1 suffer from a variety of autoimmune diseases, Abramson and his team hypothesised that the observed enamel defects may also be of an autoimmune nature
In autoimmune disease, to prevent T cells from triggering the immune system to attack body tissues, T cells developing in the thymus gland must be educated’ to discriminate between the body’s own proteins and those of foreign origin. To this end, T cells are presented with short segments of self-proteins that make up various tissues and organs in the body. When a ‘poorly educated’ T cell erroneously identifies a self-protein in the thymus as a target for attack, that T cell is labelled as dangerous and destroyed, so that it could not cause any damage after being released from the thymus.
This critical education step is impaired in APS-1 patients as a result of a mutation in a gene known as the autoimmune regulator (Aire). This gene is essential for the T cell education process: It produces a protein that is responsible for the collection of self-proteins presented to the T cells in the thymus. In their new study, scientists from Abramson’s lab in Weizmann’s Immunology and Regenerative Biology Department, led by research student Yael Gruper, sought to work out how mutations in the Aire gene lead to deficient tooth enamel production. The researchers discovered that, in the absence of Aire, proteins that play a key role in the development of enamel are not presented to the T cells in the thymus gland. As a result, T cells that are liable to identify these proteins as targets are released from the thymus, and they encourage the production of antibodies to the enamel proteins. But why do these autoantibodies damage permanent teeth and not baby teeth?
The answer to this question lies in the fact that milk teeth develop in the embryonic stage, when the immune system is not yet fully formed and cannot create autoantibodies. In contrast, the development of enamel on permanent teeth starts at birth and continues until around the age of six, when the immune system is sufficiently mature to thwart enamel development. Furthermore, the researchers found a correlation between high levels of antibodies to enamel proteins and the severity of the harm to enamel development in children with APS-1. This strengthens the assumption that the presence of enamel-specific autoantibodies in childhood can potentially lead to dental problems.
When the researchers looked into deficiencies in enamel development in people with other autoimmune diseases, they found a very similar phenomenon in children with celiac disease, a relatively common autoimmune disorder that affects around 1% of people in the West. When people with this disease are exposed to gluten, their immune system attacks and destroys the cellular layer lining the small intestine, leading to attacks on other self-proteins in the intestine.
In an attempt to understand how celiac disease, known to cause intestinal damage, may also cause damage to tooth enamel, the researchers first examined whether people with this disease have autoantibodies against enamel. They found that a large proportion of celiac patients have these autoantibodies, just as do people with APS-1. But the ‘education’ in the thymus gland of these patients seems normal, so why do they develop these antibodies? The researchers hypothesised that some proteins are found in both the intestine and the dental tissue and that these proteins play an important role in the development of tooth enamel. In this case, the antibodies that identify proteins in the intestine might move through the bloodstream to the dental tissue, where they could start to disrupt the enamel production process.
Since many celiac patients had previously been found to develop sensitivity to cow’s milk, the researchers decided to focus on the k-casein protein, a major component of dairy products. Strikingly, they found that the human equivalent of k-casein is one of the main components of the scaffold necessary for enamel formation. This led them to hypothesise that antibodies produced in the intestines of celiac patients in response to certain food antigens, such k-casein, may subsequently cause collateral damage to the development of enamel in the teeth, similarly to the way in which antibodies against gluten can eventually trigger autoimmunity against the intestine.
Indeed, they discovered that most of the children diagnosed with celiac had high levels of antibodies against k-casein from cows’ milk, which in many cases can also react against k-casein’s human equivalent expressed in the enamel matrix. This means that in theory, the same antibodies that are produced in the intestine against the milk protein could act against the human k-casein in the teeth.
These findings could have implications for the food industry. “Similarly to the lessons learned from gluten, we can assume that the consumption of large quantities of dairy products could lead to the production of antibodies against k-casein,” Abramson explains. “This protein increases the amount of cheese that can be produced from milk, so the dairy industry deliberately raises its concentration in cow’s milk. Our study, however, found that the milk k-casein is a potent immunogen, which may potentially trigger an immune response that can harm the body itself.”
Tooth enamel flaws are common, not just among people with celiac disease or APS-1. “Many people suffer from impaired tooth enamel development for unknown reasons,” Abramson says. “It is possible that the new disorder we discovered, along with the possibility of diagnosing it in a blood or saliva test, will give their condition a name. Most important, early diagnosis in children may enable preventive treatment in the future.”
Tissue regeneration might one day replace the pain and discomfort of a root canal for most people. ADA Forsyth scientists are testing a novel technology to treat endodontic diseases (diseases of the soft tissue or pulp of the teeth) more effectively. The technology may also even be applicable to other parts of the body, such as helping to regrow bones.
The study, published in The Journal of Dental Research, demonstrates regenerative properties of resolvins, specifically Resolvin E1 (RvE1), when applied to dental pulp. Resolvins are part of a greater class of Specialised Proresolving Mediators (SPMs). This class of molecule is naturally produced by the body and is exquisitely effective in the control of excess inflammation associated with disease.
“Pulpitis (inflammation of dental pulp) is a very common oral health disease that can become a serious health condition if not treated properly,” said Dr Thomas Van Dyke, Vice President at the Center for Clinical and Translational Research at ADA Forsyth, and a senior scientist leading the study.
“Root canal therapy (RCT) is effective, but it does have some problems since you are removing significant portions of dentin, and the tooth dries out leading to a greater risk of fracture down the road. Our goal is to come up with a method for regenerating the pulp, instead of filling the root canal with inert material.”
Inflammation of this tissue is usually caused by damage to the tooth through injury, cavities or cracking, and the resulting infection can quickly kill the pulp and cause secondary problems if not treated.
The study applied RvE1 to different levels of infected and damaged pulp to explore its regenerative and anti-inflammatory capacities.
There were two major findings. First, they showed RvE1 is very effective at promoting pulp regeneration when used in direct pulp-capping of vital or living pulp (replicating conditions of reversible pulpitis). They were also able to identify the specific mechanism supporting tissue regeneration.
Second, the scientists found that placing RvE1 on exposed and severely infected and necrotic pulp did not facilitate regeneration.
However, this treatment did effectively slow down the rate of infection and treat the inflammation, preventing the periapical lesions (abscesses) that typically occur with this type of infection.
Previous publications have shown that if the infected root canal is cleaned before RvE1 treatment, regeneration of the pulp does occur.
While this study focused on this technology in treating endodontic disease, the potential therapeutic impact is far reaching.
Dr Van Dyke explained, “because application of RvE1 to dental pulp promotes formation of the type of stem cells that can differentiate into dentin (tooth), bone, cartilage or fat, this technology has huge potential for the field of regenerative medicine beyond the tissues in the teeth. It could be used to grow bones in other parts of the body, for instance.”
A major analysis of all relevant published studies indicates that poor periodontal health and tooth loss may increase the risk of both cognitive decline and dementia. The finding, published in the Journal of the American Geriatrics Society, affirms a long-suspected connection between dental and cognitive health.
The analysis included 47 studies. Poor periodontal health, reflected by having periodontitis, tooth loss, deep periodontal pockets, or alveolar bone loss, was linked to a 23% increase in risk for cognitive decline and a 21% higher risk of dementia. Tooth loss on its own was associated with a 23% higher odds of cognitive decline and a 13% higher risk of dementia. The overall quality of evidence was low, however.
“From a clinical perspective, our findings emphasise the importance of monitoring and management of periodontal health in the context of dementia prevention, although available evidence is not yet sufficient to point out clear ways for early identification of at-risk individuals, and the most efficient measures to prevent cognitive deterioration,” the authors wrote.
Researchers have developed a new technique to improve understanding of how acid damages teeth over time at the microstructural level, creating a clear picture of how the damage happens.
Dentine forms the main bulk of human teeth and supports the enamel, which covers the crown surface, helping to make teeth strong and resilient, but acids from dental plaque can cause tooth decay affecting the dental structure’s integrity. This research aims to develop knowledge that leads to new treatments that can restore the structure and function of dentine.
Using in situ synchrotron X-ray microtomography to scan dentine samples while they were being treated with acid, researchers built clear 3D images of dentine’s internal structure with sub-micrometre resolution (a micrometre being one-thousandth of a millimetre). By analysing these images over the six hours of the experiment, the researchers conducted the first-ever time-resolved 3D study (otherwise known as 4D studies) of the dentine microstructural changes caused by acid.
The study, published in Dental Materials, shows that acid dissolves minerals in different structures of dentine at different rates.
Research leader Dr Tan Sui, Senior Lecturer in Materials Engineering at the University of Surrey, known for her work creating improved bio-inspired materials, said:
“Relatively little is known about how exactly acid damages the dentine inside our teeth at a microstructural level. This new research technique changes that and opens the possibility of helping identify new ways to protect dental tissues and develop new treatments.”
A study conducted by the University of Campinas (UNICAMP) has found that adults can transmit the bacteria that cause periodontitis to their children, and even remain in the mouth when the children undergo various treatments.
Periodontitis, which is preceded by gingivitis, is a bacterially caused inflammation of the periodontium, the tissue supporting the teeth. It is characterised by swollen and bleeding gums and halitosis, and can result in loss of teeth in severe cases.
Should the microorganisms responsible for the disease enter the bloodstream, they may trigger other kinds of inflammation in the body. The disease can be treated by cleaning the pockets around the teeth by a dentist or dental hygienist and administration of anti-inflammatory drugs or antibiotics.
“The parents’ oral microbiome is a determinant of the subgingival microbial colonization of their children,” the article’s wrote in their conclusion, adding that “dysbiotic microbiota acquired by children of periodontitis patients at an early age are resilient to shift and the community structure is maintained even after controlling the hygiene status”.
According to the first author of the article, dental surgeon Mabelle de Freitas Monteiro, she and her group have been researching periodontitis for ten years, and have observed both parents with the disease and their children, and noted the impact on their health.
“If the findings are applied to day-to-day dental practice, the study can be said to help design more direct approaches. Knowing that periodontal disease may affect the patient’s family is an incentive to use preventive treatment, seek early diagnosis and mitigate complications,” said Monteiro, who was supported by FAPESP via two projects.
The principal investigator for both of these projects was Renato Corrêa Viana Casarin, a professor at UNICAMP’s Piracicaba Dental School (FOP), who is the last author of the article .
In Prof Casarin’s view, parents’s care of their children’s dental hygiene should start when they are still infants.
“This pioneering study compares parents with and without periodontitis,” said Prof Casarin. “In children of the former, we found subgingival bacterial colonization at a very early age. However, ‘inheriting’ the problem doesn’t mean a child is fated to develop the disease in adulthood. Hence the importance of keeping an eye open for the smallest signs and seeking specialized help.”
According to the latest national dental epidemiological survey from 2010, 18% of children aged 12 had never been to the dentist and 11.7% had experienced bleeding of the gums. Of those in the 15-19 age group, 13.6% had never visited a dental clinic. The planned 2020 survey was postponed due to COVID. According to the São Paulo State Department of Health’s latest oral health survey in 2019 revealed that 50.5% of adults aged 35-44 complained of toothache, bleeding gums and periodontitis.
In the FOP-UNICAMP study led by Casarin and Monteiro, the team colleclected samples of subgingival biofilm and plaque from 18 adults with a history of generalised aggressive (grade C) periodontitis, their children aged 6-12, and 18 orally healthy adults.
As well as a clinical analysis, the samples were also subjected to a microbiological analysis and genetic sequencing by Ohio State University researchers.
“Children of periodontitis parents were preferentially colonized by Filifactor alocis, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Streptococcus parasanguinis, Fusobacterium nucleatum and several species belonging to the genus Selenomonas even in the absence of periodontitis,” the article states. “These pathogens also emerged as robust discriminators of the microbial signatures of children of parents with periodontitis.”
Prof Casarin told Agência FAPESP that even with bacterial plaque control and vigorous brushing, children of people with the disease still had the bacteria in their mouths, whereas the effects of dental hygiene and prophylaxis were more significant in the children of healthy subjects.
“Because the parents had periodontitis, their children assumed this community with disease characteristics. They carried the bacterial information into their adult lives,” he said, adding that the analysis of bacterial colonisation indicated the transmission was more likely from the mother. The research group’s next step is working with pregnant women to prevent bacterial colonisation of their children’s mouths.
“We’ll treat the mothers during pregnancy, before the babies are born, and try to find out if it’s possible to prevent bacterial colonization from occurring,” Casarin said, adding that studies with patients will only go ahead when the pandemic is under control.
Journal information: Monteiro, M. F., et al. (2021) Parents with periodontitis impact the subgingival colonization of their offspring. Scientific Reports. doi.org/10.1038/s41598-020-80372-4.
