The research, led by Svanishvili Nino and colleagues at Tbilisi State Medical University in Georgia, together with a collaborator at the University of Brescia in Italy, employed scanning electron microscopy with energy-dispersive X-ray spectroscopy, or SEM-EDX, to quantify elemental composition at the enamel surface, the dentin–enamel junction, and the peripulpal dentin that sits closest to the tooth’s living pulp. Forty-five extracted human teeth were longitudinally sectioned under continuous water cooling, yielding ninety paired specimens. One half of each tooth served as an untouched baseline control, while its counterpart was subjected to an acid-induced demineralization protocol designed to mimic the cyclic chemistry of dental caries.

The demineralization model was deliberately realistic. For ten days, the experimental halves cycled between an acidic acetate buffer at pH 4.3, containing calcium and phosphate ions, for six hours each weekday, and a neutral artificial saliva solution for the remaining eighteen hours. This pH-cycling regimen reproduces the repeated acid attacks and recovery periods that occur naturally in the oral cavity, rather than the crude single-soak approaches used in older laboratory models. After the cycling was complete, and again after a subsequent ten-day remineralization phase, the researchers reassessed elemental concentrations in all three zones using the same SEM-EDX technique.

At baseline, the data confirmed the classic structural hierarchy of tooth tissues. Enamel showed mean calcium levels of 27.51 percent, roughly three times higher than the values recorded at the dentin–enamel junction, which averaged 9.01 percent, and peripulpal dentin, which averaged 9.99 percent. Phosphorus followed the same pattern, peaking at 13.63 percent in enamel and dropping to around 6.7 percent in both dentin regions. Fluoride, by contrast, was uniformly scarce across all zones, with concentrations hovering between 0.044 and 0.055 percent—a reminder that, in the absence of topical fluoride exposure, the natural fluoride content of dental hard tissues is minimal.

What happened next was more revealing. After the acid challenge, calcium and phosphorus fell significantly in every zone, with paired statistical analysis confirming the reductions were highly significant at p < 0.0001. But the damage was not distributed evenly. Enamel, with its dense crystalline architecture, lost relatively little calcium, declining from 27.51 to 25.20 percent. The dentin–enamel junction and peripulpal dentin fared far worse, with calcium dropping to 6.18 and 6.01 percent respectively. Most striking of all, fluoride became completely undetectable in every demineralized sample, suggesting that even the small natural reservoir of fluoride in tooth tissue is stripped away under sustained acidic conditions.

The complete disappearance of fluoride is arguably the study’s most provocative finding. The authors argue that this makes fluoride a sensitive marker of mineral loss, one that vanishes entirely rather than declining gradually. It also extends a principle previously established for superficial enamel—that fluoride is rapidly depleted under acid challenge—into the deeper architecture of the tooth. Under severe acid exposure, the structural fluoride reservoir appears to be depleted comprehensively across the tooth cross-section, not just at the surface, underscoring the vulnerability of the underlying dentin zones that traditional caries research has often overlooked.

Following demineralization, the experimental halves were randomly assigned to one of three fluoride-based remineralization protocols, with fifteen specimens in each group. The first received a daily application of fluoride varnish for ten days. The second was treated twice daily with fluoride toothpaste, followed by light rinsing. The third underwent the identical toothpaste regimen but without rinsing, leaving the residual paste in contact with the tissue. After the treatment period, all three groups showed partial restoration of calcium and fluoride levels, confirming that fluoride-based interventions can drive meaningful mineral redeposition even in a laboratory setting.

The differences between the protocols were subtle but telling. Fluoride varnish produced the highest fluoride incorporation in enamel, reaching 0.316 percent—more than three times the level achieved by either toothpaste regimen—and this difference was statistically significant at p < 0.05. The no-rinse toothpaste group showed slightly higher fluoride retention than the rinsed group, a pattern consistent with the argument that prolonged ion availability is essential for diffusion past the superficial layers. However, when it came to calcium and phosphorus recovery, no statistically significant differences emerged among the three treatment groups in any zone, and the varnish’s fluoride advantage did not translate into superior crystal-lattice restoration in the dentin regions.

This disconnect carries an important implication. The authors suggest that the organic collagen matrix of dentin acts as a rate-limiting barrier to mineral precipitation, meaning that high superficial fluoride accumulation does not automatically guarantee uniform, tooth-wide remineralization. In other words, the chemistry of rebuilding mineral in enamel, which is almost entirely inorganic, differs fundamentally from the chemistry of rebuilding mineral in dentin, which is interwoven with a protein scaffold that responds to ionic changes in its own way. This three-dimensional view of intra-tooth mineral dynamics—tracking elemental fluxes simultaneously across enamel, the junction, and deep dentin within a paired split-sample design—is what the authors identify as the study’s principal contribution to the literature.

The findings arrive amid a growing global concern about dental caries, which remains one of the most widespread chronic diseases worldwide and is driven by a multifactorial interplay of biofilm composition, dietary habits, saliva properties, and oral hygiene. By demonstrating that dentin—particularly at the dentin–enamel junction and near the pulp—is more susceptible to demineralization than enamel, and that different fluoride delivery methods produce regionally distinct remineralization profiles, the study offers a more nuanced framework for designing preventive protocols. The authors caution that their ex vivo model cannot fully replicate the complexity of the oral environment, that the sample size was constrained by specimen availability, and that the broad age range of donors, from sixteen to sixty years, was not stratified. Future work, they note, should incorporate microhardness testing and micro-CT imaging to assess structural recovery alongside elemental composition, and should be conducted under conditions more closely approximating clinical reality. For now, the message is clear: fluoride works, but where and how well it works depends on which part of the tooth you ask.

Subject of Research: Elemental changes in tooth enamel and dentin during demineralization and fluoride-induced remineralization measured by SEM-EDX

Article Title: Elemental changes in tooth hard tissues during demineralization and fluoride-induced remineralization: an SEM-EDX study

Article References: Nino, S., Marina, M., Labanca, M., & Dea, V. (2026). Elemental changes in tooth hard tissues during demineralization and fluoride-induced remineralization: an SEM-EDX study. Acta Biochimica Polonica, 73, Article 16706. https://doi.org/10.3389/abp.2026.16706

Image Credits: AI Generated

DOI: 10.3389/abp.2026.16706

Keywords: dental caries, tooth enamel, dentin, fluoride, remineralization, SEM-EDX, demineralization, oral health, Elemental, changes, tooth, hard

Marine subsidization is a well-documented process on modern coastlines. Marine algae, seagrasses, and other coastal plants produce organic matter that washes ashore or is carried inland by tides, storms, and scavenging animals, enriching terrestrial soils and feeding land-based consumers. Ecologists have long recognized this cross-boundary nutrient transfer in contemporary settings, from seabird colonies fertilizing islands to kelp forests sustaining coastal forests. Yet, according to the authors, this phenomenon has rarely been considered in reconstructions of Cretaceous terrestrial coastal ecosystems, despite the fact that many of the most famous dinosaur-bearing rock formations in North America were deposited along the margins of the Western Interior Seaway, a vast inland sea that split the continent.

The research team focused on a geochemical signature that had puzzled paleontologists for years. Studies of Cretaceous coastal ecosystems frequently reported anomalously high carbon isotope values, expressed as δ13C, in the bioapatite of dinosaurs and other vertebrates, values much higher than expected when compared to the presumed dietary carbon sources of these animals. In terrestrial C3 plant communities, which dominated Cretaceous floras, δ13C values are relatively low. Marine plants and macroalgae, however, use a modified C3 photosynthetic pathway that results in comparatively enriched δ13C values. Any animal consuming marine-derived plant material or prey that had themselves fed on such resources should therefore carry a distinctive isotopic fingerprint in its tissues.

To test whether Cretaceous coastal vertebrates were actually tapping into marine food sources, the researchers analyzed stable carbon isotopes preserved in tooth enamel from a range of vertebrate taxa, including fish, neosuchian crocodilians, and dinosaurs. Tooth enamel is remarkably resistant to chemical alteration over geological time, making it one of the most reliable archives of an animal’s dietary carbon signature. The team compared enamel from coastal assemblages against enamel from the Cloverly Formation of Wyoming and Montana, an inland intercontinental deposit where marine influence was expected to be minimal based on established stratigraphic interpretations.

The coastal formations examined span a broad geographic and temporal range across western North America. They include the Dunvegan Formation of British Columbia and Alberta in Canada, the Wayan Formation and Draney Limestone of Idaho, the Antlers Formation of Oklahoma and Texas, the Woodbine Group and Lewisville Formation of Texas, and the Mussentuchit Member of the Cedar Mountain Formation in Utah. Together, these units represent diverse coastal environments that existed at various points during the Cretaceous period, from estuarine and deltaic settings to nearshore floodplains.

The results were striking. Coastal vertebrate enamel exhibited δ13C values up to more than 5.5 per mil above what would be expected from animals feeding exclusively on terrestrial C3 vegetation. This enrichment is consistent with the incorporation of marine-derived carbon into the diets of coastal organisms. In contrast, the upland assemblages from the Cloverly Formation showed no comparable enrichment, supporting the interpretation that the elevated isotope values in coastal settings reflect genuine marine subsidization rather than some artifact of preservation, diagenesis, or analytical methodology.

The implications of this finding extend beyond simply confirming that some dinosaurs ate things that came from the sea. Back-calculations of dietary plant δ13C values from dinosaur herbivore enamel have traditionally relied on assumptions about the isotopic composition of terrestrial C3 plants. If coastal herbivores were consuming marine algae, seagrasses, or animals that had fed on such resources, then previous estimates of dietary plant δ13C values systematically underestimated the true range of carbon sources available to these animals. Future estimations of Cretaceous vertebrate isotopic offsets must therefore account for the influx of 13C-enriched, marine-derived organic matter into terrestrial food webs.

Beyond the technical implications for isotope ecology, the study suggests that marine subsidization may have functioned as a major ecosystem and trophic driver in Cretaceous coastal environments. If substantial quantities of marine nutrients and energy were regularly flowing onto land, they could have supported higher densities of vertebrate consumers than terrestrial primary production alone would allow. This could help explain the remarkable abundance and diversity of large-bodied dinosaurs and other vertebrates in coastal depositional settings, which have sometimes been attributed solely to favorable terrestrial conditions or preservational biases.

The research also highlights the value of comparative approaches that pair coastal and inland deposits. By establishing that the Cloverly Formation, an inland deposit, lacks the isotopic enrichment seen in coastal assemblages, the study provides a baseline against which marine influence can be detected. This framework can now be applied to other Cretaceous formations around the world, potentially revealing the geographic extent and temporal variability of marine subsidization during the age of dinosaurs.

As paleontologists continue to reconstruct ancient ecosystems with ever-greater precision, the recognition that ocean and land were deeply intertwined during the Cretaceous adds a new dimension to our understanding of dinosaur ecology. The giants that roamed the shorelines of the Western Interior Seaway were not simply inhabitants of a terrestrial world; they were participants in a dynamic system where marine and terrestrial energy flows converged, shaping the structure and productivity of ecosystems in ways that scientists are only now beginning to appreciate.

Subject of Research: Marine-derived nutrient subsidies in Cretaceous coastal dinosaur ecosystems revealed by stable carbon isotope analysis of tooth enamel

Article Title: Marine subsidization of dinosaurian ecosystems

Article References: Forster, C. W., Suarez, C. A., Cullen, T. M., Zanno, L. E., & Hyland, E. G. (2026). Marine subsidization of dinosaurian ecosystems. Frontiers in Ecology and Evolution, 14, Article 1895247. https://doi.org/10.3389/fevo.2026.1895247

Image Credits: AI Generated

DOI: 10.3389/fevo.2026.1895247

Keywords: marine subsidization, Cretaceous, dinosaurs, stable carbon isotopes, tooth enamel, Western Interior Seaway, paleoecology, coastal ecosystems, δ13C, food webs, Frontiers in Ecology and Evolution, vertebrate paleontology

The study, led by Raquel Borges Amancio de Lima and Alberto Carlos Botazzo Delbem of São Paulo State University (UNESP), together with colleagues at the Federal University of São Carlos, began with a deceptively simple chemical idea. Condensed phosphates — compounds in which phosphate tetrahedra are linked through P–O–P bridges — are known to adsorb strongly onto calcium-containing mineral surfaces. Once attached, they alter surface charge and free energy, boost calcium retention, and can build a phosphate-rich interfacial layer that slows the diffusion of acids and dissolved mineral species. Sodium cyclohexaphosphate (NaCHP), a six-membered ring of phosphate groups, had already shown promise in prior studies, but with a critical caveat: on its own, it exhibited little protective effect against mineral loss. Its benefits had only emerged when paired with fluoride, because its action depended on scavenging calcium ions from the surrounding environment.

The researchers reasoned that if the limitation of NaCHP was its dependence on externally available calcium, the solution was to build the calcium directly into the molecule. Using a strong cation-exchange resin, they stripped sodium ions from commercial NaCHP dissolved in deionized water, producing cyclohexaphosphoric acid at a pH of roughly 1.0. A carefully measured calcium hydroxide suspension was then added dropwise under constant stirring until the pH reached 5.8, triggering the precipitation of the new salt, Ca6(P6O18)2. After incubation at 37 degrees Celsius for 24 hours, vacuum filtration, drying, and 12 hours of ball-mill deagglomeration, the team had a white powder of irregular, heterogeneous particles ready for rigorous scrutiny.

Characterization confirmed the transformation. Scanning electron microscopy revealed the granular morphology of both compounds, while energy-dispersive X-ray spectroscopy detected calcium peaks in CaCHP where sodium peaks had appeared in the precursor. X-ray diffraction told perhaps the most interesting structural story: compared with NaCHP, the CaCHP pattern showed narrower, more intense reflections, a reduced amorphous halo, and new diffraction peaks at both low and high angles — evidence that calcium incorporation produced a more ordered, more crystalline structure. Fourier-transform infrared spectroscopy preserved the signature P–O–P vibrational bands of the cyclic phosphate framework, while the absence of a narrow hydroxyl stretching band confirmed that no residual calcium hydroxide remained as a separate crystalline phase. In short, the cyclic ring survived the swap, and the material emerged structurally tighter than before.

With the compound in hand, the team turned to the critical question: does it actually protect enamel? They prepared eight experimental toothpastes — three containing CaCHP at 0.25, 0.5, or 1 percent, three with NaCHP at the same concentrations, a placebo, and a positive control with 0.24 percent sodium fluoride, equivalent to the 1100 ppm fluoride found in standard toothpastes. All formulations showed near-neutral pH and chemical compositions matching their nominal recipes. The test substrates were 192 polished bovine enamel blocks, divided into two conditions. Half remained sound; the other half were pre-softened with a one-minute bath in 0.75 percent citric acid at pH 3.5, mimicking the early stage of erosion. Before treatment, every block was immersed in pooled human saliva for one hour to form the acquired pellicle, the thin protein film that naturally coats teeth.

The erosive protocol was deliberately brutal. Each block was treated with its assigned toothpaste slurry for two minutes, then subjected to four consecutive one-minute citric acid challenges, with surface hardness measured by Knoop microhardness after each exposure. Because hardness inversely tracks mineral content, the percentage change in surface hardness served as a sensitive proxy for demineralization. The results were analyzed with a three-way mixed repeated-measures ANOVA, and the interaction between treatment group, substrate condition, and experimental phase proved statistically significant — meaning the protective effect of each formulation depended on both the state of the enamel and the number of acid attacks it had endured.

On sound enamel, the story unfolded in stages. After the first acid challenge, every treated group outperformed the placebo, and 1 percent CaCHP was statistically indistinguishable from fluoride. That parity held through the second and third challenges, with both fluoride and 1 percent CaCHP showing the smallest hardness losses among all groups. Only after the fourth consecutive acid bath did the protection fade, with neither fluoride nor CaCHP differing significantly from the placebo. On softened enamel, however, the outcome was more striking. There, 1 percent CaCHP remained comparable to 0.24 percent NaF and significantly more protective than both the placebo and every NaCHP formulation even after the fourth challenge (p < 0.001). The sodium precursor, by contrast, never achieved standalone protection at any concentration — a direct experimental vindication of the calcium-incorporation strategy.

Scanning electron microscopy of treated surfaces offered a qualitative glimpse of the underlying mechanism. Softened enamel treated with the placebo displayed the classic honeycomb-like appearance of exposed, dissolved enamel prisms, while fluoride- and CaCHP-treated surfaces showed less evident etching and fine deposits within interprismatic spaces. The authors are careful to note that these observations come from a small exploratory subset and cannot statistically distinguish treatments, but they are consistent with the idea that CaCHP acts differently from fluoride. Fluoride’s anti-erosive action relies on calcium-fluoride-like reservoirs that are themselves vulnerable to dissolution below pH 4. CaCHP, by contrast, may work by combining the surface affinity of cyclic phosphates with an intrinsic calcium supply, fostering calcium-phosphate-rich interfacial species that modify the local ionic environment and make the mineral–solution interface less favorable to dissolution. Two different chemistries, one similar outcome.

Why did protection persist longer on softened enamel than on sound enamel? The researchers propose that the roughened, prism-exposed topography of pre-softened surfaces offers greater surface area and more reactive sites, allowing protective deposits to become mechanically entrapped within interprismatic regions. This finding carries a practical implication: the physicochemical condition of the substrate itself shapes how well preventive treatments perform, a variable that future formulation studies cannot afford to ignore. The authors also stress the limits of their model. The in vitro design omits abrasion, salivary flow dynamics, and biofilm activity, and because it specifically addressed acid-driven demineralization, the findings cannot be extrapolated directly to bacterial caries. Ion-release kinetics, long-term stability, and the precise chemical identity of the surface deposits remain to be determined.

Even with those caveats, the significance of the result is hard to overstate. This is the first demonstration that calcium incorporation into a cyclohexaphosphate framework yields a condensed phosphate with substantial standalone anti-erosive activity — a property its sodium-containing ancestor entirely lacked. The researchers position 1 percent CaCHP not as a fluoride replacement but as a complementary bioactive agent with a potentially distinct interfacial mechanism, suitable for future evaluation either alone or in combination with fluoride. As dental erosion rises worldwide alongside consumption of acidic foods and drinks, materials that can be delivered through the most universal of oral care vehicles — the daily toothpaste — represent a genuinely scalable line of defense. A ring of six phosphate groups, threaded with calcium, may prove to be one of the more elegant molecular inventions in the ongoing battle to keep enamel intact.

Subject of Research: Synthesis of calcium cyclohexaphosphate and its protective effect against enamel erosion

Article Title: Calcium cyclohexaphosphate as a novel bioactive condensed phosphate: synthesis, physicochemical characterization, and protective effects on sound and softened enamel under erosive conditions

Article References: de Lima, R. B. A., Cavazana, T. P., Guisso, L. P., de Morais, L. A., Hosida, T. Y., Pessan, J. P., Silos Moraes, J. C., de Camargo, E. R., & Botazzo Delbem, A. C. (2026). Calcium cyclohexaphosphate as a novel bioactive condensed phosphate: synthesis, physicochemical characterization, and protective effects on sound and softened enamel under erosive conditions. Journal of Materials Science. https://doi.org/10.1007/s10853-026-13843-0

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13843-0

Keywords: calcium cyclohexaphosphate, dental erosion, tooth enamel, condensed phosphates, fluoride, toothpaste, biomaterials, hydroxyapatite, demineralization, surface hardness, X-ray diffraction, oral care

The method rests on a simple but powerful property of human biology. Tooth enamel forms during childhood and, unlike bone, is never remodelled or replaced throughout life. Any lead absorbed by a child while the enamel is mineralising is permanently sealed into its crystalline structure, creating a chemical record of the environment in which that person grew up. Because lead is a toxic metal that damages the nervous, renal and reproductive systems, and because medieval mining and smelting generated multiple routes of exposure through contaminated dust, fumes and ore-handling materials, the enamel of buried individuals preserves a direct measure of industrial pollution at the level of the household rather than the landscape. By measuring lead concentrations in enamel from people buried between roughly 650 and 1500, the researchers could reconstruct childhood exposure across the entire span of the medieval industry, from its obscure beginnings to its documented medieval peak.

The chronological breakthrough came from comparing the Peak District cemeteries with populations from across Britain, spanning the Neolithic through to the Industrial Revolution. The analysis showed that children raised in the Derbyshire mining communities of the seventh century carried lead burdens equal to, or greater than, those measured in children living in the industrialised cities of roughly 1750 to 1850. This is the first study to analyse lead contamination in the bodies of people who actually mined and smelted lead in western Europe’s largest medieval lead-producing region, and it provides the first absolute evidence that post-Roman production there was established by the mid-seventh century AD. By the mid-eighth century, the scale of operations had grown enough to contaminate the wider environment around mining centres such as Castleton, embedding the industry in the regional landscape within a few generations of its revival.

Christopher Loveluck, Professor of Medieval European Archaeology at the University of Nottingham’s Department of Classics and Archaeology, said the team was delighted to have finally confirmed definitively the date by which the early medieval lead industry was established in the Peak District, by the mid-seventh century AD, through evidence provided by the people themselves. That confirmation, he noted, supplies the foundations of what became western Europe’s largest lead-producing region between the late twelfth and sixteenth centuries. The significance is difficult to overstate. Lead was an essential medieval commodity, used for roofing, piping, coinage and the manufacture of vessels, and the Peak District’s ores underpinned economies and politics far beyond central England. Until now, however, historians and archaeologists could only infer when production resumed after the Roman withdrawal, because the physical evidence had been systematically erased by later exploitation of the same deposits.

Perhaps the most striking finding concerns inequality. Exposure to the industry’s pollution was not distributed evenly across society. Individuals buried with high-status grave goods, including weapons, generally carried much lower lead concentrations in their enamel than those from less richly furnished burials. The pattern suggests that elites may have controlled or benefited from lead production while lower-status households were more directly involved in the physically dangerous work of processing ore and smelting, exposing children within those communities to far higher levels of contamination. In chemical terms, the archaeology of status and the toxicology of childhood align: the richer the grave, the cleaner the enamel. This offers a rare, biologically grounded view of how the profits and hazards of a medieval extractive industry were divided between those who directed it and those who laboured within it.

The study also highlights the potential vulnerability of women in these mining communities. Three women analysed in the research died between the ages of around seventeen and twenty-five, and all showed elevated childhood lead exposure. While the relationship between childhood lead burden and premature death remains complex, the results suggest a possible association between high lead levels and increased health risks, one that may have been particularly significant during pregnancy, when lead stored in the skeleton can be released back into the bloodstream. Dr Anna Bloxam, Co-Director of the Castleton excavations, said that modern studies show lead can have profoundly harmful effects on the health and development of children, and that there is no safe level of exposure. She noted that all the individuals in the study survived into adulthood, but were exposed while young and growing, and that the skeletons show most of the men studied lived until middle or old age whereas the women primarily died much earlier, in young adulthood. In her view, girls and boys alike were raised in dangerously polluted home environments, an exposure likely to have caused negative health effects in life and perhaps contributed to higher rates of premature death among women of child-bearing age.

The enamel record also tracks the industry’s long arc of expansion. Lead exposure remained high throughout the medieval period and reached its greatest levels during the late twelfth and early thirteenth centuries, precisely when historical records show that Peak District lead production attained its medieval height and when environmental archives across Europe register rising atmospheric lead pollution. The human data dovetail with earlier studies of Alpine ice cores and of sediment cores from river channels, lakes and peat bogs, which identified a marked rise in atmospheric lead around 1200 attributed especially to British production. What the new research adds is the direct link between those environmental signals and the people living and working within one of Europe’s major lead-producing landscapes. The pollution recorded in distant glaciers can now be tied, chemically and chronologically, to the children who grew up breathing the fumes of the furnaces that caused it.

Isotopic analysis of the same teeth added an unexpected social finding: the mining communities of the Peak District were remarkably stable. Most individuals studied had grown up locally, indicating that the specialised knowledge of mining and smelting was passed down through generations of local families rather than sustained by large numbers of incoming workers. This intergenerational transmission of craft expertise helps explain both the durability of the industry and the persistence of its health burden, since the same households that held the technical skills also absorbed the toxic consequences across childhood after childhood. The research builds on decades of earlier archaeological investigation in the region, including work by Colin Merrony at the University of Sheffield, who identified and excavated key medieval burial sites. The combined samples came from three cemetery populations: Wigber Low in the Derbyshire White Peak, dating to the seventh century; Joule Yard at Castleton, dating from the seventh to eleventh centuries; and Spital Field at Castleton, dating from the twelfth to fifteenth centuries, together providing a unique record of communities living through the revival and expansion of medieval lead production.

Merrony said that recent excavations in Castleton have provided a great deal of new information about the people living in the Hope Valley during the medieval period, revealing more about the size of the population and showing from the archaeological evidence that these working communities were involved in industries requiring hard physical labour. The new study, he said, has enabled researchers for the first time to look beyond that broader understanding and see more deeply into the profound impact lead production had on individuals and the communities they lived in. By bringing together archaeology, history, chemistry and environmental science, the research shows how one of Britain’s most significant industrial landscapes developed, and how its effects can still be detected more than a millennium later. The findings relate to medieval mining and smelting between the seventh and fifteenth centuries and do not reflect modern environmental conditions; the legacy of historic mining in the Peak District is now well understood and carefully monitored, with land management, conservation and environmental regulation minimising any risks from former mining activity. The results will form part of the developing medieval archaeological research agenda for the Peak District National Park, funded by Historic England, and will be shared with the public through a temporary display in the region over autumn and winter 2026-27, showcasing the findings alongside archaeological discoveries from the Castleton excavations. The research was funded and supported by the University of Nottingham, the Peak District National Park Authority, Castleton Historical Society, the University of Sheffield, Sheffield Museums and Historic England, and is published in the journal Antiquity.

Subject of Research: Medieval lead mining and smelting in the Derbyshire Peak District reconstructed through lead exposure in human tooth enamel

Article Title: New research traces the origins and human impact of Britain’s largest medieval lead industry through ancient teeth

Article References: New research traces the origins and human impact of Britain’s largest medieval lead industry through ancient teeth. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Peak District, lead mining, medieval archaeology, tooth enamel, lead exposure, Castleton, Antiquity, University of Nottingham, seventh century, industrial pollution, isotopic analysis, public health

Marine subsidization is a well-documented ecological process in the modern world. Storms and tides routinely deposit marine algae, dead fish, and other ocean-derived organic matter onto beaches, where land-dwelling animals and other organisms exploit it as a convenient food source. Today, this subsidy is especially common in coastal ecosystems and becomes even more important when terrestrial food supplies falter, for example during droughts when inland vegetation is scarce. Seabirds, lizards, mammals, and insects all take advantage of these windfalls. What has remained unknown is how deep into Earth’s history this behavior extends. The new study provides the first identification of marine subsidization in prehistoric ecosystems, pushing the practice back more than 100 million years to the age of dinosaurs.

The key to the discovery lies in a chemical fingerprint carried in tooth enamel. Plants contain both light carbon-12 and heavy carbon-13 isotopes, and the ratio between them, expressed as the delta carbon-13 value, differs depending on where the plants grow. Marine plants generally carry higher carbon-13 values than land plants, and this signature passes up the food chain into the bodies of the animals that eat them. When an animal consumes food, the isotopic ratio is incorporated into its tooth enamel with a predictable upward shift, a difference of roughly 11 to 13 parts per thousand observed in the tooth enamel of living animals. This consistency makes enamel a reliable archive of diet, preserving chemical evidence long after soft tissues have vanished.

For decades, however, dinosaur teeth have presented a puzzle. The difference between the isotopic values of their presumed plant diets and the values recorded in their enamel was consistently higher than the range seen in living animals. Their delta carbon-13 values were also elevated beyond what would be expected for animals eating exclusively land-grown plants, which carry lower values than most marine plants. If dinosaurs, or the prey animals they fed upon, had been consuming marine matter, that extra input of heavy carbon could neatly explain the discrepancy. Testing this hypothesis required comparing fossils from animals that lived near the sea with those from animals that lived far inland, where marine food sources were simply unavailable.

The research team assembled fossils from sites that once lay along the coastlines of the Western Interior Seaway, a vast inland sea that split North America into two landmasses around 100 million years ago, and from the ancient Gulf of Mexico coastline. For comparison, they included fossils from land-locked sites far from any marine influence. The sampled deposits formed during two windows of the Cretaceous Period: the early Albian, roughly 113 to 107 million years ago, and the early Cenomanian, approximately 100 to 96 million years ago. The researchers powdered the fossil specimens for isotopic composition analysis and also applied laser ablation techniques, allowing them to compare chemical signatures across different regions, latitudes, and geological ages.

The results were striking. The delta carbon-13 values recorded in fossils from coastal sites were not only higher than those from the land-locked formation, but they were also consistent between coastal sites regardless of latitude or age. That uniformity is significant, because it points to a shared biological cause rather than random geological variation. According to the authors, coastal-dwelling organisms must have eaten some kind of organic matter originating from the ocean, or prey that had done so themselves. The pattern appeared across the food web, from fish to megaherbivores, indicating that the extra carbon source must have sat low in the food chain to influence both aquatic and terrestrial animals simultaneously.

Identifying the culprit required a process of ecological elimination. The mystery food source had to be an organism living in coastal but not inland habitats, and it had to remain available over many millions of years to explain the consistency of the signal across the Albian and Cenomanian deposits. Few candidates meet these criteria, the researchers concluded, besides marine macroalgae and macrophytes, in other words, seaweeds. Given that large coastal herbivores today almost universally supplement their diets with seaweed when the opportunity arises, the team argues it is likely that most of the sampled herbivorous dinosaurs behaved no differently, browsing on mats of algae and other marine vegetation left behind by the retreating tide.

Not every dinosaur in the dataset joined the beachcombing behavior, and that exception strengthens the case. Tenontosaurus tilletti, a large herbivorous dinosaur found in many locations throughout the Cretaceous, showed no evidence of marine consumption. Its delta carbon-13 value closely resembled that of modern animals that feed exclusively on land-growing plants. This contrast is important because it rules out alternative explanations, such as geological processes that might have altered the chemical traces in tooth enamel after the animals died. If burial conditions had uniformly shifted the isotopic values, all specimens from the same deposits should show the effect. Instead, the elevated signatures track dietary preference, species by species, exactly as a genuine dietary signal would.

The study does have limits that the authors acknowledge. The dataset clearly demonstrates marine subsidization in the coastal deposits examined, but it lacks data from polar and equatorial latitudes during the early Albian and early Cenomanian. Future research, the team notes, needs to determine whether the phenomenon was common across different latitudes and other time periods, such as the preceding Jurassic Period or the subsequent early Cenozoic Era. Even so, the implications reach beyond paleontology. As Forster concluded, the study emphasizes the connections between terrestrial and marine ecosystems, which are deeply intertwined and have been for hundreds of millions of years. Understanding those ancient linkages, the authors argue, highlights the importance of protecting the environmental connections that still exist along coastlines today.

Subject of Research: Marine subsidization of dinosaur-era coastal ecosystems revealed through carbon isotope analysis of fossil tooth enamel

Article Title: Dinos snacked on seafood washed up on ancient beaches, fossil study shows

Article References: Dinos snacked on seafood washed up on ancient beaches, fossil study shows. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: dinosaurs, marine subsidization, carbon isotopes, tooth enamel, Cretaceous, Western Interior Seaway, seaweed, paleoecology, coastal ecosystems, Frontiers in Ecology and Evolution, Tenontosaurus, food webs

A new study from the laboratory of Professor Janet Moradian-Oldak at the University of Southern California points to a surprisingly small piece of one protein as a critical part of the answer. The work, published in Volume 18 of the International Journal of Oral Science on August 20, 2026, focuses on ameloblastin, or Ambn, the second most abundant extracellular matrix protein in developing enamel matrix. Rather than examining the protein as a whole, the team zeroed in on a very short segment: an amphipathic helix, or AH motif, a stretch of amino acids that folds into a helix with one hydrophobic face and one hydrophilic face. This dual character allows such motifs to bind to cell membranes, physically linking the surrounding enamel matrix to the surfaces of the cells that are building it. The evolutionary pressure on this little segment appears to be intense. Within the eleven-amino-acid region targeted in the study, nine residues were identical across mouse, pig, and human ameloblastin, a degree of conservation that made the motif a compelling candidate for a mechanism connecting matrix and cell.

To test what this motif actually does in a living animal, the researchers turned to CRISPR-Cas9 genome editing. They generated mice in which the hydrophobic residues spanning amino acids Lys76 to Pro86 of the AH motif were deleted, removing the membrane-facing portion of the helix while leaving the rest of the protein intact. Before moving to the animal model, the team took care to verify that the mutation had not simply destroyed ameloblastin as a molecule. Recombinant mutant protein could still self-assemble into larger structures, although the assembly was less uniform than that of the wild-type protein. Crucially, the mutant protein’s ability to interact with ameloblast-lineage cells was markedly reduced. In other words, the edit selectively weakened the specific cell-binding function the investigators wanted to interrogate, while largely sparing the protein’s other biochemical properties. ‘Using this model, we reinforce the concept of multifunctionality of Ambn, with a selective disruption of Ambn–ameloblast interactions,’ said Professor Moradian-Oldak, underscoring that a single matrix protein can carry separable duties encoded in different structural domains.

When the mutant mice grew up, their teeth told a strikingly nuanced story. Homozygous mutant animals formed enamel that reached essentially normal thickness, so by the crude measure of quantity, enamel formation seemed intact. The quality of the material, however, was another matter entirely. Micro-computed X-ray tomography revealed delayed secretory and maturation stages of enamel development, slower densification over time, and a final mature enamel density of only about seventy percent of the wild-type plateau. Scanning electron microscopy showed a rough, sandpaper-like surface and a dramatic loss of the usual rod-and-interrod organization that defines healthy enamel. The mineral was there, but its internal architecture was not. This clean split between thickness and quality carries real biological weight. The expression levels of the major enamel matrix genes, AmelX and Amelotin-related AmelX and Enam, remained normal in the mutants, which helps explain why the overall amount of enamel could still be deposited. The AH motif appears to perform something far more specific than bulk production: it organizes the cell polarity and matrix patterning needed to convert deposited enamel into a densely mineralized, prismatic material.

Looking directly at the cells confirmed the depth of the disruption. Ameloblasts in the mutant mice were nineteen to twenty-three percent shorter than normal, a measurable change in the geometry of the enamel-forming layer. The Golgi apparatus, which in healthy ameloblasts is positioned in an orderly way to support the directional secretion of enamel matrix, showed disturbed positioning. Polarity proteins such as Pard3 and claudin-1, which normally help define the apical and basolateral identity of these highly asymmetric cells, were mislocalized. Ameloblastin itself lost its characteristic localization along the distal cell membrane and along Tomes’ processes, the specialized extensions of ameloblasts that guide enamel rod formation and which were rudimentary in the mutant animals. Together, these observations sketch a coherent mechanism: the amphipathic helix anchors ameloblastin to the cell surface, and that anchoring is required to establish and maintain the cellular polarity on which prismatic enamel depends.

The polarity defects in the mutants were mirrored by changes in cell signaling. Beta-catenin, a central transducer of the Wnt signaling pathway, shifted into the nucleus, where it can alter gene expression programs governing cell fate and organization. Phosphorylated Smad2/3, a readout of TGF-beta pathway activity, showed increased nuclear localization as well. Meanwhile, the intensity of RhoA signaling, a key regulator of the cytoskeleton and of cell shape, was reduced. Taken together, these alterations point to the possible involvement of the Wnt, TGF-beta, and RhoA-ROCK pathways in mediating the effects of the ameloblastin amphipathic helix on ameloblast organization. The matrix, in this view, is not merely a passive product of the cells; it actively talks back to them, and the AH motif appears to be one of the molecular languages of that conversation.

One of the most revealing aspects of the study came from the heterozygous mice, which carried only one copies of the disrupted allele and still produced normal enamel mineral density. Despite that apparently normal bulk mineralization, these animals showed disrupted prism-interprism architecture, altered membrane interaction, and defects in cell polarity. The finding suggests that the AH motif has a specific functional role that goes beyond simple protein dosage. Half the normal complement of functional cell-binding motif is enough to compromise the organization of enamel without changing its quantity, which argues that the motif acts as a dedicated architectural signal rather than as a generic contributor to matrix volume. This kind of separation of functions within a single protein segment is exactly what one might expect from a strongly conserved motif that has been optimized by evolution for a narrow but essential task.

The research also has a direct and clinically meaningful connection to hereditary enamel disease. Variants in the human AMBN gene are associated with amelogenesis imperfecta, a group of inherited conditions in which enamel forms abnormally or fails to form properly, often leading to sensitive, discolored, or structurally weak teeth. A previously reported truncation within the AH-motif region of the protein has been linked to contrasting clinical phenotypes and inheritance patterns, and the new mouse model now provides an experimental framework for understanding why damage to this tiny region of the protein can have such outsized consequences. ‘Our new mouse model gives researchers a powerful way to uncover how defects in this tiny region of Ambn disrupt normal enamel development. Although our findings do not yet translate into a treatment, they highlight promising biological targets for future approaches to preventing or repairing enamel defects,’ concluded Professor Moradian-Oldak.

Because human enamel, unlike bone, cannot regenerate or remodel itself once it is formed, the biology of enamel formation carries unusually high stakes for dentistry. Every strategy for preventing caries, repairing early lesions, or engineering bioinspired replacement materials ultimately depends on understanding how the original tissue was built. By demonstrating that an eleven-amino-acid membrane-binding helix in ameloblastin is sufficient to determine whether enamel becomes a densely mineralized, prismatic material or a structurally inferior substitute, the USC team has identified a molecular handle on one of the most fundamental steps in tooth development. The amphipathic helix joins a growing list of matrix-derived signals that sculpt tissue architecture by organizing the cells that build it. For the field of enamel biomineralization, and for the long-term goal of growing or regenerating enamel-like materials in the clinic, the message of this study is clear: sometimes the most important instructions come from the smallest parts of the blueprint.

Subject of Research: Role of the ameloblastin amphipathic helix motif in ameloblast polarity and prismatic enamel formation

Article Title: Ameloblastin amphipathic helix helps tooth-building cells create enamel's hidden architecture

Article References: Ameloblastin amphipathic helix helps tooth-building cells create enamel's hidden architecture. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: ameloblastin, ameloblasts, tooth enamel, enamel formation, amelogenesis imperfecta, CRISPR-Cas9, cell polarity, biomineralization, Wnt signaling, TGF-beta, RhoA-ROCK, International Journal of Oral Science