teeth – Lightsources.org

Microscopic study of milk teeth reveals mystery of death of Iberian culture newborns buried inside homes

2024/10/092024/10/10

A UAB study in collaboration with the UVic-UCC and the ALBA Synchrotron concludes that the Iberian culture (8th to 1st centuries BCE) newborns buried within domestic spaces died of natural causes, such as complications during labour or premature births, and not due to ritual practices. Researchers applied an innovative methodology, based on the study of the neonatal line of baby teeth using optic microscopy and microflourescence with synchrotron light, to analyse the teeth from 45 infant skeletal remains and precisely identified the moments of both birth and death.

The Iberian culture inhabited the eastern and southern coastal regions of the Iberian Peninsula during the Iron Age (8th to 1st centuries BCE). The most common funeral ritual of the Iberians was the cremation of the deceased and subsequent disposal of the remains in urns that were buried in necropolises. However, archaeologists have also discovered burials with remains of newborns who had not been cremated, but were rather located in areas used for housing or production purposes. These burials have generated controversy among experts. Hypotheses suggested that they could have died of natural causes, be proof of infanticide, or even of ritual sacrifices.

A study published in the Journal of Archaeological Science now provides very precise evidence in favour of the hypothesis that these newborn infants died mainly from natural causes and that, therefore, are a reflection of the high infant mortality during the first year of life in the period studied.

Researchers reached this conclusion after studying 45 infant skeletal remains from five Catalan archaeological sites from the Iberian period: Camp de les Lloses (Osona), Olèrdola (Alt Penedès), Puig de Sant Andreu and Illa d’en Reixac (Baix Empordà), and Fortalesa dels Vilars d’Arbeca (Lleida).

Researchers have applied an innovative methodology based on the histological and elemental analysis (tissue and chemical composition) of the deciduous or primary teeth present in the infant skeletal remains. By means of optical microscopy, researchers were able to visualise the growth lines of the dental crown generated in the formation of teeth during intrauterine life and until shortly after birth. This led them to identify the presence of the neonatal line that is produced at the moment of birth.

The analysis allowed them to identify the moment of birth of the individuals and their survival, as well as to determine very precisely the chronological age at the moment of death. The chronological age takes into account the time elapsed since birth and not the biological development of the skeleton.

Almost half of the infants died during the perinatal period, specifically between the 27th week of gestation and the first week of life. The vast majority of perinatal deaths did not survive the moment of birth, and many of these infants died due to premature births.

“These data reinforce the hypothesis that the majority of perinatal deaths were caused by natural factors, such as birth complications or health problems associated with prematurity, and not by cultural practices such as infanticide or ritual sacrifice, as some hypotheses have suggested,” says Xavier Jordana, Associate Professor in the Biological Anthropology Unit of the Department of Animal Biology, Plant Biology and Ecology at the UAB.

Researchers also observed that of the twenty or so infants that survived beyond the first week of life, the longest lived 67 days.

“In the sites studied, no burial of an infant beyond two months of life has been identified. This leads us to think that it could probably have been due to a cultural practice of burying in domestic spaces the infants who died in the earliest stages,” says Assumpció Malgosa, researcher at the UAB and co-author of the study.

Read more on ALBA website

Image: Burial of a perinatal individual from the Fortalesa dels Vilars (Arbeca, Lleida) site.

Credit: ARQHISTEC-GIP, UdL.

Dragons, Diamond and dinosaurs

2024/09/022024/09/16

New research conducted at Diamond gives an insight into how Komodo dragons keep their teeth razor-sharp and may provide clues to how carnivorous dinosaurs like Tyrannosaurus rex killed and ate their prey

One of the coolest animals on the planet, just got cooler.

If Komodo dragons weren’t fascinating enough already, it is now understood that the largest living predatory lizards have iron-clad teeth.

This new finding, discovered as part of studies on Diamond’s I18 and B16 beamlines, explains why their serrated, blade-shaped teeth can stay sharp and lethal through their lifetime. Looking into the teeth characteristics of these “living fossils” may provide new ways to learn about the eating habits of carnivorous dinosaurs, which haven’t been previously available.

A research team from King’s College London, led by Dr Aaron LeBlanc, aimed to discover what made the teeth of carnivorous dinosaurs so effective at cutting. They used Komodo dragons, the largest living lizards with small, blade-shaped teeth, as a modern comparison. The serrated teeth of Komodo make them a useful animal to study when trying to understand how the teeth of carnivorous dinosaurs. Dr LeBlanc’s team also looked at other serrated edged teeth from beavers, crocodiles and other reptiles.

Advanced imaging revealed the teeth have a unique adaptation: orange, iron-enriched coatings on the serrations and tips, which help maintain their cutting edges.

Iron teeth aren’t unique to reptiles – there are other animals with iron-infused enamel – but in Komodo dragons, the iron is concentrated along the cutting edges and tips of their teeth, staining them orange. This protective layer keeps the serrated edges of their teeth sharp and undamaged. On their teeth, iron is concentrated into a distinct coating of ferrihydrite, a type of iron oxide which bonds to crystalline structure of the enamel.

This discovery is surprising because Komodo dragons have very thin enamel layers (only 15-20 micrometres thick) and they replace their teeth quite frequently. Typically, such thin enamel and rapid tooth replacement wouldn’t be expected to have such a distinct and durable iron coating.

Dr LeBlanc, lecturer in Dental Biosciences at King’s College London, said:

Komodo dragons have curved, serrated teeth to rip and tear their prey just like those of meat-eating dinosaurs. We want to use this similarity to learn more about how carnivorous dinosaurs might have eaten and if they used iron in their teeth the same way as the Komodo dragon.

Unfortunately, using the technology we have at the moment, we can’t see whether fossilised dinosaur teeth had high levels of iron or not. We think that the chemical changes which take place during the fossilisation process obscure how much iron was present to start with.

With further analysis of the Komodo teeth we may be able to find other markers in the iron coating that aren’t changed during fossilisation. With markers like that, we would know with certainty whether dinosaurs also had iron-coated teeth and have a greater understanding of these ferocious predators.

Read more on Diamond website

Revolutionising research: DIAD delves into dentistry

2024/06/072024/06/13

The innovative design of Diamond’s Dual Imaging and Diffraction (DIAD) beamline provides valuable opportunities for biomedical materials science

Diamond is home to an ever-evolving array of beamlines and instruments, allowing scientists from a wide variety of disciplines to collect high-quality, high-resolution data for their groundbreaking research. In materials science, X-ray imaging and tomography experiments can determine the 3D microstructure of samples, while X-ray diffraction techniques offer the phase composition and stress distribution. Most synchrotron beamlines are designed to offer one or the other, with a few that can do both – but not at the same time. Switching between the modes can be complicated and time consuming. Diamond’s Dual Imaging and Diffraction beamline (DIAD) provides both imaging and diffraction capabilities in one instrument. Its novel dual beam design operates with two independent beams meeting at the sample position, one setup for imaging and one for diffraction. By constantly switching between the two modes, DIAD enables in situ and in operando measurements and time-resolved studies. Understanding the complex structure of tooth enamel, the factors involved in its decay and potential strategies for its remineralisation exemplify some outstanding tasks in biomedical materials science that can benefit from the dual beamline approach. In work recently published in Chemical & Biomedical Imaging, a group of researchers from the University of Oxford and the University of Birmingham (led by Professor Alexander Korsunsky) detail a proof-of-concept study that demonstrated how the unique capabilities of DIAD can be used to consider different options for remineralisation and to grade them in terms of how well they work.

Teeth: nature’s nanostructured marvels

Human teeth are a miracle of biological engineering. Their remarkable strength and resilience come from a combination of hard external enamel over an interior of flexible dentine. On the microscopic scale, enamel is built from nanoscale hydroxyapatite (HAp) crystallites, bundled together into micron-scale rods with surrounding inter-rod regions. Delving deeper into the extraordinary structure of teeth provides valuable insights for the development of strong, bio-inspired materials. However, as we’re all aware, teeth aren’t impervious, and can rot away under the onslaught of an acid-provoking modern diet. Unlike those of some other animals (such as rodents), human teeth don’t regenerate. Once they are damaged, we must face the pain of a “drill and fill” repair, or the fitting of synthetic prosthetic replacements.

Project lead Prof Alexander Korsunsky, from the University of Oxford, said:

Teeth are a fascinating example of nature’s hierarchical structuring from the nanoscale. Whereas bone and dentine, the inner part of the tooth, remain vascularised and living – meaning constantly renewing, changing, rebuilding, remodelling – enamel is one part of the human body that doesn’t. Nature effectively builds pieces of stone subjected to extreme thermal, chemical and mechanical attack, that can last up to 100 years. In our first major research project we set out to understand the processes involved in dental caries and how they interact with the structure of teeth. Now that another major four-year project has been awarded, we are out to explore what could be done to reverse caries and remineralise enamel.

Read more on Diamond website

Mind the gap – ESRF tracks defects triggered by composites in root fillings

2021/12/212021/12/22

Polymer composite fillings of root-canal treated teeth can fail over time. Scientists led by the Charité University in Berlin (Germany) have found that this is not because of the dentist’s lack of skills but rather because of stresses that build up and deform the biomaterial just after it is placed. The results are published in Acta Biomaterialia.

It is one of the most peculiar images that can come to mind: a dentist restoring severely destroyed teeth and placing fillings on a beamline at a synchrotron. It is, however, exactly what happened on beamline ID19 a while back, when a team from the Charité and TU Universities in Berlin and the ESRF examined how well composite fillings adapt to cavities in the tooth root canal orifice.

To treat cavities in teeth, dentists expose solid tooth tissue prior to “filling” the volume of missing structure with rigid biomaterials that sustain chewing forces. In the past, dentists used metals such as amalgam or gold, but today they mostly use composite materials, made of polymer and glass. Such materials, which are well resistant to damage and highly aesthetic, allow rapid recovery of tooth function. However, composites tend to fail in the long run, especially in root-canal filled teeth.

Research on ancient teeth reveals complexity of human evolution

2018/10/092018/10/10

Fossil records enable a detailed reconstruction of our planet’s history and of the evolution of our species. In particular, teeth are a sort of biological archive that record in their structures (enamel, dentine and pulp chamber) the different phases of the human evolution. An international team of researchers led by Clément Zanolli from the Université Toulouse III Paul Sabatier (France) has characterized human dental remains from Fontana Ranuccio (Latium) and Visogliano (Friuli-Venezia Giulia), Italy through a comparative high-resolution endostructural analysis based on microfocus X-ray microtomography (mCT) scanning and detailed morphological analyses. We examined the shape and arrangement of tooth tissues (see Fig. 1) and compared them with teeth of other human species (see Fig. 2).

With an age of around 450,000 years before present, the analysed dental remains from the sites of Fontana Ranuccio, located 50 km south-east of Rome, and Visogliano, located 18 km north-west of Trieste, are part of a very short list of fossil human remains from Middle Pleistocene Europe and are among the oldest human remains on the Italian Peninsula.
From the data obtained through X-ray μ-CT measurements performed at the TomoLab station of Elettra and at the Multidisciplinary Laboratory of the ‘Abdus Salam’ International Centre for Theoretical Physics in Trieste (Italy), we found that the teeth of both sites share similarities with Neanderthals but they are distinct from modern humans. This study adds to an emerging picture of complex human evolution in Middle Pleistocene Eurasia. The investigated fossil teeth show that Neanderthal dental features had evolved by around 450,000 years ago.

Image: Volume rendering of the Fontana Ranuccio (FR1R and FR2) and Visogliano (Vis. 1-Vis. 6) tooth specimens. The enamel is represented in blue while the dentine in yellow. All specimens were imaged by X-ray μCT at the Tomolab station of Elettra and at the Multidisciplinary Laboratory of the ICTP.
Credit: doi: 10.1371/journal.pone.0189773

Research shows how to improve the bond between implants and bone

2018/07/032018/07/05

Research carried out recently at the Canadian Light Source (CLS) in Saskatoon has revealed promising information about how to build a better dental implant, one that integrates more readily with bone to reduce the risk of failure.

“There are millions of dental and orthopedic implants placed every year in North America and a certain number of them always fail, even in healthy people with healthy bone,” said Kathryn Grandfield, assistant professor in the Department of Materials Science and Engineering at McMaster University in Hamilton.

A dental implant restores function after a tooth is lost or removed. It is usually a screw shaped implant that is placed in the jaw bone and acts as the tooth roots, while an artificial tooth is placed on top. The implant portion is the artificial root that holds an artificial tooth in place.

Grandfield led a study that showed altering the surface of a titanium implant improved its connection to the surrounding bone. It is a finding that may well be applicable to other kinds of metal implants, including engineered knees and hips, and even plates used to secure bone fractures.

About three million people in North America receive dental implants annually. While the failure rate is only one to two percent, “one or two percent of three million is a lot,” she said. Orthopedic implants fail up to five per cent of the time within the first 10 years; the expected life of these devices is about 20 to 25 years, she added.

“What we’re trying to discover is why they fail, and why the implants that are successful work. Our goal is to understand the bone-implant interface in order to improve the design of implants.”

The microstructure of a parrotfish tooth contributes to its toughness

2018/02/082018/02/15

During a 2012 visit to the Great Barrier Reef off the coast of Australia, ALS staff scientist Matthew Marcus became intrigued with parrotfish. “I was reminded that this is a fish that crunches up coral all day and is responsible for much of the white sand on beaches,” Marcus said. “But how can this fish eat coral and not lose its teeth?” So Marcus teamed up with Pupa Gilbert, a biophysicist at the University of Wisconsin–Madison, and an international team of researchers she assembled, to understand how parrotfish teeth work.

Because conventional microscopes can overlook the unique orientation of crystals in tooth enamel, the team used the technique called polarization-dependent imaging contrast (PIC) mapping that Gilbert invented, which uses the photoemission electron microscopy (PEEM) Beamline 11.0.1 at the ALS. The PIC maps allowed them to visualize the orientation of individual crystals of fluorapatite, the main mineral component of parrotfish teeth.

Separate experiments used tomography (Beamline 8.3.2) and microdiffraction (Beamline 12.3.2) to further analyze the crystal orientations and strains in the teeth.

>Read more on the ALS website

Image: (extract) PIC maps acquired at the tips of four different parrotfish teeth show that they consist of 100-nm-wide, microns-long crystals, bundled into “fibers” interwoven like warp and weft fibers in fabric. These fibers gradually decrease in average diameter from 5 μm at the back of a tooth to 2 μm at the tip. Intriguingly, this decrease in size is spatially correlated with an increase in hardness and stiffness. The orientation angle of the crystals is color-coded (chart at bottom).

Research on the teeth of a prehistoric fetus

2018/02/072018/02/09

It gives us information about the last months of a mother and child, who lived 27.000 years BP.

Fossil records enable a detailed reconstruction of our planet’s history and of the evolution of our species. Dental enamel is a sort of biological archive that constantly tracks periods of good and bad health, while forming. Prenatal enamel, which grows during intrauterine life, reports the mother’s history as well.

We have studied fossil records found in the “Ostuni 1” burial site, discovered in Santa Maria di Agnano in Puglia in 1991 by Donato Coppola (Università di Bari, Italy) and dated back over 27,000 years. More specifically, we were interested in the teeth of a fetus found in the pelvic area of the skeleton of a young girl. By analysing the still forming teeth of the baby, it has been possible to obtain information about the health condition of the mother during the last months of pregnancy, to establish the gestational age of the fetus, and also to identify some specificities of the embryonal development. For the first time, it has been possible to reconstruct life and death of an ancient fetus and, at the same time, to shed light on its mother’s health.

Three still-forming incisors, belonging to the fetus, have been visualized and analyzed by means of X-ray microtomography at Elettra. The preliminary analysis on a portion of the fetal mandible, realized at the TomoLab laboratory allowed us to study the still-forming incisor contained within it (see Fig. 1). Thanks to the unique properties of synchrotron radiation and using a specifically-developed methodology, a high resolution 3D analysis has been carried out on the teeth at the SYRMEP beamline. This approach, allowed us to carry out a virtual histological analysis of the precious fossil teeth, revealing the finest structures of the dental enamel in a non-destructive way.

>Read more on the Elettra website

Image: Pseudo color rendering of the virtual histological section of the Ostuni1b’s upper left deciduous central incisor. The corresponding CT scan has been acquired at the SYRMEP beamline in phase-contras mode.

X-Rays reveal the biting truth about parrotfish teeth

2017/11/152017/11/29

Interwoven crystal structure is key to coral-crunching ability

So, you thought the fictional people-eating great white shark in the film “Jaws” had a powerful bite. But don’t overlook the mighty mouth of the parrotfish – its hardy teeth allow it to chomp on coral all day long, ultimately chewing and grinding it up through digestion into fine sand. That’s right: Its “beak” creates beaches. A single parrotfish can produce hundreds of pounds of sand each year.

Now, a study by scientists – including those at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) – has revealed a chain mail-like woven microstructure that gives parrotfish teeth their remarkable bite and resilience.

The natural structure they observed also provides a blueprint for creating ultra-durable synthetic materials that could be useful for mechanical components in electronics, and in other devices that undergo repetitive movement, abrasion, and contact stress.

Matthew Marcus, a staff scientist working at Berkeley Lab’s Advanced Light Source (ALS) – an X-ray source known as a synchrotron light source that was integral in the parrotfish study – became intrigued with parrotfish during a 2012 visit to the Great Barrier Reef off of the coast of Australia.

>Read More on the ALS website

Image: Scientists studied the microstructure of the coral-chomping teeth of the steephead parrotfish, pictured here, to learn about the fish’s powerful bite.
Credit: Alex The Reef Fish Geek/Nautilus Scuba Club, Cairns, Australia