Quick Tips: Identifying Dental Diseases – Dental/Enamel Hypoplasia.

In our previous Quick Tip post on identifying dental diseases, we gave a basic overview on the different diseases that are observed. If you haven’t read it, you can find it by clicking here.

Dental hypoplasia is a condition that affects the enamel of a tooth. It is characterised by pits, grooves and transverse lines which are visible on the surface of tooth crowns. The lines, grooves and pits that are observed are defects in the enamels development. These defects occur when the enamel formation, also known as amelogenesis, is disturbed by a temporary stress to the organism which upsets the ameloblastic activity. Factors which can cause such stress and therefore disrupt the amelogenesis include; fever, malnutrition, and hypocalcemia.

Figure 1: An example of linear enamel hypoplasia.

Figure 1: An example of linear enamel hypoplasia.

It has been noted that enamel hypoplasia is more regularly seen on anterior teeth than on molars or premolars, and that the middle and cervical portions of enamel crowns tend to show more defects than the incisal third. This is due to the amelogenesis beginning at the occlusal apex of each tooth crown and proceeding rootward, towards where the crown then meets the root at the cervicoenamel line.

Figure 2: Anatomy of a tooth. Note the top third is known as either the occlusal third if in molars, or the incisal third when the tooth is an incisor or canine.

Figure 2: Anatomy of a tooth. Note the top third is known as either the occlusal third if in molars, or the incisal third when the tooth is an incisor or canine.

By studying these incidents of enamel hypoplasia within a population sample, we can be provided with valuable information regarding patterns of dietary stress and disease that may have occurred within the community.

References:

Lukacs, J.R. 1989. Dental paleopathology: methods for reconstructing dietary patterns. In M.Y. Iscan and K.A.R. Kennedy (eds), Reconstruction of life from the skeleton. New York, Alan Liss, pp. 261-86.

Ubelaker, D.H. 1989. Human Skeletal Remains: Excavation, Analysis, Interpretation (2nd Ed.). Washington, DC: Taraxacum.

White, T.D., Folkens, P.A. 2005. The Human Bone Manual. San Diego, CA: Academic Press. Pg 392-398.

This is the second post of the Quick Tips series on identifying dental diseases. The next post in this series will focus on how to identify dental caries and highlight the cause of this dental disease.

To read more Quick Tips in the meantime click here, or to learn about basic fracture types and their characteristics/origins click here!

3-Million Year Old Fossilised Metacarpals Show Evidence of Tool Use.

A recent study has put forward some important evidence of early human ancestors, in particular Australopithecus africanus, wielding tools in a human like fashion dating around 3 to 2-million years ago.

Figure 1: A recent study has put forward some important evidence of early human ancestors, in particular Australopithecus africanus (pictured), wielding tools in a human like fashion dating around 3 to 2-million years ago.

Figure 1: A recent study has put forward some important evidence of early human ancestors, in particular Australopithecus africanus (pictured), wielding tools in a human like fashion dating around 3 to 2-million years ago . ©Shaen Adey, Gallo Images/Corbis.

The study, led by Matthew Skinner from the University of Kent, compared the internal structures of the hand bones from the Australopithecus africanus and several Pleistocene hominins, which were previously considered to have not engaged in habitual tool use.

Skinner et al, found that they all have a human trabecular (spongy) bone pattern in the metacarpals, and this is consistent with the “forceful opposition of the thumb and fingers typically adopted during tool use”.

Top row: First metacarpals of the  various hominins.  Bottom row: 3-D renderings from the micro-CT scans showing a cross-section of the bone structure inside.

Figure 2: Top row: First metacarpals of the various hominids.
Bottom row: 3-D renderings from the micro-CT scans showing a cross-section of the bone structure inside. ©T.L. Kivell

The evolution of the hand, mainly the development of opposable thumbs, has been hailed as the key to success for early humans. It is thought that without the improvement of our grip and hand posture, tool technology could not have emerged and developed as well as it has.

This piece of research will provide a new discussion into when the first appearance of habitual tool use occurred in prehistory, as this study’s evidence of modern human-like tool use is dated 0.5-million years earlier than the first archaeological evidence of stone tools.

References:

Skinner, M. Stephens, N. Tsegai, Z. Foote, A. Nguyen, N. Gross, T. Pahr, D. Hublin, J. Kivell, T. 2015. Human-like hand use in Australopithecus africanusScience. 347, 6220. p395-399.
You can view this paper by clicking here.

 

If you’re a student – check out our ‘Quick Tips’ posts where we breakdown topics of AAFS into bite-sized chunks. We’re currently covering how to age and how to estimate the biological sex of skeletal remains, and also how to identify a variety of fracture types

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Unusual-ology: Unexpected Items in the Bagging Area…

Unusual-ology is a new post type which focuses on weird new articles/science areas that have cropped up and caught my eye.

Archaeologists have made a very peculiar discovery in a churchyard near the St Pancras train station in London. The researchers, led by Phil Emery from Ramboll Cultural Heritage and Archaeology, have stumbled upon a coffin dating back between 1822 and 1858.  What has made the coffin so strange is that it had a large selection of bones from many different animals mixed among human remains. Within the coffin were nine bones from a Pacific walrus (Odobenus rosmarus divergens), eight mixed sets of human remains – including three skulls, and a tortoise.

Image

Top: Collection of the walrus bones. Bottom Left: The walrus’ back right leg. Bottom Right: The skull showing visible signs consistent with craniotomy.

The coffin was originally discovered in 2003 during excavations of the horizontal burial trench underneath the station, when the Eurostar terminal moved from Waterloo to St Pancras. Emery & Wooldridge (2011) have noted that the bones discovered have marks which are consistent to dissection, which was legalised by the Anatomy Act of 1832, with one skull showing evidence of craniotomy (drilling a hole in the skull to gain access to the brain). As the animal bones were found alongside human remains, Emery believes that the bones were used as a teaching collection from a research institute and has said that:

“The animal bone consisted of a small, moderately-preserved group of eight bones derived from a walrus of a very large size and robust build.’The sample includes bones from a lower fore-limb, a fore-foot, first and second metacarpal, the lower hind limbs, fibula, calcaneum, astragalus and first cuneiform. These bones are significantly larger than their reference equivalents held at the Natural History Museum. Microscopic examination revealed that all the St Pancras walrus bones show some degree of surface erosion and butchery marks. Three clear superficial transverse knife cuts were noted.”

The walrus bones have now been moved to the London Archaeological Archive and Research Centre in Hackney, East London.

If you’ve enjoyed this new ‘Unsual-ology’ post feature – leave a comment or a like!

If you want to read more unusual science posts click here, or to read the Unusual-ology post on the Ancient Egyptian use of lettuce as an aphrodisiac, click here. Or to read about the newly discovered ‘Entrance to Hell’ click here!

 

References:

Daily Mail. 2013. The ongoing mystery around how a Pacific walrus ended up buried in a human coffin beneath London’s St Pancras station. Daily Mail News. Article available here.

Emery, P., Wooldridge, K. 2011. St Pancras burial ground: excavations for St Pancras International, the London terminus of High Speed 1, 2002–3. Gifford, London. This book can be found here. 

Telegraph. 2013. Walrus remains found buried under St Pancras station in London. Telegraph News. Available from here.

Unusual-ology: Male Spiders Self Sacrifice for Better Offspring.

Unusual-ology is a new post type which focuses on weird new articles/science areas that have cropped up and caught my eye.

The practice of monogyny is found throughout the insect kingdom, especially arachnids. One such arachnid is the make dark fishing spider (Dolomedes tenebrosus). A recent study in Biology Letters has discovered that the male arachnid willingly sacrifices itself to the female to ensure that the resulting offspring is healthy; by providing itself as a meal for the female.

Video of the mating rituals and cannibalism from the experiment – Royal Society of Journals

Schwartz et al (2013) think that this practice of sexual cannibalism may provide an ‘evolutionary advantage’, because a better fed female is more likely to provide healthy descendants. But there are certain drawbacks to this practice; if a male dark fishing spider accidentally prematurely triggers one of their pedipalps, their two feeler-like appendages near the mouth where sperm is stored, they can die. Schwartz has encountered many problems during his experiment while catching the wild male specimens; they would accidentally snag their pedipalps on a piece of cotton which would cause them to die before the experiment could take place.

References:

National Geographic. 2013. Male Spiders Self-Sacrifice, Lose Genitals. National Geographic News. Click here for the article.

Schwartz, S.K., Wagner Jr, W.E., Hebets, E., A. 2013. Spontaneous male death and monogyny in the dark fishing spider. Biology Letters. 9, 4. Click here for the journal.

If you’ve enjoyed this new ‘Unsual-ology’ post feature – leave a comment or a like!

If you want to read more unusual science posts click here, or to read the Unusual-ology post on the Ancient Egyptian use of lettuce as an aphrodisiac, click here. Or to read about the newly discovered ‘Entrance to Hell’ click here!

Unusual-ology: Ancient Greek and Roman “Entrance to Hell” discovered.

Unusual-ology is a new post type which focuses on weird new articles/science areas that have cropped up and caught my eye.

Italian archaeologists from the University of Salento, led by Francesco D’Andria, working at a Greco-Roman site of ancient have discovered the ‘Entrance to Hell’.

ImageHieropolis, known today as Pamukkale, Turkey – where the “Entrance of Hell” has been located.

This ‘Entrance to Hell’ has been discovered in Hierapolis, known today as Pamukkale, in Turkey.  Francessco and the fellow archaeologists were able to stumble upon the entrance of the temple by tracing the path of the hot springs through the ancient site. The temple, identified as the Ploutonion, has been linked to Hades and correctly identified due to an ‘engraved dedication’ to Pluto above the gate. The temple was built over a cave and underground in the thermally active area. Ploutonion was the worship ground for many ancient pilgrims who would travel to celebrate their gods and bathe within the hot springs that surround the area.

The reason why the Ploutonion has been called the ‘Entrance to Hell’ is due to the writings of the Greek geographer Strabo. Strabo mentions about the “opening of sufficient size to admit a man, but there is a descent to a great depth… The space is filled with a cloudy and dark vapour, so dense that the bottom can be scarcely be discerned.” These documents explain that the cloudy, dark vapour has caused many animals that enter to die instantly. Strabo wrote that Bulls which had entered the Ploutonion “fell down and were taken out dead” and sparrows which were thrown inside “immediately fell down lifeless.” The Ploutonion’s poisonous vapour still survives today as many dead birds have been found on this site during modern excavations. The presence of the dead birds has helped convince the archaeological team that this is in fact Ploutonion’s true ‘entrance to hell’.

If you’ve enjoyed this new ‘Unsual-ology’ post feature – leave a comment or a like!

If you want to read more unusual science posts click here, or to read the Unusual-ology post on the Ancient Egyptian use of lettuce as an aphrodisiac, click here!

References:

Biblical Archaeology Society. 2013. Hierapolis and the Gateway to Hell. Bible History Daily News. Click here for the article, and to read more of Strabo’s writing on the Ploutonion.

Daily Mail. 2013. Is this the Gate of Hell? Archaeologists say temple doorway belching noxious gas matches ancient accounts of ‘portal to the underworld’. Daily Mail News. Click here for the article.

National Geographic. 2013. Archaeologists Find a Classic Entrance to Hell. National Geographic Daily News. Click here for the article.