Tuesday, 19 July 2011

Happy teeth

Over time teeth tend to wear down. This happens particularly in populations who eat a lot of hard, unprocessed or gritty food.  The white of the enamel gives way in little patches to the material beneath it, dentine, which is softer and yellowish in colour. Osteologists can use dental wear to determine the possible age of an individual or the kind of diet they might have had.

However, as I've been looking at teeth, I've discovered something else. At a certain point, the little islands of dentine coalesce and start to look like faces. I shall demonstrate...

A cheerful 2nd molar...

Sure, this isn't a finding that will make it into the text of my thesis (unless I'm really, really struggling for word count) but it's something that everyone seems to appreciate.  How can you not enjoy looking at teeth all day when they look like this?

Another cheerful molar...

Wednesday, 13 July 2011

False teeth?

In the 18th century it was common practise to extract an unhealthy tooth from an individual and replace it with the tooth of a willing and hopefully well paid volunteer.  As unlikely as it sounds, this worked, at least occasionally.  Even now, teeth that have been displaced or knocked out can be eased back into the socket of the jaw (of their original owner, of course) and sometimes heal very well.

You'll be pleased to know however that you need no longer worry (if you ever did) about having a friends tooth forced into your dental arcade. Recent work at the Tokyo University of Science in Japan has shown that a bioengineered mouse molar tooth, grown from embryonic cells and subsequently transplanted into a jaw can successfully 'take root' and restore bone volume in the jaw.  This is the first time a complete organ has been created and transplanted in such a manner.

The transplanted tooth (bottom row) well healed and looking 
good after 45 days.  Note the lack of tooth and surrounding bone tissue in the 
control specimen,which cannot repair or replace itself.
(Image Takashi Tsuji, Tokyo University of Science)

The tooth was grown in a lining around the kidney of an adult mouse, a method which limits its application to humans at this point. However, the signs are good that one day losing teeth and the surrounding supporting tissues may not be such a bad thing - you may be able to get your very own teeth to be grown to order, using your own cells.

It's probably wise not to throw away your dentures just yet however - it's probably going to take a while to perfect the technique for application in humans.


Tuesday, 12 July 2011

Decapitations and modified Viking teeth...

In 2009, archaeologists in Weymouth, way down on the south coast of England, found a mass grave containing 54 bodies and 51 skulls. Radiocarbon dating has placed the assemblage in the 10th or early 11th century - and isotopic evidence gleaned from testing the tooth enamel of the individuals within the burial pit has revealed a cold climate origin for them all. One of them may have even grown up somewhere in the Arctic circle.  Such a group is likely then, to be a Viking raiding party - a party that was somewhat curtailed by being rounded up, stripped, hacked to death, decapitated and thrown into a large pit.  That'll teach them to go raping and pillaging, I suppose.

Heads, not attached to the people they originally were attached to...

Of particular interest though, is the teeth of one of these young Viking warriors. There are a series of distinct horizontal lines on the front teeth which may indicate deliberate modification of the teeth. Teeth can frequently become notched and altered by repetitive movement (holding twine between your teeth, or smoking a pipe for example) but this usually affects the working surfaces of the teeth, or the areas between them, not the outward face of the tooth. These lines seem to have been filed into the teeth for some reason.

Two front teeth: All I wanted for Christmas

Deliberate tooth modification is not unknown in human cultures around the world, but it is fairly unusual in Europe. Groups from Africa and Southeast Asia are well known for intentionally removing teeth, chipping and filing them or insetting them with other materials such as brass or shell, blackening them with natural dyes or incising them. Such acts may be undertaken to show group affiliation, identity, or perhaps personal achievement within the tribe or nation.  There is no reason to expect the Vikings were any different in their reasons for practising this kind of modification.  It is even possible they picked up the idea from interactions with native north Americans on their legendary travels across the globe.

If we imagine that these incised lines were once filled in with some sort of dark pigment, designed to make the unusual modification stand out from a distance, it is very likely that the warrior who owned them cut a terrifying figure to the people of ancient Weymouth. 

Didn't really do him much good in the end though.

http://www.bbc.co.uk/news/uk-england-dorset-14019172, pictures taken from the BBC video.