Hi Deb,

Thanks for your long and informative reply. I've added a picture of the occlusal surface to my folder (http://i893.photobucket.com/albums/ac137/ossamentaDW/Benbilder/Horsemolar4_occlusal.jpg). There are two very small holes on the lingual side of the occlusal surface. 

I discovered by sheer accident that the second premolar of the same mandible also has a perforation on the lingual side, below the gum line. It doesn't have any perforations on the occlusal surface, but there are some on the lingual side above the gum line. Let me know if you'd like pictures of that one as well.

Best wishes,
Lena


----- Original Message -----
From: [log in to unmask]
To: "Lena Strid" <[log in to unmask]>
Cc: [log in to unmask]
Sent: Friday, 22 January, 2010 19:11:13 GMT +00:00 GMT Britain, Ireland, Portugal
Subject: Re: [ZOOARCH] Pathological horse molar

Lena, these are caries -- a bit unusual to have such a large invasion
below the gum line, but that's what both "holes" represent. The upper
hole, more irregular in outline, was probably accompanied by inflammation
of the gums in life, but also extending downward somewhat to involve the
ligament fibers which suspend the tooth in the alveolus. This is what
produced the somewhat rough outline. Below the gum, however, the bacteria
went straight into the tooth to make the larger hole without much
involving the alveolar ligaments.

You might want to supply us with a photo showing the occlusal surface of
the same tooth. Clean it well with a toothbrush and then look to see if
there is a wee hole that goes down through any of the areas of the tooth
that would normally be filled with dentine (note: in a lower tooth,
dentine, not cementum). I would be willing to bet you blind that you'll
find one. If you find a hole, take a fine but stiffish wire and see how
deep you can probe it. It isn't unusual in such a case to find that there
was a developmental deficit, a failure to fully fill the particular zone
of the tooth, so that you may even be able to poke the wire all the way
through the tooth and see it come out the tip of one of the roots. When
this is the case, food material inevitably gets pounded down into the
hole, engendering rot right at the center of the tooth and weakening it
from within, so that caries attacking from the outside have an easier task
in making big holes from the outside.

Note overall also that caries are quite rare in all horse teeth UNTIL the
big commercial feed companies figured out, in the 1980's, that horses do
not walk into feed stores to buy bagged feed.... In the U.S., it is
required to give the "minimum guaranteed analysis" for many substances
that are in bagged livestock feed, but it is NOT required to give the
MAXIMUM amount that might be there. So these companies began putting huge
amounts of molasses into bagged feed, so much that even we who are dull
can smell it all the way across the store. When horse feed smells to the
purchaser like breakfast cereal, they say "oh this must be better stuff"
and that makes it fly off the shelves. We tracked this phenomenon at the
academy where I used to teach equine dental anatomy: they had a big
collection of horse skulls all dated as to year of acquisition, and I
never saw anything but the rare, simple round caries such as your specimen
shows until the 1980's. But after that, we started getting caries like
Swiss cheese and "buccal gumline caries", which is erosion of the entire
row of cheek teeth in a line just above the gum extending all the way from
P2 through M3, in both the upper and the lower dentitions.

So if you (or anybody else on this list) ever see "line caries" in a
Roman-era horse or any other ancient horse, I sure do want to know about
it, and caries in any horse is always interesting. I've been tracking
malocclusions, developmental and eruption problems, and caries in fossil
and recent horses for twenty years, and anybody who sends me a good one
can bet on getting a reply and probably a request to use the image in the
book that has been "in preparation" for lo these many years. Thanks for
your help! -- Dr. Deb

> Dear all,
>
> I have a Iron Age/Roman horse mandibular molar with a perforation on its
> lingual side. I think it's too smooth to suggest caries, although I'm not
> sure if it's a congenital abnormality or an abscess (can teeth abscess?
> All abcess info I've seen relate to bone, and not enamel). Does any one
> here have an idea what this can be?
>
> http://i893.photobucket.com/albums/ac137/ossamentaDW/Benbilder/Horsemolar1.jpg
> http://i893.photobucket.com/albums/ac137/ossamentaDW/Benbilder/Horsemolar3.jpg
>
> With thanks,
> Lena
>
>
> ------
> Files attached to this email may be in ISO 26300 format (OASIS Open
> Document Format). If you have difficulty opening them, please visit
> http://iso26300.info for more information.
>
>
>





------
Files attached to this email may be in ISO 26300 format (OASIS Open Document Format). If you have difficulty opening them, please visit http://iso26300.info for more information.