Re: dino dental hygiene

[frank bliss <frank@blissnet.com>]

I can only speak for my Hell Creek collections. After assembling  
several thousand teeth from various Upper Cretaceous dinosaurs I must  
admit that I have never seen a "cavity".  These teeth are usually  
essentially unmodified tooth enamel that doesn't show much of the  
ravenous effects of 65 million years of time.   Such a cavity would be  
obvious as I usually give each specimen a pretty good once over under  
magnification.  Tooth wear during herbivorous mastication usually  
resulted in shedding the teeth.  (Resulting in partial teeth we call  
spitters or poopers (PC) if they went through the digestive tract) The  
few hundred carnivorous dinosaur teeth that I am familiar (also Hell  
Creek) are usually either broken off at the root line or found with  
the root intact (rare) if not in situ with the affiliated jaw. I do  
find teeth that have been split down the center bilaterally and  
occasionally shattered pieces.   I have one amazingly nice T-rex tooth  
that was broken off about 1/2 way up the tooth then worn (polished)  
very nicely on the broken surface by chewing/biting action before it  
finally broke off at the root line.  No cavities on it either.  None  
of the 250 or so specimens of Cretaceous mammal teeth that I have  
collected and examined from my locations show any decay other than  
abrasive wear and tear that I have noticed.   I suggest here that  
tooth decay (which in modern animals is typically resultant because of  
mineral deficiencies or high oral sugar intake) was a rare phenomena  
in the Upper Cretaceous fossil record but I can't speak for other  
vertebrate assemblages in other times.  My person observations are by  
no means comprehensive across geologic time or even within the Hell  
Creek.

I have little doubt however that most of the carnivorous dinosaur  
mouths were a nasty place with all sorts of flesh eating bacteria  
residing.  Modern reptiles are not the best thing to get a nip from.  
Usually you will get some sort of bacterial infection as a result.  
(Been there, done that).  Bacterial warfare is not a new invention.

You won't find many fish cleaning a crocs mouth, they would become  
lunch.

An early bird landing in a larger theropods mouth would constitute the  
first use of dental floss when the feathers got stuck between it's  
teeth which might explain the lack of cavities in large theropod teeth.

Frank (Rooster) Bliss
MS Biostratigraphy
Weston, Wyoming
www.wyomingdinosaurs.com


On May 12, 2008, at 10:30 AM, hammeris1@bellsouth.net wrote:

> Watching hippos let various fish clean their oral cavities on NG  
> made me wonder whether or not dinosaurs and pleisiosaurs might have  
> benefited from similar activity.
>
> I know monitor lizards actually prosper from the noxious bacteria in  
> their mouths for helping to bring down their living prey - do cold- 
> blooded reptiles suffer from tooth decay?  Is it only a mammalian  
> problem?
>
> I would think a large theropod would just open its mouth and let  
> small birds (once they'd appeared) to pick out the bits of meat  
> between their teeth.
>
> What about a kronosaur in the shallows at rest letting various  
> fishes tidy their oral cavities?
>
> Does the fossil record show any dino tooth decay issues outside of  
> breaking a tooth off or having them broken by prey animal defensive  
> actions?