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...