[evan_au (OP)]

The recent Naked Scientists podcast talked about dental tools and practise, as well as the oral microbiome...
It mentioned that dentistry was not seen as a specific skill until around the 1700s.

Also around this time, sugar became more affordable for the masses.
https://en.wikipedia.org/wiki/History_of_sugar
And steam power may have produced finer quality flour in bread, so more of it was able to be broken down in the mouth.

To what extent did changes in diet affect dental health?

[alancalverd]

Whilst dentistry did not become a specific profession until recently, archaeologists have found plenty of rotten teeth and evidence of extractions, plus particular wear patterns associated with sand in the diet.

Sugar is an interesting case. I recall learning that caries was less problematic in the West Indies where people chewed raw sugar cane, than in the UK where per capita consumption was less but the product was refined - suggesting that some component of the raw juice was beneficial to dental health.

[chris]

Diet is the biggest determinant of dental health, I believe. Historically, sugar was a premium item that cost a lot to buy, so most commoners could not afford it. Consequently their teeth tended to be worn by the attritive effects of high grit content in bread and similar staples but they did not decay like the teeth of those with a "sweet tooth" and a wallet to indulge it.

I witnessed this first hand as a young teenager when I was a member of an archaeological society near where I grew up. I was very fortunate to participate in the finds processing for some quite high-status digs, including the excavation of the Knights Templar sites at Cressing: https://en.wikipedia.org/wiki/Cressing_Temple

I washed quiet a few knight's skeletons over my time, including their teeth. The striking thing was that the molars of many were worn almost flat like a slab. The reason was that the miller making the flour that went into their bread clearly lost a healthy percentage of the surfaces of his millstones into his produce, which is what wore their teeth away by middle age.

[Petrochemicals]

A fullish set in middle age, yet notice the tartar buid up through no brushing

https://www.sciencedaily.com/releases/2014/02/140223131629.htm