What specifically causes the breakdown of teeth?

ndr, 11 months ago

What is the process teeth go through in the modern world to cause this?

Our mouth has a rich community of microorganisms, among which there are many species of bacteria. Here's a simple overview:

Think about yogurt. Its characteristic sourness is achieved by fermentation of sugars naturally found in milk (lactose, and its components: glucose and galactose) by lactic acid bacteria, such as those in the genus Lactobacillus. These bacteria generate energy by converting certain sugars into lactic acid, as their name suggests. Normally, these bacteria are already present in your mouth, but they don't get to take over the other populations of bacteria, unless you introduce a lot of sugars. The long-term presence of acids in contact with the surface of the tooth may cause demineralization.

What does it mean? Enamel is the tissue found in the most external part of the tooth and is also the hardest substance in the human body; it is mostly made up of minerals (more so than bones, which have many gaps). When the pH (indicator of acidity, the lower, the more acidic) drops after a certain threshold, the acid can start to dissolve the main component of the enamel, hydroxyapatite.

How quickly after consuming a sugary drink for example does this degradation start to occur?

It depends on your oral health. Technically, it can start as soon as sugar is introduced, but if you don't have dental plaque, then there isn't much of an opportunity to keep direct contact of acid to the tooth enamel.

Normally, saliva is able to neutralize (bring back the pH to normal) the plaque in a few hours, and then tooth remineralization can occur, to some extent. On the other hand, if this happens too frequently, then you wouldn't be able to put the minerals back in your teeth.

How does tooth paste help prevent this?

Mainly by removing dental plaque (where bacteria can produce acid in direct contact with the enamel). Fluoride in tooth paste helps both with killing bacteria and, partly, with the remineralization process itself.

breadsmasher, 11 months ago

Is plaque something more than just a “covering” then? I was under the idea its like, a coating that builds up. I knew it was bad for dental health but I was never sure why

ndr, 11 months ago

Plaque is a biofilm produced by many microorganisms, mainly bacteria. A biofilm is a slimy, sticky mix of substances that can stick to surfaces (here, the enamel).

In this case, bacteria can proliferate there and release their by-products (like lactic acid). So, they can stick to the surface of the teeth and 'acidify' it directly, thus damaging it. Minerals are also lost from the tooth and end up in the plaque.

breadsmasher, 11 months ago

Do dentures / “fake teeth” suffer from plaque?

ndr, 11 months ago

If they're not made of minerals (as is the case with dentures), they cannot demineralize and suffer decay in the same way. Note that plaque, or biofilm in general, can form anywhere.

So, you should practice good oral hygiene, because plaque could cause other infections in your mouth, in particular in your gums.

INeedMana, 11 months ago

Wait, so it's mostly due to sugar in our food? Is it mainly about the processed one? Or the sugars from fruits act the same?
What about other carbohydrates? Wheat, beer, starch...
If we were eating a lot of insects (chitin) that would be bad for our teeth too?

ndr, 11 months ago

Well, to be thorough, any food source could cause problems but it is for the most part due to sugars.

Processed or natural doesn’t really matter. Carbohydrates are just long chains of sugars (glucose), put it simply. They can be broken down to individual sugars by certain enzymes, so the same applies eventually. However, they’re not as accessible as a food source as straight-up ready-to-consume sugar.

INeedMana, 11 months ago

But if processed vs natural doesn't matter then why OP is seeing a difference between our teeth and the teeth of the guy unthawed after 100k years? They also had sugars in their diet.

Let me rephrase my first question: to me your first answer sounds like "we have more dental issues because we eat more sugar. Therefore nowadays a group with diet that contains no added sugars and no candy bars, will statistically have dental state similar to people whose skulls we look at after 100k years (better than average modern human)"
Is that understanding of your point correct?

ndr, 11 months ago

Yes, the amount and the frequency are the cause. I’m no anthropologist but they did not have access to all this sugar all the time like we do now. Even our fruit is much sweeter than it used to be even only a few centuries ago (we selected for those traits).

As I said, our saliva should be able to neutralize the acids after some time, but this is not enough if we introduce sugar all the time in our mouth.