@saxicola

Over here it is better known as baking soda. I just checked my box of Arm and Hammer "pure" baking soda and it contains 100% sodium bicarbonate, so we are talking about the same thing.

This chemical is alkaline so it will reduce acid so the idea is cavities grow in acid environments. If that is the case then it makes common sense, not necessarily scientific and practical sense, keeping one's mouth at a higher pH level would be preferred.

During treatments when my mouth was just full of sores, ulcers, and pain, I found high alkaline bottled water (pH 9+) that worked well. Maybe this is all one needs. Similar to what you are doing in principle.

I did experiment with trying to increase my tap water to similar pH levels and found it very hard to do with baking soda. By the time I got it up enough it took on a quite noticable off taste. I think it was the buffering that actually changed to feel of the water. I gave up at that point and went back to the bottled version; on sale, not a bad price.

Maybe we are onto something! Keep the ideas flowing.
Don

Here is a quote from Wikipedia, so caution applies as usual.
Personal hygiene[edit]
Toothpaste containing sodium bicarbonate has in several studies shown to have a better whitening[29][29][30][31] and plaque removal effect[32][33] than toothpastes without it.
Sodium bicarbonate is also used as an ingredient in some mouthwashes. It has anti-caries and abrasive properties.[34] It works as a mechanical cleanser on the teeth and gums, neutralizes the production of acid in the mouth and also acts as an antiseptic to help prevent infections.[citation needed]
Sodium bicarbonate in combination with other ingredients can be used to make a dry or wet deodorant.[35][36] It may also be used as a shampoo.[37]
Sodium bicarbonate may be used as a buffering agent, combined with table salt, when creating a solution for nasal irrigation.[38]