There is a lot of good information here, but also a lot of personal beliefs hammered in over and over and some bad information mixed in. I gave it 4 stars because the good stuff is material you just don't tend to find elsewhere (I've never seen most of it anywhere). It's reasonably well documented but ultimately very one-note.
It's all about diet. Which doesn't add up, but I'll agree diet is very important. Unfortunately, his examples of cultures with good teeth are all very dairy-centric ones. So his proposed diet is huge with dairy (we're talking a quart of milk and several oz of cheese, every day, plus butter). To the point where he insists that dairy is necessary for dental health. Never mind that most of the world does not eat dairy (or didn't before modernization/Westernization). Somehow, all those examples got lost in translation.
The idea of someone reacting to dairy? Why it's just that they aren't using the good stuff, raw and grass-fed and low processed. Yeah, I've heard that one before. For a few people, it's true. For most of us with dairy intolerance, it's B.S. He does give a quick nod to actual dairy intolerance in the section on children, but it's less than a paragraph.
His diet is also all about meat. Just like with the dairy, he focuses on truly healthy, humanely raised, meat. That's fine, except not everyone chooses to eat meat. He does have a decent vegetarian version but it's really heavy in dairy. He is rather insulting to vegans (I'm not a vegan but I felt insulted).
The majority of the book is about what you should and shouldn't eat (mostly a couple very specific products, plus meat, seafood, and dairy). The rest is fascinating. There's a lot on what mainstream dental treatments actually do to your teeth and the rest of your body. Plus detail about accessing the need for dentist intervention and alternatives. There is an entire section on children's teeth as well. Only a few parts cover what I hoped much of the book would be about: herbs, supplements, tooth care, etc. It also only has one small chapter on gum health, which is mostly why I wanted to read the book.
Over all, it's worth reading, you just have to take some of his claims with a few grains of salt (but hey, you can brush your teeth with that salt!).