Have you been to a dentist? These things don't generally happen overnight. They may be problems you were in the process of developing before.

However, there is evidence that gum health is directly correlated to Vitamin C level. How much vitamin C are you getting in your diet? Maybe you had a significant dropoff when you changed your eating habits.

Google Ramiel Nagel. He talks about how we can repair dental damage with diet and he is a big supporter of the Weston A. Price movement. Bone broths, vitamin D, organ meats etc. Give him a youtube search, it can't hurt. In the meantime, you might want to see a dentist and make sure you don't have something else going on.

I know this sounds silly but you ought to give oil pulling a shot. I don't know why or how it works, but it really does. I do it with coconut oil and I'm positive that I've cured a lot of dental woes with it (teeth spacing tightens, tooth pain disappears in a few days of oil pulling, and my teeth get a lot whiter almost instantly).

I'd certainly suggest also utilizing bone broths, vitamin C and vitamin D3 as well, as others have suggested. Oh and also a K2 supplement might help with the plaque. I know that whenever I start to get the fuzzy feeling on my teeth I supplement K2 for a few days and it completely disappears.

Oil Pulling site

My sensitive teeth would hurt me if I didn't do dairy to get enough calcium (not enough calcium in the rest of the Paleo foods). I need 100% of the calcium RDA to feel good, not what the Paleo people say that "you don't need as much because our absorption is better". I'm personally against the Paleo belief that dairy is bad. US cow dairy IS bad, but fermented dairy, from goats/sheep/buffalo/camels is NOT bad. Dairy intolerance is usually a sign of gluten & cow dairy intolerance, not itself an intolerance for proper dairy.

As long as you're not allergic to dairy in general, do yourself a favor and start eating goat/sheep cheese, and start fermenting your own goat kefir. Kefir will build dairy tolerance for you over time. Also, you might want to start supplementing with D3, Mg and K2-Mk4 too. You mentioned digestive issues, so if you're not absorbing all the nutrients, it's possible that the calcium you ate on Paleo was not enough, because it wasn't absorbed.

I do think it's worth using Fitday (or any other diet tracker) for a time to see what, if any, nutrients you used to get from food that you're not getting now. I had bad dental problems after I switched to a paleo-ish diet, for me, it turned out to be a serious calcium deficiency. Correcting that took care of the dental problems. For you, it might be something else.

I'm surprised this hasn't come up but have you considered grinding or clenching? It causes all of those problems. It could be daytime or nighttime. People are usually unaware of the latter. There aren't any good treatments and, as I recently asked about in another question, the cause is unknown but may be developmental. Best option right now (but not a great one) is a nighttime mouthguard.