I've had bruxism issues in the past and I have also had periodontal issues in the past, pretty badly, too.
I used to get the moldable bite guard for at night when I had teeth grinding issues. I don't do this as much as I used to, but still once in a while according to my husband.
When I was a teenager I know I would grind my teeth and my mom would tell me because of course it's a distressing sound and to think of the damage that does.
I have been able to help my periodontal disease with Shine - Remineralizing Tooth Powder from orawellness.com and I also find that EcoDent floss helps, too. They sell that as well, but sometimes I find that cheaper at a natural food store. Those things have helped a lot. It has also helped me to avoid grains (most bother me anyway), and to be loading up on at least a pound of veggies a day. I find that green juice works for me because I'm sure I don't absorb things as well as I should. I take digestive enzymes when I have my veggies as I am deficient in some of those enzymes.
The way teeth are can be the effects of medication sapping nutrients, not having enough nutrients, not absorbing enough nutrients, eating too much sugar (which also depletes nutrients), eating too much phytic acid foods that aren't prepared thoroughly with soaking and such (Cure Tooth Decay by Ramiel Nagel was a good book with interesting studies, many done by Weston Price).
Although, I still struggle with nutrient deficiencies and staying on top of them has proven to be difficult and I think the medication does set me back as far as nutrients go. My oral health isn't still the best. It seemed to be improving when I wasn't taking the medication for a while (15 months), I had far less issues. Being back on it, I feel like my teeth are getting worse again.
The one time when I actually had amazing teeth while taking medication was when we were getting a local share of veggies from an organic farmer every week and the price was great. We used all those veggies, made it a real habit. My teeth looked amazing, they had never felt better! Unfortunately, the farm didn't last for the long run and we ended up moving away. I know I haven't been eating as many veggies as I need, but I really need to get on top of it again. I'm sure my mouth would thank me.
Best of wishes to you =)