7 year old Goldendoodle with a brown tooth, Vet states gingivitis

In a routine annual visit (we don't stopped vaccines on our dogs about 5 years ago after what we learned what was in the vaccines). The annual visit is a check up and we don't use anything but ⅛ tsp of garlic and they don't have any ticks, fleas, heart worm, nothing. Each year the vet test them and he's shocked at how well they are doing. Our other dog is 8 years old and we had a full panel of blood work on her and she was fine, so it's a baseline to see how she was doing after being on this program for 5 years.  About 5 years ago we switched our 2 dogs to raw pet food from an amish farm that has beef, liver, and organs organic ground up. Very healthy for them and then feed them ½ cup of raw vegetables/fruit (carrots, blueberries, green beans, some broccoli).

Our Goldendoodle back tooth turned dark brown and the vet said she has gingivitis. We began to spray and rub MMS1 solution (40x) then followed with DMSO on our dogs tooth twice a day on the tooth and gum. She was so good and would lay there and allow us to do that. The tooth has changed color. It's no longer the dark color but a light brown now and we can see some white beginning on the top of the tooth on the outside of her mouth, which was so promising. We now do it once a day. I even take my finger and rub it in gently then spray it again and top it with DMSO. We don't drown the dogs mouth with it, keep it isolated to the tooth and gum only.

The dog also drinks water with MMS (unactivated). We gradually increased the dose from 17 drops MMS per gallon to 30 drops over time and we added 1 tsp of Baja gold mineral salt to their water daily. We researched Baja gold and it has the highest natural mineral in their salt and we use it as well.

Is there anything else we could do. We are trying to avoid have her put to sleep for a teeth cleaning cause the vets use products that are not good. Our dogs coats are so shining and they are so healthy and people will remark how active they are and don't act their age at all. Just hoping she doesn't loose the tooth. The gum above the tooth was a tiny bit red but when we spray MMS and DMSO on it, it stops immediately and now the gum looks pink and healthy but the tooth appears to slowly changing color and getting lighter in color and promising with some slight white showing at the tip. But the gum area is still light brown. 

Thank you in advance for any guidance. God Bless.