Ah it sucks having bad teeth and inflamed gums. I used to be there. Very best in solving your problem.
What helped me was eating a low carb diet - avoiding wheat in particular - taking vitamin D3, along fish oil. After that my gum and teeth problems disappeared. I used to be my dentist's favorite patient. He made a good living off of me at one time. Now I have "perfect" gums according to him and no cavities to report in several years.
Much of what I learned on how to improve my dental health came from Dr.Guyenet's web sight.