My dental insurance in the US covered very little of my periodontal treatment; luckily we could afford the cost, which wasn't cheap. If I feel that I need to have a bit more intensive work, then it will be private here and off to Manchester. Up to now, I am very happy with the NHS practice and the level of care, as is my DH.
Interesting about the amount of man-made materials potentially causing gum issues. I come from a family of 'soft teeth' and one dentist years back said some of us lack certain enzymes in saliva which helps prevent cavities and other issues. I know some early problems in childhood were down to poor hygiene, overlapping, slightly twisted lower teeth (and no $$ for orthodontia) and the general standard of dentistry back in the 1950's. Then came the era of 'pull don't treat' so I lost teeth in the late 60's that would have been saved via a root canal or other treatment. So a LOT of man-made stuff in my mouth.
But back to the topic - discuss your needs with your dentist, and if the practice won't see you as often as you think necessary, IMHO, look for another practice.