I hear what you are saying, but why do people not go to the dentist? And when they go why is the standard NHS cleaning brief and not as good as a US cleaning or maybe a private practice cleaning in the UK?
People don't go to the dentist here because they simply don't like going to the dentist - not because anything is necessarily wrong with the dentists themselves, but because they have a fear of dentist work in general (anaesthetic, drilling, toot extraction etc.) - they would rather live with their bad teeth than suffer through the perceived pain of having dental work done.
I have friends who have not been to see a dentist in 10 years!
Actually, I don't think I've seen a dentist in the last 2 years... mostly because my dentist is 200 miles from where I live and only works on Tuesdays and Fridays and I work shifts... so I haven't had much time to go back and see her (you have to book appointments several weeks/months in advance and I never know when I will be available)... I just keep putting it off.
I don't think they don't do cleanings in the UK like they do in the US - I don't think I've ever had a proper cleaning in the UK and I've been going to the dentist here since I was a child... it's just not really part of the appointment.
Usually it's just a quick 3-minute appointment to have a look at my teeth and check they're okay. If I need a filling done I have to book another appointment for it, and when that appointment comes around, they just do the filling and nothing more. I don't think I've ever spent more than about 10-15 minutes in the dentist's chair at any appointment.