I used to go to a dentist where you paid £25 for the hygienist [1] to "scale and polish" before going onto the (NHS) dentist for a check-up. Rip-off as normally the dentist would do the same job while checking your teeth for cavities. In fact, I would have thought the dentist would be more likely to notice problems while scaling rather than just looking.
(This was in the late 80s when they "drilled and filled" anything brown on your teeth. And insisted on a local anaesthetic injection that was more painful than the drilling.)
[1] Should be classed with the telephone sanitisers.