I have never had an experience quite like this. Last year, I was rushing to get my teeth cleaned while I still had dental insurance. I do go to my dentist back home and the last time I checked, everything was fine.
When I got there, I waited a while to get my x-rays done and was put in a consultation room where the dentist proceeded to show me my x-rays and close ups of all the problems I had with my teeth. Apparently, I needed to get all my fillings replaced and that I needed some sort of ultrasonic specialized cleaning techniques because I had peridontal disease and all sorts of eyebrow raising b.s..
I proceeded with the cleaning which was done in a cursory fashion. There was absolutely no real scaling done and a very cursory cleaning (just some crap polish job which didn't even clean up some of the stains on my teeth). The dentist didn't bother to check up on the bad job done by the hygienist.
I never returned despite phone calls and email reminders.
I went back home to my dentist who did a full check up on me and all my fillings were fine. I had no peridontal disease and my hygienist actually appropriately scaled my teeth properly (which is what you really are paying for when you get a cleaning), got rid of all of my stains. No crazy ultrasonic technique necessary. The dentist checked my hygienist's work and told me to follow-up in 6 months.
The scary thing about dentists are you don't know really what you are getting into and place a lot of trust in them to do the job they are supposed to do. A good dentist should always check on their hygienist's work to ensure proper scaling was done because that is what a "dental cleaning" is supposed to do.