After more than a decade with no health insurance, now I have coverage
including Delta Dental.

The last tooth cleanings I had (long ago), I felt I was shortchanged. Both
times, the hygienist cut it short. Once, because she could see she was
hurting me. The discomfort was minor, and I did not want her to stop.
Another time, I was outright told it "was taking too long". In other
words, since it had been a long time since the last one the cleaning was
taking longer than the hygienist felt it should.

Both times, I let it pass without making a fuss.

These days, I'm more likely to stand up for myself. On the other hand, I
intend to be reasonable. I want what I (or rather my insurance) is paying
for. Nothing more, and nothing less.

When I get an appointment (it will be with a dentist who I have seen but
has never cleaned my teeth) for a cleaning, and if I inform them at the
time I make that appointment that it has been a long time since my last
one, am I entitled to a thorough and complete cleaning no matter how long
it takes?

Or is it accepted, not just by dentists and hygienists but also Delta
Dental, to limit the time, even if the job remains uncompleted?

My insurance pays for one cleaning per year, so I assume that coming back
for another visit would not be covered. Or will Delta Dental pay for a
cleaning that is spread over more than one visit?