I understand that what you are referring to is Root planing, where the dentist attempts to scrape clean the root surfaces of your teeth to allow an improvement in your periodontal health.
During this procedure it is quite common for the practitioner to inject small amounts of local anaesthetic to reduce the sensitivity of the procedure. It might be possible to receive a injection in your palate as well.
A topical anaesthetic might be applied to reduce the pain of the injection, but this is very subjective from person to person
My advice is just to stick it out. The pain is just for a second or two and thereafter it is over
Hope this helps!
It wasn't bad. She used the numbing gel, I think it's called oraquix. I didn't need injections. My teeth weren't sensitive, just a couple spots but it was ok. I asked her halfway through if she was even going under the gums. First she used this device that sounded like a drill, but it was ok. Then she manually scraped, which was intense but it never hurt.