My son is 12 now but when he was younger when he had a cavity they always had to give him anesthesia otherwise it would take all the nurses in the office to hold him down. I think its beneficial for my child. I haven't really took him back lately cause its so stressful for him and me too.
The dentist explained like 3 different options to us, one being they are awake (the local Im pretty sure), then there were two other options that had varying anesthesia. Talk to the dentist, and know your child. It would not be safe for my child or the dentist to do dental work without him being under. He bites if you stick things in his mouth, and he squirms. He will not hold his mouth open for a time, or allow you to prop it open. He was grabbing the whole time he was getting cleaned. These are all things to think about. The gathering of saliva in your mouth and spitting while they are working, my son in not capable of spitting like that yet. We are going to have to have dental work done, partial removal, possible cavity, and we are going to arrange him to be put under. it's the safest, for us.