While being numbed by injection my son often complained and cried, his only way of saying "slow down". He was very nervous and could have cared less to take in the sleepy gasses, even though the nurses and I both tried to remind him to. Then it took almost an hour before the dentist came back for his procedure. That's MUCH too long for an already scared seven year old with tears streaming down his eyes and shaking. By the time the dentist did arrive, my son was freaking out, though he said he didn't feel any pain, but it all was happening after such a HUGE lull in activity. We left afterwards and he was very sullen and upset, tears still welled up. I will think twice about setting up surgery like procedures for him in the future.