I used to work in a dental surgery.The dentist would give very nervous patients the choice of being sedated,but not completely asleep.He would use valium tablets or an injection of valium in the arm.It was very successful although your awake,and still need injections in your mouth For most patients it was really effective,your that out of it and relaxed,you wouldnt care if your leg was chopped of lol.And the majority of patients didn`t remember a thing,you need someone to take you home afterwards and you then sleep it off.Not all dentists do this,try and find one that specialises in nervous patients.Another dentist used gas in the same way,not to put you asleep but relax you.I don`t think that was as effective and the gas made a few patients feel/be sick.