Before the era of chemical anesthetics, hypnosis was delivered to render surgical treatment by some surgeons. In today's practice, chemical anesthesia is so effective that hypnosis is rarely used. The descriptions that none of the available anesthetic solution can achieve adequate anesthesia is extremely rare. If injection technique is employed properly, anesthesia is almost always achieved. You may need to find a dental office where an anesthesilogist is affiliated, or a dentist who is familiar with hypnosis.
I don't know if this is any use to you but I get referred to a specialist clinic in our area I am terrified of having anything done to my teeth. The technique they use at this place is an injection where you are conscious but do not remember a thing when you come round. I had two extractions a filling scrape and polish last time and I can honestly say I don't remember any of it. The only downside is you have to be referred by your own dentist and the waiting list for just an assessment is approx 6 months. Then you have to wait a further 6 months for treatment.