Good luck if you want to consider general anes. You're asking for trouble if you do it! If you have cases like that, do what I do and hook up with an OS and let their CNA do the anesthesia part. I did one last week on a 20yo patient with mild MR, combative disorder, etc. Completed 9 RCTs in 42 minutes (I love rotary endo....). A good service if you want to do it.
Now if you're talking about IV sedation, you can get that without a specialty. Takes a whole lot of classes, a whole lot more malpractice insurance, but can get some of those patients in the door that otherwise would never get their work done. Seems like too much of a hassle for me, but there are some dentists I know, besides surgeons, that do quite well from it.