Another lifelong dental phobic here, suffering with a cocktail of fears. The absolute pinnacle of my fears was reached last year when all but 3 of my teeth had to be extracted. Unfortunately no NHS dentists in our area so had to go private (the financial pain matching my dental pain). Had IV sedation (nearly 2 hours). I wasn't out for the count but it was more of an out of body experience, helping give me a feeling of detachment from what was going on. As I hadn't slept at all with anxiety the night before the surgery, once I got home the combination of fatigue and residual sedation meant I slept late into following day. So, if you can afford sedation, I would certainly go for it, it does help a lot. Be aware however you will need to undertake to have someone with you for the following 24 hours.
Good luck, and sending you hugs, lots of us on here can sympathise with you.