I had an impacted lower wisdom tooth extracted under general anaesthetic last year, in the hospital day unit. They had a chat with me first and made note of the diabetes, allergies etc and they told me what they would do, how long it would take and how I would feel when I woke up.
In the event it took very little time, and although they wouldn't let me out until I had stopped bleeding they were very good while I was there. I was given a little bag with changes of bite pad in case I needed them, a detailed aftercare sheet and phone numbers for just in case (I didn't need them). I wasn't given antibiotic because I take daily antibiotics anyway (prescribed, as I haven't a spleen).
I was also warned that once the pain killer they used wore off I would likely experience some pain. I did, but nothing mega and I've had a lot worse.
They give you a sheet before you go telling you how long to fast for etc - they mean it, and if you have eaten they will refuse to operate. Do your very best to get your blood sugars down and as level as you can. If this means going low/no carb for a few days then so be it. You'll heal much faster with normal sugar levels.
They will be aware of your diabetes and they really do deal with diabetic patients all the time. I am T1 and the only precaution I took was to be absolutely sure I'd taken my basal and all other necessary drugs. If you are at all unsure about drugs (thinking of metformin) then ring your local surgery and speak to the diabetic nurse.
Good luck; it's a doddle and you'll be fine.