Last year, I had all four teeth removed at the same time under local anesthesia. The teeth weren't impacted, and the whole process was fairly smooth. Structurally, the teeth didn't have to come out, but the consensus is that they were dragging down the overall health of my mouth, which could in turn affect my diabetes.
When I tested before going in, I was 90 -- lower than I wanted for the procedure. I had some juice and was around 150-200 while the work was done.
I ate soup and yogurt over the next few days, and was back to normal within a week. The pain meds made me tired, but didn't have much of an effect on my BG.
Overall, I think I was pretty lucky. I didn't have any doubts about my surgeon (she was fabulous!), but if I did, I would have checked in with my regular dentist and/or my endocrinologist depending on the nature of my concerns.