My oral surgeon was 100% against me going on a medication because it can cause osteonecrosis of the jaw. The problem was the doctor only saw the tiny fraction of patients who had this rare complication, not the 95-99% who greatly benefit from it.
Was it a bisphosphonate (e.g. Fossamax, Boniva, etc.)? I was on one of those for a while, and my dentist would not do any major work on me until I was off it for at least six months. He told me that osteonecrosis is rare, but is so awful he would not risk it.