Dental Problems

My two year old son digs at his teeth. He has damaged the gum around one tooth so severly that it became loose and had to be pulled. I have tried painting his nails with bad tasting medicine. I have put gloves on him at night. I have punished and praised and rewarded and although his gums seem better, I am fearful that he will lose more teeth because of this problem. I am seeking advice on 1) ways to stop this behavior (I feel my son is well adjusted, but I am to the point of considering counseling for him) and 2) could this be caused by some other medical problem that would appear to be unrelated Please help.