I have a small puss filled bump on the inside gum of tooth #29. This started about 1 week ago. This tooth had a root canal done about 20 years ago. It is also an anchor tooth for a bridge for #29-31. The bridge was replaced about 1 1/2 years ago. I was having problems with the porcelain fall off so my dentist was remaking it using gold. The pain in the gums around this tooth started about 4 weeks ago after the dentist had to pack the cord around the anchor teeth to make impressions for the new bridge.Prior to the impression, the dentist wanted to shorten-up the tooth so he "took a little off the top" of #29. He installed the new permanent bridge about 1 week ago. The bump comes and goes. He's taken X-rays twice but doesn't see anything. He said that he's concerned that the tooth make be cracked. How could that be? This tooth didn't cause me any problems until he packed the cord. When the bump is there, I can feel some pain/pressure when I bite/chew.
I'm going back for a recheck this week but I'm quickly loosing confidence. How do you diagnose a cracked tooth? Is it common for a tooth to crack this long afterwards or is it something that the dentist did when he removed the temporary crown, packed the cord or "took a little off the top"? What is the treatment?