Expert: Mark Bornfeld DDS - 2/24/2005

Question
I wrote to you once before and now am about to have the bridge crown that covers tooth 3, 4 and 5 removed because the gum margins are showing and the crown is 25 years old. After going to an endodontist who told me she sees a possible infection on the tip of #3, I went to my regular endodontist in NYC who has an excellent reputation. He said there is no infection, just the same spot that has been there forever. However, if this root canal were ever to be redone, one root is curved and it may not work and I'd wind up with an apicoectomy. Due to many reasons, I will not go through that. I would rather have it extracted and get a fixed bridge or just leave a space. My regular dentist told me that he doesn't want to put three new crowns on root canaled teeth with silver points (3 and 4 are root canaled, 5 is not). He would only re-crown them if they are redone with gutta percha. At this point, I am going out of my mind because my endo says leave them alone. Now here is my question. My periodontist who cleaned my teeth today recommended a dentist on my plan who I met and liked. He is willing to re-crown these teeth as is. My questions: can drilling off the old crown introduce bacteria into the canals? My dentist said things can leak, it can break the seal. I have had root canaled teeth re-crowned in the past when I was younger and nothing happened as far as infection or abscess. I just don't know who to listen to anymore. My gums are sore in this area and it has to be taken care of. The prospect of this is frightening, the thought of sitting on the chair for a long time to remove this 3 crown piece (all in one, looks like 3 crowns but is one piece). Also, how long does it take to drill this off? I would prefer to leave the root canals alone as long as they look fine on the x-ray and if they show anything at a later time, they could always do a root canal. Thanks again!  

Answer
Dear Karen,

Drilling off the old crowns can indeed compromise the seal of the root canal, especially in an old silver wire case. However, the seal may already be compromised, so it's difficult to say whether crown removal will make the situation worse. Silver wires are commonly thought to be outmoded due to their unreliable seal against the canal walls. I'm afraid this is a bit of a crap shoot: you may gamble by scrimping on a root canal re-treatment, and lose the whole game if the root canal fails. I prefer to offer my patients a more reliable outcome, and this would entail at least an attempt at re-treating the root canals. In the final analysis, it's your call.

It is sometimes possible to tap crowns off quickly by using one of the new and effective pneumatic crown removers. However, this can expose you to the risk of fracturing the teeth, which would essentially eliminate any chance of salvaging the teeth. This is especially true of teeth that have had root canal treatment, since these teeth are somewhat weakened and brittle. It is far safer to cut the crowns carefully off each tooth. This can be done quite quickly if the crowns are composed of gold, which is soft. If the crowns are made of porcelain or base metal alloy, the process can be quite tedious, and can take more than five minutes of drilling per tooth. Regardless of the effort required, it is often much safer to take the slow but sure route.

Hope this helps...

Mark Bornfeld DDS
www.dentaltwins.com
Brooklyn, NY