Saturday, October 25, 2014
6 tooth bridge with non-vital anchors
This 79 year old relative has had a six tooth assembly for 15 years and problems are developing. The six teeth are four anchor teeth (2 on each side of the upper eye teeth) and the two front teeth which were extracted.
18 months ago one of the anchors (second bi-cuspid?) required a root canal and crown so it was isolated and no longer served as an anchor tooth. This resulted in one tooth (next to an eyetooth) becoming the only anchor on that side. Now THAT tooth requires a root canal.
QUESTION: is having ONE non-vital bicuspid becoming the only anchor for the bridge an invitation for disaster. I think it is only a matter of time before this non-vital anchor tooth fails, possibly rendering it USELESS. Maybe this patient should consider having that 18 month old crown removed and incorporating that tooth once again as an anchor for a NEW six tooth assembly.
Hmmmm, what if the anchor teeth on the other side start to fail, i.e., require a root canal and or crown, the patient will be back in the same dilemma - despite having recently spent a several thousand on a six tooth bridge assembly !!!
Tough question to answer without seeing the bone support, periodontal condition, and the occlusion of the bridge. Obviously the more "anchors" a bridge has, the more stable it will be. As teeth are removed as anchors, the remaining teeth must pick up the strain and load lost by losing those other support teeth. This, in turn, weakens them.
The fact that one or more of the support teeth requires endodontic treatment should not really affect the ability of the tooth/teeth to act as support. I don't know why a tooth that was acting as an anchor for the bridge was isolated away from the bridge, just because it had to have root canal therapy, unless there were some extenuating circumstances as to how the tooth was attached to the bridge.
It is impossible to always predict when a tooth will require a root canal, so expecting the teeth on the other side of the bridge to suffer the same problems as the other teeth is simply a guess.
John M Nusstein, DDS
Associate Professor of Endodontics
College of Dentistry
The Ohio State University