I had root canal done on molar tooth.is composite over the ceramic bridge as strong ceramic crown? want to keep bridge if possible.thank you

Not as strong: However, it is a great alternative to replacing the bridge, especially if the bridge is fairly new and/or if the fit is still terrific. The restoration (as all restorations) needs to be monitored periodoncally for leakage and recurrent decay. If the tooth in question needed root canal therapy due to marginal decay, you should make a new bridge.

It is possible: to fill the access hole in the crown with a composite resin or similar tooth colored restoration.