OP,
There are new root canal filling materials that provide a better
seal and therefore prevent infection and are non-toxic.If you pull the root canaled tooth and put in a bridge,it is likely that you will eventually lose the two teeth that will form the bridge due to nerve damage from preparing the bridge and subsequent infection .Preparing a tooth for a bridge is also more likely to fracture a tooth that placing a filling.Ofcouse someone will say that they have no problems with their bridge but they are the exception to the rule. How much money will the dentist make if she replaces your mercury fillings and redoes your root canal vs how much she makes (now and in the future ) if she places a bridge?