What is the normal procedure to repair a missing upper molar that broke off years after a root canal due to never being crowned? would the remainder of the root have to be removed as well? would an implant be best or would a simple single

The : The first choice would be to use what remains of the tooth and restore it- if feasible. If not, then you and your dentist should consider removing the tooth and replacing it with either a dental implant or a fixed partial denture (a bridge). That would involve three teeth. I am not sure what you refer to when you mention a 'simple single tooth bridge.'.

Depends: If there is enough tooth structure left and the tooth is not infected, it could be saved. A crown lengthening procedure may need to be performed to expose tooth structure. Next a post may need to be placed in your root to support the future crown. If there is too much decay, infection or periodontal issues then an extraction with an implant or a bridge is another choice. Consult with your dentist.

Broken upper molar: Need to see the dentist at earliest.Xray is essential to diagnose better with the picture of the tooth.Most of the time is extraction followed by implant or bridge or partial denture depending upon adjacent teeth.Rarely the tooth may get crown .The dentist need to see your tooth and x-ray .Best luck.