@dmr4ever, Tymlos and Forteo are the only medications that don't pose a risk for the jawbone. In fact, either can be prescribed as adjunct medication for ONJ. The risk is small and usually you have to be on the antiresorptives for a long time to be at risk. If the injection is a bisphosphonate, then it would be better to wait.
Six months is a long time to for the tooth to hurt after a filling. But you are getting a crown. It may be that the decay was too close to the root, or maybe the tooth has cracked. If you are having a root canal that's where infection can enter the bone. How long will you wait. Are you like me just not wanting to go in or are you waiting for insurance or other windfall.
Osteonecrosis doesn't show up on dental x rays until there is substantial damage to the jaw. It is most often diagnosed through a visual exam exhibiting exposed bone or area of the gum that just won't heal.
Decay in the tooth absolutely does not indicate osteonecrosis.
If you haven't been on Fosamax for long, you shouldn't worry. If you are thinking about Reclast, I'd suggest waiting for the bone to heal.