When to crown?
What are you waiting for? Coronal leakage, fracture, or healing?
The treatment outcome can eventually either be success or failure [the more appropriate terms is “healed” or “not-healed” (Friedman 2002)]
1. If it’s healed, the waiting period (at least 6 months to be able to see radiographic changes) for the evidence of healing to become apparent is basically a waste. In fact, patients’ teeth are subject to unnecessary risk of coronal leakage and fracture for all that waiting.
2. If it doesn’t heal, what would you do?
Would you non-surgically retreat your own endo? If that’s the case, what could you do that you couldn’t have done in the first time round? If you could do it, you would have done it already. Non-surgical retreatment on your own endo is not likely to achieve anything. Therefore, if the lesion doesn’t heal the next treatment is endodontic surgery and not non-surgical retreatment. Endodontic surgery has nothing to do with post core and crown. It can be done while post core and crown is intact.
If the lesions healed, the waiting period would be a waste. If the lesions persisted, the treatment wouldn’t affect the restoration. Why wait?
References
Friedman S (2002) Prognosis of initial endodontic therapy Endodontic Topics 2, 59-88.