Thanks for providing a thoughtful question. normally pier abutment is managed by 5 /4unit FPD, provided that the abutments are periodontally sound. Again it depends on the missing teeth. I follow the principle of not crossing the canine with FPD at any given situation. Most of the times with first molar as pier abutment either maxilla or mandible i had poor prognosis, so i am not in favour of using first molar as pier abutment. Hope this article helps you
Quintessence Int. 2006 May;37(5):345-52.
The pier abutment: a review of the literature and a suggested mathematical model.
Dear sir the prognosis depends on the case selection, how perfect your laboratory process the denture, the patient itself. It is a technique sensitive . The literature gives it as good prognosis, but i personally believe it is guarded