Intact bridge fell out -- reused for implanted bridge?

Some times old bridges or crowns can be used as  temporary till a new one is fixed with some modification. How ever Maryland bridge has a different design where only the inner surface of the tooth has this prosthesis. It would be quite crude to modify and fix this. May not be esthetically and functionally upto the mark.  Your surgeon can temporarily place a bridge on the implants for a period of 6 months or till the permanent one is done.This would perform well. 

Unfortunately, attempting to fit the Maryland Bridge to the new implants is not possible.  If someone suggests differently, I would be very careful proceeding with the care.
One way to save money would be on the number of teeth implanted.  If the Maryland bridge replaced one tooth, I see no reason to place 3 implants.  You can save money with 2 implants to support 3 teeth, similar to the Maryland bridge design.  
Also, if the decayed teeth can be "fixed", I would consider that before having them extracted.  The general/restorative dentist should be treatment planning with you moving forward.  Sure, the placement  of the implants comes from the surgeon in this case, but your dentist should be in charge of the treatment planning with you.