The importance of implants Part 1

Here's the hypothetical situation:  You have had much dental work completed over the last 20 years of your life; several [7] crowns, a  3-unit bridge, root canal therapy, fillings, etc.  Excluding your wisdom teeth, you have had only 4 other extractions.  Two were not restored because they were in the very back on the same side [top and bottom], one was restored with the above stated bridge, and the other missing tooth is the reason you went to the dentist today.  After a complete exam and the necessary radiographs, you hear that several of your crowns [placed 10+ years ago] need to be remade.  In addition, one tooth is now unrestorable which will leave the left side with no molars and only one pre-molar on the top.  Your dentist says that 2 implant crowns would be the optimal treatment.  Is he right?