I have existing implants on #8 and #10. They are a few years old and are very solid. An existing crown on #9 broke off at the gum line. Course of treatment is a 3 unit implant supported bridge on 8,9,10. 9 has been extracted, however the Dentist is requiring 8 weeks healing prior to doing the impressions. Is this length of time typical? What is the reason for the long wait. Any thoughts are appreciated..