A seven-year clinical evaluation of soft-tissue effects of hydroxylapatite-coated vs. uncoated subperiosteal implants.

Subperiosteal implants have been providing a treatment modality for the edentulous and partially edentulous patient for over 35 years. A recent innovation in subperiosteal dental implant materials technology is the use of hydroxylapatite (HA) coating as a surface coating on the implanted metal framework. The purpose of this study was to compare the intermediate-term soft-tissue performance of HA-coated subperiosteal dental implants with that of uncoated subperiosteal dental implants at equivalent time periods. Four choices of each implant variety were followed for approximately six years. At five years, one patient died, so one HA-coated implant was lost to further follow-up. One uncoated subperiosteal needed to be removed at four years, due to unremitting dehiscence around the post area. The remaining implants were followed, and results indicate that the early healing sequelae appear to be hastened and that the intermediate-term status is non-problematic for all implants. Hard-tissue reactions are not necessarily apparent by direct observation. The HA-coated implants were associated with a kinder soft-tissue response, typified by a tighter, healthier soft-tissue seal around the perigingival abutment posts and no post-implantation strut dehiscence complications. HA coating appears to represent an incremental increase in performance of uncoated metallic subperiosteal dental implants, for soft-tissue as well as hard-tissue response.