Five-mm-diameter implants without a smooth surface collar: report on 98 consecutive placements.

In recent years, indications for endosseous dental implants have been extended to include partially edentulous jaws with areas of limited bone density and bone volume. Wide-diameter implants are particularly well suited for these situations. The purpose of this paper was to report on 98 consecutively placed 5-mm-diameter implants without smooth surface collars. Eight implants failed-6 at second-stage surgery, and 2 after 1 year of loading (91.8% survival rate). Sixty percent of the remaining implants had no thread above the bone level after 1 year of loading. The authors discuss the possible causes for failure and suggest guidelines to avoid failure.