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. Keywords: bone loss, dental implant, wide diameter