The purpose of the present study was to experimentally determine if cementum formation with inserting collagen fibers can be accomplished on dental implants. Titanium implants were placed in the mandible of monkeys, where apical root portions were retained. The histologic examination of undecalcified sections revealed that a cementum layer on the implant surface with inserting collagen fibers was achieved around implants placed in close relationship to retained roots; however, implants without contact to retained roots demonstrated the typical findings of osseointegration. These results demonstrate that dental implants with a true periodontal ligament can be accomplished. Keywords: cementum formation, dental implants, osseointegration, periodontal ligament, titanium implants, wound healing