Completed denture or immediate completed dentures were manufactured before operation to three patients with edentulous mandible and maxillary or severe chronic periodontitis. The remnant teeth of patients were extracted. Four Ankylos implants were implanted in mandible, and six implants were implanted in maxillary. SynCone conical bases were placed into implants, prefabricated conical crowns were inserted into conical bases, and temporary dentures were completed. After 3-12 months, temporary dentures were replaced by overdenture with casting frame. Except that one implant had been lost and was replaced by a new implant after 1 month of treatment, the rest implants had no obvious frontal resorption in 12-24 months of follow-up.