Ankylos implant system: concept and clinical application.

PROBLEM: The Ankylos system was developed in 1985 and has been in clinical use since 1987. Some of its significant design features include (1) a progressive thread structure of the endosseous implant body for targeted load distribution to the apically positioned spongy bone; and (2) the gap-free subgingival tapered connection to the abutments.
PURPOSE: The purpose of this report is to demonstrate that the Ankylos Implant System meets both the patients' and the dentists' standards of success and is suitable for use as single tooth replacements, bridge abutments, and retention elements for all regions and prosthetic indications.
METHOD: The data from 5439 implants were evaluated between October 1991 and October 2002. The implants were considered successful if the following criteria were met: (1) clinical stability and function; (2) no inflammation of the peri-implant hard and soft tissue; (3) no progressive loss of the peri-implant bone; (4) no progressive loss of the peri-implant mucosa; and (5) satisfaction of the patient. All implants placed during this period were included in the evaluation as a prospective study. The average loading period was 56.8 months. Postoperative follow-ups were made once a year by a standardized protocol. The results were classified by prosthetic application in Table 1. A total of 943 implants were placed as single tooth restoration and were followed for the duration of the study.
RESULTS: The success rate for this type of restoration was 98.7%. For free-end implant restorations, there were 1679 implants placed with a 97.9% success rate. When the edentulous area involved a large gap, a total of 805 implants were placed with a 97.3% success rate. For cases involving reduced dentition, 606 implants were used with a 95.8% success rate. Another significant finding was that the success rates classified by maxilla and mandible showed no differences.