Open Access

Purpose: Scientific evidence is limited regarding the long-term (>10 years) outcomes of large enough numbers of implants (>500) to allow for reliable comparison of subgroups. The purpose of this study was to analyze the outcomes of dental implants placed in an active University Clinic setting and followed for up to 20 years. Materials and Methods: Data documenting the implant placement, prosthetic reconstruction, and annual follow-up of patients treated at Frankfurt University were extracted from a Structured Query Language database and patients’ written records and evaluated statistically. Results: Between April of 1991 and May of 2011, 12,737 ANKYLOS® (DENTSPLY Implants Manufacturing GmbH, Mannheim, Germany) implants were placed in 4,206 patients for a variety of clinical indications. The Kaplan–Meier cumulative survival rate (CSR) was 93.3% after 204 months. Most of the failures (198/1.6%) occurred during the first year after implant placement and before prosthesis delivery. A significantly higher (p < .001) number of implants placed in the mandible and in hard quality bone failed than those placed in the maxilla or in weak and normal quality bone. Female patients had significantly higher CSRs (93.7% 204 months) than male patients (92.8% 204 months/p = .029). The implants showed low rates of peri-implant bone loss after 204 months (horizontal: 21 mm: 85.7%, vertical: 21 mm: 85.2%). Conclusion: ANKYLOS dental implants followed for up to 20 years have high CSRs and low rates of peri-implant bone loss.

Purpose: To evaluate the prevalence of peri‐implantitis (PI) and peri‐implant mucositis (PM) in a long‐term follow‐up with comparison among different PI and PM definitions, and to report on the incidence of PI. Materials and Methods: In a retrospective clinical study five different PI and PM definitions were applied onto a population with 274 implants 17 to 23 years postimplant placement. Recommendations by the Eighth European Workshop on Periodontology (EWOP) were used as base reference. Clinical and radiological measurements were considered. Risk factors were evaluated in a regression analysis. Results: After an average observation period of 18.9 years, 40.1% of the implants were diagnosed with PM and 15.0% with PI (Eighth EWOP). PI incidence reached 7.9% on implant level and 13.2% on patient level. Implants diagnosed with PI and progressive bone loss displayed exceptionally vertical bone defect configuration (BDC). Diabetes mellitus, smoking, regular maintenance, or a former periodontal infection did not show significant influence on the prevalence of peri‐implant diseases. Patients with bruxism displayed significantly less PM and PI. Conclusions: Vertical BDC seems to correspond with active PI, wherefore we estimate such a defining factor of importance. Diagnosis of PM and evaluation of probing pocket depths might be only of descriptive interest as they could lead to false‐positive results.