Clinical outcome of Screw Vent implants. A 7-year prospective follow-up study

The clinical results of 85 Screw Vent implants are described with respect to 7-year success, including radiographically detectable bone loss, survival and prosthetic quality. The 1-year results of the same material have been reported previously (De Bruyn et al. 1992). Implants were considered as successful when they were meeting with the success criteria proposed by the European Academy for Periodontology. From the 85 implants originally installed, 16 failed during the 7-year interval (18.8%), 6 were unaccounted for (7%), 21 (24.7%) did not meet the success criteria yet survived and 42 implants (49.4%) were successful. The success rate was 65.2% for the mandibular and 43.5% for the maxillary implants. Implant failures were irrespective of implant length, smoking habits, prosthetic quality or oral hygiene level. From 24 patients with a corresponding number of 60 implants, radiographs were available for bone loss analysis. The mean bone loss after 7 years was 2.92 mm (range -0.5 to 6.3) 18 out of 60 examined implants (30%) showed unacceptable radiological bone loss beyond the critical value of 2.7 mm. Implant material analysis and histomorphometric analysis of a retrieved implant are discussed. In the present clinical study, the Screw Vent implant system does not meet the success criteria proposed by the European Academy for Periodontology. The ongoing bone loss increases the risk for future implant failures and peri-implant disease.