A 5-year Longitudinal Study of the Clinical Effectiveness of ITI Solid-Screw Implants in the Treatment of Mandibular Edentulism

Purpose: The aim of this longitudinal study was to gain 5-year clinical documentation of the 1-stage surgical technique in connection with ITI solid-screw implants used in the edentulous mandible. Materials and Methods: One hundred patients with totally edentulous mandibles were treated with barretained overdentures supported by a total of 340 consecutively placed ITI solid-screw implants. The patients were followed at annual intervals for at least 5 years to evaluate implant success, longitudinal reactions of the peri-implant hard and soft tissues, and incidences of biologic and mechanical complications. Results: During the trial period, a total of 4 implants failed, all prior to loading, and 51 implants were lost to follow-up, resulting in a cumulative survival rate of 98.8% after 5 years of functional service. The success analysis included additional strictly defined events (either "first occurrence of marginal bone loss >= 4 mm" or "first occurrence of pocket depth >= 4 mm" and "first occurrence of crevicular fluid flow rate >= 2.5 mm") and resulted in a cumulative 5-year success rate of 95.7%. The median marginal bone loss experienced between implant placement and prosthetic treatment was 0.5 mm, followed by an annual bone level change of 0.1 mm for the functional period of 5 years. The increasing incidence of remarkable plaque deposits from 19% to 50% represented the difficulties of the patients in maintaining a high level of oral hygiene, particularly for the lingual surfaces. Sulcus Bleeding Index, probing depth, attachment level, and crevicular fluid flow rate were used to describe the health of the peri-implant soft tissues and remained almost within acceptable standards. Discussion: Survival and success rates of implants, amount of marginal bone loss, and periodontal indices of peri-implant soft tissues were consistent with those reported in the literature regarding implants with the submerged healing concept. Conclusion: With a cumulative survival rate of 98.8%, a cumulative success rate of 95.7%, and a median marginal bone loss of 0.5 mm during the healing period, followed by an annual rate of 0.1 mm after loading, non-submerged ITI solid-screw implants confirm the good clinical outcome of implant-supported treatment concepts for the rehabilitation of totally edentulous patients in a medium-term perspective.