Four-Millimeter-Long Posterior-Mandible Implants: 5-Year Outcomes of a Prospective Multicenter Study

Abstract

Background: There is lack of evidence on long-term success of short dental implants in reduced alveolar bone. Purpose: In this prospective 5-year study, survival and marginal bone loss of 4-mm implants, which supported fixed dental prostheses (FDPs) in severely resorbed posterior mandibles, were evaluated. Material and Methods: In 28 patients, evaluation of 86 osseointegrated 4-mm-long implants, which supported a 3- or a 4-unit FDP by crown splinting without the use of pontics or cantilevers, was performed over a 5-year period. Results: Three subjects dropped out for non-study reasons: one subject had her three implants removed after 1 year and two subjects died (six implants). Five implants in three subjects were lost between 3 and 5 years. Twenty-four subjects and 71 implants were active at the 5-year follow-up (92.2% survival). After 1 year, significant (p