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 < .001) mean (standard error of the mean [SEM]) 0.44-mm (0.05) marginal bone loss occurred. At 2, 3, and 5 years, mean (SEM) bone loss of 0.57 mm (0.06), 0.55 mm (0.07), and 0.53 mm (0.08) occurred, respectively (no significant change after 1 year). At 5 years, average plaque levels were 13.3%; 69% of the implants were plaque free. On average, mucosal bleeding occurred at 8.1% of the implants. During 5 years, two subjects experienced uncomplicated bridge loosening. No other complications occurred during the study.
Conclusion: Four-millimeter implants can support FDPs in severely resorbed posterior mandibles for 5 years with healthy peri-implant conditions.
Keywords: bone atrophy; bone loss; bone resorption; clinical trial; crown-implant ratio; short implants.
© 2014 Wiley Periodicals, Inc.