Evaluation of four designs of short implants placed in atrophic areas with reduced bone height: a three-year, retrospective, clinical and radiographic study.

The aim of the present study was to evaluate retrospectively the clinical and radiographic behaviour of four commercially-available short implants with different macrodesigns and microdesigns in areas in which the height of the bone was reduced. We took into account the success and survival, peri-implant crestal bone loss, and the level of probing at which the gum bled. Patients were included if they had been given one or more short implants (≤8.5mm long) in the posterior jaws at least three years earlier. Three hundred and ninety-one short implants were placed in 170 subjects, and were divided in four groups based on the brand of implant. The implants were evaluated one, two, and three years after they had been inserted. Short implants had a three-year survival and success rate of 90% in all groups, and bone loss was acceptable after three years with no significant differences between them. These results support the use of short implants as an effective and safe treatment. However, within the limitations of this study, the design of the implant does seem to influence the behaviour of peri-implant bone at the crestal level.