Implant over implant: an alternative method for solving malpositioned osseointegrated implants at the sinus floor.

An implant was malpositioned and osseointegrated at the maxillary sinus floor with no complications. However, unexpected bone formation over the implant made the implant nonfunctional. Because the patient rejected the removal of the implant, it was left in place while another short implant was placed into the newly formed bone in approximately the same position as the old implant to restore the posterior maxillary tooth. Within 6 months, the new implant over the old asymptomatic implant was functional. Radiographs revealed osseointegration and stable periimplant marginal bone level with no signs of infection or inflammation.