Displacement of Dental Implants into the Mandibular Bone Marrow Space - Cause and Treatment. A Case Study and Literature Review.

The purpose of this Clinical Case Letter is to investigate the pattern of dental implant displacements into the mandibular marrow space and to suggest a suitable method for the removal of the displaced implants. Five patients were consulted at the authors' institute. All patients had experienced sudden displacement of an implant into the mandibular medullary cavity. Except for one female patient, no patient had a history of osteoporosis. The displaced implants were retrieved by crestal hole widening or lateral decortication. Based on our cases and those of others, 15 cases of implant displacement into the mandibular medullary cavity have been reported. Most patients did not have a history of osteoporosis. In more than 50 % of cases (n = 8/15), the implants were confirmed to be displaced to the lingual side of the inferior alveolar nerve. The crestal approach has some limitation in terms of the operation field and risk of further displacement; therefore, a lateral window approach would be recommended in deeply displaced cases. Since persistent hypoesthesia is frequently observed to accompany fixture removal, surgeons need to be aware of the potential neurological complications after the removal of a displaced fixture.