Tilting of posterior mandibular and maxillary implants for improved prosthesis support

Rehabilitation of atrophied edentulous arches with endosseous implants in t he posterior regions is often associated with anatomic problems such as jaw shape and location of the mental loop, mandibular canal, and maxillary sin uses. The purpose of this investigation was to modify the method for implan t placement in the posterior part of the jaws to extend fixed implant-conne cted prostheses further distally, and to reduce the length of cantilevers i n complete-arch prostheses without transpositioning the mandibular nerve or performing bone grafting in the maxilla. Forty-seven consecutive patients were treated with implants (25 patients/36 mandibular implants, 22 patients /30 maxillary implants) placed in tilted positions. They were followed a me an of 40 months (mandibles) and 53 months (maxillae). In the mandible, impl ants close to the mental foramina were tilted posteriorly approximately 25 to 35 degrees. In the maxilla, the posterior implants were placed close to and parallel with the sinus walls and were titled anteriorly/posteriorly ap proximately 30 to 35 degrees. Patients gained a mean distance of 6.5 mm of prosthesis support in the mandible and 9.3 mm in the maxilla, as a result o f implant tilting. There were no implant failures in mandibles. The cumulat ive success rates in the maxilla at 5 years were 98% for tilted implants an d 93% for non-tilted implants, Paresthesias of the mental nerve were observ ed on 4 sides during the first 2 to 3 weeks after implant placement. Analys is of the load distribution in one mandibular case showed no significant di fference between tilted and the non-tilted implants, and the improved prost hesis support was confirmed. Satisfactory medium-term results concerning os seointegration and significant extension of prosthesis support show that th e method can be recommended. This technique may allow for longer implants t o be placed with improved bone anchorage.