Clinical Outcomes of Tilted Implants in the Atrophic Posterior Mandible: A Long-Term Study

Implant treatment for atrophic mandibular molars is challenging due to limited space for implant placement and the potential risk of damaging the inferior alveolar nerve. One approach to address these challenges is the angled placement of endosseous implants. We herein report the long-term outcomes of tilted implants placed in atrophic mandibles. Subjects were 12 patients who underwent intentionally tilted implant placement in the atrophic posterior mandible in our department between 2006 and 2014, and 28 implants were placed. Patients were scheduled for follow-up visits every 6 months for a clinical assessment. The minimum observation period was 7.4 years, and the maximum was 16.3 years. Vertical bone loss was monitored on follow-up panoramic radiographs with vertical bone resorption ≥3 mm included in the evaluation. Three implants (in 2 patients) were placed with bone grafting. Twenty implants had single crowns, and 8 were splinted. A radiographic assessment revealed vertical bone resorption ≥3 mm in 7 implants (25%). The 10-year cumulative survival rate was 96.4% (1 implant lost in 9.3 years). There was no damage to the neurovascular structure or permanent paresthesia. Although the rate of vertical bone resorption was high, the prognosis of tilted placement in the mandibular molar region was favorable, suggesting it has potential as a good treatment option to reduce the risk of inferior alveolar nerve damage.