Severe Alveolar Bone Atrophy of the Posterior Maxilla With Residual Bone Height ≤4 mm

This study evaluates the Bone Ring Technique, a single stage procedure that combines external sinus floor elevation and dental implant placement using an autogenous bone ring harvested from the chin. Ten patients with residual alveolar bone height ≤4 mm in the posterior maxilla will be enrolled. Implant stability (ISQ), vertical bone gain, peri implant bone density, and implant survival will be assessed over 6 months. The aim is to reduce treatment time and surgical interventions compared to traditional two stage approaches.