Inclusion Criteria:  The patients will be selected according to the following:  They have distal extension maxillary ridge with sinus pneumatization and remaining alveolar bone height 6- 8mm as verified by preoperative CBCT, have no previous denture experience. They are healthy, free from any systemic diseases relating to the bone resorption (diabetes - hyperparathyroidism). This can be achieved through medical history and clinical examination by a physician and laboratory investigations. Posterior maxillary alveolar ridge deficient in height, width and covered with healthy firm mucosa. Patients are less satisfied with conventional RPD. Absence of maxillary sinus diseases.  Exclusion Criteria:  Acute or chronic sinus pathology History of a sinus augmentation in the past in the relevant sinus Poor dental hygiene. Smoker. Compromised general health (uncontrolled diabetes, bleeding disorder