Sinus Lift Augmentation

The goal of this clinical trial is to histologically understand if collagenic or collagen enriched graft in sinus lift of healthy volunteers needing for implants in the posterior maxillae may work. The main question it aims to answer are: which material works better histologically and radiologically? Researchers will compare a collagenic graft to collagen enriched graft to see if the osteointegration of the material is the same. Participants will undergo a sinus lift with one of the two materials and after six month will undergo a bone sample collection to allow the implant insertion. twelve moths thereafter, a radiograph will be taken to measure the extension of the bone regeneration and implant behavior

thirty implants will be inserted in patients seeking implantation of their lost posterior maxillary teeth (premolar and molars) with limited bone height below the floor of the maxillary sinus, secondary to sinus pneumatization. The patients will be selected from those attending the outpatient clinic of the Oral \& Maxillofacial Surgery Department, Faculty of Dentistry, Mansoura University. 1. Clinical Evaluation • Implant stability 2. Radiographic Evaluation Vertical bone gain (VBG)