Ten patients with missing maxillary posterior teeth and maxillary sinus pneumatization in this study .the floor of maxillary sinus will be elevated using densah drill via surgical guide with simultaneous implant placement . patients will be received, clinically and radiologically examined, and managed at the Oral and Maxillofacial surgery Department, Faculty of Dentistry, Tanta University.

purpose: This study aimed to evaluate maxillary sinus lifting using Densah burs assisted via surgical guide for simultaneous implant installation in atrophic posterior maxilla.

Materials and Methods: Ten patients with missing maxillary posterior teeth and maxillary sinus pneumatization in this study .the floor of maxillary sinus will be elevated using densah drill via surgical guide with simultaneous implant placement The patients will be received, clinically and radiologically examined, and managed at the Oral and Maxillofacial surgery Department, Faculty of Dentistry, Tanta University.

Preoperative evaluation: all patients will be examined clinically and radiographically using Panoramic view to assess the condition of upper and lower jaws mainly bony tissues and Cone beam CT(CBCT) scan to identify the quality and quantity (width, length) of the bone at the surgical site, design and fabricate surgical guide.

Surgical procedure:, a crestal incision will be made and a full thickness mucoperiosteal flap will be elevated, surgical guide will be prepared and adapted to ridge, supported to the neighboring teeth. and the densah drill will be used as the same manner by manufacture ,bone graft will be inserted at the osteotomy site and the implant will be inserted at this site and using osstell ISQ scale to measure implant primary stability. Flap will be sutured using 3-0 vicryl sutures.

Postoperative evaluation: All patients will be followed up at the first week, one month and 4 months postoperatively both clinically if there is pain ,edema , inflamation and radiographically CBCT immediate and 4 months to Detect the amount of elevation will be measured by drawing a tangential line against the implant surface, just above the sinus floor, a measurement will be taken up to the point where the graft material will be seen covering the top of the implant apex ,Detect density of bone graft

Inclusion Criteria:

1. Residual bone ridge below the sinus floor ≥ 4 mm ≤6mm.
2. Patients should have no sinus pathology detected radiographically.
3. Inter arch space≥8mm.

Exclusion Criteria:

1. patients with any systemic diseases that affect osseointegration rates.
2. Heavy smokers (>14 cigarettes per day) .
3. pathological lesions in the maxillary sinus.