Sixteen patients will be selected from those attending the outpatient clinic of the Oral & Maxillofacial Surgery Department, Faculty of Dentistry, Mansoura University with age range from 20-50 years 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.

Group I (N = 8): The sinus membrane will be elevated by using balloon technique with simultaneous Implant placement.

Group II (N = 8): The sinus membrane will be elevated by using Densah burs with simultaneous Implant placement.

Inclusion Criteria:

• Patent ostium of maxillary sinus.
• Patient with missing one or more posterior maxillary teeth.
• A ridge height at the site of implantation of 4-7 mm.
• A ridge width at the site of implantation of 6 mm.
• Good oral hygiene.
• Patients in the age frame between 20 years and 50 years old.
• No gender preface in selection of the patients.
• Acceptable inter-arch space for the future prosthesis.

Exclusion Criteria:

• Any pathological condition at the site of surgery.
• Patients with systemic diseases that contra-indicate the surgical procedure such as uncontrolled diabetes mellitus, bleeding disorders, serious osseous disorders, and mental disorders.
• Heavy smoking and alcoholism.
• Parafunctional habits such as bruxism and clenching.
• Signs of acute infection or pus discharge
• Disturbed occlusion.
• Maxillary sinus inflammation.