Two groups of patients with atrophy in posterior maxilla indicated for sinus lift.

First group will be subjected to open sinus lift with chin bone graft. Second group will be subjected to sinus floor elevation using a bone ring.

Two groups of patients with atrophy in posterior maxilla indicated for sinus lift.

(A) First group will be subjected to open sinus lift with chin bone graft.

• All cases will undergo surgery under general anesthesia for sinus lift and other surgery under local anesthesia for implant placement .
• Exposure of the anterior wall of maxilla according to standardized surgical approach.
• Open sinus lift and bone graft.
• After 6 months, implant will be drilled and inserted in the recipient site according to standard protocol.
• Loading on implant after 5-6 months.

(B)Second group will be subjected to sinus floor elevation using a bone ring.

• All cases will undergo surgery under local anesthesia for implant placement in the mandibular chin and other surgery under general anesthesia for sinus lift using bone ring with the implant.
• Exposure of the mandibular chin will be done under local anesthesia using a standardized surgical approach.
• Implant will be drilled and inserted in the chin according to standard protocol.
• After 3 months, second surgery under general anesthesia to place the implant and surrounding ring in the atrophied posterior maxilla.
• The bone ring containing the implant allowed to heal for 5-6 months.

Follow up:

• Clinical evaluation will be performed at the first week post-operative.
• Three months post-operative second surgery to put the implant with surrounding ring in atrophied posterior maxilla.
• Five months post-operative to the second surgery, implant will be loaded with the final restoration.

Inclusion Criteria:

1. Patients with at least a unilateral atrophied posterior maxilla indicated for open sinus lift and graft.
2. All ages and both sexes were included in this study.
3. Patients should be free from any systemic disease that may affect normal healing of bone, and predictable outcome.
4. Patients with good general condition allowing surgical procedure under general anesthesia.
5. Patients with physical and psychological tolerance.

Exclusion Criteria:

1. Patients with high risk systemic diseases like uncontrolled diabetes. As uncontrolled diabetes has a negative impact on normal bone healing.
2. Patients with chronic sinusitis, maxillary sinus tumor or cyst. As they will affect accuracy of the procedure.
3. Patients with physical and psychological intolerance. As psychological stress will affect the immune system and patient's fitness including healing capacity. ]

Because the two interventions used in this trial are clearly different and easily recognized by the participants and investigators, neither the investigators nor participants can be blinded.