Twenty posterior maxillary edentulous sites requiring open sinus augmentation for staged dental implant placement will be studied. Group I (study group) the maxillary sinus membrane will be elevated using titanium mesh fixed by bone screws. Group II (control group) will have stainless steel screws/pins placed bucco-palatally to maintain the elevated membrane and stabilize the formed blood clot. Platelet rich fibrin (PRF) will be placed at the site of elevated membrane in both groups.

Inclusion Criteria:

• Adult male/female patients with age interval 18:60 years old.
• Patients with one or more teeth requiring implant supported dental restoration in atrophic maxilla.
• Alveolar bone height less than 5 mm at the defective site.
• Good oral hygiene.
• Patient's consensual agreement to be enrolled in the study.

Exclusion Criteria:

• Medically compromised patients with conditions contraindicating surgery (eg. uncontrolled diabetics, bisphosphonate intake, radio or chemotherapy).
• Patients with active infection at or related to the site of surgery (eg. acute sinusitis).
• Heavy smokers.
• Patients not indicated for an implant supported restoration at the time of enrollement (eg. active/untreated periodontal disease). (Patients developing any medical condition that interferes with the outcomes after enrolment in the study will be excluded).