Staged Water Sinus Lift For Inclined Maxillary Sinus Floor

Inclined maxillary sinus floor poses a greater challenge for sinus lift than flat one. Two cases with mildly insufficient alveolar bone height in posterior maxilla and inclined sinus floor ( mesiodistally and / or orofacially ) were selected for crestal approach staged water sinus lift to elevate Schneiderian membrane with Osstem CAS-Kit. The cannon drill was used to partially perforate the ostotomy bottom creating a bone window with upper and lower ends along the floor slope initially. The upper end membrane was then mobilized using the blunt umbrella tip of the depth gauge while the lower one kept intact. Saline of 1 ml was injected into the sinus via osteotomy through the cannula of membrane elevator to lift the membrane around the future implant apex with memrane integrity confirmed. Cannon drill was used to enlarge the bone window to the same size as the drill diameter after verifying membrane integrity. After final osteotomy preparation, the implants with a length at least 10 mm were inserted with a torque>20N·cm. The wound healed uneventfully without epistaxis. The ablation of upper end sinus membrane from perforated bone window on inclined floor can orient membrane elevation via the staged water sinus lift, as confirmed by the perfect halo around the implant apex both mesiodistally and orofacially on CBCT scan, indicating membrane non-perforation . No bone graft was applied onto sinus floor due to an existing minimum bone height around 7- 8mm. The staged crestal approach water sinus lift is safe and feasible for the elevation of the challenging inclined maxillary sinus floor.