10mm Sinus Lifting with the SCA Technique in the Severely Concave Sinus Floor

Case Summary 🔎

54-year-old female presented in February 2009 with a missing maxillary left first molar(#26).
Tooth #26 was extracted three weeks prior due to severe dental caries.
No significant medical history reported.

Sinus lift using a crestal approach, rather than a lateral approach, due to the concave sinus floor.
Despite only 3-4mm of residual bone height, over 10mm of elevation was achievable through the crestal approach.
The amount of sinus elevation depends on the sinus floor shape.
- The more concave the sinus floor is, easier to lift membrane. 3mm lifting would be the maximum if the floor is flat. Lift would be impossible, if the floor is convex because there is no membrane to expand.
Delayed immediate placement planned to preserve soft tissue contour and the broad bone bed.
Guided Bone Regeneration (GBR) was recommended to enhance initial stability, utilizing the cortical layer surrounding the extraction socket.

Periapical radiograph showed a highly concave sinus floor due to a long septum in the mesial side of #26.
Residual bone height of 3-4mm and a large defect at the extraction site.

CT images before implant placement. There was no specific pathology in the maxillary sinus, but a distinguish septum was seen at the mesial side and thickened membrane at the distal area.

1. Maxillary Sinus Crestal Approach

Fig 1. Gingiva healing at 3 weeks after extraction of #26. It was decided to elevate the sinus floor about 10mm by the crestal approach as a septum is present near the implant position, and the shape of the sinus wall was very concave.
Fig 2. Bone defect on the buccal area was observed. Initial drill was used to mark the insertion position.
Fig 3. The implant site was widened with a Ø4.5mm drill with a 3mm long stopper.
Fig 4. Ø3.6mm S-reamer with 4mm stopper in the SCA kit was used to drill for the opening into the sinus. 1200 rpm was used.
Fig 5. The maxillary sinus membrane was seen directly without forming a thin bone disk this time. It was intact without perforation.

2. Sinus Lift

Fig 1. Bone material (Calpore, Kyungwon, Seoul Korea) was grafted by using the bone carrier. About 0.7mm bone was inserted for elevating the membrane about 10mm. This could be done because of the severe concave wall of the sinus due to the septum.
Fig 2. 0.6cc of bone was inserted by spreading the bone inside the sinus.
Fig 3. The larger spreader was used to spread bone graft materials to the distal side with a speed of 80 rpm. The graft material was inserted 1-2mm deep into the maxillary sinus.

Periapical view after bone graft. The membrane was elevated about 10mm at the mesial side due to the existence of a septum. On the distal side, however, there was minimum membrane elevation with little bone graft. This was not only because of the absence of a septum, but also because there was a thickening of the membrane in the distal side.

3. Final Drilling & Implant Placement

Fig 1. Countersink drilling was used after bone graft due to D2 bone.
Fig 2. CMI IS 510 (Internal Submerged type) implant was placed.
Fig 3. The insertion torque value was 25 Ncm, which was sufficient for performing the one stage approach.
Fig 4. Healing abutment was connected because initial stability was satisfactory.

Periapical view after sinus bone graft and simultaneous implant placement. 10mm sinus elevation was performed, which was possible due to the severe concavity of the sinus. The distal part of the membrane was also elevated.