Long-Term Outcomes of the Minimally Invasive Sinus Crestal Approach : A Comprehensive Review and Clinical Case

Case Summary 🔎

This case reviews the long-term follow-up data on the SCA, highlighting clinical success rates, practical considerations, and an extensive case study spanning from the initial surgery to the most recent 2026 follow-up.

• Patient Profile: A 42-year-old male with normal blood pressure and no diabetes.

• Chief Complaint: The patient presented with an ill-fitting maxillary removable partial denture and desired a fixed prosthesis.

• Pre-operative Diagnosis: Teeth #25, #26, and #27 were missing. The residual bone heights at these spaces were approximately 10mm, 4mm, and 6mm respectively, with a concave-shaped sinus floor.

• Treatment Plan: Placement of three implants supporting a 3-unit Fixed Partial Denture (FPD) utilizing Class II and Class III CMI fixations

Case Presentation

1️⃣ Pre operative

2️⃣Surgical Procedure

• Drilling: Serial drilling was performed with twist drills, followed by S-reamers (Ø2.4mm for #25, Ø3.6mm for #26, and Ø3.2mm for #27) at speeds of at least 1200 rpm.

• Elevation & Grafting: At the #26 area, where available bone was only 3-4mm, micro-elevators were utilized to safely lift the membrane through the crestal opening. Approximately 0.3cc of alloplastic bone graft material (Calpore) was inserted below the elevated Schneiderian membrane.

• Implant Placement: EB type CMI implants were placed. #25 was placed 1-2mm into the sinus without a bone graft (Class II fixation) achieving 40 Ncm torque. Implants at #26 and #27 also achieved excellent primary stabilities of 40 Ncm and 30 Ncm, respectively.

3️⃣ Prosthetic & Outcome

• Due to sufficient initial stability, healing abutments were connected immediately. A definitive SCRP (Screw-and-Cement Retained Prosthesis) 3-unit FPD was cemented within just 40 days after the surgery.

• 3-Year Follow-up

• 6-Year Follow-up

  Marginal bone levels were wel maintained while 0.5mm of apices came out from the bone due to re-pneumatization, but were covered by the membrane. This may be a kind of bone remodeling phenomenon, explaining why no more bone is needed in the apex for occlusal support.

• 16-Year Follow-up: Radiographic and CT imaging at the 15-year mark demonstrated that the peri-implant marginal bone levels were very well maintained.

Conclusion

This case demonstrates that predictable implant placement can be achieved in sites with limited residual bone height using a crestal sinus elevation approach. Adequate primary stability was obtained despite reduced bone height, with insertion torque values of up to 40 Ncm. Long-term follow-up up to 16 years confirmed stable peri-implant bone levels and maintained function without complications. This suggests that the SCA technique using micro-elevators can be a reliable and minimally invasive alternative for sinus augmentation in selected cases.

Summary of Key Points

• The Sinus Crestal Approach (SCA), especially when utilizing micro-elevators, is highly effective even in cases with limited bone height (1-3mm).

• High initial stability can allow for rapid prosthetic loading.

• Long-term imaging (16+ years) proves that marginal bone levels remain stable, and minor apical re-pneumatization is a safe, natural remodeling process.