All-on-Six Implant-Supported Full-Arch Maxillary Rehabilitation With Indirect Sinus Elevation and Multi-unit Abutment Conversion: A Case Report

Full-arch implant-supported rehabilitation of the edentulous maxilla presents significant surgical and prosthetic challenges, particularly in achieving biomechanical stability and optimal esthetics. This case report describes prosthetically driven full-arch rehabilitation of a 33-year-old female patient using the All-on-Six concept in the maxillary arch. Following comprehensive clinical and Cone Beam Computed Tomography (CBCT) evaluation, six implants were placed freehand in regions #13, #14, #16, #23, #24, and #26. An indirect sinus lift was performed in the #26 region due to limited residual bone height (8 mm). The primary stability during implant placement was between 30-50 Ncm, and the Implant Stability Quotient (ISQ) value was 65; therefore, a delayed loading protocol was adopted. After a five-month healing period, multi-unit abutments (0°, 17°, and 30°) were placed to achieve prosthetic parallelism. A splinted open-tray impression technique was used, and a digital workflow with Exocad software facilitated framework design. A screw-retained porcelain-fused-to-metal (PFM) prosthesis was delivered and torqued to 35 Ncm. Mandibular rehabilitation included crown lengthening and PFM crowns. Postoperative radiographic evaluation confirmed satisfactory implant positioning and prosthetic adaptation. This case demonstrated that meticulous surgical planning, prosthetic precision, and evidence-based protocols contribute to predictable functional and esthetic outcomes in full-arch maxillary rehabilitation.