Endoscopically controlled flapless transcrestal sinus floor elevation with platelet-rich fibrin followed by simultaneous dental implant placement

Rationale: In this case study, a modified transcrestal approach was applied to the patient of extremely atrophic posterior maxilla. We analysis the Implant Stability Quotient values (ISQ) to monitor implant stability, and the cone-beam computer tomography (CBCT) to evaluate the bone regeneration. Patient concern: A 26-year-old female patient visited our hospital with no contraindications for dental implants and a loss of the maxillary right first molar. Diagnose: Examination by CBCT demonstrated the posterior maxilla was extremely atrophic, the residual bone height (RBH) of #16 was 3.5 mm. Intervention: Patient underwent a endoscopically controlled flapless sinus floor elevation. The maxillary sinus membrane was elevated by two-step, and an implant of 12 mm length was placed simultaneously. Outcomes: Twelve weeks post-surgery, the implant-level impression was finished and a full-ceramic crown was placed thereafter. Lessons: The modified transcrestal approach can be applied to augment maxillary sinus with a residual bone height less than 4 mm.