Abstract: When posterior maxillary teeth are missing, the residual bone height required for implantation is insufficient due to the lack of functional stimulation from the teeth and pneumatization of the maxillary sinus. When residual bone volume cannot ensure the initial stability of the implant, a maxillary sinus floor elevation is needed to increase bone volume in the posterior maxillary region. The "PESS" procedure is a "modified" maxillary sinus floor elevation surgery that uses platelet-rich fibrin (PRF) as a single bone graft material, with the aid of an endoscope to elevate the maxillary sinus floor through the alveolar ridge and place implants simultaneously. The PESS procedure has optimized maxillary sinus floor elevation surgery to some extent and reduced surgical trauma. This article elaborates on the principles, indications, clinical procedures, and precautions of the "PESS" procedure to provide technical support for its clinical application.

Key words: Endoscope, Bone augmentation, Platelet-rich fibrin, Internal sinus floor elevation