Spontaneous Regeneration of Lateral Sinus Wall Window Following the Removal of a Large Antral Pseudocyst: A Case Report

ABSTRACT The lateral sinus window technique has been utilized for the removal of pathological conditions within the maxillary sinus, such as antral pseudocysts, and sinus floor augmentation. Various approaches have been proposed for managing the lateral window, including repositioning the bone window, placing barrier membranes, or leaving it untreated. Information on the capacity for spontaneous regeneration at the lateral window without treatment or perforated Schneiderian membranes remains lacking. In the present case, a 53-year-old male patient was scheduled for implant placement in the left posterior maxilla, where a large antral cyst was observed. The cyst was removed through a window prepared at the lateral sinus wall and intentional perforation of the Schneiderian membrane prior to maxillary sinus floor augmentation using a staged approach. The lateral window was left uncovered without a barrier membrane. Re-entry for sinus floor augmentation and implant placement was performed after 6 months, and the previously prepared wide window was fully closed with newly formed bone. The sinus mucosa was detached from the sinus floor and elevated with a regenerated bone window attached to it. Within the limitations of the present case report, spontaneous bone regeneration of the large lateral window was observed after 6 months without further repair treatment. It was assumed that the bone surface of the lateral sinus wall and the regeneration of the damaged Schneiderian membrane had osteogenic potential. In addition, the blood supply from the posterior superior alveolar artery also played a role in bone regeneration.