Dentigerous cysts (DC) in the maxillary sinus are rare and pose challenges for effective treatment. Despite various available surgical techniques, a definitive approach remains debated. This study introduces a markerless Augmented Reality Assisted Surgery (ARAS) system that utilizes tooth image recognition and surgical simulation to enhance the precision of maxillary sinus DC extractions. Using advanced technology, such as 3-dimensional (3D) intraoral scanning and CT imaging for accurate data capture, the system aligns virtual models with patient anatomy without external markers, demonstrating a minimally invasive surgical solution. The ARAS system enabled precise surgical planning and realization of a DC extraction in the maxillary sinus by creating a bone window in direct contact with the cyst, assisting in complete removal with minimal risk to adjacent structures. The ARAS system may aid surgeons in visualizing patient anatomy during surgery, with overlays of relevant medical images, aiding in precise localization and minimizing tissue damage.