The relationship of the maxillary posterior teeth to the maxillary sinuses has important clinical connotations. One of the main risks is the rupture or perforation of the sinus membrane (Schneider) and the projection of the tooth involved in the dental extraction and procedures of surgical extraction of the roots. Rescue of a third upper molar within the maxillary sinus requires a sufficient access area, which allows visualization and extraction with ease, for this the surgical technique of the side window Caldwell-Luc is usually the first choice. The present article shows a clinical case of displacement to the maxillary sinus by iatrogeny during the extraction of a third molar, and its surgical resolution.