We present a case of odontogenic maxillary sinusitis whose sinonasal symptomatology was thought to be the consequence of a previous midfacial trauma. The patient was admitted to the Clinic of Oral and Maxillofacial Surgery after more than 10 years of exacerbations of sinonasal symptoms, which began to plague soon after a facial contusion. We decided to perform CT of paranasal sinuses, and despite the absence dental symptomatology, the dental origin of sinusitis was discovered. The majority of sinonasal symptoms resolved after appropriate dental treatment, and there was no need for nasal or sinus surgery.