Resolution of Odontogenic Sinusitis after Root Canal Treatment.

Odontogenic maxillary sinusitis (OMS) is an inflammation of the epithelial lining of the maxillary sinus mucosa caused by an odontogenic infection. This study reports a case of OMS associated with an endodontic infection in an upper first molar. The patient reported severe headache and was referred by an otorhinolaryngologist. Clinical examination revealed a periapical fistula associated with tooth 26 and cone-beam computed tomography (CBCT) revealed mucositis in the left maxillary sinus and close proximity of the palatal root of tooth 26 to this sinus. The diagnosis was odontogenic sinusitis associated with tooth 26 with necrotic pulp and a chronic periapical abscess. The tooth was submitted to root canal treatment. After 6 months, follow-up showed no symptoms and regression of the periapical lesions and mucositis. Root canal treatment is an effective procedure for the management of OMS caused by the lesions of endodontic origin.