OBJECTIVE: Raise the main findings of computed tomography of patients who underwent surgery to increase the floor of the maxillary sinus, dental implant and / or endodontic surgery and who developed maxillary sinusitis in the postoperative period. Methods: We analyzed the Computerizes Tomography in axial, coronal and sagittal planes of 18 patients referred by dentists to the Otolaryngological clinic who had undergone previous dental procedures and developed postoperative signs and symptoms consistent with maxillary sinusitis. All patients had clinical criteria for sinusitis and underwent examinations of video endoscopy and computed tomography. The Computerized Tomography images were evaluated by physicians radiologist and otolaryngologist together. In analyzing the results the patients were divided into two groups (acute and chronic maxillary sinusitis) as the duration of symptoms. RESULTS: The main findings were in continuity and opacification of the maxillary sinus, exposure of the implant within the sinus cavity, obliteration of ostiomeatal complex, signs of osteitis and bone resorption, bone fragment signals, besides the involvement of other sinuses. CONCLUSION: Computed tomography is the examination of choice in the diagnosis of these complications and fundamental in the treatment planning of patients.