Before the development of dental CT reformatting software, much of the radiographic assessment of the mandible and maxilla was performed in the dentist's office using plain radiographs. The widespread use of dental reformatting software, however, has caused the radiologist to take a more active role in evaluating the jaw. Unfortunately, most radiologists have had little experience in this area, and many of the CT findings are undescribed. Our objective, therefore, was to determine the CT appearance of dental-related inflammatory disease of the jaw and to discuss the mechanisms causing such disease. Reformatted CT scans of 400 patients referred for dental implant assessment were evaluated for abnormalities related to infection of dental origin, inflammation of dental origin, or both. The diagnosis was confirmed by surgery, clinical presentation, classic plain film appearance, or a combination of the three. The following disease processes were identified and described: periodontal lesions, periapical lesions, condensing osteitis, disuse bone atrophy associated with edentia, and maxillary sinus abnormalities associated with dental disease. Inflammatory diseases of the jaw and their sequelae are frequently seen on CT scans of patients referred for examination before dental implantation. Because radiologists now take an active role in evaluating the jaw, they need to become familiar with these findings.