Incidence of Radiographic Cystic Lesions Associated With Unerupted Teeth in Dogs

Medical records and radiographs were retrospectively reviewed over a 3-year period (2012-2015) from dogs presented to a private dental referral practice. Medical records were evaluated for the diagnosis of impacted or embedded teeth. The identified dogs' radiographs were reviewed for the presence of radiographically significant cystic lesions that were associated with the impacted or embedded teeth. Radiographic criteria were established by the authors for the purposes of identifying cystic lesions in dogs of different breeds and sizes, using established indices from human dental pathology as a basis. When histopathology results were available, they were reviewed and reported. In this study, 136 dogs ranging in age from 3 months to 17 years were diagnosed with 213 unerupted teeth during the study period. There were 62 (29.1%) of the 213 radiographically apparent cystic lesions identified based on the criteria proposed in this study. In this study, 146 (68.5%) of the 213 unerupted teeth were identified as mandibular first premolar teeth. Histopathology was obtained on 28 (45.1%) of the 62 diagnosed cystic lesions. Dentigerous cysts accounted for 20 (71.4%) of the 28 cystic lesions. Brachycephalic breeds were overrepresented in this study. Boxer, pug, Shih Tzu, and Boston terrier dogs were most likely to present with cystic lesions associated with unerupted teeth. Seventeen (85%) of the 20 cases with a histopathologic diagnosis of dentigerous cyst were found within these 4 brachycephalic breeds.