Pavlica Z., V. Erjavec, M. Petelin: Teeth Abnormalities in the Dog. Acta Vet. Brno, 2001, 70: 65-72. Teeth abnormalities can be genetically induced by disturbances in the differentiation of the dental lamina and the tooth buds, and are relatively common in dogs, especially in purebred and line-bred dogs in which the genetic fault has been perpetuated. They are most common in smallbreed dogs but occur in large breeds, too. The aim of our study was to investigate permanent tooth anomalies in dogs. In 627 dogs referred for dental treatment we observed the presence of hypodontia, impacted teeth, hyperdontia, supernumerary and hyponumerary roots, focal macrodontia, focal microdontia, gemination, concrescence, fusion, dilaceration and enamel pearls. Teeth anomalies were detected in 288 (45.93%) dogs of different skull shape. The most common anomalies in the observed population were dilaceration of the root with 99 (34.4%) third lower and upper incisors, fourth lower and upper premolars and first lower and upper molars involved and hypodontia with 93 (32.3%) first and second lower and upper premolars, and third lower molars involved. The proportion of an uncommon anomaly, such as fusion, was statistically significant (p < 0.01) for second lower and upper premolars 34 (11.8%) and lower and upper molars. 22 (7.6%) dogs had hyperodontia. The most affected teeth were the second lower and upper incisors. In 18 (6.3%) dogs we observed supernumerary roots. Hyponumerary roots, macro- and microdontia, gemination, concrescence and enamel pearls were found in less than 3 % of presented dogs. Because of this close relationship between normocclusion and periodontal health, early identification of anomalies of the teeth can allow the veterinary dentist to follow the patient and plan the treatment at an appropriate time. Dental disorders, development, dog, clinical importance