Enamel defects in standard poodle dogs in Sweden.

Several disturbances can occur in enamel formation. Amelogenesis imperfecta is an inherited enamel malformation that has not previously been reported in dogs. The aims of this study were to investigate amelogenesis imperfecta-like tooth discoloration in standard poodle dogs by histopathological characterization of discolored teeth from affected dogs, investigating whether these dogs have a common genetic background, and assessing how common this problem is in the breed. Histologically, a defect of enamel mineralization was documented. Affected enamel contained a large residual amount of organic matrix, showing that the enamel was not fully mineralized. In some sections, the enamel appeared intact, but with excessively well-defined enamel prisms which is an additional sign of poor mineralization. The abnormal enamel was identical to that seen in humans with amelogenesis imperfecta. Five of 27 standard poodle dogs present at a dog show had discolored teeth. A four-generation pedigree was available containing an example of parents also having discolored teeth one of which had amelogenesis imperfecta confirmed histologically. In all subsequent litters from these dogs, there was at least one dog with discolored teeth, and two histologically confirmed cases of amelogenesis imperfecta four generations later. Histological examination and the apparent familial occurrence indicates that amelogenesis imperfecta is a common cause of discolored teeth in standard poodle dogs in Sweden.