RESUMO
An asymptomatic pink discoloration of a maxillary right fourth premolar tooth was discovered during a routine oral examination on a 9 year-old Belgian Malinois dog. A radiolucent lesion was seen in the pulpal chamber on radiographic examination. The lesion had perforated the mesiobuccal root of the tooth. The primary differential diagnosis was idiopathic internal resorption. The tooth was treated by partial resection (removal of the mesiobuccal root and associated crown). A vital pulpotomy and amalgam restoration was performed on the remaining tooth structure. A follow-up 1 year later demonstrated a successful treatment outcome. The animal was asymptomatic and able to perform military duties. Clinical and radiographic signs of healing were evident and the tooth was functional.