Dentin dysplasia, type I, is a rare dental anomaly characterized by abnormal dentin formation affecting the roots of both primary and permanent teeth. Short, conical roots with occlusion of the pulp chamber and canal are produced. Periapical radiolucent areas are common, although no evidence of caries or trauma to the tooth may be seen. Coronal mantle dentin is unaffected, resulting in an apparently normal clinical crown. An abnormality may not be suspected until radiographs reveal pulp and root changes. Orthodontic treatment can be a successful variation of the usual treatment offered to patients, and is discussed in this case report.