Objectives: Bone-to-bone or palatal distractor has as the main advantage the fact that mechanical forces act directly on the bone in the desired area, thereby avoiding dental inclinations or undesirable movements of the maxillary segments, as well as causing no damage to the periodontium. The aim of this study is to present a case report of treatment for unilateral maxillary discrepancy associated with the presence of an impacted maxillary left canine with this type of device. Methods: A 23-year-old man was diagnosed with unilateral maxillary discrepancy associated with an impacted maxillary left canine. He was treated using unilateral subtotal LeFort I osteotomy with a palatal distractor tool associa­ted with traction of the impacted maxillary left canine. Results: The results obtained were satisfactory and the desired amount of unilateral transverse skeletal correction was achieved without any complications. Conclusion: The authors could conclude that unilateral surgically assisted maxillary expansion with the aid of palatal distractor was efficient and promoted good occlusion with reduced morbidity.