Lesch-Nyhan syndrome (SLN) is a rare inborn error of metabolism, characterized by mental retardation and self-destructive behavior that produces total or partial damage to oral and perioral tissues and/or fingers and hands. Preventing self-mutilation carries significant difficulties. Treatment modalities include drug treatment, tooth extraction, oral appliances, and orthognathic surgery, all with variable success. Two cases are presented from the same family with aggressive behavior and severe lesions on the lower lip. The first case: a 5-year-old boy with loss of maxillary and mandibular posterior teeth due to caries. Three types of devices were tried on the patient, all of which failed. It was then decided to perform extractions. The other case is that of a 6-year-old boy, who was fitted with a plate with posterior bite planes to lift the bite and an acrylic button at the level of the palatal rugae that served as a lingual stimulator. Although adjustment was required during visits, the effectiveness of the appliance for soft tissue healing was immediate and consistent throughout the 6 months of the study.