The use of a special mouthguard in the management of oral injury self-inflicted by a 4-year-old child.

This paper describes the management of self-inflicted trauma by a 4-year-old boy who was mentally retarded as a result of encephalitis in infancy. There was severe damage to his lower lip, as well as a moderate degree of injury to the skin and nail of his right thumb. Preliminary intervention was made with a mouthguard using silicone elastomeric positioner material, which soon proved ineffective because of poor retention. The problem was overcome successfully through use of a special appliance in which a heat-cured acrylic base was combined with a superstructure made of silicone positioner material retained mechanically with retention loops of 0.7 mm orthodontic wire.