Pages 237-242, Language: EnglishWilliamsonOrthodontic relapse and tooth migration are comonly observed in patients with severe postorthodontic root resorption. If conventional removable retention is not adequate, fixed splint retention is necessary. Proponents of flexible splints suggest that the difference in mobility between natural teeth and the rigid systems is responsible for the loss of cement seal in the rigid systems. Proponents of rigid splints suggest that the flexibility that allows physiologic movement of the teeth also contributes to fatigue and subsequent failure of the material in the flexible splint systems. A clinical technique for increasing retention, consequently improving the prognosis of a resin-bonded fixed splint, is described.