Self-cure polymethylmetacrylate resin is used for space retainers and many other orthodontic appliances. As these appliances are used with children or adolescents, breakage of resin often occurs. Self-cure resin can be reinforced against breakage by the addition of glass fiber (G. F. R. P.: glass fiber reinforced plastic). In order to evaluate the efficiency of reinforcement, bending properties ( JIS T6501) and tensile properties ( JIS K7113) were examined with a single material of commercially available self-cure resin and other of various kinds of reinforcement materials.
In the bending evaluation. self-cure resin without glass fiber did not satisfy with the Japanese Industrial Standard ( JIS T6501), while some of the G. F. R. P. satisfied with the Standard. In the tensile evaluation of G. F. R. P., the strength of destruction increased, the stretch of destruction decreased, the modulus of elasticity increased, and the strength of the yield point increased, when compared with self-cure resin without glass fiber.