Abstract: A bracket for orthodontics having a bracket body made of a composite resin material and a thin layer of a synthetic resin material in a dental adhesive. The synthetic resin layer is laminated on the base surface of the bracket body in such a manner that the composite resin material of the bracket body and the synthetic resin of the thin layer are mingled with each other at the boundary therebetween. The thin resin layer is composed of polymethyl methacrylate having an average molecular weight of 1000,000 or less or a polymethacrylate copolymer.

Abstract: A method and apparatus to continuously harden articles made of visible light-curable resins, including continuously moving the articles to be hardened relative to a multiplicity of sources of visible light which are independently controllable to be able to vary the radiation to which the articles is exposed during its passage while independently controlling the temperature at which this takes place; and apparatus to accomplish this such that a large number of the objects to be irradiated passing through the hardening apparatus have the same exposure history to the visible light and to heating or cooling respectively. As the result, there is substantially no variation in the physical properties of these photo-polymerized products.

Abstract: A method to continuousky harden light-curable resins, by irradiating at least one shaped article made of a light-curable resin by continuously moving the article past a multiplicity of light sources while changing the flux of the irradiated light in multiple steps corresponding to the moving positions of the object and an apparatus to accomplish this method including means to continuously move the article relative to the multiple irradiation sources and means to adjust the flux density in multiple steps corresponding to the moving positions of the article. Specifically, the flux density of the light irradiated on the moving article is changed stepwide depending upon the position and the location of the article and the polymerization speed of the article and the hardening depth can be controlled in relation to its position and time.