Abstract: The present disclosure provides an orthodontic article including the reaction product of the polymerizable composition. Further, the present disclosure provides polymerizable compositions and methods of making an orthodontic article. The method includes obtaining a polymerizable composition and selectively curing the polymerizable composition to form an orthodontic article. Further, methods are provided, including receiving, by a manufacturing device having one or more processors, a digital object comprising data specifying an orthodontic article; and generating, with the manufacturing device by an additive manufacturing process, the orthodontic article based on the digital object. A system is also provided, including a display that displays a 3D model of an orthodontic article; and one or more processors that, in response to the 3D model selected by a user, cause a 3D printer to create a physical object of an orthodontic article.

Abstract: A hydronic type of heating system is operated by a burner control system that relies on measuring the boiler water temperature and comparing the temperature change with a rate of rise set into a burner control means to determine whether the boiler is being properly operated. This system allows for heating the boiler water to a sufficient temperature before circulating the water through the heat exchange means to thereby prevent condensation on the outside of the boiler heat exchanger to eliminate rusting.