A mains electricity (AC-powered), hand-held, device intended to be used to activate the polymerization of: 1) a dental resin-based material in the oral cavity; and/or 2) a surgical adhesive/sealant during an open-surgery procedure. It typically includes a light source [e.g., halogen, fluorescent, light-emitting diode (LED)] that emits light in the visible, or less frequently, ultraviolet spectrum, mounted in a handpiece that is typically attached to or used with a portable control unit or charging station.