Abstract: A housing containing an electrical energy source is coupled between a first end cap comprising a control and an interstitial member comprising an LED selectively electrically couplable to the electrical energy source by the control, and a second end cap coupled to the interstitial member comprises an optical filtering component in optical alignment with light emitted by the LED. At least a portion of an exterior of at least one of the housing, the first end cap, the interstitial member, and the second end cap may have a cross-sectional shape that is not substantially circular. The end caps, housing, interstitial member, and optical filtering component may each be sealingly interconnected. A method of using the apparatus may comprise directing light emitted by the apparatus into a human oral cavity without inserting the apparatus into the human oral cavity.