A short wavelength visible light-emitting toothbrush with an electronic interlock control device preventing operation when the toothbrush is removed from the user's mouth. The electronic interlock control over operation is necessary to prevent accidental eye exposure to the high intensity light source with a wavelength in the range of 400 nm to 500 nm. The light-emitting toothbrush activates upon formation of an electrical circuit between the brush handle in contact with the users hand and the brush head or brush bristles in contact with moisture contained in a human mouth such as saliva or water mixed with toothpaste but deactivates immediately when removed from the mouth, thus protecting the user's eyes from direct exposure to the high power light source contained in the brush-head.