A closed system mouthpiece uses light and heat generation to activate a gel formulation to increase its volume. The gel formulation is coated into the mouthpiece, which is inserted into the users mouth. Application of heat above a threshold temperature causes the gel to transform into foam and expand out of the mouthpiece and into the oral cavity. The mouthpiece creates a hermetic seal such that the foam expands out throughout the oral cavity into nooks and crannies that are normally difficult to access. Activation of a light source embedded within the mouthpiece enhances the bacteria killing properties of the foam material. The pH balance of the mouth is restored by the inventive method and apparatus to a neutral level in the range of 6.75 to 7.25.
