The present invention provides for a dental appliance, mouthguard and/or divers mouthpiece using an anti-microbial composition that combines the use of an elastomeric polymer composition with micronized or submicron sized particles of metal or organo/inorgano metal complexes. In addition, the use of an anti-microbial composition for use with a diver's air delivery hose to prevent breathing of contaminated air is also described.