A self-customizable dental appliance adapted to lie within the mouth of a person including occlusal pads with a connecting arch or a u-shaped style base with upstanding labial and lingual walls. The appliance is formed of a semi-crystalline polyolefin polymer or crystallizable blend. In one embodiment, the appliance is formed of elastomeric propylene-ethylene polypropylene, optionally including high density polypropylene. An optional occlusal lifting pad can be used in the self-customizable dental appliance.