A method for forming a custom-molded oral appliance for positioning a user's jaw proximate to centric occlusion is disclosed. The method includes heating a thin sheet of material comprising a polycaprolactone polymer. The thin sheet of material is positioned within the user's mouth. The user's jaw is positioned proximate to centric occlusion. The thin sheet of material is molded around at least respective portions of the user's upper and lower dental arches such that each of the respective portions of the user's upper and lower dental arches form respective impressions on opposite sides of the thin sheet of material. The thin sheet of material is transitioned to a substantially non-deformable state.