Abstract: A self-approximating intraoral isolation device to be used during dental procedures requiring a dry field of operation. The inventive device includes a fluid-resistant shell comprising a receptacle portion and an extruded region that receives the teeth through an opening in a sealing portion. Upon application of the forces of the opposing arches of the jaws, the extruded portion of the shell brings into closer approximation the sealing region of the device, improving upon previously described devices.