Abstract: A dental appliance whereby the device isolate particular teeth from the tongue and body fluids within the patient's mouth, captures the residue from the treatment therein and props the patient's mouth open. The device comprises a flexible cup-shaped member comprising a bottom portion and at least one side with at least one aperture formed therethrough. A flexible sealing element comprising a slit therethrough sealingly covers the aperture. The aperture is sized and configured to receive at least one molar through the slit and the adjacent aperture so that the molar is received within the member and the sealing element seals the gap between the tooth and the device.