Abstract: An oral nighttime appliance consists of a somewhat resilient U-shaped base substantially complementary with a person's dental arch. At least one integral lip protrudes from anterior edges of the U-shaped base, and a substantially rigid hourglass-shaped flap is connected into and partially spanning the gap between the posterior legs of the U-shaped base, and protrudes rearward and downward. A second flap, nearly semicircular and rigid, extends rearward and upward from the posterior of the base into which one end of the second flap is secured.