A jaw-strengthening device has a first receiver that receives a first row of teeth having first and second molar sections, a first air chamber within the first receiver positioned in a first molar section of the first receiver, a second air chamber within the first receiver positioned in a second molar section of the first receiver, and an egress valve, that permits egress and prevents ingress of air, in communication with the first and second air chambers, a second receiver that receives a second row of teeth having first and second molar sections, a third air chamber within the second receiver positioned in a first molar section of the second receiver, a fourth air chamber within the second receiver positioned in a second molar section of the second receiver, and an ingress valve in communication with the third and fourth air chambers.