breathing better will change your life at laeast as much as fixing your jaw. its a game changer, you ll sleep much better, you wont be so wired, your posture will get better, etc etc.
if you are based in the us, look up the postural restauration institute, they have brought the russian s technique into the 21st century. and to come full circle, asside from breath and posture they look at your occlusion. everything is conected to everything..