It is essential that the practitioner determine the factors that are etiologically operative in oral myofunctional therapy in order to establish effective methods of intervention. Of these methods, cephalometrics and facial analysis are especially valuable in revealing and differentiating open-bite syndrome. We indicated two cases treated with only the theory of myofunctional therapy and evaluated with cephalometric radiographs and intraoral photos. This is the first report to evaluate for treatment change of myofunctional therapy with cephalometric radiographs.