The aim of this prospective controlled investigation was to analyze the short-term cephalometric treatment outcomes, according to the denture frame analysis proposed by Sato, of rapid palatal expansion (RPE) and facial mask (FM) therapy. Methods. A group of 21 patients with Class III malocclusion treated with the RPE and FM (TG) was compared with untreated Class III controls (CG). The mean age of treatment group was 8.8 years; treatment consisted of 4 weeks of RPE activation (0.20 mm/die) followed by 14 hours wear of the FM for a mean of 333.1 days. As CG were used the data published by Tanaka and Sato. Pre- and post-treatment cephalometric values were compared and statistical analyzed with one sample t-test. A P-value