BackgroundThe aim of this retrospective study was to cephalometrically evaluate the skeletal and dental effects of the transverse sagittal maxillary expander (TSME), for the correction of sagittal and transverse maxillary deficiency in class I, II, and III malocclusions.MethodsThe sample for this retrospective study included 45 patients (mean age, 8.4 years; 26 females, 19 males; 15 skeletal class I subjects, 15 skeletal class II subjects, and 15 skeletal class III subjects) with maxillary bilateral cross-bite.For each patient, a lateral cephalogram was obtained before treatment and at the end of the retention period. Changes in the groups during the observation period were calculated, compared, and statistically analyzed with a t-test.ResultsThe cephalometric values before T0 and T1 showed significant changes.ConclusionsThe TSME can produce skeletal changes due to the transverse force and sagittal effects on the maxillary alveolar process. These modifications have benefic effects in classes I, II, and III. The data obtained in this study permit us to underline the fact that TSME can be used in all of the skeletal classes, with good vertical and sagittal results.