Aim: To examine the skeletal and dental changes, together with soft tissue profile changes, that occur after rapid maxillary expansion. Methods: Cephalometric films taken before and after rapid maxillary expansion formed the basis of the study material of 10 male and 10 female patients, an average of 12.8 years of age. The expansion continued an average of 5.2 weeks with the activation of the expansion screw at twice a day (2
1⁄4 turn = 0.5 mm). The changes in skeletal and soft tissue profile, incisor relationship, and lip structure were examined in sagittal and vertical directions on the lateral cephalometric films. The measurements were evaluated by a paired t test. Results and Conclusion: Important skeletal and soft tissue changes were seen in sagittal and vertical vectors. After rapid maxillary expansion, it was observed that while the maxilla and maxillary incisors moved anteriorly, the nose tip and soft tissue of A point followed the hard tissue. After expansion, middle and lower facial dimensions increased vertically. World J Orthod 2002;3:217–222.