Aim:To develop a method of measuring tooth movement 3-dimensionally and to investigate the effects on the teeth and basal bones when using distal jet treatment for moving molars distally. Methods: A method of superimposing 3-dimensional dental images was developed to measure tooth movement. Cephalometric analysis was also used to measure skeletal and dental changes. The distal jet group consisted of 15 patients, 9 females and 6 males, with a mean age of 14.6 ± 2.3 years. Results: The mean maxillary first molar distal movement was 2.4 ± 1.8 mm with distal tipping of 1.9 ± 1.6 degrees and lateral movement of 1.2 ± 0.9 mm. The second premolar moved mesially an average of 1.4 ± 1.2 mm. The mean maxillary incisor mesial movement was 1.5 ± 1.5 mm with mesial tipping of 2.6 ± 1.5 degrees. There were no statistically significant skeletal changes. Conclusion: This method allowed precise measurement of tooth movement by superimposing 3-dimensional dental images on the computer. The results of this study demonstrated the effectiveness of the distal jet in distalizing the molars bodily. However, in reaction to distal molar movement, reciprocal mesial movement of the premolar and anterior teeth was observed.