Abstract: Objective: To investigate the vertical changes of jaws of skeletal class Ⅲ patients with high and low angle in different growth stages. Methods: Skeletal class Ⅲ malocclusion patients with high and low angles were selected and divided into pre-growth spurts, peak period, and post-growth spurts. There were 30 cases in the high-angle group and low-angle group at each stage. The lateral cephalograms were taken and analyzed. Results: In the high-angle group, the changes of PP-FH angle, MP-FH angle and Y-axis angle increased first and then decreased, the former showed a decreasing trend, and the latter two were in the opposite direction. SGo/NMe decreased first and then increased, the overall trend was decreasing. The above changes were statistically different in addition to the pre and the post peak comparison. In the low-angle group, PP-FH angle decreased first and then increased. The overall trend was decreasing. MP-FH angle and Y-axis angle gradually reduced, SGo/NMe gradually increased. The above changes were statistically significant. The occlusal plane decreased in both high and low angle groups, and the changes were statistically different. Conclusion: In the process of growth and development, the vertical changes of the jaw in class Ⅲ malocclusion patients with high angle and low angle facial skeletal types demonstrated significant differences.

Key words: Class Ⅲ malocclusion, Craniofacial growth, CVS method, Cephalometry