Background: The purpose of this study is to investigate the effects of non-extraction fixed orthodontic treatment on the vertical mandibular alveolar bone level. Methods: This study examined 49 patients who had been treated with a non-extraction treatment modality. The mean age of the patients at the start of treatment was 19 years and 5 months, and treatments were carried out for a mean length of 21 months. By comparison, the study's control group consisted of 62 subjects with a mean age of 21 years and 2 months. The study was performed by using panoramic radiographs that had been taken of the study and control subjects. A reference line that passed from the top point of the right and left mental foramen was applied to the panoramic radiographs. In the area from the distal of the lower canine to the mesial of the second molar, vertical lines were constructed from the alveolar crest ridges to this reference line. Pre-and post-treatment data were compared between the intra-and inter-groups. Results: In the treatment group, statistically significant increases in the alveolar bone level were found. These increments were also significantly different from those of the control group. Conclusion: Non-extraction orthodontic treatment has capability of increasing vertical alveolar bone level when compared with the control group.