The Effectiveness of In-house Clear Aligners and Traditional Fixed Appliances in Achieving Good Occlusion in Complex Orthodontic Cases: A Randomized Control Clinical Trial

Objective: To compare the effectiveness and efficiency of the in-house clear aligners with the traditional fixed appliances in treating premolar-extraction-based complex cases. Materials and methods: A single-centered, 2-arm parallel-group randomized controlled clinical trial was conducted on thirty-six (12 males, 24 females; mean age: 21.24 ± 2.33) patients with severe crowding who required orthodontic treatment with four first premolars extraction. The patients were equally and randomly divided into two groups: The in-house clear aligners (CA) group and the fixed appliances (FA) group. All the measurements were made on the pre-and post-treatment dental cast models. The effectiveness was evaluated using Little's irregularity index (LII) and the Peer Assessment Rating index (PAR). The efficiency was evaluated by studying the treatment duration. Two sample t-tests and chi-square tests were used to test for significant differences between the two groups. Bonferroni correction was applied, and the adjusted alpha level was set at 0.006. Results: Before treatment, there were no significant differences between the two groups regarding LII in the upper and lower jaws (p˃0.006). After treatment, the mean LII decreased in both groups, with no significant differences between the two studied groups (p˃0.006). There were no significant differences in all studied PAR domains between the two groups (p˃0.006). The mean score reduction in the CA group was 28.39 (±8.51) points, whereas it was 26.39 (±5.76) points in the FA group, with no significant differences between the two groups. All the patients in this study were improved. However, a great improvement was achieved in 88.9% of the patients in the CA group and 91.7% in the FA group, with no significant differences between them (p=0.674). The average treatment duration in the CA group was 23.27 (±5.28) months, whereas the average was 26.20 (±5.27) in the FA group, with no significant difference between the two groups. Conclusion: In-house clear aligners can be effective as fixed appliances in achieving good occlusion when treating complex orthodontic cases when suitable teeth movement protocol is used.