Evaluation of Gingival Crevicular Interleukin-1β Levels in Patients Undergoing Clear Aligners vs. Fixed Orthodontic Therapy

Background: Tooth movements induced by orthodontic force cause an inflammatory response in the periodontium that is mediated by cytokines, including Interleukin-1beta (IL-1β). Fixed appliances produce different biomechanical forces, which have the potential to modulate GCF cytokines compared to clear aligners. The study aimed to determine the levels of gingival crevicular fluid (GCF) IL-1β in patients receiving clear aligner treatment compared to those receiving fixed appliances. Methods: This cross-sectional analytical research was conducted at a tertiary care dental hospital between From February to June 2025. 100 (50 clear aligner patients and 50 fixed appliance patients), 18-30 years old participants were recruited. Samples of GCF were obtained as a baseline and 1 month after treatment. IL-1β levels were measured by Enzyme-Linked Immunosorbent Assay (ELISA). The significance level was set as p < 0.05. Results: No significant difference was found between baseline IL-1 levels (54.7 ± 9.3 vs. 56.1 ± 10.1 pg/L, CI: 2.5-5.3, p = 0.47). At 1 month, IL-1β levels were significantly elevated in the non-MAR group (92.4 ± 12.6 vs. 71.8 ± 10.9 pg/L, CI: 16.3-24.9, p < 0.001). Increases within the group were noted in both groups (clear aligners: 17.1 ± 6.2; fixed appliances: 36.3 ± 7.8, both p < 0.001). The difference between the groups persisted after controlling for confounders (CI: 15.7-23.0, p < 0.001). Conclusion: Both appliance systems increased GCF IL-1β levels, but fixed appliances produced a significantly larger inflammatory response than clear aligners, even after adjustment for potential confounders.