Evaluation of the Biomechanical Response of Orthodontic Tooth Movement to Clear Aligner vs Fixed Orthodontic Appliance

Abstract Background: Orthodontic tooth movement (OTM) is mediated by biologic responses of the periodontal ligament (PDL) and alveolar bone to applied mechanical forces, involving release of inflammatory mediators such as interleukin-1β (IL-1β) and prostaglandin E2 (PGE2) that promote osteoclast activation and bone remodeling. Intraoral biomarkers in gingival crevicular fluid (GCF) reflect these tissue changes and can be used to monitor inflammatory and metabolic responses during treatment. Digital technologies, including intraoral scanning and 3D superimposition, allow precise quantification of tooth movement over time. Objective: This prospective, randomized comparative clinical study aims to compare the biological and mechanical responses of orthodontic tooth movement in patients treated with clear aligners versus conventional fixed appliances. Methods: Twenty adult patients (aged 18-25 years) with mild dental crowding will be randomly assigned to either a fixed appliance group (n=10) or a clear aligner group (n=10). Baseline and follow-up GCF samples will be collected to quantify IL-1β and PGE2 using enzyme-linked immunosorbent assay (ELISA). Tooth mobility will be assessed using Periotest analysis, and 3D digital models obtained from intraoral scans will be superimposed to measure the amount of tooth movement over time. Secondary outcomes include clinical measures of mobility and patient-reported pain. Expected Outcomes: It is anticipated that both treatment modalities will induce measurable increases in inflammatory biomarkers and tooth movement; however, differences in the magnitude and temporal patterns of IL-1β, PGE2, tooth mobility, and 3D-quantified displacement are expected due to the continuous forces of fixed appliances versus intermittent forces of aligners. Previous studies have shown that GCF cytokine levels rise with orthodontic force application in both aligner and fixed appliance treatments, with some variations between groups. Conclusion: This study will provide new clinical evidence comparing biological mediator profiles and mechanical outcomes between clear aligners and fixed orthodontic appliances, improving understanding of tissue responses and informing clinical decision-making in contemporary orthodontic practice

NCT Number	NCT07399483
Lead Sponsor	Mansoura University
Conditions	Orthodontic Tooth Movement, Tooth Movement
Enrollment	20 participants
Start Date	2025-08-01
Primary Completion	2026-08-01 (estimated)
Study Completion	2026-11-01 (estimated)
Updated on ClinicalTrials.gov	2026-02-10