Evaluating Clear Aligner Performance by Bone Strain Measurement: A Novel Experimental Approach

Abstract

Purpose: Clear aligner therapy has gained popularity; however, treatment outcomes often remain suboptimal, emphasizing the need to evaluate the biomechanical performance of clear aligners. Previous experimental studies have focused on measuring forces transferred to tooth models, but the absence of a periodontal ligament in these models limits their ability to simulate realistic orthodontic processes. This study introduces a novel method for assessing clear aligner performance using bone strain as a key indicator. Methods: An experimental device was developed, featuring a dental model with a periodontal ligament substitute fabricated from polyvinyl siloxane and a strain measurement system equipped with two strain gauges embedded in the bone component. The device’s feasibility was evaluated by simulating the orthodontic treatment of a proclined maxillary central incisor, where bone strains were measured under controlled conditions of imposed forces up to 10 N applied to the crown and orthodontic forces exerted by clear aligners with activation angles of 1 and 2 degrees. Results: The results demonstrated that the fabrication technique for the periodontal ligament substitute was effective, achieving uniform thickness, while the strain gauges embedded in the dental model exhibited satisfactory accuracy when validated against the theory. Furthermore, the device reliably detected variations in bone strain across different force levels and aligner activation angles. Conclusion: These findings confirm the effectiveness of the proposed method and device in evaluating aligner performance, offering significant potential for future comparative studies of clear aligner designs and treatment protocols, thereby contributing to advancements in orthodontic research and improved clinical outcomes.