Randomized In-Vivo Comparison of 3D-Printed and Thermoformed Clear Aligners: A Multi-Subject, Time-Dependent Analysis of Adaptation and Trueness

This prospective clinical study aims to evaluate and compare the in vivo adaptation and trueness of clear aligners fabricated using thermoforming and direct three-dimensional (3D) printing technologies.

Inclusion Criteria: Healthy adult volunteers ≥18 years; good general and oral health with clinically acceptable oral hygiene; dentition adequate to support passive upper clear aligner wear as judged by the investigator; willing and able to attend all study visits over 4-6 months and comply with aligner wear and study procedures; able to provide written informed consent and HIPAA authorization. Exclusion Criteria: Active dental or periodontal disease or other oral conditions that could interfere with study procedures; need for active orthodontic treatment or other dental procedures during the study period; poor oral hygiene or failure to follow instructions at screening; medical or systemic conditions or medications that could compromise participation or outcomes; concurrent participation in another interventional study; (optional) pregnancy or planned pregnancy during the study period.