Background: Although a variety of factors can affect how well clear aligner therapy works, one that stands out as being extremely important in determining the mechanical and clinical aspects of aligners is the material utilized in their construction. Objective: The current study's objective was to assess, through a comparative randomized clinical trial, the biomechanical effects of various aligner material thicknesses on upper central incisors with horizontal ellipsoid composite attachments. Materials and Methods: A total of 32 patients were enrolled in the trial; 16 were treated with 0.8 mm thick PET-G aligners (Group A) and 16 with 0.75 mm thick PET-G aligners (Group B). There are four main phases involved in making clear aligners: 1) Impression. 2) Online configuration and design. 3) 3D printing dental models and exporting STL files. 4) Aligns fabrication and thermoforming. Both before and after therapy, records were gathered. Results: The migration of the incisal edge and the root apex showed significant variations between Groups A and B in this study. Significant root movement (mean movement: 1.2 mm) was linked to Group A, but no discernible movement in the incisal edge (mean movement: -0.1 mm) was observed. As opposed to this, Group B was linked to nearly exclusively moving incisal edges (mean movement: 2.8 mm), and the root apex moved on average absolutely nowhere (mean movement: -0.2 mm). Thus, a lower thickness of PET-G was strongly linked with controlled tipping movement (p-value: <0.001), whereas a higher thickness of PET-G was significantly associated with root displacement (p-value: <0.001). Conclusion: Based on our results, it was clear that PET-G with a greater thickness was linked to root movement as opposed to crown movement. Low thickness aligners, on the other hand, caused almost minimal root movement. These results can assist orthodontists in selecting the right aligner material on an individual basis in order to accomplish a range of necessary ideal tooth motions.