## 4 Discussion
Despite this variability, the average thickness of 0.76 mm serves as a central reference. The thickness of 0.76 mm was chosen after conducting several preliminary in vitro studies to determine the most suitable thickness. These studies evaluated various configurations and identified 0.76 mm as the optimal choice, as it provides a balance between maintaining appropriate orthodontic forces and ensuring patient comfort. This conclusion is supported by the findings of [PERSON] et al. [25] who demonstrated that this thickness allows for effective stress relaxation properties while retaining sufficient force application over time. By designing the NOXI aligners with thickness gradients centered around this 0.76 mm average, the study aimed to explore the advantages of differential thickness in achieving biomechanically optimal force distributions. This approach complements the use of uniform thickness in the AS and F22 aligners, enabling a robust comparison of different design strategies. The NOXI design incorporates differentiated thicknesses and the configuration chosen takes into account the anchorage value, which varies according to the root surface and the natural dissipation of force in the terminal portions of the arch [16]. The increased thickness at the gingival edge amplifies the force where needed, ensuring effective and customizable distribution. Three-dimensional printing and the properties of PA allow the force to be calibrated as needed, eliminating the need for attachments and improving aesthetics. The material maintains a constant force intensity due to reduced stress relaxation, making NOXI an aligner that combines targeted forces, aesthetics, and limited daily use, overcoming the limitations of traditional aligners [25]. The introduction of NOXI represents an innovative solution addressing some of the main challenges highlighted in the current literature on clear aligners. A recent study analyzing Instagram content explored patient experiences with clear aligner therapy, emphasizing that key discomorts are associated with aesthetic issues (e.g., visibility of attachments), difficulties in speaking and eating, and the pain related to continuous aligner wear [26]. With its design tailored for nightly use, limited to 12 h per day, NOXI significantly reduces the social and functional impact of treatment compared to traditional 20-22 h daily protocols. This feature directly addresses patients' needs for comfort and quality of life, minimizing disruptions in daily activities. Additionally, the attachment-free design, made possible by the advanced mechanical properties of polyamide (PA), enhances aesthetics and increases patient acceptance of the treatment--a critical factor for compliance. The Instagram study also highlighted how the initial phase of treatment is often accompanied by high aesthetic and functional expectations, which may diminish during the treatment phase due to pain or operational difficulties [26]. The use of materials such as PA in NOXI, with high elastic memory and stress stability, helps mitigate these issues by ensuring consistent and predictable orthodontic forces even after extended periods. These clinically relevant aspects of NOXI, combined with reduced wear time and the elimination of attachments, demonstrate its potential to significantly improve patient comfort and satisfaction, making orthodontic treatment less invasive and more aligned with individuals' social and personal needs. The aim of this in vitro study was to compare the initial and final force values of three types of NOXI aligners, characterized by different thicknesses and gingival margin cuts, with two types of thermorformed aligners made of the same material and thickness but with different gingival margin cuts.