WHAT WE KNOW ABOUT CLEAR ALIGNERS

What_We_Know_About_Clear_Alignersapak

BIOMECHANICAL CONSIDERATIONS IN CLEAR ALIGNER TREATMENTS

Ege Korkmaz

Private Practice of Orthodontics, Mersin, Türkiye

Korkmaz E. Biomechanical Considerations in Clear Aligner Treatments. In: Hancıoğlu Kırcelli B, editor. What We Know About Clear Aligners 1st ed. Ankara: Türkiye Klinikleri; 2025. p.27-39.

ABSTRACT

Clear aligner therapy has become a significant orthodontic treatment alternative to traditional fixed appliances, offering both aesthetic and comfort benefits. Unlike conventional braces, aligners are nearly invisible and removable, making them particularly appealing to adult patients and those seeking a more discreet treatment option. However, the success of clear aligners depends on multiple factors, including careful planning, patient compliance, and a thorough understanding of biomechanics. Aligners apply controlled forces through elastic deformation, the tooth surface, and attachments, generating targeted forces that facilitate complex dental movements. Recent advancements, such as optimized attachments and power ridges, have significantly improved force application and movement precision. These innovations allow for better control of tooth positioning and improve treatment efficiency. However, challenges remain, including maintaining force consistency over time and preventing undesirable effects such as tipping. The performance of aligners is heavily influenced by their material properties. While they can apply gentle and continuous forces, their relatively low resilience makes them susceptible to deformation, requiring frequent replacements. Understanding key biomechanical principles such as the centre of resistance, force vectors, and moment magnitude is essential for optimising treatment efficacy. Proper attachment placement and design play a critical role in minimising unwanted movements and improving force distribution. Despite continuous improvements, the predictability of aligner treatment outcomes still varies. While aligners are effective in cases requiring arch expansion and anterior bite closure, they often struggle with complex movements like bodily tooth translation and precise torque control, both of which are critical for achieving optimal results in many cases. Overcoming these limitations remains an area of active research and development. Pre-treatment digital visualisation may seem to improve predictability, but biological variability, the biomechanical properties of materials, and patient compliance remain significant factors influencing final treatment outcomes. Maintaining lower activation levels per aligner is crucial to preserving force consistency and minimising deformation risks, ultimately contributing to more predictable tooth movements. While challenges such as limited torque control and patient-dependent success persist, the future of clear aligners remains promising. Advancements in material science, digital treatment planning, and appliance design continue to improve movement accuracy and expand the range of cases aligners can effectively treat. As these innovations progress, clear aligners are expected to become an even more valuable and versatile option in modern orthodontic care.

Keywords: Orthodontic appliances, removable; Biomechanical phenomena; Tooth movement techniques; Orthodontic appliance design; Tooth root

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