关键词: 无托槽隐形矫治器, 热压膜材料, 应力, 硬度, 弹性模量, 吸水性

Abstract: In recent years，aesthetic and comfortable clear aligners have been increasingly favored by patients. Thermoplastic materials，as the main material for clear aligners，have attracted widespread attention. The study on the properties of thermoplastic materials shows that the stress release，stress relaxation，hardness，elastic modulus and water absorption are affected by self-factors such as the type of materials and physical and chemical structure，and external factors such as thermoforming and aging. Compared with the ideal orthodontic thermoplastic materials，the properties of existing thermoplastic materials are still imperfect. Improving thermoplastic materials properties through blending modification，surface modification，and changing the number of material layers is the focus of current research. Therefore，this article reviews the research progress in the performance of thermoplastic materials of clear aligners and the influencing factors.

Key words: clear aligner, thermoplastic materials, stress, hardness, elastic modulus, water absorption