四种热压膜正畸材料力学性能的比较

A comparative study of mechanical properties of commercialized dental thermoplastic materials

目的比较临床常用的4种热压膜材料在不同条件下的力学性能，为临床制作隐形矫治器选择材料提供依据。方法A、B、C和D4种热压膜材料厚度均为1．0mm。测试在3种处理方式下进行：未处理、热成形后和恒温水浴浸泡两周后，比较材料在以上处理后的拉伸屈服应力和断裂伸长率，并比较材料在室温条件下，1h内的应力松弛速率。结果经热成形后，4种材料拉伸屈服应力均低于未处理组，断裂伸长率均大于未处理组；经浸泡两周后，4种材料拉伸屈服应力均高于热成形组，而断裂伸长率均小于热成形组。除材料A外，不同处理方式对其他3种材料力学性能的影响具有统计学意义（P〈0．05）。在室温条件下，A材料1h内的应力松弛速率为0．01N／s，显著低于C和D（P〈0．05），与B相比，差异无统计学意义（P〉0．05）。结论热压膜材料的力学性能受到使用环境的影响，A材料的力学性能在不同测试条件下表现最佳，与其他3种材料相比，适宜制作隐形矫治器。

Objective To compare the mechanical properties of different dental optimal material selection for orthodontic appliance. Methods Four commercialized thermoplastic products under different test conditions, and provide the suggestion of thermoplastic products were tested. The tear strength, elongation at break and stress relaxation of these materials were measured under different test conditions. Results The tear strength declined after thermoforming, and rose again after 2 weeks of distilled water immersion. The elongation at break rose after thermoforming, and declined after 2 weeks of distilled water immersion. No significant changes were observed for brand A under different test conditions. Brand A showed the slowest stress relaxation of 0.0148 N/s. Conclusions The mechanical properties of thermoplastic materials were influenced by environmental factors. Brand A exhibited optimal cornprebellsive properties.