The influence of various aging protocols, representing and accelerating influences present in the dental context, on possible changes in the microstructure and mechanical properties of thermoplastics was investigated. In order to minimize the complexity of the systems, first pure polymers and then later the equivalent dental polymeric materials were analyzed. Pure polymers (Poly(methyl methacrylate) – PMMA, Polyoxymethylene homopolymer – POM-H, Polyether ether ketone – PEEK, Nylon 12 – PA12, Polypropylene – PP) were analyzed before as well as after applying different aging protocols relevant to the oral environment (ethanol, thermocycling, alkaline and acidic setting) by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermoanalytical parameters used were glass transition temperature (T), melting peak and crystallization peak temperature (T T) and decomposition behavior. The combinations of pure polymers and viable aging protocols analyzed within this study were identified via TGA or DSC as PA12 & thermocycling, POM-H & denture cleanser/lactic acid/ethanol, PP & lactic acid. The dental polymeric materials PMMA and POM due to aging in lactic acid showed slight but significantly (p < 0.01) reduced Vickers and partly Martens hardness. PEEK showed the greatest material resistance within this study.

中文翻译：

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牙科热塑性塑料的老化过程 - 热分析研究以及对维氏硬度和马氏硬度的影响

研究了各种老化方案的影响，代表和加速牙科环境中存在的影响，对热塑性塑料的微观结构和机械性能的可能变化。为了最大限度地减少系统的复杂性，首先分析了纯聚合物，然后分析了等效的牙科聚合物材料。在应用与口腔环境相关的不同老化方案之前和之后对纯聚合物（聚甲基丙烯酸甲酯 - PMMA、聚甲醛均聚物 - POM-H、聚醚醚酮 - PEEK、尼龙 12 - PA12、聚丙烯 - PP）进行了分析（通过差示扫描量热法 (DSC) 和热重分析 (TGA) 进行乙醇、热循环、碱性和酸性设置）。使用的热分析参数是玻璃化转变温度（T）、熔融峰和结晶峰温度（TT）以及分解行为。本研究中分析的纯聚合物和可行的老化方案的组合通过 TGA 或 DSC 确定为 PA12 和热循环、POM-H 和假牙清洁剂/乳酸/乙醇、PP 和乳酸。牙科聚合物材料 PMMA 和 POM 由于在乳酸中老化而表现出轻微但显着 (p < 0.01) 的维氏硬度和部分马氏硬度降低。 PEEK 在本研究中表现出最大的材料耐受性。