AIM To gain information in a laboratory setting about the effect of thermal treatment of epoxy resin-based and zinc oxide-eugenol-based sealers. METHODOLOGY AH Plus and Pulp Canal Sealer (PCS) were exposed to thermal treatment at 37, 47, 57, 67, 77, 87 and 97 °C for 30 s. According to clinically relevant considerations, intracanal sealer temperature is likely not to exceed 60 °C during warm vertical root canal filling. Heat application is recommended for less than 30 s during continuous wave technique, but might exceed this threshold in complex cases. Furthermore, heat treatment at 97 °C was performed for 60 and 180 s to simulate inappropriate implementation of warm vertical filling techniques. Specimens were heated inside 2-mL plastic tubes in a thermo-controlled water bath until the temperatures were reached and kept at this temperature for the determined period of time. Afterwards, specimens were cooled to body temperature and physical properties (setting time, flow, film thickness according to ISO 6876) were assessed. Chemical properties (Fourier transformed infrared spectroscopy) were assessed after complete setting of the specimens in an incubator at 37 °C and 100% humidity. Statistical analysis of physical properties was performed using Kruskal-Wallis test (P = 0.05). RESULTS The setting time of AH Plus and PCS decreased when temperature and duration of heat application increased. Whilst the setting time of AH Plus decreased from 622 min at 20 °C (for 30 s) to 381 min at 97 °C (for 180 s; P < 0.05), heat treatment of PCS at 97 °C for 180 s led to an immediate setting of the material. From 20 °C (for 30 s) to 97 °C (for 30 s), the setting time of PCS decreased from 80.1 to 41.0 h (P < 0.05). Film thickness and flow were not relevantly influenced by thermal treatment except for PCS at 97 °C for 180 s. FT-IR spectroscopy did not reveal any chemical changes of either sealer after thermal treatment. CONCLUSIONS Thermal treatment simulating clinically relevant temperature levels and heating times did not lead to any substantial physical or chemical changes at all temperature levels when heating did not exceed 60 s. AH Plus and Pulp Canal Sealer can be considered suitable for warm root filling techniques.

中文翻译：

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暴露于模拟管内热的牙髓封闭剂的物理化学研究：环氧树脂和氧化锌丁香酚。

目的在实验室环境中获得有关环氧树脂基和氧化锌丁香酚基密封剂热处理效果的信息。方法论AH Plus和纸浆管道封闭器（PCS）在37、47、57、67、77、87和97°C下进行热处理30 s。根据临床相关考虑，在温暖的垂直根管充盈过程中，根管内封闭剂温度可能不超过60°C。在连续波技术中，建议加热时间不超过30 s，但在复杂情况下可能会超过此阈值。此外，在97°C的温度下进行了60和180 s的热处理，以模拟不适当地实施暖垂直填充技术。将样品在2 mL塑料管内的温控水浴中加热，直至达到温度，并在此温度下保持确定的时间。之后，将样品冷却至体温并评估物理性能（凝结时间，流量，膜厚（根据ISO 6876））。在37°C和100％湿度的培养箱中完全放置标本后，评估化学性能（傅立叶变换红外光谱）。使用Kruskal-Wallis检验对物理性质进行统计分析（P = 0.05）。结果随着温度和加热时间的增加，AH Plus和PCS的凝固时间减少。AH Plus的凝固时间从20°C（30 s）的622分钟减少到97°C（180 s; P <0.05）的381分钟，PCS在97°C的温度下热处理180 s导致材料立即凝固。从20°C（持续30 s）到97°C（持续30 s），PCS的凝固时间从80.1减少到41.0 h（P <0.05）。膜厚度和流量不受热处理的影响，除了PCS在97°C持续180 s以外。FT-IR光谱未显示热处理后任一密封剂的任何化学变化。结论当临床温度不超过60 s时，模拟临床相关温度水平和加热时间的热处理不会在所有温度水平上引起任何实质性的物理或化学变化。AH Plus和纸浆管道密封剂可被认为适用于暖根灌装技术。PCS的凝固时间从80.1减少到41.0 h（P <0.05）。膜厚度和流量不受热处理的影响，除了PCS在97°C持续180 s以外。FT-IR光谱未显示热处理后任一密封剂的任何化学变化。结论当临床温度不超过60 s时，模拟临床相关温度水平和加热时间的热处理不会在所有温度水平上引起任何实质性的物理或化学变化。AH Plus和纸浆管道密封剂可被认为适用于暖根灌装技术。PCS的凝固时间从80.1减少到41.0 h（P <0.05）。膜厚度和流量不受热处理的影响，除了PCS在97°C持续180 s以外。FT-IR光谱未显示任何密封剂在热处理后的任何化学变化。结论当临床温度不超过60 s时，模拟临床相关温度水平和加热时间的热处理不会在所有温度水平上引起任何实质性的物理或化学变化。AH Plus和纸浆管道密封剂可被认为适用于暖根灌装技术。结论当临床温度不超过60 s时，模拟临床相关温度水平和加热时间的热处理不会在所有温度水平上引起任何实质性的物理或化学变化。AH Plus和纸浆管道密封剂可被认为适用于暖根灌装技术。结论当临床温度不超过60 s时，模拟临床相关温度水平和加热时间的热处理不会在所有温度水平上引起任何实质性的物理或化学变化。AH Plus和纸浆管道密封剂可被认为适用于暖根灌装技术。