AIM To investigate the chemical changes affecting different types of gutta-percha and endodontic sealers during heating, and correlate changes with the heating capacity of different heat carriers. METHODOLOGY The heating capacity of three endodontic heat carriers was evaluated using thermocouples to produce heat profiles. The devices were activated at different temperature set-ups, in continuous or cut-out modes. Chemical changes of six brands of gutta-percha and four types of sealers were assessed in real time during heating using micro-Raman spectroscopy equipped with a heating stage. Raman spectra of each tested material were averaged and compared at different temperature levels. The sealers were further assessed by Fourier transform infrared (FT-IR) spectroscopy. RESULTS None of the tested heat carriers achieved the temperature levels that were set by the devices and recommended by the manufacturer. The use of continuous heating mode resulted in higher rises in temperature than the 4 s cut-out mode that reached 110 °C. The various brands of gutta-percha exhibited different chemical changes in response to heat. Some changes even occurred below temperature levels generated by the heating devices. All sealers revealed changes in their chemical composition upon heating. Changes in epoxy resin- and zinc oxide-eugenol-based sealers were detectable at 100 °C, with structural alterations beyond that temperature and irreversible changes after cooling. Water loss was irreversible in BioRoot, but its chemical structure was stable as well as for the TotalFill. CONCLUSIONS The heating capacity of endodontic heat carriers needs to be standardized, so that the temperatures delivered by the tips are the same as that set on the dial. Practitioners should be aware of the actual temperatures generated by these devices, and the suitability of sealers to be used at the temperature levels achieved.

中文翻译：

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加热对牙根填充材料进行实时化学分析：安全温度水平指南。

目的研究加热过程中影响不同类型牙胶和牙髓封闭剂的化学变化，并将其与不同热载体的热容量相关联。方法学使用热电偶评估三个牙髓热载体的热容量，以产生热量分布。在不同的温度设置下以连续或切断模式激活设备。使用配备加热台的微拉曼光谱仪，在加热过程中实时评估了六个品牌的牙胶和四种密封剂的化学变化。对每种测试材料的拉曼光谱求平均值，并在不同温度水平下进行比较。通过傅立叶变换红外（FT-IR）光谱进一步评估密封剂。结果所测试的热载体均未达到设备设定的温度水平和制造商建议的温度水平。连续加热模式的使用导致温度升高，比4 s截止模式（达到110°C）要高。各种品牌的牙胶都表现出不同的化学变化，以响应热量。甚至在加热设备产生的温度水平以下也会发生一些变化。所有密封剂在加热后均显示出化学成分的变化。在100°C时，可以检测到基于环氧树脂和氧化锌丁香酚的密封剂的变化，其结构变化超过该温度，冷却后出现不可逆变化。在BioRoot中失水是不可逆的，但其化学结构以及TotalFill都是稳定的。结论牙髓热载体的加热能力需要标准化，以使针尖传递的温度与刻度盘上设定的温度相同。从业人员应了解这些设备产生的实际温度，以及在达到的温度水平下使用密封剂的适用性。