Purpose: The main goal of this study was to evaluate the impact of different ionizing radiation doses on the mineral (carbonate/phosphate ratio, crystallinity index [CI]) and organic (amide III/phosphate, amide I sub-band ratios) structures, as well as the microhardness, of enamel and dentin, along with their influence on the bonding strength stability of the etch-and-rinse (ER) and self-etch (SE) dental adhesive strategies.

Materials and methods: Enamel and dentin human tissue specimens were irradiated (with 0, 20, 40, and 70 Gy radiation doses, respectively) and sectioned to perform an attenuated total reflection-Fourier transform IR spectroscopy assay (ATR-FTIR) and the Vickers microhardness (VHN) test to conduct a biochemical and biomechanical evaluation of the tissues. Regarding the adhesive properties, restored enamel and dentin specimens exposed to the same radiation doses were submitted to microshear bond strength (μSBS) tests for enamel in immediate time (IM) and to microtensile bond strength (μTBS) tests after for IM and 12-month (12 M) period of time, Mann–Whitney U tests were implemented, using the ATR-FTIR data for significant differences (α < 0.05), and three- and two-way analyses of variance, along with post-testing, were performed on the μTBS and μSBS data (MPa), respectively (Tukey post hoc test at α = 0.05).

Results: The ATR-FTIR results showed a significant decrease (p < .05) in the amide III/phosphate ratio after 20 Gy for the enamel and after 40 Gy for the dentin. The CI was significantly reduced for both tissues after a dose of 70 Gy (p < .05). All radiation doses significantly decreased microhardness values, relative to the respective enamel and dentin controls (p < .05). In both tissues and adhesive strategies, the decrease in bond strength was influenced by ionizing radiation starting from 40 Gy. The ER strategy showed high percentages of enamel cohesive failure. In general, ER in both tissues showed greater and more stable bond strength than SE against increased radiation doses and long term.

Conclusions: It is possible to conclude that structural alterations of enamel and dentin are generated by all radiation doses, decreasing the microhardness of dental hard tissues and influencing bond strength over time, starting at 40 Gy radiation dose. The etch-and-rinse strategy demonstrates better adhesive performance but generates cohesive fractures in the enamel.

目的：本研究的主要目的是评估不同电离辐射剂量对矿物（碳酸盐/磷酸盐比率，结晶度指数[CI]）和有机物（酰胺III /磷酸盐，酰胺I子带比率）的影响，以及牙釉质和牙本质的显微硬度，以及它们对蚀刻和冲洗（ER）和自蚀刻（SE）牙科粘合剂策略的粘合强度稳定性的影响。

材料和方法：对牙釉质和牙本质人体组织标本进行辐照（分别使用0、20、40和70 Gy辐射剂量）并切片以进行衰减的全反射傅里叶变换红外光谱分析（ATR-FTIR）和维氏显微硬度（VHN）测试以对组织进行生化和生物力学评估。关于胶粘剂的性能，将修复后的牙釉质和牙本质样品暴露于相同的辐射剂量后，立即对其进行微剪切粘结强度（μSBS）测试，对牙釉质进行即时（IM）测试，对IM和12个月后进行微拉伸粘结强度（μTBS）测试（12 M）时间段内，使用ATR-FTIR数据进行显着性差异（α<0.05）进行了Mann–Whitney U检验，并进行了三方和双向方差分析以及后检验在μTBS和μSBS数据（MPa）上，

结果： ATR-FTIR结果显示 ，釉质20 Gy后和牙本质40 Gy后，酰胺III /磷酸盐比率显着降低（p <.05）。剂量为70 Gy后，两个组织的CI均显着降低（p  <.05）。相对于牙釉质和牙本质对照，所有辐射剂量均显着降低了显微硬度值（p  <.05）。在组织和粘附策略中，从40 Gy开始的电离辐射都会影响结合强度的降低。ER策略显示出高百分比的搪瓷内聚破坏。通常，在增加辐射剂量和长期使用的情况下，两个组织中的ER均显示出比SE更大，更稳定的结合强度。

结论：可以得出结论，从40 Gy辐射剂量开始，所有辐射剂量都会产生牙釉质和牙本质的结构改变，从而降低牙齿硬组织的显微硬度并影响粘结强度。蚀刻和冲洗策略显示出更好的粘合性能，但在搪瓷中产生了内聚破裂。