Dental Materials Research Lab, College of Dentistry, Faculty of Health Science, University of Manitoba, Winnipeg, MB, Canada.
Department of Restorative Dentistry, College of Dentistry, Faculty of Health Science, University of Manitoba, 780 Bannatyne Ave., Room 227, Winnipeg, MB, R3E 0W2, Canada.
Clin Oral Investig. 2019 May;23(5):2227-2233. doi: 10.1007/s00784-018-2645-1. Epub 2018 Oct 3.
The main aim was to evaluate the effect of postponing the curing of the adhesive layer until the first layer of composite resin is applied-hereby oxygen-inhibited layer (OIL) formation and its detrimental effect on the degree of conversion (DC) of self-etch adhesives should be prevented. For this purpose, the degree of conversion and shear bond strength of four current market self-etch adhesives were evaluated, assessing the effect of curing the adhesives anaerobically and then under two different thicknesses of composite resin, and compare this to the samples cured alone and in air.
The degrees of conversion were obtained by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, after the samples were prepared on a glass slide. The samples were either light-cured in air or anaerobically under a clear matrix strip alone, under 2 mm of cured composite resin or under 4 mm of cured composite resin. To determine the shear bond strength (SBS), extracted molars were halved and set in acrylic. Prefabricated cured cylinders of composite resin (TPH 3, 2.4 mm in diameter) of two different lengths are placed over the adhesives under the following conditions: light-cured conventionally (2-mm-long cylinder) and light-cured anaerobically under the uncured end of the piece of composite resin (using both 2- and 4-mm-long cylinders as separate treatments). After another incubation for 24 h at 37 °C, the samples were subjected to shearing using the Bisco Shear Bond Strength Tester.
The degree of conversion of the one-step self-etch adhesives was not statistically different when cured anaerobically under a clear matrix strip or cured anaerobically under 2 mm of composite resin. These results were greater than those cured under 4 mm. Shear bond strength between samples cured in air and anaerobically were similar under 2 mm of composite resin tubes, while those cured anaerobically under 4 mm of resin showed lower shear bond strength.
When cured anaerobically, one-step self-etch adhesives show a greater degree of conversion and no significant difference in degree of conversion and shear bond strength when compared to those cured in air under the same thickness of composite resin.
The results obtained from DC and SBS analysis show promise in placing the uncured adhesive under the composite resin and curing both the adhesive and restoration material simultaneously.
本研究的主要目的是评估延迟固化黏接层的效果，直至应用第一层复合树脂，从而防止氧抑制层（OIL）形成及其对自酸蚀黏接剂的转化率（DC）的不利影响。为此，评估了四种市售自酸蚀黏接剂的 DC 和剪切黏结强度，评估了在两种不同厚度的复合树脂下，将黏接剂厌氧固化，然后与单独在空气中固化的样本进行比较。
通过衰减全反射傅里叶变换红外（ATR-FTIR）光谱法，在玻璃载玻片上制备样本后获得 DC。样本在空气中或单独在透明基质条下进行厌氧光固化，然后分别在 2mm 厚的复合树脂下或 4mm 厚的复合树脂下进行光固化。为了确定剪切黏结强度（SBS），将磨牙对半切开并嵌入丙烯酸中。将两种不同长度的预制复合树脂固化圆柱体（TPH 3，直径 2.4mm）放置在黏接剂上方，条件如下：常规光固化（2mm 长的圆柱体）和在复合树脂未固化端下厌氧光固化（分别使用 2mm 和 4mm 长的圆柱体作为单独的处理）。在 37°C 下孵育 24h 后，使用 Bisco 剪切黏结强度测试仪对样本进行剪切。
一步自酸蚀黏接剂在透明基质条下厌氧固化或在 2mm 厚的复合树脂下厌氧固化时，其 DC 无统计学差异。这些结果大于在 4mm 厚的复合树脂下的结果。在 2mm 厚的复合树脂管下，空气中固化和厌氧固化的样本之间的 SBS 相似，而在 4mm 厚的树脂下厌氧固化的样本显示出较低的 SBS。
当在厌氧条件下固化时，一步自酸蚀黏接剂显示出更高的 DC，与在相同厚度的复合树脂下空气固化相比，其 DC 和 SBS 无显著差异。
从 DC 和 SBS 分析中获得的结果表明，在复合树脂下放置未固化的黏接剂，并同时固化黏接剂和修复材料具有一定的前景。
