School of Dentistry, Universidade Federal Fluminense, Niterói, Rio de Janeiro, Brazil.
Paulo Picanço School of Dentistry - Research Division, Fortaleza, Brazil.
Odontology. 2022 Jul;110(3):569-576. doi: 10.1007/s10266-022-00693-w. Epub 2022 Mar 1.
This study aimed at evaluating the influence of glass-fiber post (GFP) relining with composites of different opacities on resin cement layer thickness (CLT), bond strength (BS) to root dentin, and resin cement degree of conversion (DC%). Standardized roots of 52 bovine incisors had their canals prepared and were distributed into 4 groups (n = 10 for CLT and BS; n = 3 for DC%) according to the post used: WP3 (Control)-Whitepost DC3; groups DE, EN and TR-Whitepost DC0.5 relined, respectively, with dentin, enamel, and translucent shade composites. After cementation, specimens were sectioned into six 1.0 mm-thick discs that were submitted to push-out BS test. CLT and failure pattern were evaluated using a stereomicroscope and DC% by micro-Raman spectroscopy. Data were analyzed by two-way ANOVA and Tukey test (α = 0.05). The control group showed greater CLT than all relined groups (p < 0.05), which did not differ from each other (p > 0.05). Groups relined with low opacity composites (TR; EN) showed the highest BS and DC% means (p < 0.05). BS was not different among root thirds (p > 0.05), while DC% decreased from cervical to apical third (p < 0.05). Adhesive failures between cement and dentin were predominant, except for group DE with frequent mixed failures. It could be concluded that composite opacity did not influence CLT, which was thinner when GFP were relined and that relining GFP with lower opacity composites led to higher BS and DC%.
本研究旨在评估不同不透明度的玻璃纤维桩（GFP）复合材料衬里对树脂水门汀层厚度（CLT）、树脂水门汀与根管牙本质粘结强度（BS）和树脂水门汀的转化率（DC％）的影响。将 52 颗牛切牙的标准化根管制备后，根据使用的桩体将其分为 4 组（CLT 和 BS 每组 n=10；DC%每组 n=3）：WP3（对照）-Whitepost DC3；DE、EN 和 TR 组分别用牙本质、釉质和半透明色复合材料衬里 Whitepost DC0.5。粘结后，将标本切成 6 个 1.0mm 厚的圆盘，进行推出 BS 试验。使用立体显微镜评估 CLT 和失效模式，使用微拉曼光谱评估 DC%。数据采用双因素方差分析和 Tukey 检验（α=0.05）进行分析。对照组的 CLT 大于所有衬里组（p<0.05），但彼此之间无差异（p>0.05）。低不透明度复合材料衬里组（TR；EN）的 BS 和 DC%平均值最高（p<0.05）。根的三个部分的 BS 没有差异（p>0.05），而 DC%从颈部分到根尖部分逐渐降低（p<0.05）。除了 DE 组经常出现混合失效外，粘结剂与牙本质之间的粘结失效是主要的失效模式。可以得出结论，复合材料的不透明度不会影响 CLT，当 GFP 被衬里时 CLT 会变薄，而用低不透明度复合材料衬里 GFP 会导致更高的 BS 和 DC％。
