Department of Restorative Dentistry and Cariology, Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland; Turku University Hospital, TYKS, University of Turku, Turku, Finland.
Department of Restorative Dentistry and Cariology, Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland.
Dent Mater. 2022 Aug;38(8):1419-1431. doi: 10.1016/j.dental.2022.06.031. Epub 2022 Jul 2.
To determine whether smear layer management, via conservative etching protocols, and the hydrophobic-rich content of hybrid layers would affect the fatigue strength of resin-dentin interfaces.
Bar-shaped dentin beams obtained from sound third molars were wet-polished for 30 s. Dentin was etched with 32 % ortho-phosphoric acid for 3 or 15 s, 10 % meta-phosphoric acid for 15 s or by a prime-and-rinse application using a mild universal adhesive (Scotchbond Universal, 3M ESPE). Self-etch application served as control. Coating was performed with a solvent-free bisGMA-based resin. Composite buildups were made with a nanofilled composite. Resin-dentin beams with twin-bonded interfaces were sectioned and stored in deionized water for 24 h at 37 ℃ before 4-point flexural quasi-static monotonic testing (n = 16). Stress-life fatigue behavior was evaluated under cyclic loading (n = 35) by the staircase method at 4 Hz. The tension side of cyclic-loaded unfractured beams were evaluated under SEM, along with the micro-morphology of etched dentin surfaces. Monotonic data was analyzed by two-way ANOVA followed by the Tukey Test and cyclic-loaded data by Kruskal-Wallis on Ranks (α = 0.05).
Etching protocols and higher hydrophobic-rich content produced significantly higher fatigue life distributions (p < 0.05). Dentin demineralization was ranked as OPA 15 s > MPA 15 s > OPA 3 s > P + R > SE. Less aggressive etching and coating reduced crack formation at hybrid layers.
Current oversimplification trends in resin-dentin bonding constitute a trade-off between hybridization quality and easier adhesive handling. Controlled dentin etching and increasing the hydrophobic-rich content of hybrid layers may be necessary to extend the longevity of mild universal adhesives.
确定保守酸蚀方案下的玷污层管理和混合层的疏水性含量是否会影响树脂-牙本质界面的疲劳强度。
从健康的第三磨牙中获得条状牙本质梁，用湿抛光法抛光 30 秒。用 32%正磷酸酸蚀 3 秒或 15 秒，10%中磷酸酸蚀 15 秒，或用温和通用粘结剂（Scotchbond Universal，3M ESPE）进行预涂-冲洗处理。自酸蚀处理作为对照。用无溶剂双酚 A 基树脂进行涂层。用纳米复合树脂制作复合堆积物。将具有双粘结界面的树脂-牙本质梁切割，并在 37℃下的去离子水中储存 24 小时，然后进行四点弯曲准静态单调测试（n=16）。通过 4Hz 的阶梯法在循环加载下（n=35）评估应力寿命疲劳行为。通过扫描电子显微镜评估循环加载未断裂梁的张力侧，并评估酸蚀牙本质表面的微观形貌。单调数据通过双向方差分析（ANOVA），然后是 Tukey 检验，循环加载数据通过 Kruskal-Wallis 秩检验（α=0.05）进行分析。
酸蚀方案和更高的疏水性含量产生了显著更高的疲劳寿命分布（p<0.05）。牙本质脱矿程度的排序为 OPA 15s>MPA 15s>OPA 3s>P+R>SE。更温和的酸蚀和涂层减少了混合层中裂纹的形成。
当前树脂-牙本质粘结的过度简化趋势是在杂交质量和更容易的粘结剂处理之间的权衡。控制牙本质酸蚀和增加混合层的疏水性含量可能是延长温和通用粘结剂寿命所必需的。
