OBJECTIVE This study investigated the effect of plasma-treated leno weaved ultra-high-molecular-weight polyethylene fiber placement on gap formation and microtensile bond strength (MTBS) of a bulk-fill composite in deep cavity. METHODS Resin composite molds (3 mm width, 4 mm depth) were treated with Clearfil SE Bond 2 and restored with 3 techniques : (1) Surefil SDR flow (SDR) placed in bulk (BLK), (2) SDR placed in two unequal increments (INC) and (3) SDR placed after an increment of SDR placed with wetted polyethylene fiber (Ribbond Ultra) at the cavity floor (FRC). As a control, the cavities were bulk-filled with SDR and no bonding agent (n = 12). All the specimens were subjected to real-time and 3D imaging by SS-OCT (1330 nm) to calculate the total volume of gap formed (mm3) at the cavity floor and between the composite increments. For MTBS, the occlusal cavities of the similar dimensions (3 × 3 × 4 mm3) were prepared on extracted molars with similar composite placement techniques (BLK, INC and FRC). After 24 h 37 °C water storage, the specimens were sectioned using a diamond saw to create 0.7 × 0.7 mm2 beams for MTBS, and subjected to bond testing at a crosshead speed of 1 mm/min. Data for both tests was analyzed by one-way ANOVA and multiple-comparisons with Bonferroni correction (α = 0.05). RESULTS The gap volumes were different among the groups (p < 0.05). The largest cavity floor gaps (mm3) were observed in the control group (2.00 ± 0.08); followed by BLK (0.74 ± 0.20) and INC (0.02 ± 0.01). In FRC, the cavity floor was gap-free in all specimens but some separation was observed between the two increments. MTBS values (MPa) were 13.8 ± 7.6, 31.7 ± 12.5 and 28.3 ± 8.5 for BLK, INC and FRC groups. There was no significant difference between FRC and INC and both were different from BLK (p < 0.05). SIGNIFICANCE Gap formation of the bulk-fill composite at cavity floor was significantly reduced with the placement of a fiber-reinforced increment at the base of the deep preparation. The fiber-reinforced increment acts as a shrinkage stress breaker and protects the bonded interface at deep dentin.

中文翻译：

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纤维增强对深层制备中填充复合材料的适应性和粘结强度的影响。

目的本研究调查了等离子处理的纱罗编织超高分子量聚乙烯纤维放置对深腔中填充复合材料的间隙形成和微拉伸粘合强度（MTBS）的影响。方法用Clearfil SE Bond 2处理树脂复合材料模具（宽3 mm，深4 mm），并用3种技术修复：（1）将Surefil SDR流（SDR）散装（BLK），（2）将SDR放在两个不相等的位置增量（INC）和（3）将SDR放置在型腔底部（FRC）上的湿聚乙烯纤维（Ribbond Ultra）放置的SDR增量之后。作为对照，用SDR完全填充型腔，而没有粘合剂（n = 12）。所有样品均通过SS-OCT（1330 nm）进行实时和3D成像，以计算在型腔底部和复合材料增量之间形成的间隙的总体积（mm3）。对于MTBS，使用类似的复合材料放置技术（BLK，INC和FRC）在提取的磨牙上制备相似尺寸（3×3×4 mm3）的咬合腔。在37°C的水储存24小时后，将样品用金刚石锯切成0.7×0.7 mm2的MTBS光束，并以1 mm / min的十字头速度进行粘合测试。通过单因素方差分析和Bonferroni校正（α= 0.05）的多重比较分析两种测试的数据。结果两组间的间隙体积不同（p <0.05）。在对照组中观察到最大的腔底间隙（mm3）（2.00±0.08）。其次是BLK（0.74±0.20）和INC（0.02±0.01）。在FRC中，所有标本的模腔底面均无间隙，但在两个增量之间观察到一些分隔。BLK的MTBS值（MPa）为13.8±7.6、31.7±12.5和28.3±8.5，INC和FRC组。FRC和INC之间没有显着差异，并且两者均与BLK不同（p <0.05）。意义通过在深层准备工作的底部放置纤维增强的增量，可以大大减少空腔底部的填充复合材料的空隙形成。纤维增强的增量充当收缩应力的破坏者，并保护深牙本质处的粘结界面。