Bucuta Stefan, Ilie Nicoleta
Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr. 70, 80336, Munich, Germany,
Clin Oral Investig. 2014 Nov;18(8):1991-2000. doi: 10.1007/s00784-013-1177-y. Epub 2014 Jan 11.
The aim of this study was to quantify the blue light that passes through different incremental thicknesses of bulk fill in comparison to conventional resin-based composites (RBCs) and to relate it to the induced mechanical properties.
Seven bulk fill, five nanohybrid and two flowable RBCs were analysed. Specimens (n = 5) of three incremental thicknesses (2, 4 and 6 mm) were cured from the top for 20 s, while at the bottom, a spectrometer monitored in real time the transmitted irradiance. Micro-mechanical properties (Vickers hardness, HV, and indentation modulus, E) were measured at the top and bottom after 24 h of storage in distilled water at 37 °C. Electron microscope images were taken for assessing the filler distribution and size.
Bulk fill RBCs (except SonicFill) were more translucent than conventional RBCs. Low-viscosity bulk fill materials showed the lowest mechanical properties. HV depends highly on the following parameters: material (ηp (2) = 0.952), incremental thickness (0.826), filler volume (0.747), filler weight (0.746) and transmitted irradiance (0.491). The bottom-to-top HV ratio (HVbt) was higher than 80 % in all materials in 2- and 4-mm increments (except for Premise), whereas in 6-mm increments, this is valid only in four bulk fill materials (Venus Bulk Fill, SDR, x-tra fil, Tetric EvoCeram Bulk Fill).
The depth of cure is dependent on the RBC's translucency. Low-viscosity bulk fill RBCs have lower mechanical properties than all other types of analysed materials. All bulk fill RBCs (except SonicFill) are more translucent for blue light than conventional RBCs.
Although bulk fill RBCs are generally more translucent, the practitioner has to follow the manufacturer's recommendations on curing technique and maximum incremental thickness.
本研究的目的是量化与传统树脂基复合材料（RBC）相比，通过不同增量厚度的大块充填材料的蓝光，并将其与诱导的机械性能相关联。
分析了七种大块充填材料、五种纳米混合材料和两种可流动的RBC。对三种增量厚度（2、4和6毫米）的试样（n = 5）从顶部固化20秒，同时在底部，一台光谱仪实时监测透射辐照度。在37℃的蒸馏水中储存24小时后，在顶部和底部测量微机械性能（维氏硬度，HV，和压痕模量，E）。拍摄电子显微镜图像以评估填料的分布和尺寸。
大块充填RBC（除SonicFill外）比传统RBC更半透明。低粘度大块充填材料显示出最低的机械性能。HV高度依赖于以下参数：材料（ηp(2)=0.952）、增量厚度（0.826）、填料体积（0.747）、填料重量（0.746）和透射辐照度（0.491）。在2毫米和4毫米增量的所有材料中（Premise除外），底部与顶部的HV比（HVbt）高于80%，而在6毫米增量中，仅在四种大块充填材料（Venus Bulk Fill、SDR、x-tra fil、Tetric EvoCeram Bulk Fill）中有效。
固化深度取决于RBC的半透明度。低粘度大块充填RBC的机械性能低于所有其他类型的分析材料。所有大块充填RBC（除SonicFill外）对蓝光的半透明度高于传统RBC。
尽管大块充填RBC通常更半透明，但从业者必须遵循制造商关于固化技术和最大增量厚度的建议。
