Macan Matea, Marošević Ana, Špiljak Bruno, Šimunović Luka, Par Matej, Marovic Danijela, Juric-Kacunic Danijela, Tarle Zrinka
Department of Endodontics and Restorative Dental Medicine, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia.
Department of Orthodontics, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia.
Materials (Basel). 2023 Jul 7;16(13):4868. doi: 10.3390/ma16134868.
This study analysed flexural properties, microhardness, and the degree of conversion (DC) of five bulk-fill composites under clinically relevant conditions (4 mm thick specimens) in comparison to 2 mm specimens according to ISO 4049. Additionally, the effect of rapid polymerisation on 4 mm specimens was evaluated after accelerated aging. DC was measured using Fourier transform infrared spectrometry at 2 and 4 mm thick layers, while flexural properties and Vickers microhardness were tested using 16 × 2 × 2 mm or 16 × 2 × 4 mm specimens. Three polymerisation protocols were used: (I) "ISO": 2 mm thickness, 1000 mW/cm, double-sided; (II) "10 s": 4 mm thickness, 1000 mW/cm, one-sided; and (III) "3 s": 4 mm thickness, 2600 mW/cm, one-sided. Mechanical properties were tested after 1 day, after 10,000 thermocycles, and after 10,000 thermocycles followed by a 7-day immersion in absolute ethanol. The "ISO" protocol produced a higher DC and microhardness of all materials. Elastic modulus was significantly higher for the "ISO" protocol compared to the 4 mm specimens. The differences in flexural strength for all polymerisation protocols were equalised after thermocycling and immersion in absolute ethanol. All tested materials met the ISO 4049 flexural strength requirement (80 MPa) for all polymerisation methods and all aging conditions. Rapid polymerisation achieved nearly optimal properties (ISO), except for elastic modulus, which was significantly reduced in 4 mm samples.
本研究分析了五种大块充填复合材料在临床相关条件下（4毫米厚试样）的弯曲性能、显微硬度和转化率（DC），并根据ISO 4049标准与2毫米试样进行了比较。此外，在加速老化后评估了快速聚合对4毫米试样的影响。使用傅里叶变换红外光谱法在2毫米和4毫米厚的层中测量DC，而使用16×2×2毫米或16×2×4毫米的试样测试弯曲性能和维氏显微硬度。使用了三种聚合方案：（I）“ISO”：2毫米厚度，1000毫瓦/平方厘米，双面；（II）“10秒”：4毫米厚度，1000毫瓦/平方厘米，单面；（III）“3秒”：4毫米厚度，2600毫瓦/平方厘米，单面。在1天后、10000次热循环后以及10000次热循环后再在无水乙醇中浸泡7天后测试机械性能。“ISO”方案使所有材料的DC和显微硬度更高。与4毫米试样相比，“ISO”方案的弹性模量显著更高。在热循环和浸泡在无水乙醇后，所有聚合方案的弯曲强度差异均得到平衡。对于所有聚合方法和所有老化条件，所有测试材料均满足ISO 4049弯曲强度要求（80兆帕）。除弹性模量外，快速聚合实现了几乎最佳的性能（ISO），4毫米样品中的弹性模量显著降低。
