Cornelio Roberto Belloti, Wikant Aksel, Mjøsund Hanne, Kopperud Hilde Molvig, Haasum Johan, Gedde Ulf Wiel, Örtengren Ulf Thore
Department of Clinical Dentistry/Faculty of Health Sciences, The Arctic University of Norway , Tromsø , Norway.
Acta Odontol Scand. 2014 Aug;72(6):440-7. doi: 10.3109/00016357.2013.856467. Epub 2013 Nov 21.
The aim of this work was to assess the influence of the bis-EMA content on the degree of conversion (DC) and its effect on the water sorption and solubility.
In a polytetrafluorethylene (PTFE) mould, 30 samples (Ø = 5 mm, height = 2 mm) of four experimental dental composite resins were cured for 10 s, 20 s and 40 s. The DC was analysed by Fourier Transform (FT)-Raman spectroscopy. To analyse sorption and solubility, six samples (Ø = 15 mm and thickness = 1 mm) of each composite (n = 72) were stored in water at 37°C for different storage periods: 24 h, 7 days and 30 days.
When cured for 20 or 40 s the DC increased with the increasing content of bis-EMA. However, the presence of 15 wt% of bis-GMA did not affect the DC, except when cured with 10 s irradiation time. This study also found a correlation between the content of bis-EMA and the reduced values for sorption and solubility, for all storage times used, when the materials were cured with 20 s.
The DC of mixtures with higher content of bis-EMA is affected by the presence of bis-GMA at lower energy density delivered from the curing device, suggesting that the restrictions caused by the presence of hydrogen bonds is dependent of the irradiation time used.
本研究旨在评估双甲基丙烯酸缩水甘油酯（bis-EMA）含量对转化率（DC）的影响及其对吸水性和溶解性的作用。
在聚四氟乙烯（PTFE）模具中，将四种实验性牙科复合树脂的30个样本（直径 = 5毫米，高度 = 2毫米）分别固化10秒、20秒和40秒。通过傅里叶变换（FT）-拉曼光谱分析转化率。为了分析吸水性和溶解性，每种复合材料的六个样本（直径 = 15毫米，厚度 = 1毫米）（n = 72）在37°C的水中储存不同时间：24小时、7天和30天。
当固化20秒或40秒时，转化率随双甲基丙烯酸缩水甘油酯（bis-EMA）含量的增加而提高。然而，15 wt%的双甲基丙烯酸缩水甘油酯（bis-GMA）的存在并不影响转化率，除非固化时间为10秒。本研究还发现，当材料在20秒固化时，在所有使用的储存时间内，双甲基丙烯酸缩水甘油酯（bis-EMA）含量与吸水性和溶解性的降低值之间存在相关性。
在固化设备提供的较低能量密度下，双甲基丙烯酸缩水甘油酯（bis-GMA）的存在会影响双甲基丙烯酸缩水甘油酯（bis-EMA）含量较高的混合物的转化率，这表明氢键的存在所造成的限制取决于所使用的照射时间。
