Bolhuis Peter B, de Gee Anton J, Kleverlaan Cornelis J, El Zohairy Ahmed A, Feilzer Albert J
Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Louwesweg 1, 1066 EA Amsterdam, The Netherlands.
Dent Mater. 2006 Mar;22(3):223-33. doi: 10.1016/j.dental.2005.03.016. Epub 2006 Jan 26.
Recent studies have shown that adhesives containing acidic monomers combined with composites can adversely effect the polymerization reaction producing low bond strengths. This phenomenon may also occur in making composite build-ups, jeopardizing one of the key factors for a successful core build-up restoration. The aim of this study was to investigate the contraction stress development and bond strength to dentin of core build-up resin composites combined with adhesives of various acidities. In addition the hypothesis tested was that light irradiation through chemical-cured composites during curing does not influence contraction stress or bond strength to dentin.
The chemical-cured (Clearfil Core) and light-cured (Clearfil Photo Core) core build-up resin composites were combined with two light-cured adhesives, Clearfil SE Bond (pH=1.8) and One-Step Bond (pH=4.3) and two dual-cured adhesives, Clearfil Photo Bond (pH=2.5) and All-Bond 2 (pH=6.1). Contraction stress development (at C=3) was determined for a period of 30 min in a universal testing machine where the opposing bonding surfaces were glass and dentin. After the 30 min period, the specimens were loaded in tension to determine the bond strength to dentin. To test the hypothesis, the combinations of the chemical-cured composites with the four bonding systems were also light irradiated for 40s right at the start of curing.
For all composite-adhesive combinations tested, the adhesion to dentin resisted the developing polymerization contraction stresses. Both, dentin as a substrate to bond at and the use of adhesives, were showed to play an important role in keeping the contraction stresses low. The chemical-cured composite (Clearfil Core) combined with the light-cured adhesive SE Bond (pH=1.8) showed for both contraction stress and bond strength significant lower values than the other combinations. The hypothesis was accepted for combinations of the chemical-cured composite with All-Bond 2 and One-Step Bond, but was not supported by combinations with Clearfil SE Bond or Clearfil Photo Bond, as a significant increase in contraction stress was found. The higher values found for bond strength were not significant.
Besides combinations of chemical-cured core build-up composites with light or dual-cured adhesives as recommended by the manufacturer, also combinations with adhesives of other manufacturers are compatible, provided that the pH is higher than approximately 4.3. Chemical-cured core build-up composites combined with light-cured adhesives with a pH as low as 1.8 lead to a significantly lower stress and bond strength compared to other combinations. Light irradiation during curing through a combination of a chemical-cured composite and a low pH adhesive reactivates polymerization.
近期研究表明，含酸性单体的粘合剂与复合材料结合会对聚合反应产生不利影响，导致粘结强度降低。这种现象在制作复合树脂堆塑时也可能发生，危及成功进行核桩修复的关键因素之一。本研究的目的是调查核桩树脂复合材料与不同酸度粘合剂结合时的收缩应力发展情况以及与牙本质的粘结强度。此外，所检验的假设是，在固化过程中通过化学固化复合材料进行光照射不会影响收缩应力或与牙本质的粘结强度。
将化学固化（Clearfil Core）和光固化（Clearfil Photo Core）核桩树脂复合材料与两种光固化粘合剂Clearfil SE Bond（pH = 1.8）和One-Step Bond（pH = 4.3）以及两种双重固化粘合剂Clearfil Photo Bond（pH = 2.5）和All-Bond 2（pH = 6.1）相结合。在万能试验机中，以玻璃和牙本质作为相对的粘结表面，测定30分钟内的收缩应力发展情况（在C = 3时）。30分钟后，对试件施加拉伸载荷以测定与牙本质的粘结强度。为检验该假设，在固化开始时，对化学固化复合材料与四种粘结系统的组合也进行了40秒的光照射。
对于所有测试的复合 - 粘合剂组合，与牙本质的粘结力抵抗了聚合收缩应力的发展。牙本质作为粘结的底物以及粘合剂的使用，在保持低收缩应力方面均发挥了重要作用。化学固化复合材料（Clearfil Core）与光固化粘合剂SE Bond（pH = 1.8）结合时，收缩应力和粘结强度均显著低于其他组合。对于化学固化复合材料与All-Bond 2和One-Step Bond的组合，该假设得到接受，但对于与Clearfil SE Bond或Clearfil Photo Bond的组合则不成立，因为发现收缩应力显著增加。粘结强度的较高值并不显著。
除了制造商推荐的化学固化核桩复合材料与光固化或双重固化粘合剂的组合外，与其他制造商的粘合剂组合也是相容的，前提是pH值高于约4.3。与pH低至1.8的光固化粘合剂结合的化学固化核桩复合材料相比其他组合，会导致应力和粘结强度显著降低。在固化过程中，通过化学固化复合材料和低pH值粘合剂的组合进行光照射会重新激活聚合反应。
