Department of Preventive Dentistry, Periodontology and Cariology, Center for Dental Medicine, University of Zurich, Plattenstrasse 11, CH-8032 Zurich, Switzerland.
J Am Dent Assoc. 2011 Aug;142(8):950-6. doi: 10.14219/jada.archive.2011.0302.
The authors conducted an in vitro study to investigate the influence of various curing protocols on subsurface microhardness of dual-cured resin-based composites.
The authors filled molds with four dual-cured resin-based composite core buildup materials: Clearfil DC Core Automix (Kuraray, Tokyo), Core•X flow (Dentsply DeTrey, Konstanz, Germany), LuxaCore Z-Dual (DMG, Hamburg, Germany) and MultiCore Flow (Ivoclar Vivadent, Schaan, Liechtenstein). They light cured the specimens for 20 or 60 seconds immediately after the filling procedure (time delay, 0 seconds) or after a 90-or 300-second delay. Self-cured specimens served as controls. The authors tested 15 specimens in each group. They measured the Knoop hardness number (KHN) at depths of 0.25, 2.00 and 5.50 millimeters two weeks after the initiation of polymerization.
Light curing with Core•X flow, LuxaCore Z-Dual and MultiCore Flow did not result in significantly higher KHNs at any depth compared with those for the self-cured control specimens. For Clearfil DC Core Automix, immediate light curing for 60 seconds resulted in significantly higher KHNs than those for self-cured specimens only at a depth of 5.50 mm (P=.0171). The study results showed no significant differences in KHN at different depths for Core•X flow specimens, independent of the curing protocol. All other materials exhibited a significant decrease in KHN at increased depths in only one of the six light-cured groups.
The results of this study show that photoactivation of the tested dual-cured materials provided no clinically relevant benefit compared with self-curing with regard to the degree of microhardness.
The dominant self-curing mode allows placement of the tested buildup materials in areas inaccessible to a curing light.
作者进行了一项体外研究，以调查不同固化方案对双固化树脂基复合材料亚表面显微硬度的影响。
作者用四种双固化树脂基复合材料核修复材料填充模具：Clearfil DC Core Automix（Kuraray，东京）、Core•X flow（Dentsply DeTrey，康斯坦茨，德国）、LuxaCore Z-Dual（DMG，汉堡，德国）和 MultiCore Flow（Ivoclar Vivadent，沙安，列支敦士登）。他们在填充后立即对试件进行 20 秒或 60 秒的光固化（延迟时间为 0 秒），或者在 90 秒或 300 秒后进行光固化。自固化试件作为对照。每组测试 15 个试件。聚合启动后两周，在 0.25、2.00 和 5.50 毫米深度测量维氏硬度数（KHN）。
与自固化对照组相比，用 Core•X flow、LuxaCore Z-Dual 和 MultiCore Flow 进行光固化在任何深度都没有导致明显更高的 KHN。对于 Clearfil DC Core Automix，立即光固化 60 秒仅在 5.50 毫米深度时导致 KHN 明显高于自固化试件（P=.0171）。研究结果表明，Core•X flow 试件在不同深度的 KHN 没有差异，与固化方案无关。在六个光固化组中的一个中，只有其他所有材料在一个光固化组中表现出明显的 KHN 随着深度的增加而降低。
本研究结果表明，与自固化相比，测试的双固化材料的光激活在显微硬度程度上没有提供临床相关的益处。
主要的自固化模式允许将测试的堆积材料放置在无法用固化光到达的区域。
