Development of a low-color, color stable, dual cure dental resin

作者：Oei James D; Mishriky Maged; Barghi Nasser; Rawls H Ralph; Cardenas H Lee; Aguirre Rene; Whang Kyumin^*

来源：Dental Materials, 2013, 29(4): 405-412.

DOI：10.1016/j.dental.2013.01.005

• Color stability
• Low color
• Dual cure
• Thiourea
• Hydroperoxide
• Onium ion

Dual-cure (DC) resins are mainly used as cements due to high initial color (generally yellow) and large color shift (Delta E*) after polymerization as compared to light-cured resins. However, even as cements, this color shift is clinically unacceptable, especially when used to cement thin veneers. %26lt;br%26gt;Objective. To develop a novel DC initiator system with both lower initial color (less yellow, i.e., whiter) and smaller Delta E*. %26lt;br%26gt;Methods. The effect of using an allyl thiourea (T)/cumene hydroperoxide (CH) self-cure (SC) initiator system in combination with a photo-co-initiator, p-octyloxy-phenyl-phenyl iodonium hexafluoroantimonate (OPPI), in a commercial DC resin cement (PermaFlo DC, Ultradent Products, Inc.) was investigated. Initial color and Delta E* were assessed for 6 weeks in vitro under accelerated aging conditions (75 degrees C water bath). Rockwell(15T) hardness was used to assess degree of cure (DoC) and the three-point bending test was used to assess mechanical properties. %26lt;br%26gt;Results. PermaFlo DC (control) was significantly harder than all experimental groups without OPPI but had up to three times higher initial color and four times greater color shift (Delta E* = 27 vs. 8). With OPPI, hardness in the experimental groups increased significantly and several were comparable to the controls. Initial color and Delta E* increased slightly (Delta E* = 9), but was still 3 times less than that of PermaFlo DC. DC samples containing OPPI had comparable modulus and ultimate transverse strengths to those of the controls. %26lt;br%26gt;Conclusions. DC resins that use the T/CH initiator system are weaker but have extremely low color and Delta E*. The addition of OPPI increases DoC and mechanical properties to clinically acceptable levels and maintains extremely low color and Delta E*. Significance. With this novel initiator system, DC resins potentially can now have comparable color and color stability to light-cure resins and be used in broader esthetic dental applications to improve color stability and reduce shrinkage stress in restorative composites.

• 出版日期2013-4