Lee H L, Orlowski J A, Rogers B J
Int Dent J. 1976 Jun;26(2):134-51.
Both self-cured and UV-cured resin-base dental materials are used in preventive, restorative, and orthodontic dentistry. Polymerization is initiated in both systems by free radicals. Self-curing materials generate free radicals by means of chemical compounds included in their formulation. UV-curing systems rely upon externally-supplied, long wavelength, ultraviolet radiation to produce free radicals within the material. Therefore, although the major chemical components of both systems are similar in many respects, each system has particular advantages and disadvantages over the other, which must be recognized by the practitioner. Substantial differences exist, for example, in the color stability of these two types of materials, because of the fact that the UV-cured system cannot include UV absorbers, which protect the self-cured systems from discoloration after exposure to sunlight. UV-cured systems require a limitation on the maximum depth of filled restorative that can be cured at one time, since the filler particles attenuate UV radiation. The limit-layer is generally established as 1-1-5 mm maximum thickness. Therefore, UV-cured filled systems are more time-consuming in restorations of deeper cavities. This liability is also in evidence as it affects the degree of polymerization of UV-cured filled systems. The uncertainty of complete polymerization is apparently responsible for highly erratic compressive strength data found with UV-cured restoratives. Normally, the amount of unpolymerized monomer is much less predictable in UV-cured systems, over that which is obtained in self-cured materials. The presence of a larger fraction of unpolymerized monomer creates a greater potential for pulpal injury from UV-cured restorative materials. The catalyst used in several UV-cured systems is benzoin methyl ether, a compound of rather high toxicity (LD50:300 mg/kg). The safety of using UV radiation in the vicinity of oral mucosa has not been firmly established. The design of the UV lamp should provide for focusing all radiation onto hard tissue. However, UV-cured systems do offer several advantages over self-cured systems. They normally are one-component systems and therefore are more convenient to use in certain types of applications, e.g., fissure sealing. UV-cured systems also provide an unlimited working time, an important advantage for specific applications.
自固化和紫外线固化的树脂基牙科材料都用于预防、修复和正畸牙科。两种体系中的聚合反应均由自由基引发。自固化材料通过其配方中所含的化合物产生自由基。紫外线固化体系依靠外部提供的长波长紫外线辐射在材料内部产生自由基。因此，尽管两种体系的主要化学成分在许多方面相似，但每种体系相对于另一种都有其特定的优缺点，从业者必须认识到这些。例如，这两种材料的颜色稳定性存在显著差异，因为紫外线固化体系不能包含紫外线吸收剂，而紫外线吸收剂可保护自固化体系在暴露于阳光后不褪色。紫外线固化体系对一次固化的填充修复体的最大深度有限制，因为填料颗粒会使紫外线辐射衰减。限制层的最大厚度一般设定为1-1.5毫米。因此，在较深窝洞的修复中，紫外线固化填充体系更耗时。这种不利因素在影响紫外线固化填充体系的聚合程度时也很明显。完全聚合的不确定性显然是导致紫外线固化修复体抗压强度数据极不稳定的原因。通常，紫外线固化体系中未聚合单体的量比自固化材料中更难预测。较大比例的未聚合单体的存在使得紫外线固化修复材料对牙髓造成损伤的可能性更大。几种紫外线固化体系中使用的催化剂是苯偶姻甲醚，这是一种毒性相当高的化合物（半数致死量：300毫克/千克）。在口腔黏膜附近使用紫外线辐射的安全性尚未得到确凿证实。紫外线灯的设计应能将所有辐射聚焦到硬组织上。然而，紫外线固化体系相对于自固化体系确实具有一些优势。它们通常是单组分体系，因此在某些类型的应用中，如窝沟封闭，使用起来更方便。紫外线固化体系还提供无限的工作时间，这对特定应用来说是一个重要优势。
