Lopes Lawrence Gonzaga, Franco Eduardo Batista, Pereira José Carlos, Mondelli Rafael Francisco Lia
Department of Preventive and Oral Reabilitation, Dental School, Federal University of Goiás, Goiânia, GO, Brazil.
J Appl Oral Sci. 2008 Jan-Feb;16(1):35-42. doi: 10.1590/s1678-77572008000100008.
The aim of this study was to evaluate the polymerization shrinkage and shrinkage stress of composites polymerized with a LED and a quartz tungsten halogen (QTH) light sources. The LED was used in a conventional mode (CM) and the QTH was used in both conventional and pulse-delay modes (PD). The composite resins used were Z100, A110, SureFil and Bisfil 2B (chemical-cured). Composite deformation upon polymerization was measured by the strain gauge method. The shrinkage stress was measured by photoelastic analysis. The polymerization shrinkage data were analyzed statistically using two-way ANOVA and Tukey test (p < or = 0.05), and the stress data were analyzed by one-way ANOVA and Tukey's test (p < or = 0.05). Shrinkage and stress means of Bisfil 2B were statistically significant lower than those of Z100, A110 and SureFil. In general, the PD mode reduced the contraction and the stress values when compared to CM. LED generated the same stress as QTH in conventional mode. Regardless of the activation mode, SureFil produced lower contraction and stress values than the other light-cured resins. Conversely, Z100 and A110 produced the greatest contraction and stress values. As expected, the chemically cured resin generated lower shrinkage and stress than the light-cured resins. In conclusion, The PD mode effectively decreased contraction stress for Z100 and A110. Development of stress in light-cured resins depended on the shrinkage value.
本研究的目的是评估用发光二极管（LED）和石英钨卤素灯（QTH）光源聚合的复合材料的聚合收缩率和收缩应力。LED以传统模式（CM）使用，QTH以传统模式和脉冲延迟模式（PD）使用。所使用的复合树脂为Z100、A110、SureFil和Bisfil 2B（化学固化）。聚合时的复合变形通过应变片法测量。收缩应力通过光弹性分析测量。聚合收缩数据使用双向方差分析和Tukey检验进行统计学分析（p≤0.05），应力数据通过单向方差分析和Tukey检验进行分析（p≤0.05）。Bisfil 2B的收缩率和应力平均值在统计学上显著低于Z100、A110和SureFil。总体而言，与传统模式相比，脉冲延迟模式降低了收缩率和应力值。在传统模式下，LED产生的应力与QTH相同。无论激活模式如何，SureFil产生的收缩率和应力值均低于其他光固化树脂。相反，Z100和A110产生的收缩率和应力值最大。正如预期的那样，化学固化树脂产生的收缩率和应力低于光固化树脂。总之，脉冲延迟模式有效地降低了Z100和A110的收缩应力。光固化树脂中应力的产生取决于收缩值。
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