da Silva-Jñnior Maciel E, de Fz Lizarelli Rosane, Bagnato Vanderlei S, Tonetto Mateus R, Simões Flávio, Borges Álvaro H, Bandéca Matheus C, de Andrade Marcelo F
Department of Restorative Dentistry, Araraquara School of Dentistry, UNESP-Universidade Estadual Paulista, St. Humaita 1680 Araraquara, 14801903, Sao Paulo, Brazil, e-mail:
Department of Physics, USP-Universidade de Sao Paulo Sao Carlos, Brazil.
J Contemp Dent Pract. 2018 Jan 1;19(1):3-12.
With the development of the light-emitting diode (LED) to photo-activate composite resin, greater intensities could be reached without greater elevation of temperature in the mass of the composite resin and in the dental structure arisen from the irradiance in comparison to halogen equipments. This new scenario created a necessity to investigate the influence of temperature over the composite polymerization.
Several curing temperatures (Tcure- 0, 25, 50, 75, and 100°C) were used to polymerize a composite resin (Filtek Z250, 3M ESPE) for 40 and 60 s, using the halogen equipment Gnatus Optilight Digital (halogen) and two LEDs that use a new technology to assembly the diodes: LEC 1000 and bright LEC (MM Optics) (LED 1 and LED 2 respectively). The influence of curing temperature, added by the other variables studied, was evaluated using a methodology developed and improved at IFSC/USP, in which the penetration of a fluorescent dye in the body of the photopolymerized composite resin was quantified using fluorescence spectroscopy.
According to the final data submitted to an analysis of variance, the presence of two groups of results could be verified: Between 0 and 25°C, both had a great percentage of the dye penetration compared with other Tcure with a variation in penetration from 69.26 ± 8.19% to 90.99 ± 3.38%. In this analysis, the effects of time and temperature were highly notable (p < 0.05) and the lesser value of dye penetration took place at 60 s of photoactivation This penetration was, in average, smaller with the Tcure of 25°C. The results showed that there was an interaction between the equipment and time and between time and temperature; the other group is regarding the Tcure was from 50, 75, and 100°C, despite the p = 0.05, the effect of temperature was notable. The penetration of the dye ranged from 8.87 ± 3.55 to 39.47 ± 8.9%. The effects of equipment and time were highly notable. The penetration with the time of 60 s was in average smaller. Except with the equipment LED 1, the percentages of the dye penetration were greater with the Tcure of 100°C. The smallest average was the Tcure of 50°C and 60 s of photoactivation.
Based on the available data regarding the influence of curing temperature on the polymerization process of composite resins, was possible to concluded that small increments of heat increased the degree of conversion. We can assume that the energy supply through the generation of heat by the photopolymerizing devices can function as a heating medium for the reagent system by reducing its viscosity and increasing the mobility and agitation of its components.
The dentist must be aware of the effects that exist between the activation devices on the light output and their heat transmission to the composite and the tooth itself. This heat transmission might create a polymer with better characteristics.
随着发光二极管（LED）用于光固化复合树脂的发展，与卤素设备相比，在不使复合树脂本体和牙体结构因辐照而温度大幅升高的情况下，可达到更高的强度。这种新情况使得有必要研究温度对复合树脂聚合的影响。
使用几种固化温度（Tcure - 0、25、50、75和100°C）对复合树脂（Filtek Z250，3M ESPE）进行40秒和60秒的聚合，使用卤素设备Gnatus Optilight Digital（卤素）以及两种采用新技术组装二极管的LED：LEC 1000和亮LEC（MM Optics）（分别为LED 1和LED 2）。通过IFSC/USP开发和改进的一种方法来评估固化温度以及其他研究变量的影响，该方法通过荧光光谱法定量荧光染料在光固化复合树脂体内的渗透情况。
根据提交给方差分析的最终数据，可以验证存在两组结果：在0至25°C之间，与其他固化温度相比，两者的染料渗透百分比都很高，渗透变化范围为69.26±8.19%至90.99±3.38%。在此分析中，时间和温度的影响非常显著（p < 0.05），且在光激活60秒时染料渗透值最小。在25°C的固化温度下，这种渗透平均较小。结果表明设备与时间之间以及时间与温度之间存在相互作用；另一组关于固化温度为50、75和100°C，尽管p = 0.05，但温度的影响显著。染料的渗透范围为8.87±3.55至39.47±8.9%。设备和时间的影响非常显著。60秒时的渗透平均较小。除了LED 1设备外，100°C的固化温度下染料渗透百分比更大。最小的平均值是50°C的固化温度和60秒的光激活。
基于关于固化温度对复合树脂聚合过程影响的现有数据，可以得出结论，小幅度的热量增加会提高转化率。我们可以假设光聚合装置通过产热提供的能量可以作为试剂系统的加热介质，降低其粘度并增加其组分的流动性和搅动。
牙医必须了解激活设备在光输出以及它们向复合树脂和牙齿本身的热传递之间存在的影响。这种热传递可能会产生具有更好特性的聚合物。
