Professor, Department of Dentistry, Federal University of Sergipe, Aracaju, Brazil.
Professor, Department of Restorative Dentistry, Division of Biomaterials and Biomechanics, Oregon Health & Science University, Portland, Ore.
J Prosthet Dent. 2017 Nov;118(5):631-636. doi: 10.1016/j.prosdent.2016.12.013. Epub 2017 Apr 3.
The cementation of ceramic veneers using light-polymerized resin cement is largely dependent on the proper light activation of the cement. Light activation using high irradiance could shorten the time required to lute multiple restorations.
The purpose of this in vitro study was to evaluate the light transmission of dental light-polymerizing units through ceramic cylinders and its effect on the polymerization kinetics of a resin cement.
Ceramic ingots (IPS Empress Esthetic, shade ET1) were sectioned to produce cylinders 0.5, 1.0, and 2.0 mm thick. Two light-emitting diode units were evaluated: SmartLite Focus and Valo Cordless, the latter used in either Standard or Xtra Power (XP) modes. Light transmission (average of irradiance, total energy, and light-emission profile) through the cylinders was measured (n=3). The polymerization kinetics of a resin cement light polymerized through the ceramic was monitored for 5 minutes (n=3). The degree of conversion was measured again after 72 hours. Data were individually analyzed with 2-way ANOVA and the Tukey HSD test (α=.05).
Valo at XP presented the highest values of irradiance and SmartLite the lowest, irrespective of the ceramic thickness. Regarding the total energy, XP showed the lowest values. The total energy and irradiance lessened with the increase in ceramic thickness. In general, except for Valo at XP, the ceramic thickness did not affect the degree of conversion. Valo at XP and interposing 2.0 mm ceramic resulted in the lowest values of Rp.
The reduction of total energy and irradiance by ceramic interposition had only a slight effect on polymerization kinetics.
陶瓷贴面的粘结剂采用光固化树脂粘结剂，在很大程度上取决于粘结剂的适当光激活。高强度光激活可以缩短多个修复体的粘结时间。
本体外研究的目的是评估牙科光聚合单元通过陶瓷圆柱体的光透射及其对树脂粘结剂聚合动力学的影响。
将陶瓷锭（IPS Empress Esthetic，色号 ET1）切割成 0.5、1.0 和 2.0 毫米厚的圆柱体。评估了两种发光二极管单元：SmartLite Focus 和 Valo Cordless，后者分别在标准或 Xtra Power（XP）模式下使用。通过圆柱体测量光透射（辐照度、总能量和发光分布的平均值）（n=3）。通过陶瓷光聚合的树脂粘结剂的聚合动力学在 5 分钟内进行监测（n=3）。72 小时后再次测量转化率。使用 2 因素方差分析和 Tukey HSD 检验（α=.05）分别对数据进行分析。
无论陶瓷厚度如何，XP 模式的 Valo 呈现出最高的辐照度值，而 SmartLite 则呈现出最低的辐照度值。至于总能量，XP 显示出最低的值。总能量和辐照度随着陶瓷厚度的增加而减少。一般来说，除了 XP 模式的 Valo 之外，陶瓷厚度不会影响转化率。XP 模式的 Valo 和插入 2.0 毫米陶瓷导致 Rp 值最低。
陶瓷插入导致总能量和辐照度的减少对聚合动力学只有轻微影响。
