Objective

To evaluate the effect of exposure time and moving the light-curing unit (LCU) on the degree of conversion (DC) and Knoop microhardness (KH) of two resin cements that were light-cured through ceramic.

Methods

Two resin cements: AllCem Veneer APS (FGM) and Variolink Esthetic LC (Ivoclar Vivadent) were placed into a 0.3 mm thick matrix in 6 locations representing the canine to canine. The resins were covered with 0.5 mm thick lithium disilicate glass-ceramic (IPS e.max CAD, Ivoclar Vivadent). A motorized device moved the LCUs over the ceramic when the LCU was on. Two single-peak LCUs: Elipar DeepCure-L (3M Oral Care) and Emitter C (Schuster), and one multi-peak: Bluephase G2 (Ivoclar Vivadent) were used with 3 different exposure protocols: a localized exposure centered over each tooth for 10 or 40 s; moving the tip across the 6 teeth for a total exposure time of 10 or 40 s; and moving the tip across the 6 teeth resins for a total exposure time of 60 or 240 s. After 24 h, the DC and KH were measured on the top surfaces and the data was analyzed using three-way ANOVA and Tukey’s tests (α = 0.05).

Results

Interposition of 0.5 mm of ceramic reduced the irradiance received by the resin by approximately 50%. The 40 s localized exposure over each tooth always produced significantly higher DC and KH values. Moving the LCUs with a total exposure time of 10 s resulted in the lowest DC and KH. There was no beneficial effect on the DC or KH when the multi-peak (violet-blue) LCU (Elipar DeepCure-L or Bluephase G2), but the lower light output from a small tip LCU reduced the DC and KH values (Emitter C).

Significance

Moving the LCUs when photo-curing light-cured resin cements is not recommended. This study showed that a single-peak LCU could activate a resin cement that uses Ivocerin™ as well as the multi-peak LCU.

中文翻译：

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曝光时间和固化光的移动对光固化树脂水泥的转化度和努氏显微硬度的影响。

目的

为了评估曝光时间和移动光固化单元（LCU）对通过陶瓷光固化的两种树脂水泥的转化度（DC）和努氏显微硬度（KH）的影响。

方法

将两种树脂水泥：AllCem单板APS（FGM）和Variolink Esthetic LC（Ivoclar Vivadent）放置在0.3 mm厚的基质中的6个位置，分别代表了犬与犬之间的位置。用0.5mm厚的二硅酸锂玻璃陶瓷（IPS e.max CAD，Ivoclar Vivadent）覆盖树脂。打开LCU时，电动设备会将LCU移到陶瓷上。使用了两个单峰LCU：Elipar DeepCure-L（3M口腔护理）和Emitter C（Schuster），以及一个多峰：Bluephase G2（Ivoclar Vivadent），它具有3种不同的暴露方案：针对每个牙齿居中的局部暴露10或40 s；将尖端移过6颗牙齿，整个暴露时间为10或40 s；并在6种牙齿树脂上移动笔尖，使其总暴露时间为60或240 s。24小时后，α = 0.05）。

结果

插入0.5 mm的陶瓷可使树脂接收到的辐照度降低约50％。每个牙齿上40 s的局部暴露始终会产生明显更高的DC和KH值。移动LCU的总曝光时间为10 s，可得到最低的DC和KH。当多峰（紫蓝色）LCU（Elipar DeepCure-L或Bluephase G2）对DC或KH没有任何有益影响，但是小尖端LCU的较低光输出会降低DC和KH值（发射器C ）。

意义

不建议在光固化光固化树脂胶粘剂时移动LCU。这项研究表明，单峰LCU可以激活使用Ivocerin™以及多峰LCU的树脂胶粘剂。