Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, zhejiang university, Hangzhou, Zhejiang, China.
PeerJ. 2024 Sep 26;12:e18021. doi: 10.7717/peerj.18021. eCollection 2024.
This study aimed to investigate the impact of the duration of light curing unit (LCU) usage and the use of infection control barriers on the hardness of Bulk Fill composite resin after curing. The hypotheses were that extended usage of the LCU would not reduces its output power and resin hardness, and that the presence of polyethylene film barriers exacerbates the reduction in resin hardness.
Based on the absence or presence of polyethylene film (PE) and the number of layers used, a 3M LED curing light (EliparTM DeepCure-S; 3M ESPE, St Paul, MN, USA) was divided into three groups: PE0, PE1, and PE3. The curing light was used 30 times daily for 20 s per exposure, at frequencies of 0, 6, and 12 months. Maximum output power tests were conducted for each group of curing lights. Custom-made plastic modules were used to stack Bulk Fill composite resin (Filtek Bulk Fill Posterior Restorative; 3M ESPE) to a thickness of 4 mm. Each group of curing lights was used to cure the modules in a direct contact manner for 20 s. Vickers hardness measurements were taken at the top and bottom surfaces of the resin specimens using a digital microhardness tester. A one-way or two-way ANOVA analyzed the power of LCUs, Vickers hardness of Bulk Fill composite resin, and hardness decrease percentage across groups. Pairwise comparisons used the Tukey test (α = 0.05).
As the duration of usage increased, both the power of the curing light and the hardness of the resin significantly decreased. Significant differences were observed in power and resin hardness among the PE0, PE1, and PE3 groups. When the duration of usage was 6 months or less, only multi-layered PE films led to a significant increase in the percentage decrease of hardness of cured resin from top to bottom. However, at 12 months, both single-layer and multi-layered PE films resulted in a significant increase in the percentage decrease of hardness of cured resin from top to bottom.
The output power of the light curing unit decreases with prolonged usage, thereby failing to meet the curing requirements of Bulk Fill composite resin. The use of single-layer PE as an infection control barrier is recommended.
本研究旨在探讨光固化器（LCU）使用时间的长短和使用感染控制屏障对聚合后块状充填复合树脂硬度的影响。研究假设是，LCU 的延长使用不会降低其输出功率和树脂硬度，并且聚乙烯薄膜屏障的存在会加剧树脂硬度的降低。
根据是否存在聚乙烯薄膜（PE）和使用的层数，3M LED 固化灯（EliparTM DeepCure-S；3M ESPE，明尼苏达州圣保罗）分为三组：PE0、PE1 和 PE3。固化灯每天使用 30 次，每次曝光 20 秒，频率为 0、6 和 12 个月。对每组固化灯进行最大输出功率测试。使用定制的塑料模块将块状充填复合树脂（Filtek Bulk Fill Posterior Restorative；3M ESPE）堆叠至 4mm 厚。每组固化灯以直接接触的方式对模块进行 20 秒的固化。使用数字显微硬度计在树脂试件的顶部和底部表面测量维氏硬度。使用单向或双向方差分析对 LCU 的功率、块状充填复合树脂的维氏硬度和组间硬度降低百分比进行分析。使用 Tukey 检验（α=0.05）进行两两比较。
随着使用时间的延长，固化灯的功率和树脂的硬度都显著降低。在 PE0、PE1 和 PE3 组之间，功率和树脂硬度都有显著差异。在使用时间为 6 个月或更短时间内，只有多层 PE 薄膜会导致从上到下固化树脂硬度降低的百分比显著增加。然而，在 12 个月时，单层和多层 PE 薄膜都会导致从上到下固化树脂硬度降低的百分比显著增加。
光固化器的输出功率随着使用时间的延长而降低，从而无法满足块状充填复合树脂的固化要求。建议使用单层 PE 作为感染控制屏障。
