Objective

This study aimed to investigate the effects of (i) a high-irradiance (3s) light-curing protocol versus (ii) two standard-irradiance (10s) protocols on 2D temperature maps during intra-dental photo-irradiation within a molar cavity restored with either Ultra-Rapid Photo-Polymerized Bulk Fill (URPBF) composites or a pre-heated thermo-viscous bulk-fill composite, compared to a standard bulk-fill resin-based-composite (RBC). The specific objectives included visual assessment of the temperature maps and quantitative assessment of several temperature/time plots at four different locations.

Methods

A caries-free lower first molar cavity served as a natural tooth mold. Resin composites were placed without intermediary adhesive. Two URPBF composites (PFill; PFlow) and one pre-heated thermo-viscous bulk-fill composite (Viscalor: VC) were compared to a contemporary bulk-fill composite (One Bulk Fill: OBF). Two LED-LCU devices were used: Bluephase PowerCure (PC) and Elipar S10 (S10), with three light-irradiation protocols (PC-3s, PC-10s and S10-10s). 2D temperature maps over the entire coronal area were recorded for 120 s during and after irradiation using a thermal imaging camera. Changes at four different levels were selected from the data sets: (0, 2 and 4 mm from the cavity top and at 1 mm below the dentin cavity floor). The maximum temperature attained (T_max), the mean temperature rise (ΔT), the time (s) to reach maximum temperature and the integrated areas (°C s) under the temperature/time (T/t) plots were identified. Data were analysed via three-way ANOVA, One-way ANOVA, independent t-tests and Tukey post-hoc tests (p < 0.05).

Results

All RBCs showed qualitatively similar temperature-time profiles. PFlow reached T_max in the shortest time. PC-3s (3000 mW/cm²) generated comparable ΔT to S10-10s, except with PFill, where ΔT was greater. Despite the same irradiance (1200 mW/cm²), Elipar S10 led to higher T_max and ΔT compared to PC-10s. The highest T_max and ΔT were observed at the 2 mm level, and the lowest were at 1 mm depth into the underlying dentin.

Significance

Coronal 2D temperature maps showed rises largely confined within the bulk-fill RBC materials, with maxima at 2 mm rather than 4 mm depth indicating some extent of thermal insulation for the underlying dentin and pulp. RBCs polymerized via different irradiation protocols showed similar temperature changes. With the PC-3s protocol – also with pre-heated VC – minimal temperature rises at 1 mm within dentin suggest their clinical safety when sufficient remaining dentin thickness is present.

中文翻译：

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填充树脂复合材料日冕产生的时空温度场：热成像研究

客观的

本研究旨在研究 (i) 高辐照度 (3s) 光固化方案与(ii) 两种标准辐照度 (10s) 方案在修复磨牙腔内的牙内光辐照期间对二维温度图的影响与标准的散装填充树脂基复合材料(RBC)相比，使用超快速光聚合散装填充(URPBF) 复合材料或预热的热粘性散装填充复合材料。具体目标包括温度图的视觉评估和四个不同位置的几个温度/时间图的定量评估。

方法

无龋下第一磨牙腔用作天然牙模。树脂复合材料在没有中间粘合剂的情况下放置。将两种 URPBF 复合材料（PFill；PFlow）和一种预热的热粘性散装填充复合材料（Viscalor：VC）与现代散装填充复合材料（一种散装填充：OBF）进行了比较。使用了两种 LED-LCU 设备：Bluephase PowerCure (PC) 和 Elipar S10 (S10)，具有三种光照射协议（PC-3s、PC-10s 和 S10-10s）。使用热成像相机在辐照期间和辐照后记录整个日冕区域的二维温度图，持续 120 秒。从数据集中选择了四个不同水平的变化：（距腔顶部 0、2 和 4 毫米以及距牙本质腔底部 1 毫米处）。达到的最高温度 (T _max)、平均温升 (ΔT)、达到最高温度的时间 (s) 和温度/时间 (T/t) 图下的积分面积 (°C s)。通过三向方差分析、单向方差分析、独立 t 检验和 Tukey事后检验（p < 0.05）分析数据。

结果

所有 RBC 都显示出性质相似的温度 - 时间曲线。PFlow达到了T_最大值在最短的时间。PC-3s (3000 mW/cm ² ) 产生的 ΔT 与 S10-10s 相当，但 PFill 除外，其中 ΔT 更大。尽管具有相同的辐照度 (1200 mW/cm ² )，但与 PC-10s 相比，Elipar S10 导致更高的 T _max和 ΔT。在 2 mm 水平观察到最高的 T _max和 ΔT，最低的是在下层牙本质的 1 mm 深度处。

意义

冠状 2D 温度图显示上升主要局限于散装 RBC 材料，最大值在 2 毫米而不是 4 毫米深度，表明下面的牙本质和牙髓具有一定程度的隔热性。通过不同辐照方案聚合的红细胞显示出类似的温度变化。使用 PC-3s 协议 - 也使用预热的 VC - 牙本质内 1 毫米的最小温度上升表明当存在足够的剩余牙本质厚度时，它们的临床安全性。