Department of Operative and Preventive Dentistry, University of Bonn, Welschnonnenstrasse. 17, 53111, Bonn, Germany.
Lasers Med Sci. 2012 Mar;27(2):297-303. doi: 10.1007/s10103-010-0875-9. Epub 2011 Jan 13.
Heat generation during the removal of dental restorative materials may lead to a temperature increase and cause painful sensations or damage dental tissues. The aim of this study was to assess heat generation in dental restoration materials following laser ablation using an ultrashort pulse laser (USPL) system. A total of 225 specimens of phosphate cement (PC), ceramic (CE), and composite (C) were used, evaluating a thickness of 1 to 5 mm each. Ablation was performed with an Nd:YVO(4) laser at 1,064 nm, a pulse length of 8 ps, and a repetition rate of 500 kHz with a power of 6 W. Employing a scanner system, rectangular cavities of 1.5-mm edge length were generated. A temperature sensor was placed at the back of the specimens to record the temperature during the ablation process. All measurements were made employing a heat-conductive paste without any additional cooling or spray. Heat generation during laser ablation depended on the thickness of the restoration material (p < 0.05) with the highest values in the composite group (p < 0.05), showing an increase of up to 17 K. A time delay for temperature increase during the ablation process depending on the material thickness was observed in the PC and C group (p < 0.05) with highest values for cement (p < 0.05). Employing the USPL system for removal of restorative materials, heat generation has to be considered. Especially during laser ablation next to pulpal tissues, painful sensations might occur.
在去除牙科修复材料的过程中会产生热量，可能会导致温度升高，并引起疼痛感觉或损伤牙体组织。本研究旨在评估使用超短脉冲激光（USPL）系统激光烧蚀后牙科修复材料的产热情况。共使用了 225 个磷酸钙水泥（PC）、陶瓷（CE）和复合树脂（C）样本，每个样本的厚度为 1 到 5 毫米。使用 Nd：YVO4 激光在 1064nm 波长、8ps 脉冲长度和 500kHz 重复率下以 6W 的功率进行烧蚀，采用扫描系统生成 1.5mm 边长的矩形腔。在样本背面放置温度传感器以记录烧蚀过程中的温度。所有测量均在没有任何额外冷却或喷雾的情况下使用热传导膏进行。激光烧蚀过程中的产热量取决于修复材料的厚度（p<0.05），复合材料组的产热量最高（p<0.05），最高可达 17K。在 PC 和 C 组中观察到烧蚀过程中温度升高的时间延迟取决于材料厚度（p<0.05），水泥组的温度最高（p<0.05）。在去除修复材料时使用 USPL 系统，必须考虑产热问题。特别是在靠近牙髓组织的激光烧蚀过程中，可能会引起疼痛感觉。
