A New Laser-Processing Strategy for Improving Enamel Erosion Resistance
A New Laser-Processing Strategy for Improving Enamel Erosion Resistance
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DOI：
10.1177/0022034517718532
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发表时间：
2017-09-01
影响因子：
7.6
通讯作者：
Poprawe, R.
中科院分区：
文献类型：
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作者：
Esteves-Oliveira, M.;Wollgarten, S.;Poprawe, R.
在本研究中，一种新的自动激光加工策略，允许标准化照射的天然牙区进行了研究。目的是找到一种激光参数的组合，可以在釉质表面引起超过600摄氏度的温度升高，同时不损伤釉质，避免纸浆中超过5.5摄氏度的温度变化，并提高釉质的抗侵蚀性。将77个牛牙釉质样本随机分为6个激光组和1个阴性对照组（C/未处理/n = 11）。扫描策略（7 × 3 mm）用于CO2激光处理（λ = 10.6 μ m，0.1-18 J/cm（2）），具有不同的脉冲持续时间，即20 μ s（G20）、30 μ s（G30）、55 μ s（G55）和490 μ s（G490），以及2个修改的脉冲距离（G33 d，G40 d）。在表面（热成像仪/50 Hz）、底面（热电偶）和牙髓室使用热浴和人磨牙（n = 10）进行温度变化的测量。此外，还进行了组织学和X射线衍射（XRD/n = 10）。使用超过6天的侵蚀循环测试侵蚀，包括每天6次浸入柠檬酸（2 min/0.05 M/pH = 2.3）。使用轮廓仪测量表面损失，并进行统计分析和双向重复测量方差分析（α = 0.05）。只有G20达到了地表温度要求（619 +/- 21.8摄氏度），在底部（5.3 +/- 1.4摄氏度），并在纸浆（2.0 +/- 1.0摄氏度），不引起矿物相变化，显著减少釉质表面损失（-13.2 +/- 4.0 μ m）与C（-37.0 +/- 10.1 μ m，P < 0.05）相比。激光扫描策略（20 μ s/2 kHz/1.25 J/cm（2），3.4 mm/s）已被确立，符合生物安全性标准，并显着增加体外牙釉质抗侵蚀性（64%）。
In the present study, a new automatic laser-processing strategy allowing standardized irradiation of natural tooth areas was investigated. The objective was to find a combination of laser parameters that could cause over a 600 degrees C temperature increase at the enamel surface while not damaging enamel, avoiding temperature change above 5.5 degrees C in the pulp and increasing enamel erosion resistance. Seventy-seven bovine enamel samples were randomly divided into 6 laser groups and 1 negative control (C/no treatment/n = 11). A scanning strategy (7 x 3 mm) was used for the CO2 laser treatment (lambda = 10.6 mu m, 0.1-18 J/cm(2)) with different pulse durations-namely, 20 mu s (G20), 30 mu s (G30), 55 mu s (G55), and 490 mu s (G490), as well as 2 modified pulse distances (G33d, G40d). Measurements of temperature change were performed at the surface (thermal camera/50 Hz), at the underside (thermocouples), and at the pulp chamber using a thermobath and human molars (n = 10). In addition, histology and X-ray diffraction (XRD/n = 10) were performed. Erosion was tested using an erosive cycling over 6 d, including immersion in citric acid (2 min/0.05 M/pH = 2.3) 6 times daily. Surface loss was measured using a profilometer and statistical analysis with a 2-way repeated-measures analysis of variance (alpha = 0.05). Only G20 fulfilled the temperature requirements at the surface (619 +/- 21.8 degrees C), at the underside (5.3 +/- 1.4 degrees C), and at the pulp (2.0 +/- 1.0 degrees C), and it caused no mineral phase change and significant reduction of enamel surface loss (-13.2 +/- 4.0 mu m) compared to C (-37.0 +/- 10.1 mu m, P < 0.05). A laser-scanning strategy (20 mu s/2 kHz/1.25 J/cm(2), 3.4 mm/s) has been established that fulfilled the criteria for biological safety and significantly increased enamel erosion resistance (64%) in vitro.