Heat diffusion and debris screening in Er:YAG laser ablation of hard biological tissues
Heat diffusion and debris screening in Er:YAG laser ablation of hard biological tissues
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DOI：
10.1007/s003400050423
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发表时间：
1998-04-01
影响因子：
2.1
通讯作者：
Funduk, N
中科院分区：
文献类型：
--
作者：
Majaron, B;Sustercic, D;Funduk, N
本文研究了热扩散对中红外激光消融硬组织的影响，采用Er：YAG激光脉冲，脉冲长度为100 μ s ~ 1 ms，能量变化，不经水喷雾冷却，对牙本质和牙釉质切片进行热扩散。在短脉冲持续时间下，在两种受试组织中消融的开始都是突然的。并且由于碎片对坑底部的屏蔽，坑深度随着所施加的激光能量密度准几何地增加。在这种效果的定量分析中，观察到的弹坑直径与所施加的激光能量密度的变化必须考虑在内。改进的分析模型表明，脉冲宽度对碎片屏蔽效果的影响。在较长的脉冲持续时间，烧蚀效率显着降低在注量接近烧蚀阈值，这导致在烧蚀过程中的双阈值字符。这种效应归因于在激光脉冲期间热从相互作用区域的扩散。一个简单的分析模型的热扩散和消融前沿动态预测的注量间隔，这种效果可以预期，取决于脉冲持续时间和治疗组织的属性。
The influence of heat diffusion on mid-infrared laser ablation of hard organic tissues was investigated by applying Er:YAG laser pulses with pulse lengths from 100 mu s to 1 ms and of varying energy to dentin and enamel slices without water-spray cooling. At short pulse durations, the onset of ablation is abrupt in both tissues under test. and the crater depths increase quasi-logarithmically with applied laser fluence as a result of debris screening of the crater bottom. In a quantitative analysis of this effect, the observed variation of crater diameters with the applied laser fluence must be taken into account. The influence of the pulse duration on the debris screening effect is demonstrated by an improved analytical model of the process. At longer pulse durations, the ablation efficiency is significantly reduced at fluences close to the ablation threshold, which results in a double-threshold character of the ablation process. This effect is attributed to diffusion of heat from the interaction region during the laser pulse. A simple analytical model of heat diffusion and ablation front dynamics is presented that predicts the fluence interval where this effect can be expected, depending on pulse duration and properties of the treated tissue.