University of Sydney, Institute of Photonics and Optical Science, School of Physics, Sydney, New South Wales 2006, Australia.
J Biomed Opt. 2009 Sep-Oct;14(5):054046. doi: 10.1117/1.3253396.
Laser ultrasonic nondestructive evaluation (NDE) methods have been proposed to replace conventional in vivo dental clinical diagnosis tools that are either destructive or incapable of quantifying the elasticity of human dental enamel. In this work, a laser NDE system that can perform remote measurements on samples of small dimensions is presented. A focused laser line source is used to generate broadband surface acoustic wave impulses that are detected with a simplified optical fiber interferometer. The measured surface wave velocity dispersion spectrum is in turn used to characterize the elasticity of the specimen. The NDE system and the analysis technique are validated with measurements of different metal structures and then applied to evaluate human dental enamel. Artificial lesions are prepared on the samples to simulate different states of enamel elasticity. Measurement results for both sound and lesioned regions, as well as lesions of different severity, are clearly distinguishable from each other and fit well with physical expectations and theoretical value. This is the first time, to the best of our knowledge, that a laser-based surface wave velocity dispersion technique is successfully applied on human dental enamel, demonstrating the potential for noncontact, nondestructive in vivo detection of the development of carious lesions.
激光超声无损评估（NDE）方法已被提出，以替代传统的体内牙科临床诊断工具，这些工具要么具有破坏性，要么无法量化人类牙釉质的弹性。在这项工作中，提出了一种可以对小尺寸样品进行远程测量的激光 NDE 系统。采用聚焦激光线源产生宽带表面声波脉冲，并用简化的光纤干涉仪进行检测。所测量的表面波速度频散谱反过来用于表征样品的弹性。NDE 系统和分析技术已通过对不同金属结构的测量进行了验证，然后将其应用于评估人类牙釉质。在样品上制备人工损伤以模拟牙釉质弹性的不同状态。对于健康和受损区域以及不同严重程度的损伤，测量结果彼此之间可以清晰地区分，并且与物理预期和理论值吻合良好。据我们所知，这是首次成功地将基于激光的表面波速度频散技术应用于人类牙釉质，展示了非接触、无损的体内检测龋齿病变发展的潜力。
