Water-mdeiated Ablation of Hard Biotissue with Pulse Lases
|School||Fujian Normal University|
|Keywords||Laser Ablation Hard Biotissue Water-mediated Ablation Temperature Rise Ablation Characteristics|
Laser-induced hard biotissue ablation has broad applications in dentistry and bone surgery, the basic research and development of new medical technologies are the hot topics in the field of laser surgery and medicine. Systematic studies on hard bone biotissue morphology, ablation rate and efficiency, chemical structure components and temperature rise with typical wavelength of lasers under water environment were presented in the dissertation by combining theoretical analysis and experimental means.At first, the structure, fundamental components and optical properties of hard biotissue were summarized, the biological hard tissue ablation model and mechanism of laser-induced were reviewed, and water-mediated ablation mechanism was illustrated in detail.Secondly, the investigation on ablation of bone hard tissue by pulse CO2 laser with an assisted of water-film was carried out. The influence of the water film attached on tissue surface on ablation effects, such as the appearance of ablation incision, ablation rate and efficiency, thermal injury and morphological and micro-structural changes were evaluated by stereoscopic microscope, Optical Coherence Tomography (OCT), Scanning Electron Microscope (SEM) and histopathology, respectively.Thirdly, the experimental study of one-dimensional dynamic ablation of dentin in vitro by using Er:YAG laser with water spray were carried out, and compared with the samples treated diamond drills. The morphological and micro-structural changes were evaluated by Atomic Force Microscopy (AFM) and SEM. The Raman spectroscopy of dentin before and after treatment was acquired, and components were analysed.Finally, compared irradiational methods, the special and temporal distribution of temperature on enamel induced by pulse Er:YAG laser with different pulse duration a-nd numbers of pulse were evaluated.The temperature in the pulp chamber were recor-d by K-thermocouple when enamel in vitro was irradiated by pulse Er.YAG laser with or without water cooling.