Investigation Of Bovine Shank Bone In Vitro Ablation By Pulsed CO₂Laser With Water Environment

Laser-induced hard biotissue ablation has broad applications in dentistry and bone surgery. How to improve the efficiency of laser ablation and reduce the thermal damage of the organization are the hot topics in the field of laser ablation. Base on development status and clinical needs of laser ablation technology at home and abroad, the influence of scanning technology and dynamic focusing conditions on bovine shank bone in vitro ablation effects and properties of energy transmission with pulsed CO2laser under water environment are presented in this paper.At first, the structure, fundamental components and optical properties of bone hard tissue were summarized, the dynamic ablation model and mechanism of bone hard tissue were reviewed, the principle of laser scanning technology were illustrated in detail.Secondly, Novel device based on the principle of connected vessels (patent number:21120170854.6) was designed to control water layer thickness in the paper. The exploratory experiments of energy transmission properties with pulsed CO2laser at different water layer thickness and temperature were also provided.Thirdly, the investigation on the influence of focusing conditions on bovine shank bone in vitro ablation under water environment was carried out with pulsed CO2laser. The focusing conditions includes:fixfocus, estimating focusing and manual focusing. The appearance of ablation incision, ablation rate and efficiency, thermal injury, morphological and micro-structural changes were respectively evaluated by stereoscopic microscope, optical coherence tomography (OCT), scanning electron microscope (SEM) and histopathology.Finally, the dynamic scanning system was built base on the principle of laser scanning technology and the in vitro experiment of the dynamic ablation of fresh bovine shank bone with pulsed CO2laser under water environment was executed. The feasibility of dynamic ablation system and the influence of scanning technology on ablation effects were assessed in term of the scan path, scan speed and corner of delay.