微机器人控制飞秒激光的临床自动化牙体预备基础研究

Tooth preparing is the most basic and commonly used method for all kinds of tooth diseases treatment. Currently tooth preparing is only completed by manual operation, but it is difficult to meet the standards of clinical practices requests, medical quality is difficult to control. In response to these shortcomings and problems, international's first dental clinical automation tooth preparing micro-robotic system (patented) supported has been invented and manufactured with money from the National Science & Technology Pillar Program during the 12th Five-Year Plan. However, there are still certain basic theoretical issues, such as the influence of plasma shield on efficiency, temperature, precision and relative solution, and so on. Based on the above study, research contents of this project are: ① the suitable plasma density real-time control is solved by investigating variable electrode magnetic field; ②appropriate temperature real-time control in confined space, cavitas pulpae is realized with specific spatial arrangement of fluid-cooled theory; ③ a real-time precise control of automatic tooth preparing process is realized by exploring real-time plasma spectra detection and analysis methods and determining the physical parameters of the femtosecond laser ablating the different tissues of the tooth; ④the safe handling of the entire tooth preparing process automation and in case of emergency is achieved using CCD and real-time monitoring system and built-in accelerometer sensors;⑤ the related experiments in vitro and animal teeth is completed. These studies can lay the foundation for clinical tooth preparing automation.

牙体预备，是口腔医生治疗各类牙齿疾病最常用和基本的方法。目前只能靠手工操作来完成，难以达到临床操作规范提出的标准要求，医疗质量难以控制。针对上述缺点和问题，在“十二五”国家科技计划项目支持下，已发明并制作了国际首台以超短脉冲激光为动力的口腔临床自动化牙体预备微型机器人系统（已获专利），但目前仍存在密闭空间内等离子体屏蔽对切削效率、温度、精度的影响及如何解决等临床应用前期的基础理论问题，本项目拟在上述基础上研究：①可变电极磁场解决密闭空间内等离子体屏蔽实时控制；②特定的空间流体气冷布局理论实现密闭空间、髓腔内适宜的温度实时控制；③探索实时等离子光谱检测分析方法，确定飞秒激光作用于不同牙体组织的物理参数，实现对自动化牙体预备过程实时精确控制；④采用CCD实时监测及系统内置加速传感器实现整个自动化牙体预备过程及应急情况下的安全处理；⑤进行相关的离体牙和动物实验，为临床牙体预备自动化奠定基础。

牙体预备，是口腔医生治疗牙齿硬组织疾病最基本的临床操作技能。目前仅凭手工操作来完成，难以达到教科书所要求的操作规范和标准，医疗质量难以控制。针对上述临床问题，已研制出口腔临床微机器人牙体预备系统，为加快该系统临床应用的步伐，本项目针对密闭空间内等离子体屏蔽对切削效率、温度、精度的影响及如何解决等临床应用前期的基础理论问题展开研究，主要内容包括①可变电极磁场解决密闭空间内等离子体屏蔽实时控制；②特定的空间流体气冷布局理论实现密闭空间、髓腔内适宜的温度实时控制；③探索实时等离子光谱检测分析方法，确定飞秒激光作用于不同牙体组织的物理参数，实现对自动化牙体预备过程实时精确控制；④采用CCD实时监测及系统内置加速传感器实现整个自动化牙体预备过程及应急情况下的安全处理；⑤进行相关的离体牙和动物实验。项目组通过四年的努力，目前已从精度、效率及安全性方面对系统进一步优化与完善，初步实现可变电极磁场实时控制等离子体屏蔽，提高了激光切削效率；选用超音速喷嘴转送冷空气方式，达到有效的降温效果，可使温度控制在38度之内；通过对激光的重要参数（如功率、重频、光斑直径等）进行排列组合，在不同牙体硬组织进行大样本实验，探索出二维切削牙本质和牙釉质时激光扫描层数与切削深度之间定量关系曲线呈现线性非直线上升趋势，通过线性拟合得出最大切削深度范围内脉冲层数与切削深度的定量关系函数式分别 为d=10.547n-7.5465；R2=0.9796；d=10.16n-6.04；R2=0.9778。三维切削正方形窝洞单次进给量越小，则差值越小，即以每切削5层步进45µm设定Z轴的进给速度，切削深度精度可控制在1.91µm和2.25µm；为保证系统的安全性，在系统中集成了微型CCD和加速传感器以保证应急情况下患者的人身安全；基于以上研究基础，项目组通过仿头模内离体牙自动化牙体预备实验验证了系统的精度及安全性。通过该项目的支持，较系统地研究自动化牙体预备精度控制及安全防护相关基础理论和关键技术，优化了系统的整体性能，并完成了将该系统相关专利授权于国外发达国家以完成后期产业化，为实现自动化牙体预备系统临床应用奠定了基础。