激光脉宽和脉冲数对牙齿温升过程的影响

Influence of Pulse Width and Pulse Number on Temperature Distribution of Tooth

目的:激光辐照牙齿温升过程的研究可为临床治疗提供理论依据。方法:采用有限差分法,求解热传导方程,模拟了Nd:YAG激光辐照牙齿的温升过程.研究了脉宽和脉冲数对牙齿温度分布随时间演化过程。结果:研究结果表明,在确定的脉宽和脉冲数情况下,在激光辐照牙齿表面时,牙齿表面温度迅速升高并达到最大值;辐照结束后,牙齿表面温度缓慢降低。牙髓腔壁温度随深度增大而降低。将激光能量平均分配给多个脉冲作用时,牙齿表面温度降低,而牙髓的温度升高。随这脉宽的增大,牙齿表面温度峰值和牙髓温度均升高。结论:结合牙髓温度阈值,得到治疗时最多脉冲数。

Objective： To give a good evidence for clinical treatment through studying tooth temperature rising process produced by laser radiation. Methods： Based on the finite difference, the temperature distribution of the tooth varying with the time was simulated by heat conduction equation. The influence of pulse width and pulse num- ber on the temperature of tooth was investigated. Resluts： The results show that surface temperature of tooth in- creases quickly and reaches a maximum value during laser radiation, decreases slowly after laser radiation. The tooth temperature decreases with the depth increasing. When the laser energy is assigned to muhiple pulses, the surface temperature of tooth decreases and the temperature of the dental pulp increased. The surface temperature of tooth and dental pulp temperature both increase with the pulse width increment. Conclusion： Based on the tempera ture threshold of the dental pulp, the maximum value of pulsed numbers is given.