Physics Department, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran,
Lasers Med Sci. 2015 Feb;30(2):645-51. doi: 10.1007/s10103-013-1390-6. Epub 2013 Jul 19.
The authors report the simulation of temperature distribution and thermally induced stresses of human tooth under CO2 pulsed laser beam. A detailed tooth structure comprising enamel, dentin, and pulp with realistic shapes and thicknesses were considered, and a numerical method of finite element was adopted to solve time-dependent bio-heat and stress equations. The realistic boundary conditions of constant temperature for those parts embedded in the gingiva and heat flux condition for those parts out of the gingiva were applied. The results which were achieved as a function of energy density (J/cm(2)) showed when laser beam is irradiated downward (from the top of the tooth), the temperature and thermal stresses decrease quickly as a function of depth that is a result of strong absorption of CO2 beams by enamel. This effect is so influential that one can use CO2 beams to remove micrometer layers while underlying tissues, especially the pulp, are safe from thermal effects.
作者报告了 CO2 脉冲激光束下人牙温度分布和热诱导应力的模拟。考虑了详细的牙齿结构，包括具有真实形状和厚度的釉质、牙本质和牙髓，并采用有限元数值方法求解时变生物热和应力方程。将恒定温度的实际边界条件应用于嵌入牙龈的部分，以及牙龈外部分的热通量条件。作为能量密度（J/cm(2)）函数获得的结果表明，当激光束从牙齿顶部向下照射时，由于牙釉质对 CO2 光束的强烈吸收，温度和热应力随深度的增加而迅速降低。这种影响非常大，以至于人们可以使用 CO2 光束去除微米级的层，同时使底层组织，特别是牙髓，免受热效应的影响。
