Raucci-Neto Walter, Raquel Dos Santos Carla, Augusto de Lima Fabrício, Pécora Jesus Djalma, Bachmann Luciano, Palma-Dibb Regina Guenka
School of Dentistry, University of Ribeirão Preto-UNAERP, Avenida Constábile Romano, Ribeirão Preto, SP, CEP 14096-900, Brazil.
Lasers Med Sci. 2015 May;30(4):1231-6. doi: 10.1007/s10103-014-1579-3. Epub 2014 Apr 23.
The aim of this study was to evaluate thermal changes, dentin ablation removal capacity, and morphological aspects of sound and demineralized human dentin surface irradiated with different output energies of an erbium: yttrium-aluminium-garnet (Er:YAG) laser. Eighty sound human tooth specimens were assigned into two groups: demineralized dentin and sound dentin (control group). The dentin groups were subdivided into four subgroups (n = 10) according to the irradiation energy used (120, 160, 200, or 250 mJ) at a constant frequency level of 6 Hz, in focused mode, and under refrigeration. Quantitative analysis of the sound and carious dentin ablation was performed using light microscopy (LM) by measuring (mm) the remaining demineralized tissue with the Axion Vision™ software. Qualitative analysis was performed using the images obtained with a scanning electron microscope (SEM), and the temperature increase was recorded with an infrared digital thermometer. The Er:YAG laser promoted a gradual increase in temperature for all groups, and no difference was observed between the sound and demineralized dentin. The groups of 200 and 250 mJ showed the highest values, yet a variation in temperature did not exceed 5 °C. The energy output of 120 mJ selectively removed demineralized tissue when compared to 250 mJ, while also providing more regular surfaces in the cavity preparation. It was concluded that the temperature increase during sound and demineralized dentin removal had a strong positive correlation with the Er:YAG laser energy level output. However, the higher energies used did not present selectivity to the demineralized tissue, and the parameters used did not cause an increase in temperature over 5 °C.
钇铝石榴石（Er:YAG）激光照射正常和脱矿的人牙本质表面时的热变化、牙本质消融去除能力以及形态学方面。80颗正常人类牙齿标本被分为两组：脱矿牙本质组和正常牙本质组（对照组）。根据在6Hz恒定频率水平、聚焦模式和冷却条件下使用的照射能量（120、160、200或250mJ），将牙本质组再细分为四个亚组（n = 10）。使用光学显微镜（LM）通过Axion Vision™软件测量（mm）剩余的脱矿组织，对正常和龋坏牙本质的消融进行定量分析。使用扫描电子显微镜（SEM）获得的图像进行定性分析，并用红外数字温度计记录温度升高情况。Er:YAG激光使所有组的温度逐渐升高，正常牙本质和脱矿牙本质之间未观察到差异。200和250mJ组显示出最高值，但温度变化不超过5°C。与250mJ相比，120mJ的能量输出选择性地去除了脱矿组织，同时在窝洞制备中也提供了更规则的表面。得出的结论是，在去除正常和脱矿牙本质过程中的温度升高与Er:YAG激光能量水平输出呈强正相关。然而，使用的较高能量对脱矿组织没有选择性，并且所使用的参数不会导致温度升高超过5°C。
