研究了Er:YAG激光消融离体牙本质过程中激光脉宽对消融阈值、消融深度以及消融后牙硬组织微结构的影响。使用50 μs到1 ms脉宽的Er:YAG激光对人牙本质在无喷水冷却下消融实验，通过体式光学显微镜观察样品消融切口进而测量消融坑洞深度，利用扫描电镜(SEM)观察消融后牙本质的形态。实验结果表明，随着激光脉宽的增加，Er:YAG激光对人牙本质的消融阈值、消融深度呈现逐渐增大的趋势，同时还观察到高能量密度消融实验中牙小管封闭以及牙本质熔融现象。该实验结果对了解Er:YAG激光消融牙硬组织的微观过程及牙科治疗应用具有参考价值。

The influence of pulse length on Er:YAG laser ablation of hard dental tissue during ablation,especially in the aspect of the ablation threshold and ablation rate and the microstructure were studied. Er:YAG laser were used with pulse lengths from 50 μs to 1 ms and different energies to ablate dentine samples with no spray cooling. Ablation depth of the hole were measured by observing the ablation incision under optical microscope and apply scanning electron microscope to observe morphology changes of dentin after irradiation. Results show that with the increase of pulse length,Er:YAG laser ablation threshold of dentin and the ablation depth of the hole showed a trend of increasing gradually. The results of the experiment show that the increase of pulselength and energy density can make the occlusion of tooth tubular and melt dentine gradually. People should choose appropriate pulselength and energy density of Er:YAG laser in practical treatment, which can reduce the damage.