Universidade Paulista, Department of Endodontics, São Paulo, SP 04043-200, Brazil.
J Biomed Opt. 2012 Jan;17(1):015006. doi: 10.1117/1.JBO.17.1.015006.
Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 °C was considered acceptable as a safe threshold when applying the diode laser.
The results showed that only 3.5-W output power increased the outer surface temperature above the critical value.
The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls.
激光辐照引起的温度变化可促进周围牙体组织的损伤。本研究评估了在不同设置下，810nm 半导体激光对根管内照射时，最近拔出的下颌切牙的温度变化。50 个下颌切牙被扩大到 ISO 40 号锉的根尖尺寸。最后用 17%乙二胺四乙酸、0.2%十二烷基硫酸钠生物清洁剂和无菌水冲洗后，样本通过连续模式从根尖到冠部以 5 个不同的输出功率（1.5、2.0、2.5、3.0 和 3.5W）进行圆形运动进行照射。使用两个热电偶装置测量根尖和中部三分之一的两侧的温度变化。当应用半导体激光时，7°C 的温升被认为是安全的临界值。
结果表明，只有 3.5W 的输出功率会使外表面温度超过临界值。
为避免在根管内照射时薄牙本质壁过热，建议的输出功率可规定为等于或小于 3W。
