Research & Development Institute, Vale do Paraíba University, Av. Shishima Hifumi, 2911, São José dos Campos, 12244-000, SP, Brazil.
Lasers Med Sci. 2011 Mar;26(2):143-7. doi: 10.1007/s10103-009-0752-6. Epub 2010 Feb 11.
In vitro studies have provided conflicting evidence of temperature changes in the tooth pulp chamber after low-level laser irradiation of the tooth surface. The present study was an in vitro evaluation of temperature increases in the human tooth pulp chamber after diode laser irradiation (GaAlAs, λ = 808 nm) using different power densities. Twelve human teeth (three incisors, three canines, three premolars and three molars) were sectioned in the cervical third of the root and enlarged for the introduction of a thermocouple into the pulp chamber. The teeth were irradiated with 417 mW, 207 mW and 78 mW power outputs for 30 s on the vestibular surface approximately 2 mm from the cervical line of the crown. The highest average increase in temperature (5.6°C) was observed in incisors irradiated with 417 mW. None of the teeth (incisors, canines, premolars or molars) irradiated with 207 mW showed temperature increases higher than 5.5°C that could potentially be harmful to pulp tissue. Teeth irradiated with 78 mW showed lower temperature increases. The study showed that diode laser irradiation with a wavelength of 808 nm at 417 mW power output increased the pulp chamber temperature of certain groups of teeth, especially incisors and premolars, to critical threshold values for the dental pulp (5.5°C). Thus, this study serves as a warning to clinicians that "more" is not necessarily "better".
体外研究对牙齿表面低水平激光照射后牙髓腔温度变化的结果提供了相互矛盾的证据。本研究通过使用不同的功率密度对人牙髓腔在二极管激光照射（GaAlAs，λ=808nm）后温度升高进行了体外评估。十二颗人类牙齿（三颗切牙，三颗尖牙，三颗前磨牙和三颗磨牙）在根的颈三分之一处被切开，并扩大以将热电偶引入牙髓腔。牙齿在冠颈线约 2mm 处的颊面用 417mW、207mW 和 78mW 的功率输出照射 30s。用 417mW 照射的切牙观察到平均最高温升（5.6°C）。用 207mW 照射的任何牙齿（切牙、尖牙、前磨牙或磨牙）均未出现可能对牙髓组织有害的高于 5.5°C 的温升。用 78mW 照射的牙齿显示出较低的温升。该研究表明，波长为 808nm、功率输出为 417mW 的二极管激光照射会增加某些组别的牙齿（尤其是切牙和前磨牙）的牙髓腔温度，达到牙髓的临界阈值（5.5°C）。因此，本研究提醒临床医生，“更多”并不一定“更好”。
