Thermal Effects of 445 nm Laser Irradiation on the Bovine Tongue Tissues Ex Vivo

The purpose of this study was to employ the use of thermographic techniques to compare temperature changes and thermal heat transfer patterns in soft tissues when using the 445nm-diode laser with initiated and non-initiated tips. Methods: Bovine tongue slices measuring 5 mm in thickness were placed in between two microscopy glass slides at a distance of 11 cm from a thermographic camera. Fifteen 2 cm long incisions were made along the surface of the soft tissue parallel to the glass slides and the camera capture field. Incisions were performed using a 445nm diode laser (continuous wave at 2 watts) with 320μm-thick glass initiated and non-initiated fiber tips for a total 30-second irradiation period. The maximum temperature changes in oC (ΔT) in the soft tissues, as well as the vertical and lateral heat transfer (in mm), were recorded at 10-second intervals for a duration of 30 seconds, using the thermographic images captured using the infrared camera and a special image analysis software. Descriptive statistical analysis occurred to evaluate the temperature changes over the critical temperature threshold. Results: The maximum ΔT in oC for the initiated lasers was 17.48 ± 9.05 and for non-initiated lasers was 10.72 ± 2.29. The heat transfer in the two groups for vertical/lateral was 7.50 ± 1.4/18.30 ± 4.01 for the initiated lasers and 7.10 ± 1.82/19.24 ± 3.86 for the non-initiated lasers. Conclusion: Initiated tips and non-initiated tips of 445nm laser present deep penetration depths and high temperatures in bovine homogenous soft tissues. The irradiation period and clinical indication must be strictly followed to avoid complications from overheating in soft tissues.