Thermographic Changes During Soft Tissue Incisions with Diode Infrared Lasers

This study aimed to demonstrate temperature changes and heat transfer patterns in soft tissues when using infrared (IR) diode lasers, utilizing thermographic techniques. Bovine tongue slices (5 mm thick) were placed between two glass slides at 11 cm from a thermographic camera. Twenty-two centimeter-long incisions were made along the soft tissue parallel to the camera capture field. Incisions were performed using the 970 and 980 nm lasers (continuous wave, 2-watt, 320 μm-thick glass initiated, and noninitiated fiber tips, 30-sec irradiation). The maximum temperature changes in ^oC (ΔT) and the vertical and lateral heat transfer (in mm) were recorded for 30 sec, using the thermographic images captured using the IR camera. The ΔT and the amount of lateral and vertical heat distribution were measured in 10-sec intervals for a 30-sec irradiation period. A repeated analysis of variance (ANOVA) (p < 0.05) statistical test was used to analyze the statistical differences between the average ΔT and heat transfer patterns between the initiated and noninitiated lasers. The maximum ΔT for the 970 nm diode laser with initiated tips at the 30-sec mark was 17.81 ± 11.48, while the maximum ΔT for the 980 nm diode laser with initiated tips was 13.24 ± 6.90 (p = 0.041). Statistically significant differences between the vertical and horizontal heat transfer patterns were noted between the initiated and noninitiated diode lasers. The 980 nm diode laser with initiated tips proved to have statistically significant greater vertical and lateral heat transfer when compared to the 970 nm diode laser. The 970 nm diode laser with noninitiated tips proved to have a statistically significant higher heat distribution when compared to the 980 nm laser with noninitiated tips. Different near-IR lasers present differences in lateral heat and tissue penetration, using initiated or noninitiated fibers, and due to these differences, power settings and irradiation period must be considered to avoid risks due to overheating.