Thermal propagation of 810nm diode laser in porcine dermal tissues

Objectives: To assess heat propagation during use of a diode laser into layers of porcine dermal tissues.

Methods: Two freshly slaughtered pigs-feet were used. One-millimeter-thick layers of porcine skins were obtained with a precision meat slicer from one foot and kept in water at 36.5°C (±0.2°). The second foot was kept immersed in tap-water bath at 36.5°C (±0.2°) to mimic body temperature. Skin layers previously prepared were placed at different time on the 2nd pig-foot to create a 1mm, 2mm and 3mm layers therefore simulating maximum tissue thickness (TT) of the oral mucosa. A thermocouple probe was inserted between the layers (1mm; 2mm and 3mm respectively) and the skin of the pig-foot. Probe location was identified by tissue palpation. An 810nm soft-tissue diode laser (Odyssey 2.4G, Ivoclar Vivadent, Inc) was used at two different watt-power, 0.8 and 1.0-watts in both continuous and pulsed mode respectively. Tip of the laser was initiated and an approximate 0.5mm radius circles were performed around the terminal portion of the thermocouple probe. At each skin layer, five temperatures readings were obtained at the first clinical visible sign of tissue ablation. Tip of the laser was used in a touch-and-go fashion.

Results: At 0.8-watts pulsed-mode heat propagation was 40.3°C (±0.3°), 39.8°C (±0.2°), 38°C (±0.3°) at each TT of 1mm, 2mm and 3mm; at 1.0-watts heat propagation was 40.1°C (±0.3°), 38.4°C (±0.3°), 37.6°C (±0.4°) at each TT. 0.8-watts continuous-mode showed heat propagation of 40.1°C (±0.3°), 39.2°C (±0.2°), 38.2°C (±0.5°) at each TT of 1mm, 2mm and 3mm; heat propagation at 1.0-watts continuous-mode was 41.5°C (±0.4°), 39.3°C (±0.7°), 38.2°C (±0.5°) at each TT.

Conclusion: Heat produced from soft-tissue laserization at 0.8 and 1.0-watts in pulsed and continuous-mode propagates into dermal tissues. Baseline physiological temperature increased up to a maximum of 5.0°C suggesting safety of these laser settings.