Incision properties and thermal effects of CO2 lasers in soft tissue

Thermal and histological events resulting from soft tissue incision using CO2 lasers at 9.3 μ or 10.6 μ, fitted with a hollow wave guide or an articulated arm delivery system respectively, were investigated. In 9 fresh pigs' mandibles, standardized incisions 3 cm in length were made in the oral mucosa. Incisions were performed in the cw mode at 1 W, 4 W, and 12 W. Thermal events were measured in adjacent soft tissues using thermocouples. Incisions were dissected out, fixed, embedded in paraffin wax, sectioned and stained with Serius Red. The Students' t-test for paired data was used to compare zones of necrosis, zones of collagen damage and thermal events. No significant temperature rise was measured during irradiation at any timepoints or power settings (p < 0.05). Results were very similar for the two lasers with significantly different results obtained only at the 12 W setting (p < 0.05). Vertical incision depths and horizontal incision widths did not differ significantly (p < 0.0001) at 12 W and 4 W. Horizontal and vertical zones of necrosis did not differ significantly (p < 0.0001) either between the two lasers at 12 W and 4 W. Thus the thermal and histological events occurring during soft tissue incision were similar using these two lasers, despite the difference in wavelength and delivery system