Purpose: The aim of this study was to analyze the interaction between the high-power diode laser and the dental root surface. Materials and Methods: Twenty-one single-rooted teeth were divided into 3 experimental groups. Group 1: Root surfaces were treated with scaling and root planing followed by high-power diode laser irradiation in the gated-pulsed mode (wavelength 808 nm, 400 μm optical fiber used parallel to the root surface, 1.5 W for 30 s, 10 Hz, pulse width of 50 μs). Group 2: Root surfaces were treated as in group 1, but irradiated in the continuous- wave mode. Group 3: Control – scaling and root planing using a Gracey curette. The temperature variation, root surface morphology, and proliferation of fibroblasts cultured on the root surfaces were analyzed. Results: There was an increase in temperature within the biological safety limits; it was significantly higher for group 2. Irradiation modified the smear layer, which exhibited rough areas intermingled with smooth areas. Open dentinal tubules were not observed. The fibroblasts proliferated throughout the experimental time (0 to 3 days). The growth curves of all groups were similar. Conclusion: Under the conditions of this study, we concluded that the use of high-power diode laser for root-surface conditioning is thermally safe and causes similar superficial morphological changes independent of the irradiation mode used. Additionally, these lased root surfaces are biocompatible, because cell adhesion and growth were not impaired.
Keywords: cell culture, diode laser, root surface