Dye-assisted diode laser ablation of carious enamel and dentine

Carious dentine and enamel from extracted human teeth were ablated using a semiconductor diode laser in conjunction with an applied dye, indocyanine green. This technique offers selective ablation with minimal risk of thermal damage to surrounding dental tissues because uptake of the dye and its irradiation by the laser together control the ablation. In this study, various laser powers and dye concentrations were used to ablate previously extracted human teeth with moderate caries. The mass of material ablated and the temperature rise in the pulp and at the surface were recorded, and the ablated surface was examined by microscopy. The ablation was efficient and the rise in the pulp temperature slight. Ablation efficiency and surface temperature were both found to increase with laser irradiance and with dye concentration. No surface cracks or fissures were seen in electron microscope examination and the hardness of the laser-treated surfaces was comparable to that of healthy tissue. The dye-assisted laser ablation technique offers considerable potential for clinical caries removal and dentine, enamel and pulp sterilization, whilst leaving healthy tissue intact. The diode laser can deliver its energy via simple optical fibre and is cheaper and much smaller than the conventional high power lasers used in other studies.