Laser-dye ablation technique for removal of carious dentin and enamel

A GaAlAs semiconductor diode laser operating at a wavelength of 796 nm has been used in conjunction with Indocyanine Green (ICG) dye to ablate carious dentin and enamel from extracted human teeth. The laser-dye ablation technique offers selective ablation as it is controlled by the placement of the ICG dye. In contrast with other laser techniques, the risk of collateral thermal damage is substantially reduced. The diode laser is-suitable for ordinary fiber delivery and is cheaper and more compact than the higher power CO2, Er:YAG, Nd:YAG and Argon lasers currently being used by researchers. This paper reports the ablation of dental caries in fifty extracted teeth with various laser diode powers and dye concentrations. The mass of material ablated, temperature rise in the pulp and surface temperature were measured. The ablation was found to be efficient with negligible thermal damage to surrounding tissue. At the same time average:surface temperatures reached during ablation may be sufficient to sterilize the treated surface. Hardness measurements and scanning electron microscopy of the laser treated cavity surfaces show the new surfaces to be suitable for placement of a dental filling. The procedure offers considerable potential for clinical caries desiccation or removal, and dentin, enamel and pulp sterilization, whilst leaving healthy tissue intact.