Laser Effects On Dental Hard Tissues

The use of lasers in dentistry has been considered for over 20 years. Higher-energy density lasers were shown to fuse enamel but were potentially unsafe. Subsequently, low-energy density laser radiation was shown to affect artificial caries lesion formation. Recent studies have shown that carbon dioxide lasers can successfully be used at low-energy densities to fuse enamel, dentin, and apatite. Our studies have shown that specific wavelengths are highly efficient. These wavelengths are directly related to the infrared absorption regions of apatite. We have conducted studies with enamel and dentin, using pulsed CO2 laser radiation in the 9.32-μm to 10.49-μm region with energy densities in the 10 to 50 J.cm -2 range. This laser treatment caused surface fusion and inhibition of subsequent lesion progression and markedly improved the bonding strength of a composite resin to dentin. Similar studies have shown no pulpal damage or permanent deleterious effect on soft tissues. This improved understanding of the scientific rationale for the interaction of CO2 lasers with teeth can lead to several clinical applications. This will depend, however, on the development of a technology to direct a specific frequency laser beam precisely to a desired site.