The potential use of the laser as a heat source in preventive dentistry is very promising. However, the tooth is a very complex organism which is easily damaged. This paper surveys several factors that are known regarding the interaction of lasers with human teeth. The status of two of the more promising preventive techniques currently under development is discussed: the enhancement of fluoride uptake and the application of durable pit and fissure sealants. Areas where additional work is required to bring the laser into the dental clinic are outlined.