2790nm Er, Cr: YSGG laser is called erbium laser. Solid biomass’s water molecules, organic matter, and inorganic hydroxyapatite can strongly absorb it. It can use less energy to get a greater effect. This advantage is beyond the reach of other wavelengths of laser, so it not only can cut soft tissue accurately but also can cut enamel dentin efficiently without causing thermal damage to the dental pulp. The working principle of 2790nm Er, Cr: YSGG laser: transferring the energy to the coaxial water-air mixture by using the fluid dynamics and powerful absorption of laser energy by atomized water particles to produce the expansion and acceleration. High-energy and high-kinetic energy water beams are formed by high-velocity arrangement and then cutting soft tissue fast.