Which laser has the least absorption in healthy dental hard tissues?

The Nd:YAG laser at 1064 nm has the least absorption in healthy dental hard tissues compared to the other options. This specific wavelength is less absorbed by enamel and dentin, which allows it to penetrate more deeply without causing significant thermal damage to the surrounding tissues.

In dental applications, the degree of absorption by different wavelengths significantly affects how lasers interact with tissue. Wavelengths like 2780 nm and 2940 nm, used by Er,Cr:YSGG and Er:YAG lasers respectively, are more readily absorbed by water and hydroxyapatite, leading to more effective ablation but also a higher risk of damaging healthy hard tissues.

Similarly, the CO2 laser's wavelength at 9300 nm is highly absorbed in water and organic materials, making it more suitable for soft tissues rather than hard dental tissues. The higher absorption at these wavelengths translates to less penetration and could result in increased risks of damage to the healthy structure of teeth or other dental tissues.

Thus, the Nd:YAG laser stands out when considering a treatment option that minimizes absorption in healthy dental hard tissues, making it a safer choice for certain dental procedures.