Volume: 2014 | Number: 1
ISSN (print): 1855-9913 | ISSN (web): 1855-9921
CASE REPORT: The Use of 2940 nm Er:YAG Laser in Cavity Preparation
The pulsed Er:YAG laser (2940 nm) has been recognized as the first choice for ablation of human hard tissues with minimal side effects. This is due to the properties of the Er:YAG laser wavelength, which provide the strongest absorption in water. The water content in enamel is lower than in dentin, which is why we use higher energy and frequency settings to remove carious enamel. Laser energy is absorbed by water molecules, rapidly heating a small volume. The vaporization of the water creates high subsurface pressure and leads to an explosive removal of the surrounding mineral. It is easier to work conservatively with the laser than with the conventional burr. The water content in carious tissue is higher than healthy tissue, which means that for the same settings, the laser ablation rate will be higher in carious tissue than in healthy tissue. This is also clearly audible during laser ablation, the individual laser pulses in carious tissue are more muted, and as you pass over healthy tissue the pulses make a sharper, more crisp or high-pitched sound. As we move in to the dentin we lower our energy and frequency settings since ablation is faster in dentin because of its higher water content. Even lower energy and frequency parameters are required for the final modification to create a retentive surface for the filling material. The surface should be exposed to a few shots while the laser beam is continuously moved across the treatment area. Laser surface modification results in a good adhesion of the filling material, eliminating the need for acid etching. After the modification, dry the surface with air and then apply the adhesive and composite material.
Article: J. LA&HA, Vol. 2014, No.1; pp.39-41.