Product Code: JLA_19_3_185

Authors:
Leily Macedo Firoozmand
Andressa Pereira da Silva
Carlos Rocha Gomes Torres
Department of Restorative Dentistry, Sa˜o Jose´ dos Campos School of Dentistry, Sa˜o Paulo State, Brazil

Background and objectives: To assess the microhardness of dentin subsurface after Er: yttrium-aluminum-garnet (YAG) and Nd:YAG laser irradiation. Study design/materials and methods: Twenty-four bovine incisors, without pulp, were used. The vestibular surface was worn out until the dentin was reached and divided in mesial and distal regions. The samples were divided into two groups: GI-distal, irradiated by Er:YAG laser, and GII-distal, irradiated by Nd:YAG laser. The mesial area was protected so as to not receive the laser irradiation. The measurements were made on Vickers digital microhardmeter. Results: For GI—there was no significant statistical difference, CI(−4.59 to 0.78), between the values of irradiated (55.61±4.38) and unirradiated (57.51±4.00) areas. For GII—the values were higher for the irradiated (62.21±6.48) compared to the unirradiated (57.82±5.42) area, CI(1.65 to 7.13). Conclusions: There was an increase of dentin microhardness when the Nd:YAG was used, but the Er:YAG did not cause significant alterations in dentin microhardness.