Microhardness evaluations of CAD/CAM ceramics irradiated with CO 2 or Nd:YAP laser.

Authors :: El Gamal A
Rocca JP
Fornaini C
Medioni E
Brulat-Bouchard N
Source :: Laser therapy [Laser Ther] 2017 Mar 31; Vol. 26 (1), pp. 13-18.
Publication Year :: 2017
Abstract: Background and Aims: The aim of this study was to measure the microhardness values of irradiated computer-aided design/computer-aided manufacturing (CAD/CAM) ceramics surfaces before and after thermal treatment.<br />Materials and Methods: Sixty CAD/CAM ceramic discs were prepared and grouped by material, i.e. lithium disilicate ceramic (Emax CAD) and zirconia ceramic (Emax ZirCAD). Laser irradiation at the material surface was performed with a carbon dioxide laser at 5 Watt (W) or 10 W power in continuous mode (CW mode), or with a neodymium:yttrium aluminum perovskite (Nd:YAP) laser at 10 W on graphite and non-graphite surfaces. Vickers hardness was tested at 0.3 kg f for lithium disilicate and 1 kg f for zirconia.<br />Results: Emax CAD irradiated with CO <subscript>2</subscript> at 5 W increased microhardness by 6.32 GPa whereas Emax ZirCAD irradiated with Nd:YAP decreased microhardness by 17.46 GPa.<br />Conclusion: CO <subscript>2</subscript> laser effectively increases the microhardness of lithium disilicate ceramics (Emax CAD).

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