Microhardness evaluations of CAD/CAM ceramics irradiated with CO2 or Nd:YAP laser

Ahmed El Gamal; Jean Paul Rocca; Carlo Fornaini; Etienne Medioni; Nathalie Brulat-Bouchard

doi:10.5978/islsm.17-OR-01

Microhardness evaluations of CAD/CAM ceramics irradiated with CO₂ or Nd:YAP laser

Laser Ther. 2017 Mar 31;26(1):13-18. doi: 10.5978/islsm.17-OR-01.

Authors

Ahmed El Gamal¹, Jean Paul Rocca¹, Carlo Fornaini^{1

2}, Etienne Medioni¹, Nathalie Brulat-Bouchard³

Affiliations

¹ Micoralis laboratory EA 7354, University Côte d'Azur, Nice, France.
² Group of Applied ElectroMagnetics, Information Engineering Department, University of Parma, Italy.
³ Mines ParisTech-Centre de Mise en Forme des Matériaux (CEMEF), CNRS-UMR 7635, Sophia Antipolis, France.

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.

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 kgf for lithium disilicate and 1 kgf for zirconia.

Results: Emax CAD irradiated with CO₂ at 5 W increased microhardness by 6.32 GPa whereas Emax ZirCAD irradiated with Nd:YAP decreased microhardness by 17.46 GPa.

Conclusion: CO₂ laser effectively increases the microhardness of lithium disilicate ceramics (Emax CAD).

Keywords: CAD/CAM ceramic; CO2 laser; Microhardness; Nd:YAP laser.