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Abstract
This study was designed to set up proper laser parameters including laser type, power intensity and time of application for glazing of a particular glass-ceramic. The effect of laser glazing of the glass-ceramics on structural, morphological and the topographical characteristics; roughness and hardness, and consequently optical properties was investigated, evaluated and compared with the recommended glazing technique. Two commercially available lithium disilicate ceramics; IPS E-max press and IPS E-max CAD, were used and fabricated by two different techniques: conventional lost wax (Injectable heat {u2013} pressed) and machinable Computer Aided Design / Computer Aided Manufacturing (CAD/CAM) techniques.A total number of 100 samples;50 for each material, (5mm diameter and 2 mm thickness) were fabricated. After discs fabrication, two glazing techniques were adopted to the ceramic samples namely; conventional glazing and laser glazing. Conventional glazing was conducted according to the manufacturer’s instructions. Meanwhile, for laser glazing, CO₂ laser device was used where specimens were subjected to 20 watt Power using, 200 J Energy and 10 seconds application time repeated three times with a resting period of 10 seconds between each application. Ceramic samples were then evaluated and characterized using X-Ray Diffraction analysis and scanning electron microscope. Surface roughness evaluation before and after glazing was conducted using white light Profilometry. In addition, microhardness was measured using Vickers{u2019}s microhardness tester. Finally, color change measurement was done using Spectrophotometer