Influence of Different Surface Finishing Protocols on the Wear Behavior of Lithium Disilicate Glass-Ceramics

To evaluate the effect of different finishing protocols on the wear behavior of lithium disilicate glass-ceramics (LD).

Specimens were produced from LD prefabricated CAD/CAM blocks and divided into three groups according to the surface treatment (n = 8): control, polishing, and glaze. Ceramic specimens were subjected to wear testing using a dual-axis chewing simulator. A 49-N load was applied in the axial direction combined with a lateral movement (1-mm path) using an LD spherical piston for a total of 106 cycles. Qualitative analysis of the wear surface was performed using an optical microscope. Quantitative analysis of surface roughness and volume loss was performed using a confocal microscope and a 3D-image editing software, respectively. Surface roughness and volume loss data were analyzed using Friedman's nonparametric statistical test for repeated measures and the Student-Newman-Keuls test (α = .050).

There were statistical differences for surface roughness and volume loss of LD specimens in the different experimental conditions (P < .001). The control and polishing groups showed similar surface roughness and volume loss values for all testing times. The glaze group had greater wear volume after 103, 104, and 105 cycles. After 106 cycles, surface roughness and volume loss were similar in all groups. For the piston, surface roughness was similar over time and among groups.

A distinct wear behavior was found for glazed glass-ceramic specimens compared to control and polished specimens. At the end of the simulation, the surface roughness and volume loss was similar for the groups.