Study on assessment of surface Roughness and Translucency of Artificially aged Zirconia and Lithium Disilicate Veneers an In-Vitro Study

Statement of Problem: Multiple studies have been conducted to evaluate the effect of aging on the mechanical properties of computerized-aided design and computerized-aided manufacturing (CAD/CAM)-based zirconia; however, there is a scarcity of literature discussing the effect of aging on change in translucency and surface roughness for both Translucent zirconia and lithium disilicate. Aim of the study: To evaluate the surface roughness and translucency of zirconia and lithium disilicate veneers aged by artificial aging. Materials and Methods: Twenty laminate veneers from two different materials were fabricated on typhodont of upper left lateral incisors. 10 zirconia laminates (Dentsply Cercon HT) {Group 1} and 10 lithium disilicate (IPS Emax CAD for Cerec and Inlab) {Group 2} laminates were milled by CAD/CAM milling machine (Dentsply Sirona). The veneers were sintered at 1450 degree celsius with heating rate of 8 degree Celsius and holding time was about 2 hours. All specimens were subjected to an aging procedure low thermal degradation (LTD) using an autoclave (134_C, 2 bar pressure) for 5 hours. Translucency parameter and surface roughness were evaluated. Results: With high translucency zirconia after L-TD, there was no statistically significant change in mean Surface roughness after aging. Lithium disilicate had the highest surface roughness values. There was a significant difference (p = 0.001) after artificial ageing. With high translucency zirconia and Lithium disilicate both there was no statistically significant decrease in mean translucency parameter after aging. Conclusion: Lithium disilicate had the highest surface roughness values that is statistically significant increase in surface roughness (p = 0.001) after artificial ageing. The surface roughness values of translucent zirconia are under an acceptable limit of 0.2 µm. The differences recorded between translucency of translucent zirconia and LDS ceramics are not significant after L-TD.