Evaluation of optical and mechanical properties of newly developed monolithic CAD/CAM materials after aging

With the widespread use of CAD/CAM systems in dentistry, many restorative materials have been produced. In our study, we aimed to evaluate the change in optical and mechanical properties of newly developed translucent monolithic zirconia (TMZ) (Cercon HT Dentsply, Sirona, USA), zirconia-reinforced lithium silicate (ZLS) materials (Celtra Duo, Dentsply, Germany) and lithium disilicate (LS2) material (IPS e.max CAD, Ivoclar Vivadent, Liechtenstein) with aging. 60 discs of 12mm diameter and 1,2 mm thickness were produced from high translucent materials. Samples to be measured for biaxial flexural strength (BFS) were grouped as control (n=20), 3-hours aging (n=20) and 6-hours aging (n=20). The aging process was applied in an autoclave under 134ºC, 0.2MPa pressure. The BFS of the control groups and aged samples were measured with the piston on three balls test. For optical evaluation, L, a, b values of the samples (n=10) were measured by spectrophotometry before aging, after 3 hours and 6 hours aging. ΔE00 values and translucency parameters (TP) were calculated. The data were evaluated statistically. In our study, BFS values were found as TMZ> LS2> ZLS in control, 3 hours and 6 hours aging groups (p<0.05). While aging increased the BFS of TMZ samples, it decreased the BFS of ZLS samples (p<0.05). BFS of the LS2 material was not significantly affected by the aging (p>0.05). All the materials have undergone color change as a result of aging, but this change was within acceptable limits (ΔE00 <1.8). The ΔE00 value of the ZLS was above the perceptibility threshold (ΔE00 >0.8). There was a decrease in the translucency of all materials used in the study, but this decrease was not statistically significant. Cercon HT, Celtra Duo and IPS emax CAD monolytic ceramic materials were found to be mechanically and optically endurant after a clinical use of about 15 years in this in vitro study. Key Words: CAD/CAM, zirconia, translucency, mechanic, optic