In-vitro evaluation of optical behavior of esthetic restorations fabricated with CAD/CAM systems after different surface finishing procedures and aging process

With the production of nano-ceramic and hybrid materials, it is intended to combine the advantages of ceramics and composite materials. These materials that used for esthetic restorations can be prepared with different surface finishing procedures after produced with CAD/CAM systems. The purpose of this study was to evaluate optical properties of 5 different esthetic CAD/CAM materials with different chemical composition after different finishing procedures and UV aging process. In this study, Lava Ultimate (LU), Cerasmart (CE), Vita Enamic (EN), Vita Suprinity (SP) and Vita Mark II (VM) materials were used. Total of 150 square-shaped samples (14×12×1mm) at A1 shade were prepared with low speed sectioning saw (Micracut 125 Low Speed Precision Cutter, Metkon, Turkey) (n=10). Color measurements were carried out after different surface finishing procedures as control (C), manual polishing (M), glazing (G) and UV aging process, using a spectrophotometer device (Vita Easyshade Advance 4.0, Vita Zahnfabrik). L*, a*, b*, C (chroma) and h (hue) parameters were recorded and ΔE* values were calculated. Data were statistically analysed using Two-Way Anova, Fisher's LSD Test and Paired Samples T-test (p<0,05). For SP and VM blocs, glazing technique resulted in a significantly higher L1* value compared with the other surface finishing groups (p<0,05). b1* values of LU, CE, SP and VM materials control sub-groups, showed a significant difference than manual polishing and glaze groups. C1 value of SP material was found higher than other materials (p<0,05). The highest h1 value was obtained in the LUG group (p<0,05). After UV aging process, there were significant differences between L1*-L2*, a1*-a2*, b1*-b2*, C1-C2 ve h1-h2 parameters of nanoceramic and hybrid materials subgroups; except h1-h2 value of LUG (p¬¬=0,158), CEK (p¬¬=0,314) and CEG (p¬¬=0,215) groups. Statistically significant differences were found among color change parameters of nanoseramic and hybrid materials after UV aging. The highest ΔE* value was obtained in LU glaze group (ΔE*=22,7),while at least VM control group (ΔE*=0,86). The highest mean color change value was observed in the material of LU (ΔE*=20,18) and it is followed by CE (ΔE*=16,64), EN (ΔE*= 5,77), SP (ΔE*=1,93) and VM (ΔE*=1,26) blocs. There were no statistically significant difference between ΔE* values of SP and VM groups (p˃0,05). Glazing technique resulted in a higher ∆E* value compared with the others for the LU and CE materials (p<0,001). EN material showed lower discoloration rate than than manual polishing (∆E*=6,6) and control groups (∆E*=6,09) after glaze application (∆E*=4,64). Color change value was not affected by surface finishing procedures for the VM and SP blocs after aging (p˃0,05). The cases which highly esthetic requirements are demanded especially in the anterior region, ceramic matreials seems to be better choice than nanoceramic and hybrid materials. In terms of color stability, manual polishing is recommended for LU and CE, and glazing procedure for EN material. It is possible to create comparable glazing surfaces for ceramic materials by using manual polishing techniques. Key words: CAD/CAM, nanoceramic, hybrid materials, color, UV aging