Comparative color and surface parameters of current esthetic restorative CAD/CAM materials

Abstract

Purpose: The purpose of this study was to derive and compare the inherent color (hue angle, chroma), translucency (TP_SCI), surface gloss (ΔE^*_SCE-SCI), and surface roughness (R_a) amongst selected shades and brands of three hybrid CAD/CAM blocks [GC Cerasmart (CS); Lava Ultimate (LU); Vita Enamic (VE)].

Materials and methods: The specimens (N = 225) were prepared into square-shaped (12 × 12 mm²) with different thicknesses and shades. The measurements of color, translucency, and surface gloss were performed by a reflection spectrophotometer. The surface roughness and surface topography were assessed by white light interferometry.

Results: Results revealed that hue and chroma values were influenced by the material type, material shade, and material thickness (P < .001). The order of hue angle amongst the materials was LU > CS > VE, whereas the order of chroma was VE > CS > LU. TP_SCI results demonstrated a significant difference in terms of material types and material thicknesses (P ≤ .001). TP_SCI values of the tested materials were ordered as LU > CS > VE. ΔE^*_SCE-SCI and R_a results were significantly varied amongst the materials (P < .001) and amongst the shades (P < .05). The order of ΔE^*_SCE-SCI amongst the materials were as follows LU > VE ≥ CS, whereas the order of R_a was CS ≥ VE > LU.

Conclusion: Nano-ceramic and polymer-infiltrated-feldspathic ceramic-network CAD/CAM materials exhibited different optical, inherent color and surface parameters.

Keywords: Chroma; Hue; Hybrid ceramics; Surface roughness; Translucency.

Fig. 1. The visible (400 – 700 nm) reflectance spectra for tested specimens illustrating variations in their reflectance.

Fig. 2. Hue angle (h_ab^*), chroma (C_ab^*), and translucency (TP_SCI) comparison according to the mean value and standard deviation of the tested materials in each shade and thickness. Different lower case letters indicate statistical difference inside the respective group (P < .05).

Fig. 3. Representative white light interferometer microscope images of tested CAD/CAM materials with 1 mm thicknesses in each selected shade. All images were taken at ×50 magnification.

Fig. 4. Representative SEM images of tested CAD/CAM materials with 2 mm thicknesses in A1-HT/1M1-HT shade. The specimens were polished with metallographic SiC papers (FEPA #800, 1200, 2400, 4000). The images were taken at ×500 magnification.