Effects of ultraviolet weathering aging on the color stability and biocompatibility of various computer-aided design and computer-aided manufacturing glass–ceramic materials

Abstract

ObjectivesThis study assessed the changes in color stability and biocompatibility of computer-aided design and computer-aided manufacturing (CAD-CAM) glass–ceramics after ultraviolet weathering (UW) aging. MethodsA total of 300 plate-shaped specimens (12.0 × 14.0 × 1.5 mm3) were prepared using a leucite-reinforced glass–ceramic (IPS Empress CAD; E), a lithium disilicate (IPS e.max CAD; M), and two zirconia-reinforced lithium silicate (Celtra Duo; C, Vita Suprinity; V) glass–ceramics. Specimens were divided into three groups (n = 25, each), subjected to water storage at 37 °C for 24 h (control group), or UW aging at 150 kJ/m2 (first-aged group) or 300 kJ/m2 (second-aged group). The color stability, mechanical and surface properties, and biocompatibility of the CAD-CAM glass-ceramics were investigated experimentally, followed by statistical analysis. ResultsThe brightness and redness or greenness were reduced in all groups after aging. After the first aging, V exhibited the largest color change and E exhibited the smallest color change. After the second aging, E exhibited the highest nanoindentation hardness and Young's modulus. The surface roughness was the highest for V after the first aging. Furthermore, the hydrophilicity of the materials increased after aging process. The cell proliferation/viability of human gingival fibroblasts was the highest in E before and after aging. Almost all cells survived for all groups based on a live/dead assay. ConclusionsLeucite-reinforced glass–ceramic exhibit the highest color stability and biocompatibility after aging. The color stability and biocompatibility of CAD-CAM glass–ceramics depend on the aging process and material type. Clinical significanceVarious CAD-CAM glass–ceramics exhibit adequate color stability after UW aging. The leucite-reinforced glass–ceramics exhibit the highest color stability, cell proliferation, and viability after aging. The color stability, mechanical and surface properties, and biocompatibility of the glass–ceramics depend on the aging process and material type.