Surface and fracture properties of lithium disilicate and resin-Matrix CAD/CAM ceramics

PURPOSE: To characterize hardness and fracture toughness of ceramic CAD/CAM materials with different composition (IPS e.max CAD and MAZIC Duro) and thicknesses (1mm and 1.5mm). MATERIALS AND METHODS: Blocks of CAD/CAM esthetic restorative materials (IPS e. max CAD "EC" and MAZIC Duro "MD"), forty discs were fabricated with dimensions of 10 mm × 1 mm and 10 mm × 1.5 mm. All discs were prepared using a precision cutting machine. Discs were then subjected to hardness, fracture toughness tests. RESULTS: Data were analyzed using independent t-tests and Two-way ANOVA (p < 0.05). For hardness test, at 1 mm and 1.5mm thicknesses, MAZIC Duro (MD) recorded a not statistically significant higher mean value of hardness (459.836 ± 20.549 HV) (468.818 ± 17.574 HV) compared to IPS e.max CAD (EC) (456.596 ± 38.102 HV) (463.346 ± 11.399 HV) (p = 0.816 and p = 0.420, respectively). For fracture toughness test, at 1 mm thickness, MAZIC Duro (MD) recorded a highly statistically significant higher mean value of fracture toughness (5.360 ± 0.133 MPa) compared to IPS e.max CAD (EC) (4.744 ± 0.151 MPa) (p < 0.001). While at 1.5 mm thickness, MAZIC Duro (MD) recorded a not statistically significant higher mean value of fracture toughness (5.291 ± .089 MPa) compared to IPS e.max CAD (EC) (5.285 ± 0.330 MPa) (p = 0.956). CONCLUSION: MAZIC Duro (MD) showed slightly higher hardness than IPS e.max CAD (EC) at both 1 mm and 1.5 mm thicknesses, but the difference was not statistically significant. For fracture toughness, MD was highly significant at 1 mm thickness, while at 1.5 mm, both materials performed similarly with no significant difference.