OBJECTIVES: To evaluate the mechanical and physical properties of three glass-ceramic CAD/CAM systems; Vita Suprinity PC (Vita ZahnFabrik), Cerrec Tessera (Dentsply-Sirona), and IPS e.max CAD (Ivoclar Vivadent).
MATERIALS AND METHODS: For each material, CAD/CAM blocks were sectioned into a total of N=108 (n=12 per group) test discs with a diameter of 11.3 mm core drill and used the precision saw machine. Specimens were divided into three groups (1) glaze control, (2) polish only, and (3) ground after manufacturer glaze. Specimens were randomly assigned for the biaxial flexural strength test then each group was tested under three conditions post-treatment: (1) static, (2) thermal cycling for 5000 cycles, and (3) cyclic loading at 200,000 cycles. The biaxial flexural strength test was preformed according to ISO 6872-2015 using an Instron universal testing machine. Thermal artificial aging cycling was from 5° to 55°C, while fatigue was used for about 20% of the static failure load for 200,000 cycles. Vickers indentation was performed to test microhardness and fracture toughness. Also, surface roughness was measured for each group using a stylus contact profilometer. Additionally, surface topography and crystal microstructure analysis by SEM and crystallographic structural analysis by X-ray diffraction were done. Data were analyzed using one-way ANOVA test or least square regression (α = 0.05) and the post hoc Tukey HSD test.
RESULTS: Significant differences were observed in the mean of biaxial flexural strength between the three glass-ceramics materials. The highest mean flexural strength for static was IPS e.max CAD 385.91 ± 46.23 MPa, then Vita Suprinity PC glazed 355.72 ± 72.44 MPa, followed by CEREC Tessera glazed 323.40 ± 61.01 MPa. After thermal cycling and fatiguing, there were no significant effects in flexural strength for CEREC Tessera; however, there was an increase in flexural strength for IPS e.max CAD and Vita Suprinity PC. Vickers Hardness was highest for CEREC Tessera with 7.19 ± 0.47 GPa, then Vita Suprinity PC at 7.05 ± 0.73 GPa, followed by IPS e.max CAD 5.79 ± 0.77 GPa. The fracture toughness for IPS e.max CAD was the highest with 1.97 ± 0.12 MPa.m1/2, CEREC Tessera 0.93 ± 0.05 MPa.m1/2, and Vita Suprinity PC 0.85 ± 0.08 MPa.m1/2.
CONCLUSIONS: IPS e.max CAD polished outperformed Vita Suprinity PC and CEREC Tessera with respect to flexural strength under different aging conditions. In contrast, Vita Suprinity PC had the highest strength in every aging condition among the glazing group.
Clinically Significant: Although all three materials might be suitable for single restorations, caution is needed when choosing material, especially as the rough surface from clinical adjustments may reduce its strength.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/44944 |
| Date | 26 July 2022 |
| Creators | Mullayousef, Hashem Ali |
| Contributors | Giordano, Russell, Fan, Yuwei |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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