Tamer A Hamza1, Rana M Sherif2. 1. Department of Crowns and Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Misr International University, Cairo, Egypt. 2. Department of Fixed Prosthodontics, Faculty of Oral and Dental Medicine, Cairo University, Egypt.
Abstract
PURPOSE: To compare the fracture resistance of monolithic reinforced glass-ceramic restorations with bilayer zirconia-based restorations. MATERIALS AND METHODS: Fifteen ceramic crowns were fabricated on epoxy dies duplicated from a stainless steel master die. They were divided into 3 equal groups (n = 5) according to the type of ceramic material used: group I, monolithic lithium disilicate (IPS e.max CAD), group V, monolithic zirconia-reinforced lithium silicate (Vita Suprinity), and group B (bilayered zirconia substructure with veneering ceramic). All specimens were cemented on epoxy dies with a self-adhesive resin cement (Rely X Unicem), subjected to a chewing simulator, and then loaded until fracture in a universal testing machine. The results were tabulated and statistically analyzed using one-way ANOVA to compare among the 3 materials. The Bonferroni post hoc test was used for pairwise comparisons when the ANOVA test was significant. RESULTS: Zirconia-reinforced lithium silicate (Vita Suprinity) crowns showed the highest statistically significant (p < 0.05) mean fracture resistance values (1742.9 ± 102.7 N), followed by lithium disilicate (IPS e.max CAD) (1565.2 ± 89.7 N). Bilayered zirconia-based crowns showed the lowest statistically significantly mean fracture resistance values (1267.8 ± 86.1 N). CONCLUSIONS: Monolithic reinforced glass-ceramics (lithium disilicate and zirconia-reinforced lithium silicate) have better fracture resistance than bilayered zirconia-based ceramics. CLINICAL IMPLICATIONS: The use of monolithic reinforced ceramic restorations (lithium disilicate and zirconia-reinforced lithium silicate) is preferred to bilayered zirconia-based restorations to avoid chipping of the ceramic veneer.
PURPOSE: To compare the fracture resistance of monolithic reinforced glass-ceramic restorations with bilayer zirconia-based restorations. MATERIALS AND METHODS: Fifteen ceramic crowns were fabricated on epoxy dies duplicated from a stainless steel master die. They were divided into 3 equal groups (n = 5) according to the type of ceramic material used: group I, monolithic lithium disilicate (IPS e.max CAD), group V, monolithic zirconia-reinforced lithium silicate (Vita Suprinity), and group B (bilayered zirconia substructure with veneering ceramic). All specimens were cemented on epoxy dies with a self-adhesive resin cement (Rely X Unicem), subjected to a chewing simulator, and then loaded until fracture in a universal testing machine. The results were tabulated and statistically analyzed using one-way ANOVA to compare among the 3 materials. The Bonferroni post hoc test was used for pairwise comparisons when the ANOVA test was significant. RESULTS:Zirconia-reinforced lithium silicate (Vita Suprinity) crowns showed the highest statistically significant (p < 0.05) mean fracture resistance values (1742.9 ± 102.7 N), followed by lithium disilicate (IPS e.max CAD) (1565.2 ± 89.7 N). Bilayered zirconia-based crowns showed the lowest statistically significantly mean fracture resistance values (1267.8 ± 86.1 N). CONCLUSIONS: Monolithic reinforced glass-ceramics (lithium disilicate and zirconia-reinforced lithium silicate) have better fracture resistance than bilayered zirconia-based ceramics. CLINICAL IMPLICATIONS: The use of monolithic reinforced ceramic restorations (lithium disilicate and zirconia-reinforced lithium silicate) is preferred to bilayered zirconia-based restorations to avoid chipping of the ceramic veneer.
Authors: Fernando Zarone; Maria Irene Di Mauro; Pietro Ausiello; Gennaro Ruggiero; Roberto Sorrentino Journal: BMC Oral Health Date: 2019-07-04 Impact factor: 2.757