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Interfacial Fracture Toughness of Adhesive Resin Cement—Lithium‐Disilicate/Resin‐Composite Blocks
Author(s) -
Mesmar Samer,
Ruse N. Dorin
Publication year - 2019
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/jopr.12672
Subject(s) - materials science , composite material , adhesive , scanning electron microscope , composite number , toughness , fracture toughness , ceramic , layer (electronics)
Purpose Resin composite blocks (RCB) are advocated as alternative to ceramic blocks (CB). Prior to use, adherence to these materials should characterized. This study aimed to test the null hypothesis (H 0 ) that material and surface treatment combinations do not influence interfacial fracture toughness (K IC ) of a self‐cured adhesive resin cement [RelyX Ultimate (RXU)] to RCB or CB, under nonaged and aged conditions. Materials and Methods Two RCB, Lava Ultimate (LU) and Enamic (EN), and one CB, IPS e.max Press (EMP) were used. Half‐size [(6 × 6 × 6 × 6 mm)] specimens were prepared for EMP (n = 30), EN (n = 30), and LU (n = 60). RCB specimens were prepared by wet cutting/grinding, while CB specimens were pressed. Surfaces of EMP and EN were preconditioned with hydrofluoric acid (5%); surfaces of LU were sandblasted with either 27 μm alumina (LUS) or 30 μm silica‐modified alumina Rocatec soft (LUR). All specimens were bonded with Scotchbond Universal adhesive and RXU. Additionally, twenty (4 × 4 × 4 × 8 mm) RXU specimens were prepared. All specimens were stored in water at 37°C and tested after 1 and 60 days. Interfacial K IC was determined with the notchless triangular prism specimen K IC test. Results were analyzed with two‐way ANOVA and Scheffé multiple means comparisons (α = 0.05). Preconditioned and selected fractured surfaces were characterized with scanning electron microscopy. Results At 24 hours, LUS‐RXU and LUR‐RXU had significantly higher interfacial K IC than EN‐RXU and EMP‐RXU and were not different from K IC of RXU. Aging lead to a significant decrease in K IC of RXU and interfacial K IC of LUS‐RXU, LUR‐RXU, and EMP‐RXU; interfacial K IC of EN‐RXU was not affected. Based on the results, H 0 was rejected. Conclusion Under the conditions of this study, at 24 hours, interfacial K IC of LUS‐RXU and LUR‐RXU was superior to EMP‐RXU and EN‐RXU. Aging in water at 37°C did not affect interfacial K IC of EN‐RXU but adversely affected K IC of RXU and the other interfacial K IC . Clinical Implications : The results suggest that RXU and its adherence to LU and EMP deteriorates upon exposure to water at 37°C. In making clinical decisions related to material selection, practitioners should consider in vitro results.