Abstract :
[en] The objective of this study was to evaluate the interfacial fracture toughness (IFT) of composite cement with dispersed filler (DF) versus
polymer-infiltrated ceramic network (PICN) computer-aided design and computer-aided manufacturing (CAD-CAM) composite blocks
after 2 different surface pretreatments using the notchless triangular prism (NTP) test. Two DFs (Cerasmart [CRT] and Lava Ultimate
[LVA]), 2 PICNs (Enamic [ENA] and experimental PICN [EXP]), and e.max CAD lithium disilicate glass-ceramic (EMX, control) prism
samples were bonded to their counterparts with Variolink Esthetic DC composite cement after either hydrofluoric acid etching (HF)
or gritblasting (GR). Both procedures were followed by silanization. All samples (n = 30 per group) were thermocycled (10,000 cycles)
and tested for their IFT in a water bath at 36°C. Moreover, representative samples from each group were subjected to a developed
interfacial area ratio (Sdr) measurement by profilometry and scanning electron microscopy (SEM) characterization. EXP-HF gave the
highest IFT (1.85 ± 0.39 MPa·m1/2), followed by EMX-HF and ENA-HF, while CRT-HF gave the lowest (0.15 ± 0.22 MPa·m1/2). PICNs
gave significantly better results with HF, and DF showed better results with GR. A 2-way analysis of variance indicated that there
were significantly higher IFT and Sdr for PICNs than for DF. A positive correlation (r2 = 0.872) was found between IFT and Sdr. SEM
characterization showed the specific microstructure of the surface of etched PICNs, indicating the presence of a retentive polymerbased
honeycomb structure. Etching of the typical double-network microstructure of PICNs causes an important increase in the Sdr
and IFT, while DF should be gritblasted. DF exhibited significantly lower Sdr and IFT values than PICNs. The present results show the
important influence of the material class and surface texture, and consequently the micromechanical bond, on the adhesive interface
performance of CAD-CAM composites
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