Objective: Hydrofluoric-acid etching followed by silanization is a routine clinical protocol for durable bonding to glass ceramics. Simplifying ceramic-bonding procedures, new technological developments involve the inclusion of a silane coupling agent in a self-adhesive composite cement. To investigate the effectiveness of the incorporated silane coupling agent, shear bond strength (SB) to ceramic and dentin, contact angle of water (CA), transmission electron microscopy (TEM), X-ray diffraction (XRD) and 29Si nuclear magnetic resonance (NMR) assessments were correlatively conducted.
Materials and methods: SB to glass ceramic was measured without ('immediate') and with ('aged') 50K thermocycles upon application of (1) the silane-containing self-adhesive composite cement Panavia SA Cement Universal ('SAU'), being light-cured: 'SAU_light', (2) 'SAU_chem': chemically cured SAU, (3) 'SAP_light': light-cured Panavia SA Cement Plus ('SAP'), and (4) 'SAP_CP': SAP light-cured after separate silanization using Clearfil Ceramic Primer Plus ('CP'). CA was also measured on glass ceramic. The cement pastes before and upon mixing were characterized using 29Si NMR. SB of SAU or SAP onto dentin was measured. Finally, the cement-dentin interface was characterized by TEM and XRD.
Results: The immediate and aged SB to glass ceramic of SAU did not significantly differ from those of SAP_CP, while they were significantly higher than those of SAP. CA of SAU did not significantly differ from that of SAP_CP, but it was significantly higher than CA of SAP. 29Si NMR revealed siloxane bonds after mixture. SB of SAU and SAP to dentin did not show any significant difference. SEM, TEM and XRD confirmed tight and chemical interaction, respectively.
Significance: Incorporating silane in a 10-MDP-based self-adhesive composite cement combined efficient silane-coupling ability at the ceramic surface with effective bonding ability at dentin.
Keywords: NMR; Silane; bond strength; cement; ceramic; dentin; electron microscopy.
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