Properties of particulate resin-luting agents with phosphate and carboxylic functional methacrylates as coupling agents



This study investigated properties of resin-luting agents using silane [3-(trimethoxysilyl)propyl methacrylate (TSPM)], phosphoric acid methacrylate (PAM) [mono/bis(methacryloyloxyethyl (di)hydrogen phosphate)], or carboxylic acid methacrylate (CAM) [mono-2-(methacryloyloxy)ethyl maleate] as coupling agents between the inorganic and organic phases. Ba-B-Al-Si microparticles (3 μm) and SiO2 nanoparticles (7 nm) were coated with TSPM, PAM, or CAM (control = no filler coating). A Bis-GMA/triethyleneglycol dimethacrylate comonomer was loaded with 60% mass of inorganic fillers. The properties evaluated were degree of C[DOUBLE BOND]C conversion (DC), flexural strength (σ), and modulus (Ef), Knoop hardness number (KHN), and film thickness (FT). Dispersion/interaction of the particles with the resin phase was assessed by scanning electron microscopy (SEM). No significant differences in DC were observed. For σ and Ef, TSPM > CAM > Control > PAM. For KHN, TSPM > CAM > PAM = Control. For FT, TSPM < Control < CAM < PAM. The SEM analysis revealed clustering of nanoparticles for all groups and better organic–inorganic phases interaction for TSPM and CAM. The use of TSPM generated agents with improved properties as compared with the acidic methacrylates, with CAM showing better performance than PAM. The use of PAM generated agents with properties usually poorer compared with the material with no coupling agent. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013