Dental Composites Based on Dimethacrylate Resins Reinforced by Nanoparticulate Silica

Abstract

This paper describes morphological differences and associated functional properties of dental composites based on dimethacrylate resins reinforced by nanoparticulate silica filler modified according to different silanization procedures. Surface morphology of the materials was evaluated by means of AFM, while nanohardness and elasticity modulus of the surface layer - by nanoindentation and abrasion - gravimetrically. The effects of silane treatment of nanoparticulate silica surface on possible filler loading, mechanical properties and abrasion resistance of the composites were discussed. The influence of the amount and kind of silane coupling agent on the example of 3 -methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane were presented. The modification of nanoparticulate silica with 3 -methacryloxypropyltrimethoxysilane enabled the introduction of 15% more filler than modification with vinyltrimethoxysilane. The abrasion resistance depended strongly on the composite morphology and the micromechanical parameters of the surface layer. The composite modified with vinyltrimethoxysilane, containing the highest percentage of filler particles smaller than 1 μm in diameter, exhibited the lowest abrasion (0.3 vol.%). Abrasive wear seemed to be a linear function of nanoindentation hardness with the correlation coefficient of R2 = 0.96. The highest hardness of the surface layer of commercial composite (130 MPa) resulted in the highest abrasive wear (7.7 vol.%). The type and the quantity of silane coupling agent used for silica modification strongly influence the morphology and mechanical and tribological properties of the dental composites. The application of more than the calculated, optimal amount of silane to nanosilica modification enables higher filler loading, but the composites exhibit inferior mechanical characteristics. Nanoindentation hardness of surface layer showed to be the most useful parameter in estimation of material susceptibility to abrasion.

Viscosity, Degree of Polymerization, Water Uptake, and Water Solubility Studies on Experimental Dichloro-BisGMA-Based Dental Composites

“…The hydrophilic, amorphous fumed silica (A200) with an average particle size of 12 nm, 200 ± 25 m 2 /g Brunauer-Emmett-Teller (BET) specific surface area, ≤1.5 mass loss on drying, and 3.7-4.5 pH [16] was modified with 10 wt% of organosilane (γ-MPS), following previously described methods [16][17][18][19]. A200 is a commercially available, lowcost, and modifiable silica, with applicable properties for use in dental composites [20].…”

Effects of Silica Nanoparticles and Silica-Zirconia Nanoclusters on Tribological Properties of Dental Resin Composites

“…Silanization grade affects roughness and hardness. Silanization prevents the loss of surface particles because of the covalent bond between particles and matrix, and hardness depends on the type and quantity of the silanization agent as well as the method of surface modification [17]. Figure 5 shows the particle size distribution of the silica and silica-zirconia nanoclusters obtained by spray drying.…”

“…is may be due to the fact that all materials have same filler concentration, and literature postulates that hardness depends on the quantity of filler [9,10,14,25]. However, other studies postulate that the hardness and other tribological properties are determined not only by the quantity of filler but also by the type and quantity of silanizing agent, as well as the method of surface modification of the filler [17,48].…”

“…is is because hardness also depends on the type and quantity of the silanization agent, the method of surface modification [17], the dispersion degree of nanoparticles, the particle size, and the hardness of the filler particles, since harder particles exhibit higher surface hardness in the composite [18].…”

The influence of silver nanoparticles introduced into RTV-silicone matrix on the activity against Streptococcus mutans

“…Important way to increase the properties of dental materials is introduction of nanofillers [13,14]. Microbiological resistance of silicone materials can be also modified with additional fillers [15].…”