TY - JOUR
T1 - Development of mechanical properties in dental resin composite
T2 - Effect of filler size and filler aggregation state
AU - Rodríguez, Henry A.
AU - Kriven, Waltraud M.
AU - Casanova, Herley
N1 - This work was supported by COLCIENCIAS and Sumicol S.A. , Colombia, Grant 1115-562-38446 Cto 0162-2014 . This research was carried out in part in the Frederick Seitz Materials Research Laboratory, Center for Microanalysis of Materials at the University of Illinois at Urbana-Champaign, United States.
PY - 2019/8
Y1 - 2019/8
N2 - The aim of this work was to study the effect of filler size and filler aggregation state on the mechanical properties of dental resin composites evaluated at filler loadings between 20 wt% and up to 76.5 wt%. Non-aggregated silica nanoparticles (SiNP MPS ) (80 nm), doughnut-shaped silica nanoclusters obtained by spray drying (SDSiNP MPS ) (3.5 μm) and amorphous barium-alumina borosilicate microparticles (BaAlBoSi MPS ) (1.0 μm), functionalized by 3-methacryloxypropyl trimethoxysilane (MPS), were the fillers incorporated into resin matrix dental composites composed of triethylene glycoldimethacrylate (TEGDMA), urethane dimethylacrylate (UDMA), bisphenol A polyethylene glycol diether dimethacrylate (Bis EMA), and bisphenol A glycidyl methacrylate (BisGMA) (0.3:0.7:1:1 weight ratio, respectively). The mechanical properties developed in the resin composites were correlated with the formation of percolated-like particle networks, as observed by scanning electron microscopy (SEM), and volume fraction percolation thresholds (ϕ c ) calculated from a percolation model. Resin composites with non-aggregated SiNP MPS showed an apparent percolation threshold ϕ c = 0.15 (i.e. 27 wt%); above this filler concentration and up to a volume fraction of particles (ϕ P ) of 0.24 (i.e. 40 wt%) there was an increase in the flexural modulus and the compressive strength of the resin composite. However, a further increase in filler concentration diminished all its mechanical properties due to a decrease in the particle-matrix adhesion strength, demonstrated by the increase in surface roughness and fracture steps as observed by SEM images. On the other hand, a resin composite filled with doughnut-shaped silica nanoclusters (SDSiNP MPS ) showed an apparent percolation threshold ϕ c = 0.41 (i.e. 60 wt%); increasing filler loading over this concentration generated an improvement in its mechanical properties, except the flexural strength also due to a decrease in the particle-matrix adhesion strength. The resin composites obtained with amorphous individual BaAlBoSi MPS microparticles (1.0 μm) and BaAlBoSi MPS microparticle aggregates (ca. 40.0 μm) showed an apparent percolation threshold ϕ c = 0.41 (i.e. 64 wt%) that promoted an improvement in all their mechanical properties. SEM image of BaAlBoSi MPS resin composite at high filler loading (≥ 60 wt%) showed a decrease in fracture steps and no presence of voids, indicating a better adhesion between amorphous BaAlBoSi MPS particles and the polymeric matrix, which explains the improvement of mechanical properties. Resin composites filled exclusively with silica doughnut-shape nanoclusters or amorphous BaAlBoSi MPS microparticles could develop mechanical properties similar to or even better than those obtained by mixing nanofillers with spherical nanoclusters, which are commonly used in commercial resin composites.
AB - The aim of this work was to study the effect of filler size and filler aggregation state on the mechanical properties of dental resin composites evaluated at filler loadings between 20 wt% and up to 76.5 wt%. Non-aggregated silica nanoparticles (SiNP MPS ) (80 nm), doughnut-shaped silica nanoclusters obtained by spray drying (SDSiNP MPS ) (3.5 μm) and amorphous barium-alumina borosilicate microparticles (BaAlBoSi MPS ) (1.0 μm), functionalized by 3-methacryloxypropyl trimethoxysilane (MPS), were the fillers incorporated into resin matrix dental composites composed of triethylene glycoldimethacrylate (TEGDMA), urethane dimethylacrylate (UDMA), bisphenol A polyethylene glycol diether dimethacrylate (Bis EMA), and bisphenol A glycidyl methacrylate (BisGMA) (0.3:0.7:1:1 weight ratio, respectively). The mechanical properties developed in the resin composites were correlated with the formation of percolated-like particle networks, as observed by scanning electron microscopy (SEM), and volume fraction percolation thresholds (ϕ c ) calculated from a percolation model. Resin composites with non-aggregated SiNP MPS showed an apparent percolation threshold ϕ c = 0.15 (i.e. 27 wt%); above this filler concentration and up to a volume fraction of particles (ϕ P ) of 0.24 (i.e. 40 wt%) there was an increase in the flexural modulus and the compressive strength of the resin composite. However, a further increase in filler concentration diminished all its mechanical properties due to a decrease in the particle-matrix adhesion strength, demonstrated by the increase in surface roughness and fracture steps as observed by SEM images. On the other hand, a resin composite filled with doughnut-shaped silica nanoclusters (SDSiNP MPS ) showed an apparent percolation threshold ϕ c = 0.41 (i.e. 60 wt%); increasing filler loading over this concentration generated an improvement in its mechanical properties, except the flexural strength also due to a decrease in the particle-matrix adhesion strength. The resin composites obtained with amorphous individual BaAlBoSi MPS microparticles (1.0 μm) and BaAlBoSi MPS microparticle aggregates (ca. 40.0 μm) showed an apparent percolation threshold ϕ c = 0.41 (i.e. 64 wt%) that promoted an improvement in all their mechanical properties. SEM image of BaAlBoSi MPS resin composite at high filler loading (≥ 60 wt%) showed a decrease in fracture steps and no presence of voids, indicating a better adhesion between amorphous BaAlBoSi MPS particles and the polymeric matrix, which explains the improvement of mechanical properties. Resin composites filled exclusively with silica doughnut-shape nanoclusters or amorphous BaAlBoSi MPS microparticles could develop mechanical properties similar to or even better than those obtained by mixing nanofillers with spherical nanoclusters, which are commonly used in commercial resin composites.
KW - Dental resin composite
KW - Mechanical properties
KW - Microfillers
KW - Nanoclusters
KW - Nanofillers
KW - Percolation model
KW - Solvent evaporation method
KW - Spray drying
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U2 - 10.1016/j.msec.2019.03.090
DO - 10.1016/j.msec.2019.03.090
M3 - Article
C2 - 31029321
AN - SCOPUS:85063674062
SN - 0928-4931
VL - 101
SP - 274
EP - 282
JO - Materials Science and Engineering C
JF - Materials Science and Engineering C
ER -