TY - JOUR
T1 - In vitro aging of dental composites in water - Effect of degree of conversion, filler volume, and filler/matrix coupling
AU - Ferracane, J. L.
AU - Berge, H. X.
AU - Condon, J. R.
PY - 1998/12/5
Y1 - 1998/12/5
N2 - The purpose of this study was to evaluate the long-term effect of aging in water on the physical properties of experimental composites having systematically controlled differences in degree of conversion (DC), filler volume fraction (V(f)), and percentage of silane-treated fillers. Composites were made with a 50% Bis-GMA:50% TEGDMA light-cured resin and a 1-2 μm (average size) strontium glass filler (+ 5 wt% SiO2 microfiller). For composites A-E, the DC was varied from 56-66% by changing the curing time; for D and F-I, the V(f) was varied from 28-62 vol%; and for D and J-M, the percent of fillers with a silane coupling agent (γ-MPS) was varied from 20- 100%. Fracture toughness (K(Ic)), flexure strength (FS), elastic modulus (E), and hardness (KHN) were tested after soaking in water at 37°C for 1 day, 6 months, 1 year, and 2 years. The K(Ic) was reduced 20-30% for all composites after 6 months, with minimal changes thereafter. The FS was reduced for several composites at 6 months, but only those with poor cure (A and B) were lower at 2 years than they were initially. The E was not reduced for most composites. Hardness was reduced for most composites after 6 months, but many returned to their original levels at 2 years. Long-term aging in water caused a reduction in the K(lc), independent of composition, but had little effect on other properties, suggesting limited degradation of composites in water.
AB - The purpose of this study was to evaluate the long-term effect of aging in water on the physical properties of experimental composites having systematically controlled differences in degree of conversion (DC), filler volume fraction (V(f)), and percentage of silane-treated fillers. Composites were made with a 50% Bis-GMA:50% TEGDMA light-cured resin and a 1-2 μm (average size) strontium glass filler (+ 5 wt% SiO2 microfiller). For composites A-E, the DC was varied from 56-66% by changing the curing time; for D and F-I, the V(f) was varied from 28-62 vol%; and for D and J-M, the percent of fillers with a silane coupling agent (γ-MPS) was varied from 20- 100%. Fracture toughness (K(Ic)), flexure strength (FS), elastic modulus (E), and hardness (KHN) were tested after soaking in water at 37°C for 1 day, 6 months, 1 year, and 2 years. The K(Ic) was reduced 20-30% for all composites after 6 months, with minimal changes thereafter. The FS was reduced for several composites at 6 months, but only those with poor cure (A and B) were lower at 2 years than they were initially. The E was not reduced for most composites. Hardness was reduced for most composites after 6 months, but many returned to their original levels at 2 years. Long-term aging in water caused a reduction in the K(lc), independent of composition, but had little effect on other properties, suggesting limited degradation of composites in water.
KW - Aging
KW - Dental composite
KW - Elastic modulus
KW - Fracture toughness
KW - Hardness
KW - Strength
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U2 - 10.1002/(SICI)1097-4636(19981205)42:3<465::AID-JBM17>3.0.CO;2-F
DO - 10.1002/(SICI)1097-4636(19981205)42:3<465::AID-JBM17>3.0.CO;2-F
M3 - Article
C2 - 9788511
AN - SCOPUS:0032488231
SN - 0021-9304
VL - 42
SP - 465
EP - 472
JO - Journal of Biomedical Materials Research
JF - Journal of Biomedical Materials Research
IS - 3
ER -