The Fracture Toughness Characteristics of Three Dental Composite Resins

Higo, Yakichi; Damri, D.; Nunomura, Shigetomo; Kumada, Keigo; Sawa, Norihiko; Hanaoka, Koji; Teranaka, Toshio; Iwamoto, T

doi:10.3233/bme-1991-1403

Cited by 7 publications

(4 citation statements)

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“…The weight‐average molecular weight ( M w ) is 1.0 × 10 6 . Ring‐type constant K specimens18 were used in the tests to clarify the relation between the K th value at which detectable crack propagation occurs at a given time and crack‐growth rate. The dimension of the ring specimen machined from the sheet is shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…The dimension of the ring specimen machined from the sheet is shown in Figure 1. The ring specimens have a relatively wide constant K value region under a constant loading condition in the crack‐length range between 3.0 and 7.3 mm (see the literature18). Thus, this type of specimen can be used to clarify the correlation between the K value and the crack‐propagation rate.…”

Section: Methodsmentioning

confidence: 99%

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Effects of humidity on environmental stress cracking behavior in poly(methyl methacrylate)

Ishiyama

Sakuma

Shimojo

et al. 2001

J Polym Sci B Polym Phys

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Environmental stress cracking (ESC) in poly(methyl methacrylate) under different humidity conditions has been investigated. Constant stress-intensity factor (K) ring-type specimens were prepared, and all specimens were equilibrated at five different humidity conditions for about two years. ESC tests were carried out under the same humidity as specimens had been stored. Acoustic emission (AE) signals during ESC tests were also measured to examine the crack-growth behavior. The threshold K value (K th ) tended to increase with increasing humidity. At a relative humidity (RH) of 11%, crack growth occurred gradually until 40 ks under a K value of 0.70 MPam 1/2 , and then the crack-growth rate began to increase and AE events were observed. A laser microscopic observation indicated that the crack extended by the coalescence between a main crack and a microcrack ahead of the main crack tip. AE signals generated are considered to be associated with the coalescence. At 98% RH, an incubation period where no crack growth was observed existed under a K value of 0.94 MPam 1/2 , but the crack began to grow suddenly after that incubation period. This suggests that the craze at the crack tip may become weaker with increasing loading time under high humidity.Although the crack-growth rate at 98% RH was higher than that at 11% RH, no AE events were observed. This suggests that the crack extended stably in the craze at a crack tip, and sorbed water may make the craze growth easy. All the results suggest that two different ESC mechanisms are activated depending on sorbed water that are varied by humidity.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Effects of humidity on environmental stress cracking behavior in poly(methyl methacrylate)

Ishiyama

Sakuma

Shimojo

et al. 2001

J Polym Sci B Polym Phys

Self Cite

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“…In a study from 1991, Higo et al [50] used a fracture mechanics approach to investigate the fracture toughness behavior of three commercial composite resins for dental use named Clearfil photo posterior, P-50 and Occlusin. The outcome of that study was that Occlusin exhibited higher fracture toughness values than any other resin when employing a ring specimen test procedure.…”

Section: Fracture Mechanics Aspects Of Dental Compositesmentioning

confidence: 99%

Fracture of Dental Materials

Söderholm¹

2012

Applied Fracture Mechanics

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“…for fracture toughness evaluation of composites [1][2][3][4]. However, problems exist in both the light curing procedure as well as the inherent brittleness of the cured material that results from the large content of inorganic powders and fillers, that make it difficult to fabricate standard-sized composite specimens such as are required for fracture toughness evaluation.…”

Section: Several Different Types Of Specimen Geometries and Experimenmentioning

confidence: 99%

Tensile fracture testing and energy evaluation of a light-cured composite resin

2010

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The brittle fracture of a light-cured composite resin used in dental restoration was examined using a high-speed extensometer, consisting of an optical fiber and a position-sensing detector (PSD). Single-edge-cracked specimens for tensile testing were fabricated by packing the composite between two rectangular plates of polymethyl methacrylate (PMMA). In order to study the dynamic effect of brittle fracture and the nonelastic effect of the material, the specimens were pin-loaded with a special jig so that they could split and fly apart in the loading direction after fracture. The flying height and residual deformation of the split specimen were measured to estimate the elastic energy E e and nonelastic energy E n , respectively. The fracture energy E f required to create a new fracture surface was obtained by subtracting E e and E n from the external work U ex applied to the specimen. The results showed that the ratio E f /U ex was about 32% for the composite specimen over a wide range of the fracture load, while it was about 45% for the PMMA specimen. The energy release rate G f was also estimated using E f. The results indicated that, although G f increased with the fracture load, the increasing slope for the composite specimen was smaller than that of the PMMA specimen.

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The Fracture Toughness Characteristics of Three Dental Composite Resins

Cited by 7 publications

References 0 publications

Effects of humidity on environmental stress cracking behavior in poly(methyl methacrylate)

Effects of humidity on environmental stress cracking behavior in poly(methyl methacrylate)

Fracture of Dental Materials

Tensile fracture testing and energy evaluation of a light-cured composite resin

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