A fractographic investigation of PMMA bone cenent focusing on the relationship between porosity reduction and increased fatigue life

James, Susan P.; Jasty, Murali; Davies, J.P.; Piehler, H. R.; Harris, William H.

doi:10.1002/jbm.820260507

Cited by 131 publications

(87 citation statements)

References 8 publications

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“…All pore sizes demonstrated a high fatigue resistance at one million cycles when using A LB despite a decrease in endurance limit from injection-molded PEEK. It also appears that, qualitatively, PEEK-SP-450 had a slightly lower fatigue strength than PEEK-SP-250, in agreement with the finding that larger pores initiate more and larger fatigue cracks than small pores and therefore might have a greater effect on the fatigue life [21,22]. Interfacial shear testing was also performed on PEEK-SP samples to investigate the mechanical integrity between the porous layer and solid core.…”

Section: Discussionsupporting

confidence: 65%

Do Surface Porosity and Pore Size Influence Mechanical Properties and Cellular Response to PEEK?

Torstrick

Evans

Stevens

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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Background Despite its widespread use in orthopaedic implants such as soft tissue fasteners and spinal intervertebral implants, polyetheretherketone (PEEK) often suffers from poor osseointegration. Introducing porosity can overcome this limitation by encouraging bone ingrowth; however, the corresponding decrease in implant strength can potentially reduce the implant's ability to bear physiologic loads. We have previously shown, using a single pore size, that limiting porosity to the surface of PEEK implants preserves strength while supporting in vivo osseointegration. However, additional work is needed to investigate the effect of pore size on both the mechanical properties and cellular response to PEEK. Questions/purposes (1) Can surface porous PEEK (PEEK-SP) microstructure be reliably controlled? (2) What is the effect of pore size on the mechanical properties of PEEK-SP? (3) Do surface porosity and pore size influence the cellular response to PEEK? Methods PEEK-SP was created by extruding PEEK through NaCl crystals of three controlled ranges: 200 to 312, 312 to 425, and 425 to 508 lm. Micro-CT was used to characterize the microstructure of PEEK-SP. Tensile, fatigue, and interfacial shear tests were performed to compare the mechanical properties of PEEK-SP with injectionmolded PEEK (PEEK-IM). The cellular response to PEEK-SP, assessed by proliferation, alkaline phosphatase activity, vascular endothelial growth factor production, and calcium content of osteoblast, mesenchymal stem cell, and preosteoblast (MC3T3-E1) cultures, was compared with that of machined smooth PEEK and Ti6Al4V. Results Micro-CT analysis showed that PEEK-SP layers possessed pores that were 284 ± 35 lm, 341 ± 49 lm, and 416 ± 54 lm for each pore size group. Porosity and

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Section: Discussionsupporting

confidence: 65%

Do Surface Porosity and Pore Size Influence Mechanical Properties and Cellular Response to PEEK?

Torstrick

Evans

Stevens

et al. 2016

Clinical Orthopaedics &Amp; Related Research

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“…In specimens subjected to thermal cycling, a river pattern, or cleavage steps, appeared on the fractured surface for the adhesive systems that showed higher bond strengths. 31 The increased fracture resistance of adhesive resin is possibly through crack pinning, crack branching by toughening and plastic deformation of the resin component. Therefore, more energy is needed for crack propagation.…”

Section: Discussionmentioning

confidence: 99%

Effect of Thermal Cycling on Enamel Bond Strength of Single-step Self-etch Systems

Amano

Yamamoto

Tsubota

et al. 2006

Operative Dentistry

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After thermal cycling, some recently introduced simplified bonding systems showed no change in enamel bond strengths. The systems used were Absolute, Clearfil tri-S Bond, G-Bond and One-Up Bond F Plus. Bovine mandibular incisors were mounted in self-curing resin, and the facial surfaces were wet ground with #600 SiC paper. Adhesives were applied on the prepared enamel surfaces and light irradiated according to each manufacturer's instructions. Resin composites were condensed into a mold (ø4x2 mm) and light irradiated for 30 seconds. Thirty specimens per adhesive systems were divided into 1 of 3 test groups (n=10) following storage in water at 37°C for 24 hours. The specimens were then stored in 37°C water for 24 hours, followed by thermal cycling 10,000 and 20,000 times between 5°C and 60°C. After each storage condition, the specimens were tested in shear mode at a crosshead speed of 1.0-mm/minute. One-way ANOVAs and Tukey HSD test at a level of 0.05 were conducted.After 24 hours of water storage, the mean enamel bond strengths ranged from 11.3 to 16.9 MPa, and Clearfil tri-S Bond showed significantly higher bond strength. After thermal cycling, the mean bond strengths ranged from 8.3 to 20.7 MPa. The changes in enamel bond strengths were different among the adhesive systems tested. Failure modes after the test were commonly adhesive failure associated with partial cohesive failure adhesive in resin.

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“…Defects, acting as stress risers, lead to fatigue-failure, 8 but improved methods of mixing cement have reduced their number. 9 Centrifugation produces an increase of 54% in the ultimate tensile strength and of 136% in the fatigue-life when compared with a control group.…”

Section: Discussionmentioning

confidence: 99%

The inadequacy of standard radiographs in detecting flaws in the cement mantle

Reading

McCaskie

Gregg

1999

The Journal of Bone and Joint Surgery. British volume

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Radiological assessment of the cement mantle is used routinely to determine the outcome of total hip replacement. We performed a simulated replacement arthroplasty on cadaver femora and took standard postoperative radiographs. The femora were then sectioned into 7 mm slices starting at the calcar, and high-resolution faxitron radiographs were taken of these sections.Analysis of the faxitron images showed that defects in the cement mantle were observed up to 100 times more frequently than on the standard films. We therefore encourage the search for a better technique in assessing the cement mantle. If outcome measures are to be an important tool in orthopaedic research, the systems used for assessment must be reliable.1,2 Aseptic loosening is commonly assessed by the use of conventional radiographs to identify migration, defects in the cement mantle and radiolucent lines at the implant interfaces. Gruen, McNeice and Amstutz 3 described the widely used seven-zone system which allows the localisation of fractures in the cement and radiolucent lines at both the cement-bone and prosthesis-bone interfaces. Johnston et al 4 used the Gruen system as a basis for a more comprehensive evaluation which included clinical data, observations about the position of the stem and heterotopic ossification. Barrack, Mulroy and Harris 5 analysed the quality of cementing and described four grades on postoperative radiographs.These methods have been widely used to measure outcome and to demonstrate the effectiveness of various techniques.3-6 Concerns have been raised over the reliability of radiographs used for assessment. The three systems outlined above were the subject of a study on interobserver and intraobserver error, 7 which concluded that the levels of intraobserver error were moderate and that those between observers were poor or fair and, at times, less than would be expected by chance alone. Johnston et al 4 , in describing their system, stated that they did not believe that the true meaning of a radiolucency was known. Our study used a simulated arthroplasty as a model but it was not an experiment on bone cement as an isolated material. A comparison was made of standard postoperative radiographs and highresolution faxitron images of sections of the implanted specimen. The number of defects seen in the cement mantle was counted for each system and the presence of radiolucent lines assessed. Materials and MethodsWe used six pairs of human femora, obtained by informed consent from relatives at post mortem and stored freshlyfrozen. The simulated arthroplasty used the standard Charnley system in a class-one microbiological safety cabinet. Faxitron radiograph enlarged to show defects (dark areas).

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A fractographic investigation of PMMA bone cenent focusing on the relationship between porosity reduction and increased fatigue life

Cited by 131 publications

References 8 publications

Do Surface Porosity and Pore Size Influence Mechanical Properties and Cellular Response to PEEK?

Do Surface Porosity and Pore Size Influence Mechanical Properties and Cellular Response to PEEK?

Effect of Thermal Cycling on Enamel Bond Strength of Single-step Self-etch Systems

The inadequacy of standard radiographs in detecting flaws in the cement mantle

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