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- Kjellson, Fred, et al.
(författare)
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Tensile properties of a bone cement containing non-ionic contrast media
- 2001
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Ingår i: Journal of Materials Science: Materials in Medicine. - 1573-4838. ; 12:10-12, s. 889-894
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Tidskriftsartikel (refereegranskat)abstract
- The addition of contrast media such as BaSO4 or ZrO2 to bone cement has adverse effects in joint replacements, including third body wear and particle-induced bone resorption. Ground PMMA containing particles of the non-ionic water-soluble iodine-based X-ray contrast media, iohexol (IHX) and iodixanol (IDX), has, in bone tissue culture, shown less bone resorption than commercial cements. These water-soluble non-ceramic contrast media may change the mechanical properties of acrylic bone cement. The static mechanical properties of bone cement containing either IHX or IDX have been investigated. There was no significant difference in ultimate stress between Palacos R (with 15.0 wt % of ZrO2) and plain cement with 8.0 wt % of IHX or IDX with mass median diameter (MMD) of 15.0 or 16.0 microm, while strain to failure was higher for the latter (p < 0.02). The larger particles (15.0 or 16.0 microm) gave significantly higher (p < 0.001) ultimate tensile strengths and strains to failure than smaller sizes (2.4 or 3.6 microm). Decreasing the amount of IHX from 10.0 wt % to 6.0 wt % gave a higher ultimate tensile strength (p < 0.001) and strain to failure (p < 0.02). Scanning electron microscopy (SEM) showed the smaller contrast media particles attached to the surface of the polymer beads, which may prevent areas of the acrylate bead surface from participating in the polymerization. In conclusion, the mechanical properties of bone cement were influenced by the size and amount of contrast medium particles. By choosing the appropriate amount and size of particles of water-soluble non-ionic contrast media the mechanical properties of the new radio-opaque bone cement can be optimized, thus reaching and surpassing given regulatory standards.
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| 3. |
- Liljensten, E, et al.
(författare)
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Hydroxyapatite granule/carrier composites promote new bone formation in cortical defects.
- 2000
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Ingår i: Clinical implant dentistry and related research. - : Wiley. - 1523-0899 .- 1708-8208. ; 2:1, s. 50-9
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Tidskriftsartikel (refereegranskat)abstract
- A great deal of interest has been focused on finding substitutes for autogenous bone grafts. Among the most interesting materials are different calcium phosphate compositions (e.g., hydroxyapatite [HA]), due to their biocompatible properties in hard and soft tissue.
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| 4. |
- Nilsson, Malin K, et al.
(författare)
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Factors influencing the compressive strength of an injectable calcium sulfate-hydroxyapatite cement.
- 2003
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Ingår i: Journal of Materials Science: Materials in Medicine. - 1573-4838. ; 14:5, s. 399-404
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Tidskriftsartikel (refereegranskat)abstract
- A biphasic injectable bone substitute, suitable for filling bone defects, that sets in the body, based on calcium sulfate and hydroxyapatite (HA), is presented. For applications in bone defects the compressive strength is important to assure support of the defect site during loading when the patient is weight bearing. To control the strength, the influence of four different factors; the liquid-to-powder (L/P) ratio, the HA particle morphology, the HA content and the amount of accelerator, were investigated. alpha-Calcium sulfate hemihydrate (CSH) and four different HA powders (three sintered and one spray-dried) were used. All differed in size and morphology. CSH and each HA powder were mixed together with distilled water to form the bone substitute. An accelerator, in form of calcium sulfate dihydrate, was added to the powder phase to obtain an adequate setting time. Cylindrical specimens were compression tested. A lower L/P-ratio gave stronger cement, but was more difficult to inject. The shape and the morphology of the HA particles influenced the strength, and reducing the amount of HA increased the strength. The amount of accelerator (calcium sulfate dihydrate) had no influence. (C) 2003 Kluwer Academic Publishers.
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| 5. |
- Nilsson, Malin K, et al.
(författare)
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Monitoring the setting of calcium-based bone cements using pulse-echo ultrasound
- 2002
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Ingår i: Journal of materials science. Materials in medicine. - 0957-4530 .- 1573-4838. ; 13:12, s. 1135-1141
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Tidskriftsartikel (refereegranskat)abstract
- We present a new technique, based on pulse-echo ultrasound, for monitoring the entire setting process of injectable bone cement. This research has been motivated by the lack of satisfying standards. The main problem with existing standards is the subjectivity, which leads to poor reproducibility. Because of this the results are not comparable between different research groups. A strong advantage with the proposed technique is that if low-intensity ultrasound is used, it provides a non-destructive analysis method. Once the cement paste has been applied to the measurement cell, no manipulation is needed throughout the entire setting process. The problem of the ultrasound affecting the setting of certain cement materials has been investigated, and solutions are discussed. The propagation of ultrasound is temperature-dependent, and therefore a technique for automatic compensation for temperature variations is discussed briefly. The testing was performed on -calcium sulfate hemihydrate (CSH) and mixtures of CSH and -tricalcium phosphate (-TCP). The results show that the acoustic properties of the cement are strongly correlated with the setting time, the density, and the adiabatic bulk modulus. The measured initial and final setting times agree well with the Gillmore needles standard. An important difference compared to the standards, is that the technique presented here allows the user to follow the entire setting process on-line.
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