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Effect of additive particles on mechanical, thermal, and cell functioning properties of poly(methyl methacrylate) cement.

Khandaker M, Vaughan MB, Morris TL, White JJ, Meng Z - Int J Nanomedicine (2014)

Bottom Line: We found that flexural strength and fracture toughness were significantly greater for PMMA specimens that incorporated silica than for the other specimens.All additives prolonged the time taken to reach maximum curing temperature and significantly improved cell adhesion of the PMMA samples.The results of this study could be useful for improving the union of implant-PMMA or bone-PMMA interfaces by incorporating nanoparticles into PMMA cement for orthopedic and orthodontic applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK, USA.

ABSTRACT
The most common bone cement material used clinically today for orthopedic surgery is poly(methyl methacrylate) (PMMA). Conventional PMMA bone cement has several mechanical, thermal, and biological disadvantages. To overcome these problems, researchers have investigated combinations of PMMA bone cement and several bioactive particles (micrometers to nanometers in size), such as magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica. A study comparing the effect of these individual additives on the mechanical, thermal, and cell functional properties of PMMA would be important to enable selection of suitable additives and design improved PMMA cement for orthopedic applications. Therefore, the goal of this study was to determine the effect of inclusion of magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica additives in PMMA on the mechanical, thermal, and cell functional performance of PMMA. American Society for Testing and Materials standard three-point bend flexural and fracture tests were conducted to determine the flexural strength, flexural modulus, and fracture toughness of the different PMMA samples. A custom-made temperature measurement system was used to determine maximum curing temperature and the time needed for each PMMA sample to reach its maximum curing temperature. Osteoblast adhesion and proliferation experiments were performed to determine cell viability using the different PMMA cements. We found that flexural strength and fracture toughness were significantly greater for PMMA specimens that incorporated silica than for the other specimens. All additives prolonged the time taken to reach maximum curing temperature and significantly improved cell adhesion of the PMMA samples. The results of this study could be useful for improving the union of implant-PMMA or bone-PMMA interfaces by incorporating nanoparticles into PMMA cement for orthopedic and orthodontic applications.

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(A) Evex mechanical test system (Evex Analytical Instruments Inc., Princeton, NJ, USA) used for the three-point flexural and fracture tests in the different PMMA samples. (B) Fabricated indenter and support fixtures for flexural tests. (C) Alignment of a notched specimen during fracture tests. During the tests, two lines perpendicular to each other were drawn to align the center of the notch with the center of the roller on the indenter using a Nikon stereomicroscope and NIS BR software (Nikon, Tokyo, Japan).Abbreviation: PMMA, poly(methyl methacrylate).
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f1-ijn-9-2699: (A) Evex mechanical test system (Evex Analytical Instruments Inc., Princeton, NJ, USA) used for the three-point flexural and fracture tests in the different PMMA samples. (B) Fabricated indenter and support fixtures for flexural tests. (C) Alignment of a notched specimen during fracture tests. During the tests, two lines perpendicular to each other were drawn to align the center of the notch with the center of the roller on the indenter using a Nikon stereomicroscope and NIS BR software (Nikon, Tokyo, Japan).Abbreviation: PMMA, poly(methyl methacrylate).

Mentions: Evex mechanical test system (Evex Analytical Instruments Inc., Princeton, NJ, USA) were used for the three-point flexural and fracture tests on the different PMMA samples (Figure 1A). Following the manufacturer’s recommendations, PMMA specimens were prepared by hand mixing 2.2 g of PMMA powder with 1.1 mL of methyl methacrylate monomer using a powder to monomer ratio of 2:1. Ten wt% (0.22 g) of the selected AP were mixed with 1.98 g of PMMA beads to prepare PMMA with AP-added PMMA cements. The mixers were added with 1.1 mL of methyl methacrylate monomers maintaining the same powder to monomer ratio of 2:1 for preparation of the respective PMMA-AP samples (PMMA-MgO, PMMA-HAp, PMMA-CS, PMMA-BaSO4, and PMMA-SiO2). All samples were cured in a custom-made mold13 at 60 kPa (the pressure used during orthopedic surgical procedures)27 to a block of size 20×8×10 mm. The pressure was applied at exactly 3 minutes after the start of mixing and was sustained throughout the curing period (approximately 15 minutes).18 To prepare American Society for Testing and Materials F417-78 standard flexural test samples (Figure 1B),28 20×4×2 mm blocks were cut from the 20×8×10 mm block using an IsoMet® low-speed cutter (Buehler, Lake Bluff, IL, USA). A 4×0.012×0.5 inch wafering blade was used to cut the samples. To prepare the American Society for Testing and Materials E399-83 single-edge notch bend test samples (Figure 1C),29 20×4×2 mm blocks were cut from a 20×8×10 mm block using the low-speed cutter. To prepare the single-edge notch bend test samples, a center notch was cut at the middle of the 20×4×2 mm cement samples using the low-speed cutter. A 4×0.012×0.5 inch wafering blade was used to cut the samples. The samples were stored in an antistatic ziplock bag at room temperature.


Effect of additive particles on mechanical, thermal, and cell functioning properties of poly(methyl methacrylate) cement.

Khandaker M, Vaughan MB, Morris TL, White JJ, Meng Z - Int J Nanomedicine (2014)

(A) Evex mechanical test system (Evex Analytical Instruments Inc., Princeton, NJ, USA) used for the three-point flexural and fracture tests in the different PMMA samples. (B) Fabricated indenter and support fixtures for flexural tests. (C) Alignment of a notched specimen during fracture tests. During the tests, two lines perpendicular to each other were drawn to align the center of the notch with the center of the roller on the indenter using a Nikon stereomicroscope and NIS BR software (Nikon, Tokyo, Japan).Abbreviation: PMMA, poly(methyl methacrylate).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043713&req=5

f1-ijn-9-2699: (A) Evex mechanical test system (Evex Analytical Instruments Inc., Princeton, NJ, USA) used for the three-point flexural and fracture tests in the different PMMA samples. (B) Fabricated indenter and support fixtures for flexural tests. (C) Alignment of a notched specimen during fracture tests. During the tests, two lines perpendicular to each other were drawn to align the center of the notch with the center of the roller on the indenter using a Nikon stereomicroscope and NIS BR software (Nikon, Tokyo, Japan).Abbreviation: PMMA, poly(methyl methacrylate).
Mentions: Evex mechanical test system (Evex Analytical Instruments Inc., Princeton, NJ, USA) were used for the three-point flexural and fracture tests on the different PMMA samples (Figure 1A). Following the manufacturer’s recommendations, PMMA specimens were prepared by hand mixing 2.2 g of PMMA powder with 1.1 mL of methyl methacrylate monomer using a powder to monomer ratio of 2:1. Ten wt% (0.22 g) of the selected AP were mixed with 1.98 g of PMMA beads to prepare PMMA with AP-added PMMA cements. The mixers were added with 1.1 mL of methyl methacrylate monomers maintaining the same powder to monomer ratio of 2:1 for preparation of the respective PMMA-AP samples (PMMA-MgO, PMMA-HAp, PMMA-CS, PMMA-BaSO4, and PMMA-SiO2). All samples were cured in a custom-made mold13 at 60 kPa (the pressure used during orthopedic surgical procedures)27 to a block of size 20×8×10 mm. The pressure was applied at exactly 3 minutes after the start of mixing and was sustained throughout the curing period (approximately 15 minutes).18 To prepare American Society for Testing and Materials F417-78 standard flexural test samples (Figure 1B),28 20×4×2 mm blocks were cut from the 20×8×10 mm block using an IsoMet® low-speed cutter (Buehler, Lake Bluff, IL, USA). A 4×0.012×0.5 inch wafering blade was used to cut the samples. To prepare the American Society for Testing and Materials E399-83 single-edge notch bend test samples (Figure 1C),29 20×4×2 mm blocks were cut from a 20×8×10 mm block using the low-speed cutter. To prepare the single-edge notch bend test samples, a center notch was cut at the middle of the 20×4×2 mm cement samples using the low-speed cutter. A 4×0.012×0.5 inch wafering blade was used to cut the samples. The samples were stored in an antistatic ziplock bag at room temperature.

Bottom Line: We found that flexural strength and fracture toughness were significantly greater for PMMA specimens that incorporated silica than for the other specimens.All additives prolonged the time taken to reach maximum curing temperature and significantly improved cell adhesion of the PMMA samples.The results of this study could be useful for improving the union of implant-PMMA or bone-PMMA interfaces by incorporating nanoparticles into PMMA cement for orthopedic and orthodontic applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering and Physics, University of Central Oklahoma, Edmond, OK, USA.

ABSTRACT
The most common bone cement material used clinically today for orthopedic surgery is poly(methyl methacrylate) (PMMA). Conventional PMMA bone cement has several mechanical, thermal, and biological disadvantages. To overcome these problems, researchers have investigated combinations of PMMA bone cement and several bioactive particles (micrometers to nanometers in size), such as magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica. A study comparing the effect of these individual additives on the mechanical, thermal, and cell functional properties of PMMA would be important to enable selection of suitable additives and design improved PMMA cement for orthopedic applications. Therefore, the goal of this study was to determine the effect of inclusion of magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica additives in PMMA on the mechanical, thermal, and cell functional performance of PMMA. American Society for Testing and Materials standard three-point bend flexural and fracture tests were conducted to determine the flexural strength, flexural modulus, and fracture toughness of the different PMMA samples. A custom-made temperature measurement system was used to determine maximum curing temperature and the time needed for each PMMA sample to reach its maximum curing temperature. Osteoblast adhesion and proliferation experiments were performed to determine cell viability using the different PMMA cements. We found that flexural strength and fracture toughness were significantly greater for PMMA specimens that incorporated silica than for the other specimens. All additives prolonged the time taken to reach maximum curing temperature and significantly improved cell adhesion of the PMMA samples. The results of this study could be useful for improving the union of implant-PMMA or bone-PMMA interfaces by incorporating nanoparticles into PMMA cement for orthopedic and orthodontic applications.

Show MeSH
Related in: MedlinePlus