Acrylic bone cements: Effects of the poly(methyl methacrylate) powder size and chitosan addition on their properties (original) (raw)
Related papers
Effects of ingredients on thermal and mechanical properties of acrylic bone cements
Journal of Applied Polymer Science, 2009
There is a very delicate relation between the amounts of all the ingredients present in the cement composition and the properties of the product. In this study, homogeneous poly(methyl methacrylate) (PMMA) microspheres were prepared by suspension polymerization technique, and used in cement formulations. Various acrylic cements with different compositions were prepared by using PMMA microspheres, methyl methacrylate (MMA) monomer, radiopaque agent of barium sulfate (BaSO 4 ), inorganic particles of hydroxyapatite (HA), initiator and chain stopping agent of 1dodecyl mercaptan (DDM). The effects of these additives on mechanical and thermal properties of the resultant cements were examined. Addition of 8% HA relative to the solid parts caused an increase in both tensile and compressive strengths from 20.40 to 25.20 MPa, and from 84.04 to 89.57 MPa, respectively, while curing temperature was decreased about 3 degrees. Chain stopping agent of DDM caused a sharp decrease about 30 degrees in the curing temperature. Radiopaque agent of barium sulfate caused inverse effect on mechanical and thermal properties.
Relationship between the morphology of PMMA particles and properties of acrylic bone cements
Journal of Materials Science: Materials in Medicine, 1996
Bone cements are mainly based on acrylic polymers, poly(methyl methacrylate) (PMMA) being the most representative. The curing process (cold curing) is the result of the free radical polymerization of a mixture of beads of PMMA and methyl methacrylate (MMA), initiated by benzoyl peroxide (BPO) and activated by the presence of a tertiary amine, the most classical being N,N-dimethyl-4-toluidine (DMT). In this workthe results on the effect of the size and size distribution of PMMA beads and the concentration of DMTand BPO on the setting parameters, the residual monomer content and the mechanical properties (tension and compression) of the cured systems are presented. The use of relatively larger diameter PMMA beads improves the characteristic parameters of the curing process (decreasing the peak temperature and increasing the setting time), without detrimental effects on the mechanical properties of the cured cement.
Journal of Applied Polymer Science, 2012
In this work, a thermal and a dynamic mechanical study of new formulations self-curing acrylic bone cements is reported. The basic formulation of poly(methylmethacrylate) (PMMA)-based acrylic bone cements has been modified with biodegradable polyesters such as poly(L-lactic acid), poly(b-hydroxybutyrate), and different kinds of thermoplastic starches. Differential scanning calorimetry (DSC) (dynamic and isothermal conditions), thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and scanning electron microscopy (SEM) were used to determine the influence of the biodegradable polymer in the behavior of the biomedical formulations. DSC assay revealed a strong dependence of the polymerization enthalpy (DH cur) with increasing solid : liquid ratio and a low influence of the nature of the added biodegradable polymer on glass transition. TGA analysis showed the different mechanism of PMMA-biodegradable polymer interaction depending on the solubilization of the added polymer in methylmethacrylate monomer during curing. DMTA showed the reinforcing capacity of segregated phases of the polymer included in the cement. The solubilization of aliphatic polyesters in the resulting PMMA polymerized phase led to a drop in mechanical stiffness observed from storage modulus (E 0) profiles. Moreover, tan d shifts to higher temperatures (4-7 C) during a second scan, confirming the presence of residual monomer content. V
Biomaterials, 1996
The effect of the size and the size distribution of poly(methyl methacrylate) (PMMA) beads on the classical kinetic parameters, peak temperature and setting time, for acrylic bone cement formulations prepared with PMMA particles in the range 10-60~m of average diameter and a relatively wide size distribution is analysed. In addition, the combined effects of the concentration of the free radical initiator benzoyl peroxide and the activator N,N-dimethyl-4-toluidine for the different particle sizes are studied and compared with those of commercially available formulations like CMW or Rostal. The results obtained indicate that the use of PMMA particles with average diameter of 50-60pm, and a relatively wide size distribution (lO-140pm diameter), significantly changes the curing parameters (peak temperature and setting time) of the cement formulations in comparison with the classical behaviour of the commercial systems CMW and Rostal, without any noticeable loss in the mechanical properties, such as tensile strength, elastic moduli, compressive strength and plastic strain.
International Journal of Nanomedicine, 2014
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.
Biomaterials, 2002
This work reports the development of new partially biodegradable acrylic bone cements based on corn starch/cellulose acetate blends (SCA), prepared by the free radical polymerization of methyl methacrylate and acrylic acid at low temperature. Amounts of biocompatible, osteoconductive and osteophilic mineral component such as hydroxylapatite (sintered and non-sintered), were incorporated in different percentages to confer a bone-bonding character to the bone cements in this type of applications. All cement formulations were characterized by 1 H NMR spectroscopy. Curing parameters and mechanical properties were determined finding formulations which complete the ASTM legislation. Hydration degree, degradation studies, as well as bioactivity tests were performed in all prepared formulations. The developed systems show a range of properties that might allow for their application as self-curing bone cements, exhibiting several advantages with respect to other commercially available bone cements. r
Journal of Applied Polymer Science, 2003
This study related to the preparation of chitosan microspheres by means of reacting chitosan with -tricalcium phosphate (-TCP) and glutaraldehyde by crosslinking reaction in the oil phase, followed by de-oil and purification processes to get the product. Three cement composites, Pure P, C1P1, and C2P1, were prepared by the polymerization of poly(methyl methacrylate) (PMMA) bone cement in the presence of 0, 50, and 66.7% chitosan/-TCP microspheres, respectively. The result revealed the chitosan/-TCP microspheres obtained was in the size range of 50 -150 m. The presence of chitosan/-TCP microspheres in the prepared composites decreased the ultimate tensile strength, whereas the modulus remained the same as compared with the commercial PMMA bone cement. Addition of chitosan/-TCP microspheres into commercial PMMA cement significantly improved the handling property of the cement paste-that is, the increased setting time and less stickiness behavior of this paste was beneficial, in manipulation, to the operation and easier fittings to the shape and gap of the bony defect and interface. The decreased curing temperature was also less harmful to the surrounding tissues. From scanning electron micrograph observations, chitosan/-TCP microspheres can completely mix with bone cement powder and the prepared composites could provide scaffold for osteoblast cells growth and thus improve defects of commercial PMMA bone cement.
Thermal and mechanical properties of hydroxyapatite impregnated acrylic bone cements
Polymer Testing, 2004
Improvement of mechanical, thermal and biological properties of acrylic-based bone cements by adding various chemicals is a novel research area. Among these additives, hydroxyapatite (HA) is proven to be a biocompatible and osteoconductive material and it strongly integrates with bone. In this study, HA-containing acrylic bone cements were prepared and thermal and mechanical properties of the resultant cements were examined.