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At least 991 records · Page 55Linked to original sources
PubMed2007

Evaluation of an accelerated aging medium for acrylic bone cement based on analysis of nanoindentation measurements on laboratory-prepared and retrieved specimens.

The thrust of the study was a critical evaluation of the efficacy of a medium (30% v/v H(2)O(2), at 60 degrees C) that has been suggested in a literature report as being suitable for simulating the oxidative aging process, seen in vivo, in the acrylic bone cement mantles of total hip and knee joint replacements. For this purpose, quasi-static and dynamic nanoindentation measurements were used to obtain material properties--elastic modulus, E; hardness, H; and the variation of the storage and loss moduli with the frequency of the applied indenting force--of PalacosR acrylic bone cement specimens after various periods of immersion (7, 14, 21, and 28 days) in the aging solution, and of specimens prepared from cement mantles retrieved from cemented total hip joint replacements after various times in vivo (0.92-21 years). Also, best-fit relationships were obtained between E and time in the H(2)O(2) solution (t), H and t, E and in vivo time (T), and H and T. This body of results points to the possibility that the aging solution is effective, although the evidence is not conclusive.

Biomechanical Phenomena↗
PubMed2000

Dependence of Temperature-Sensitivity of Poly(N-isopropylacrylamide-co-acrylic acid) Hydrogel Microspheres upon Their Sizes.

Monodisperse poly(N-isopropylacrylamide-co-acrylic acid) hydrogel microspheres were prepared by a membrane emulsification method using membranes of pore diameters of 0.33, 0.73, 1.15, and 1.70 µm. The hydrogels were synthesized by polymerization of 3.6 M N-isopropylacrylamide (N-IPAAm or NIPAM) and 0.4 M acrylic acid (AAc). Their surface properties were studied by measuring the electrophoretic mobility of the microspheres in electrolyte solutions at pH 7.4 at 25, 30, 33, 35, 40, and 45 degrees C. Poly(N-IPAAm-co-AAc) microspheres have shown negative mobility. More negative values of electrophoretic mobility were obtained with the smaller microspheres than the larger ones at each temperature. The surface charge density of the microspheres increased and their surfaces became harder above 35 degrees C, since the microspheres contained thermosensitive poly(N-IPAAm) moiety and LCST increased by the addition of AAc, while that of poly(N-IPAAm) was 33 degrees C. It has recently been found that the smaller microspheres exhibit the stronger dependence of both surface charge density and softness on the temperature. Copyright 2000 Academic Press.

Journal Article↗
PubMed1986

The effect of posterior spinal fixation with acrylic cement on the vertebral growth plate and intervertebral disc in dogs.

We have attempted to clarify the serial histological changes in the growing spine of dogs following posterior fixation with acrylic cement. Twenty-four male mongrel dogs aged 8 weeks were used for the study. The lumbar spine from L.3 to L.5 was fixed posteriorly with acrylic cement. Three dogs were then sacrificed every four weeks up to 32 weeks, and the histological changes of the vertebral disc, growth plate and vertebral bodies were observed by light microscopy. Thinning of the growth plate and distortion of the cartilage columns has been demonstrated, but premature fusion of the growth plate did not result and vertebral body growth continued. Anterior wedging of the intervertebral disc was seen with some thinning of the bony trabeculae of the vertebral body. Degeneration of the nucleus pulposus resulted, with replacement by fibrous tissue. The normal horizontal arrangement of the fibres of the annulus fibrosus altered to a vertical configuration by 32 weeks.

Animals↗
PubMed1977

[Intraoperative temperature measurements at the acrylic bone/cement interface in total hip endoprosthetic (TEP) implantations (author's transl)].

Temperature measurements are reported effected by aid of thermocouples enclosed in tubules in TEP-implantations of the hip. Two techniques were employed: the first using as acrylic bone cement Palacos or Sulfix-6 without concomitant cooling, the second Palacos after precooling of the femur with crushed ice/water mixtures. The first method yielded, at the acrylic bone cement/bone interface, temperatures above the coagulation point of the protein (56 degrees C). The novel technique of implantation is described, i.e. the cooling of the bone with ice-water prior to the cement implantation. This technique provides a means of restricting the average temperature at the aforesaid interface to 45 degrees C.

Bone Cements↗
PubMed1983

Reaction to methylmethacrylate in bone metastases treated by surgical curetting and filling with acrylic cement. Histological study of a case.

A femur bone metastasis from breast carcinoma was treated by curetting and filling with acrylic cement and osteosynthesis. The histological study of the resected proximal third of the femur five months after surgery shows a thin layer of connective tissue between bone and cement. There are no neoplastic cells in this connective tissue nor in the spongious bone of the proximal femur. Instead the diaphyseal channel is fully invaded with neoplastic cells. Pathogenesis and validity of surgical treatment by the emptying and filling with acrylic cement of bone metastases are discussed.

Aged↗
PubMed1986

Quincke's edema in a dialysis patient after administration of acrylic bone cement: possible role of ethylene oxide allergy.

A 33-year-old female dialysis patient suffered from osteomyelitis and luxation of the dens axis with cervical myelopathy. In the past she had had three attacks of anaphylaxis after treatment with dialyzers that had been sterilized with ethylene oxide. IgE-type antibodies directed against human serum albumin-ethylene oxide complexes could be demonstrated in the patient's serum by radioallergosorbent techniques. Immediately after an operation in which acrylic bone cement (Palacos-R) sterilized with ethylene oxide was implanted for stabilization of the cervical spine, the patient developed massive edema of the larynx, pharynx, and tongue, suggesting Quincke's edema. It is concluded that ethylene oxide present in acrylic bone cement may induce acute allergic reactions in sensitized patients. Dialysis patients may be at special risk, since the incidence of ethylene oxide allergy in this patient population is about 10%.

Adult↗
PubMed1983

Acrylic bone cement: in vitro and in vivo property-structure relationship--a selective review.

The nature and curing characteristics of acrylic bone cement are presented to give some basic understanding of the key to improving its performance in in vivo clinical use. The use of electron paramagnetic resonance (EPR) spectroscopy in the (polymerization) setting and curing/aging of bone cement under in vitro and in vivo conditions is presented. The current research effort to improve the implant fixation by precoating the prosthesis with acrylic polymers is also discussed.

Bone Cements↗
PubMed2000

Rapid chondrolysis after an intra-articular leak of bone cement in treatment of a benign acetabular subchondral cyst: an unusual complication of percutaneous injection of acrylic cement.

Percutaneous injection of methylmethacrylate is now increasingly employed to treat bone lesions, both malignant and benign. However, the risks of this procedure are still to be fully established. In this report, we describe a case of rapid chondrolysis appearing after the intra-articular leakage of cement during injection of an acetabular subchondral cyst, resulting in hip replacement. Although the mechanism of such chondrolysis is unknown, this event suggests a chondrolytic effect of the acrylic cement. Thus, it is essential to systematically search for the presence of an intra-articular passage before injecting bone cement into a peri-articular cyst. This unusual complication highlights the need for rigorous evaluation of the benefits and risks of percutaneous injection of acrylic cement in the treatment of benign lesions, especially close to an articulation.

Acetabulum↗
PubMed2002

Japanese acrylic hemi-arthroplasty of the hip with a 45-year follow-up without revision.

We report the case of a patient who underwent acrylic hemi-arthroplasty of the hip and survived 45 years without revision. The patient had undergone hemi-arthroplasty of the hip at the age of 17 years following failure of a previous hemi-arthroplasty at the age of 12 years. We saw her 45 years later and carried out physical examination, standard radiographs of the hip as well as computed tomography. In addition, we reviewed the literature concerning the acrylic prosthesis and discussed the reasons for long-term durability.

Arthroplasty, Replacement, Hip↗
PubMed2006

Improved mechanical properties of acrylic bone cement with short titanium fiber reinforcement.

Acrylic bone cements are widely used in total joint arthroplasties to grout the prosthesis to bone. The changes in the tensile properties and fracture toughness of polymethylmethacrylate (PMMA) bone cements obtained by the addition of control and heat treated short titanium fibers are studied. Heat treatment of titanium fibers is conducted to precipitate titania particles on the fiber surface, which may improve the biocompatibility of the metal. Control (non-heat treated) and heat treated short titanium fibers (250 microm long and 20microm diameter) were used as reinforcements at 3 volume %. X-ray diffraction indicated the presence of a rutile form of titania due to the heat treatments. Results indicate that the tensile and fracture properties of unfilled bone cement were improved by the addition of control and heat-treated fibers. The fracture properties of bone cements reinforced with control titanium fibers were at least 10% higher than those reinforced with heat treated titanium fibers. Therefore, we recommend further studies on the use of non-heat treated titanium fibers to reinforce acrylic bone cement.

Coated Materials, Biocompatible↗
PubMed1976

An accidental tarsorrhaphy caused by acrylic adhesive.

A 10-year old boy accidently splashed acrylic adhesive in his left eye. I separated the eyelids by cutting adherent eyelashes with the use of a biomicroscope for magnification illumination. Tests with rabbits demonstrated that the solvent nitromethane dissolved the adhesions but diluted the glue and led to adhesions between the tarsal portion of the eyelid and the cornea. I used acrylic adhesions successfully for a temporary relief of irritation in a patient with Bell's palsy.

Accidents, Home↗
PubMed1989

The influence of Streptococcus mutans on adhesion of Candida albicans to acrylic surfaces in vitro.

Adhesion of Candida albicans and Streptococcus mutans was studied by incubation of radiolabelled cells with acrylic test specimens in a chemically defined growth medium. Strep. mutans adhered firmly in the presence of sucrose, while C. albicans was only loosely attached to the acrylic in both glucose and sucrose media. Firm adhesion of C. albicans occurred when the yeast was incubated simultaneously with Strep. mutans, in the presence of sucrose. The adhesion of C. albicans was also stimulated by incubation with Strep. mutans culture supernatants. Adhesion was not affected by the presence of partially purified glucosyltransferase from Strep. mutans IB. Coaggregation between C. albicans and Strep. mutans upon growth in sucrose medium was observed by light and scanning electron microscopy. No coaggregation was observed in the presence of glucose.

Bacterial Adhesion↗
PubMed1980

The effect of acrylic cement on the union of internally fixed experimental fractures of the femoral shaft in the rabbit.

Ninety rabbits had an osteotomy of the femoral shaft followed by medullary nail fixation. They were divided into three groups: group 1 acted as controls; in group 2 intramedullary acrylic cement was added; and in group 3 an external collar of acrylic cement was added at the osteotomy site. Bone healing was assessed by histological examination which included fluorochrome vital staining, vascular perfusion techniques and microradiology. All the osteotomies in groups 1 and 2 united. There was, however, a 100 per cent failure rate in group 3.

Animals↗
PubMed1987

Treatment of unstable intertrochanteric fractures with Sarmiento valgus osteotomy and acrylic cement augmentation.

Seventy unstable intertrochanteric fractures (Kyle III) were treated by Sarmiento valgus osteotomy, fixation with a sliding hip-screw and plate, and augmentation of the posteromedial upper femoral defect with acrylic cement. Immediate full weight bearing walking was started after the operation. Forty-two patients were followed up for more than 1 year (average 21.4 months). Excellent or good results were obtained in 71.4 per cent. However, there was mechanical failure in which the hip screw cut out of the femoral head superolaterally in 8.6 per cent. Comparison was made between the results of the present technique and our previously reported technique which consisted of Dimon-Hughston medial displacement osteotomy, fixation with sliding hip screw and acrylic cement augmentation to the upper posteromedial femoral defect. It was found that the result of the latter technique is slightly better, probably because of the more rigid reduction.

Aged↗
PubMed1986

Dimensional stability of autopolymerizing acrylic resin impression trays.

A study was undertaken to determine the optimal interval between fabrication of an autopolymerizing acrylic resin custom impression tray and making a final impression. Twenty mandibular arch-shaped trays, 10 each of Fastray and Formatray resin, were evaluated for dimensional change. Both materials behaved similarly. Cross-arch contraction of the borders of buccal flanges and unilateral expansion of the borders of buccal-to-lingual flanges were observed. These changes indicate distortion. Linear dimensional changes occurred throughout 6 hours, which suggests that any impression made in a methyl methacrylate acrylic resin custom impression tray should be poured as soon as is conveniently possible. Significant linear dimensional changes were observed for only 40 minutes from the initiation of tray fabrication. This study concludes that while an aged tray is preferred, it is acceptable to make an impression in an autopolymerizing resin custom impression tray after 40 minutes.

Chemical Phenomena↗
PubMed1994

Transverse strength and fatigue of denture acrylic-glass fiber composite.

OBJECTIVES: The aims of this experiment were: 1) to test the effect of a high concentration of continuous glass fibers on the transverse strength of test specimens made of heat-cured acrylic resin; and 2) to determine the fatigue weakening of both unreinforced and continuous glass fiber-reinforced specimens of heat-cured acrylic resin shaped into upper complete dentures. METHODS: A three-point loading test was used to determine the transverse strength of test specimens (n = 30 per group). The fatigue test was the constant deflection test (n = 10 per group). RESULTS: The results revealed that, compared to unreinforced specimens, continuous glass fibers at a concentration of 58 wt% enhanced the transverse strength of the test specimens up to 146% (p < 0.001) and increased the fatigue resistance (p < 0.001) during 5 x 10(5) loading cycles. SIGNIFICANCE: This study suggests that by incorporating glass fibers into PMMA denture bases, the strength of the denture can be increased.

Composite Resins↗
PubMed1989

Properties of poly(2-hydroxyethyl acrylate) networks.

Hydrogels, based on poly(2-hydroxyethyl acrylate) cross-linked with 1,4 butanediol dimethacrylate, were studied in respect to their swelling and mechanical behaviour. The determination of Young's modulus at r.t. permitted the calculation of average molecular weight between cross-links. This value could, in turn, be correlated with water-swelling data to give indicative values of the interaction parameter for the system poly(2-hydroxyethyl acrylate)-water.

Absorption↗
PubMed1990

Glycidyl acrylate plasma glow discharged polymers.

A homogeneous glycidyl acrylate polymer (GAP) has been grafted on to polytetrafluoroethylene (PTFE) and polyethylene (PE) using a modified plasma glow discharge technique with glycidyl acrylate. The polymeric layer appears to be extremely stable to acidic media and to common organic solvents. The modified surface can be derivatized via epoxy groups with hydroxy and amino compounds including sugars and amino sugars. These derivatized surfaces have been characterized by Fourier transform infrared (FTIR) spectroscopy and contact angle measurements. The wide variety of compounds which can be attached provides flexibility in the design of surfaces for the study of a range of biological interactions.

Adsorption↗