Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CEMENTATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,387 records · Page 77Linked to original sources
PubMedDate not supplied

Biomechanical evaluation of kyphoplasty with calcium sulfate cement in a cadaveric osteoporotic vertebral compression fracture model.

BACKGROUND CONTEXT: Vertebral compression fractures can cause deformity, pain, and disability. Kyphoplasty involves percutaneous insertion of an inflatable balloon tamp into a fractured vertebra followed by injection of polymethylmethacrylate (PMMA) bone cement. PMMA has several disadvantages such as potential thermal necrosis and monomer toxicity. Calcium sulfate cement (CSC) is nontoxic, osteoconductive, and bioabsorbable. PURPOSE: To evaluate the biomechanical performance of CSC for kyphoplasty in cadaveric osteoporotic vertebral bodies. STUDY DESIGN: Destructive biomechanical tests using fresh cadaveric thoracolumbar vertebral bodies. METHODS: Thirty-three vertebral bodies (T9 to L4) from osteoporotic cadaveric spines were disarticulated, stripped of soft tissue, and measured for height and volume. Each vertebral body was compressed at 0.5 mm/s using a hinged plating system on a materials testing machine to create an anterior wedge fracture and reduce the anterior height by 25%. Pretreatment strength and stiffness were measured. Two KyphX inflatable balloon tamps were used to reexpand each vertebral body. After randomization, three groups were created: Group A-no cement; Group B-PMMA; Group C-calcium sulfate cement. Groups B and C were filled with the corresponding cement to 25% of the vertebral body volume. All vertebral bodies were then recompressed by 25% of the post-kyphoplasty anterior height to obtain posttreatment strength and stiffness. RESULTS: Treatment with PMMA restored vertebral strength to 127% of the intact level (4168.2 N+/-2288.7) and stiffness to 70% of the intact level (810.0 N/mm+/-380.6). Treatment with CSC restored strength to 108% of the intact level (3429.6 N+/-2440.7) and stiffness to 46% of the intact level (597.7 N/mm+/-317.5). CSC and PMMA were not significantly different for strength restoration (p=.4). Significantly greater strength restoration was obtained with either PMMA or CSC, compared with the control group (p=.003 and .03, respectively). Stiffness restoration tended to be greater with PMMA than for CSC, but this difference was not statistically significant (p=.1). Both cements had significantly greater stiffness when compared with the control group (p=.001 and p=.04, respectively). CONCLUSIONS: Use of CSC for kyphoplasty yields similar vertebral body strength and stiffness as compared with PMMA. It may be a useful alternative bone cement for kyphoplasty. Further studies are required to assess the bioabsorption of CSCs after kyphoplasty in vivo.

Aged↗
PubMed2002

Residual stress due to curing can initiate damage in porous bone cement: experimental and theoretical evidence.

Residual stress due to shrinkage of polymethylmethacrylate bone cement after polymerisation is possibly one factor capable of initiating cracks in the mantle of cemented hip replacements. No relationship between residual stress and observed cracking of cement has yet been demonstrated. To investigate if any relationship exists, a physical model has been developed which allows direct observation of damage in the cement layer on the femoral side of total hip replacement. The model contains medial and lateral cement layers between a bony surface and a metal stem; the tubular nature of the cement mantle is ignored. Five specimens were prepared and examined for cracking using manual tracing of stained cracks, observed by transmission microscopy; cracks were located and measured using image analysis. A mathematical approach for the prediction of residual stress due to shrinkage was developed which uses the thermal history of the material to predict when stress-locking occurs, and estimates subsequent thermal stress. The residual stress distribution of the cement layer in the physical model was then calculated using finite element analysis. Results show maximum tensile stresses normal to the observed crack directions, suggesting a link between residual stress and pre-load cracking. The residual stress predicted depends strongly on the definition of the reference temperature for stress-locking. The highest residual stresses (4-7 MPa) are predicted for shrinkage from maximum temperature; in this case, magnitudes are sufficiently high to initiate cracks when the influence of stress raisers such as pores or interdigitation at the bone/cement interface are taken into account (up to 24 MPa when calculating stress around a pore according to the method of Harrigan and Harris (J. Biomech. 24(11) (1991) 1047-1058). We conclude that the damage accumulation failure scenario begins before weight-bearing due to cracking induced by residual stress around pores or stress raisers.

Algorithms↗
PubMed2002

Micro-shear bond strength of dual-cured resin cement to glass ceramics.

OBJECTIVES: The aim of this study was to investigate the effects of sandblasting, etching, and a silane coupling agent on the ability of dual-cured resin cement to bond to glass ceramics designed for in indirect adhesive restoration. METHODS: A cast glass ceramic (Olympus Castable Ceramics) with a crystalline phase consisting of mica and beta-spondumene was selected as the substrate material. The glass surfaces, which were sandblasted, polished, or etched with phosphoric acid or hydrofluoric acid (HF), were bonded with a dual-cured resin cement (Panavia Fluoro Cement) using a dentin adhesive system (Clearfil SE Bond), both with and without a silane coupling agent. A micro-shear bond test was carried out to measure the bond strength of the resin cement to the glass surface. Each glass surface was bonded and tested using the shear test. In addition, surfaces with the bonding removed after the shear bond test, the adhesive interface between the glass and cement, and an etched glass surface without any bonding, were studied morphologically using scanning electron microscopy or field emission scanning electron microscopy. RESULTS: Usage of a silane coupling agent effectively raised the bond-strength values of resin cement (Fisher's PLSD, P<0.01). The effectiveness of using phosphoric acid etching to improve bonding was not clear (Fisher's PLSD, P>0.01). HF-etching for 30s seemed to over-etch the glass surface, resulting in adverse effects on bonding (Fisher's PLSD, P<0.01). SIGNIFICANCE: The micro-shear bond strength between Olympus Castable Ceramics and resin cement can be increased by the silane coupling agent used along with an acidic primer.

Acid Etching, Dental↗
PubMed1990

Factors of glass-ionomer cements influencing the bond strength to resin composites.

The bond strength between composites and various particle sizes of glass-ionomer cements was investigated. The best bond strength was obtained after use of a small-particle cement and with the highest powder-to-liquid ratio employed for mixing the cement. In addition, use of a small-particle cement and the highest powder:liquid ratio produced cements with significantly stronger tensile strengths. Failure usually occurred within the cement. Consequently, the recorded bond strength actually reflected the tensile strength of the relevant cement.

Composite Resins↗
PubMed1999

The influence of clinically induced variability on the bi-axial fracture strength of cemented aluminous core porcelain discs.

OBJECTIVES: Zinc phosphate cements are supplied in powder/liquid form so that a range of mixing ratios are naturally generated in clinical practice. However, these cements are known to have a deleterious effect on dental ceramics and the impact of variations in cement mixing on the strength of dental porcelain was investigated in the present study. METHODS: Vitadur-N core porcelain was fabricated into discs (15 mm diameter and 2 mm thickness), zinc phosphate cements of different mixing ratios were applied to the discs to produce a luting cement thickness and the samples were stored for 24 h prior to testing in a water-bath at 37 +/- 1 degrees C. The mean fracture strength, standard deviation and associated Weibull moduli (m) of the coated porcelain discs were determined as a function of mixing ratio using bi-axial flexure (ball-on-ring) by fracturing sets of 30 specimens coated with cements manipulated at different mixing ratios. RESULTS: The strength data for the coated porcelain discs showed little variation in magnitude and consistency ranging from 108 +/- 8.3 MPa (m = 14.0 +/- 2.6) at 1.7 g/ml to 112 +/- 8.5 MPa (m = 14.6 +/- 2.7) at 2.6 g/ml and 108 +/- 8.1 MPa (m = 14.4 +/- 2.6) at 3.2 g/ml. However, the plots of survival probability against strength for coated specimens prepared using mixing ratios below that recommended by the manufacturers' for luting purposes (2.6 g/ml), appeared to develop an asymmetry at the lower values of strength. SIGNIFICANCE: It was proposed that the increased corrosive acidic environment for cements prepared at mixing ratios below 2.6 g/ml may have extended pre-existing flaws in the porcelain discs thereby possibly producing the asymmetry in the survival distributions.

Aluminum Oxide↗
PubMed2002

Platelet release of transforming growth factor-beta and beta-thromboglobulin after in vitro contact with acrylic bone cements.

Three methacrylate-based bone cements used for the fixation of joint prostheses were evaluated: Sulfix-60 (Sulzer Orthopedic Inc., Baar, Switzerland). CMW1 (DePuy International Ltd., England). and CMW2 (DePuy International Ltd., England). The cements after polymerization were put in contact in vitro with platelet-rich plasma. Plasma, in contact only with siliconized glass, was used as a negative control. After contact, platelet number. beta-thromboglobulin (beta-TG), and transforming growth factor-beta1 (TGF-beta1) were determined. The Student's paired t test showed that the ccments induced no significant modifications of platelet number. CMWI and Sulfix-60 determined a significant increase in beta-TG compared with the negative control. All cements determined a significant increase in TGF-beta1. Significant differences were also seen in the levels of beta-TG and TGF-beta1 between cements with a content of benzoyl peroxide < 1 (Sulfix-60) and those with a content > 1 (CMW1 and CMW2). The cement with zirconium dioxide (Sulfix-60) produced higher levels of beta-TG and TGF-beta1, compared to those with barium sulphate (CMW1 and CMW2). In conclusion, all the cements induced the secretion of TGF-beta1 CMW1 and Sulfix-60 determined also a significant release of beta-TG. Platelet activation induced by the cements from one side could contribute to the pathogenesis of deep venous thrombosis, that often occurs after prosthetic implant and is caused also by other factors, including surgical trauma and venous stasis. From the other side, activated platelets can release growth factors favoring bone formation.

Acrylic Resins↗
PubMed2003

Devitrification of ionomer glass and its effect on the in vitro biocompatibility of glass-ionomer cements.

The effects of devitrification of an ionomer glass with a molar composition 4.5SiO(2).3Al(2)O(3).1.5P(2)O(5).3CaO.2CaF(2) on cement formation and in vitro biocompatibility were investigated. Differential thermal analysis was used to study the phase evolution in the glass, and to determine the heat treatments for production of glass-ceramics. X-ray diffraction patterns from glass frit heat-treated at 750 degrees C for 2h contained peaks corresponding to apatite (JCPDS 15-876), whereas for samples heat-treated at 950 degrees C for 2h apatite and mullite (JCPDS 15-776) were the major phases detected. Transmission electron microscopy (TEM) confirmed that apatite and apatite-mullite phases were present after heat treatments at 750 degrees C and 950 degrees C respectively. Glass and glass-ceramics were ground to prepare <45microm powders and glass ionomer cements were produced using a ratio of 1g powder: 0.2g PAA: 0.3g 10% m/v tartaric acid solution in water. In vitro biocompatibility was evaluated using cultured rat osteosarcoma (ROS) cells. Scanning electron microscopy (SEM) showed that cells colonised the surfaces of cements prepared using untreated ionomer glass and glass crystallised to form apatite (750 degrees C/2h). However, quantitative evaluation using MTT and total protein assays indicated that more cell growth occurred in the presence of cements prepared using ionomer glasses crystallised to apatite than cements prepared using untreated glass. The least cell growth and respiratory activity was observed on cements made with crystallised glass containing both apatite and mullite. It was concluded that the controlled devitrification of ionomer glasses could be used to produce GIC bone cements with improved biocompatibility.

Animals↗
PubMed2003

In vitro ageing of brushite calcium phosphate cement.

In vivo studies investigating the use of brushite cements have demonstrated mixed results with one or more of dissolution, hydrolysis, fragmentation and long term stability being demonstrated. It has been suggested that sample volume, implant location, and species can affect in vivo behaviour. As few in vitro studies on this cement system have been performed, this study aimed to compare the effects of static and dynamic in vitro ageing protocols on the phase composition, weight loss and mechanical properties of brushite cement. The effects of immersion liquid to cement volume ratio (LCVR) and sample volume on phase composition were investigated and comparative in vitro experiments were also performed in foetal bovine serum. It was determined that the weight loss after 28 days was up to seven times higher in serum than in phosphate buffered saline (PBS) and that fragmentation accounted for most of the weight loss observed. Hydroxyapatite was formed in PBS but not in serum when aged in refreshed media at all LCVRs investigated. This study has highlighted that LCVR, media refresh rate and media composition are critical to brushite cement performance. It appears that brushite cement removal from an implant site may be complex and dependent on physiological processes other than simple dissolution. A better understanding of these processes could provide the means to engineer more precise calcium phosphate cement degradation profiles.

Animals↗
PubMed2004

Backgrounds of antibiotic-loaded bone cement and prosthesis-related infection.

Antibiotic-loaded bone cement has been in use for over 30 years for the fixation of total joint arthroplasties, although its mechanism of action is still poorly understood. This review presents the backgrounds of bone cements, prosthesis-related infection and antibiotic-loaded bone cements. It is shown that antibiotic-loaded bone cement has a significant effect on bacteria, particularly in animal and clinical studies. However, recently, antimicrobial resistance among bacteria has been ascribed to the antibiotic-loaded bone cement. The unresolved issues both regarding the action of antibiotic-loaded bone cement and the nature of the antimicrobial resistance necessitate further research into the interaction of antibiotic-loaded bone cement and bacteria.

Animals↗
PubMed2004

Investigation of fatigue crack growth in acrylic bone cement using the acoustic emission technique.

Failure of the bone cement mantle has been implicated in the loosening process of cemented hip stems. Current methods of investigating degradation of the cement mantle in vitro often require sectioning of the sample to confirm failure paths. The present research investigates acoustic emission as a passive experimental method for the assessment of bone cement failure. Damage in bone cement was monitored during four point bending fatigue tests through an analysis of the peak amplitude, duration, rise time (RT) and energy of the events emitted from the damage sections. A difference in AE trends was observed during failure for specimens aged and tested in (i) air and (ii) Ringer's solution at 37 degrees C. It was noted that the acoustic behaviour varied according to applied load level; events of higher duration and RT were emitted during fatigue at lower stresses. A good correlation was observed between crack location and source of acoustic emission, and the nature of the acoustic parameters that were most suited to bone cement failure characterisation was identified. The methodology employed in this study could potentially be used as a pre-clinical assessment tool for the integrity of cemented load bearing implants.

Acoustics↗
PubMed1998

Flow intrusion characteristics and fracture properties of titanium-fibre-reinforced bone cement.

Two clinically relevant considerations for a new bone cement are its fracture properties and flow intrusion characteristics. We present data for a titanium-fibre-reinforced poly(methyl methacrylate) (Ti-PMMA). The fracture properties presented are a concise review of previously published material, while the flow intrusion observations are new. We performed fracture toughness and fatigue fracture experiments. Two types of fatigue specimens were designed and tested. A 'smooth' specimen represented the extreme case of minimum surface flaws. The lifetime of a 'smooth' specimen incorporates fatigue crack initiation (FCI) and fatigue crack propagation (FCP). 'Notched' specimens were created by machining a sharp notch into cylindrical specimens. The sharp notch effectively eliminated FCI from a random surface flaw and thus we made the assumption that the lifetime of the notched specimen was a function of FCP only. Fatigue testing was performed on rotating-bending fatigue machines until failure. Fibre addition resulted in a significant increase in fracture toughness over the control bone cement. Fibre addition and the combination of fibre addition and centrifugation increased the fatigue crack initiation and propagation resistance of the bone cement. For the intrusion studies, eight femurs were obtained from four dogs. The femurs were prepared following a procedure similar to that in human hip replacement surgery. One of the pair of femurs from each dog was filled with non-reinforced bone cement and the other was filled with Ti-PMMA. A stainless-steel rod was inserted into the cement to simulate the insertion of a prosthesis stem. The cemented bones were sectioned and then stained with Alizarin Red S to distinguish the bone from the PMMA or Ti-PMMA. Because of the irregular bone morphology, it was not practical to quantify intrusion depth, but instead to make general observations on the intrusion characteristics. The Ti fibres did not generally flow into the small openings; however, fibre addition did not hinder the bone cement's ability to penetrate into bone interstices.

Animals↗
PubMed1998

Mechanical strength of calcium phosphate cement in vivo and in vitro.

Two different kinds of calcium phosphate cement were developed for implant fixation: cement A comprised of alpha-tricalcium phosphate (alpha-TCP) 95% and dicalcium phosphate dihydrate (DCPD) 5%, and cement B comprised of alpha-tricalcium phosphate 90% and dicalcium phosphate dihydrate 10%. The compression strength and pullout force of the new materials were tested both in vitro and in vivo. Microscopic observations were performed on the interface between bone and cement. Cement A showed a greater mechanical strength than cement B. The results suggest the clinical possibility of this calcium phosphate cement, which could be used as a material for enhancing implant fixation.

Animals↗
PubMedDate not supplied

Basic properties of calcium phosphate cement containing atelocollagen in its liquid or powder phases.

The basic properties of calcium phosphate cement (CPC) containing atelocollagen, the main component of the organic substrate in bone, were studied in an initial evaluation for the fabrication of modified CPC. The setting time of conventional CPC (c-CPC) was prolonged to over 100 min when c-CPC contained 1% or more atelocollagen. The diametral tensile strength (DTS) of c-CPC decreased linearly with the collagen content, descending to below the detection limit when the c-CPC contained 3% or more atelocollagen. Therefore, use of c-CPC as the base cement seems inappropriate for the fabrication of atelocollagen-containing CPC. In contrast, the cement set at 9-34 min when fast-setting CPC (FSCPC) was used as the base cement and contained 1-5% atelocollagen, respectively. Although addition of atelocollagen resulted in the decrease of DTS of the set mass, the DTS was approximately the same, 6-8 MPa, at contents of atelocollagen between 1% and 5%. When atelocollagen was added to FSCPC, the handling property was improved significantly. The paste also became more adhesive with increase in atelocollagen content. These properties are desirable for its use in surgical procedures since, for example, bony defects can be filled easily and without a space interposed between the bone and cement paste. Although there are some disadvantages for the addition of atelocollagen to CPC, it can be accepted as long as FSCPC was used as the base cement. We conclude that further evaluations of the effects of atelocollagen, such as biocompatibility, bone synthesis, and bone replacement behaviour should be done, using FSCPC as the base cement.

Biocompatible Materials↗
PubMed1999

Effect of powder grinding on hydroxyapatite formation in a polymeric calcium phosphate cement prepared from tetracalcium phosphate and poly(methyl vinyl ether-maleic acid).

The primary aim of this study was to determine if cements based on poly(methyl vinyl ether-maleic acid) (PMVE-Ma) and tetracalcium phosphate resulted in hydroxyapatite formation. In addition, the mechanical strength of this type of polymeric calcium phosphate cement was evaluated. Cements were prepared by mixing, in a powder/liquid mass ratio of 3.0, an aqueous solution of PMVE-Ma (mass fraction = 25%) and tetracalcium phosphate powders ground for various periods of time. The tetracalcium phosphate powders and set cements were characterized by means of X-ray powder diffraction and scanning electron microscopy. Mechanical strengths of the cements were tested 24 h after mixing. Prolonged grinding of tetracalcium phosphate powder decreased particle size and/or crystallite size and increased lattice distortion. This enhanced the reactivity of the tetracalcium phosphate powder and elevated the extent of crosslinking between PMVE-Ma molecules, resulting in improved mechanical strength. Hydroxyapatite formation was detected in the cement prepared with the most finely ground tetracalcium phosphate powder. The conversion of residual tetracalcium phosphate particles to more thermodynamically stable hydroxyapatite crystals will reduce the solubility of the polymeric cement and increase its biocompatibility.

Calcium Phosphates↗
PubMed1997

Repair of craniofacial defects with hydroxyapatite cement.

PURPOSE: The objective of this study was to evaluate the course of healing of craniofacial bone defects when filled with hydroxyapatite cement and to determine whether adding various percentages by weight of demineralized bone powder to the cement will result in enhanced bone formation. MATERIALS AND METHODS: The model for the study was the canine calvarium. The implants were placed into cranial defects and harvested at 3 or 6 months for qualitative evaluation by light microscopy, microradiography, and quantitative histomorphometry. RESULTS: The implantation of hydroxyapatite cement resulted in characteristic replacement of the material with new bone ingrowth. The addition of demineralized bone powder to the hydroxyapatite cement appeared to improve the handling characteristics of the cement; however, improvement in the replacement of the material by bone was not observed. The implantation of only allogeneic demineralized bone showed limited new bone formation within the defect site. CONCLUSIONS: Hydroxyapatite cement formed an effective osseoconductive scaffold for bone replacement. The addition of demineralized bone powder to the cement to serve as a carrier of osseoinductive factors did not result in additional bone being formed.

Animals↗
PubMed2000

Retentive and compressive strengths of modified zinc oxide-eugenol cements.

OBJECTIVES: This investigation sought to improve the handling and physical properties of a commonly used temporary zinc oxide-eugenol cement by changing the base/accelerator (B/A) ratio or combining it with a petroleum jelly or fluoride varnish. METHODS: Twelve modifications of a temporary cement were evaluated in terms of retentive strength, compressive strength at 24 h, film thickness and by scanning electron microscopy. RESULTS: Decreasing the B/A mixing ratio increased the retentive and compressive strengths, but reduced the film thickness of the cement. By increasing the percentage of incorporated petroleum jelly or fluoride varnish in the cement, there was a progressive decrease in the retentive and compressive strengths and in film thickness. CONCLUSIONS: Modifications of a zinc oxide-eugenol temporary cement to change the B/A ratio or to incorporate additives resulted in variations in physical properties. All modified forms of the cement had a film thickness less than 25 microns and a compressive strength below 35 MPa. With a wide range of retentive strength, modified forms of zinc oxide-eugenol cement may be found to have diverse clinical applications.

Analysis of Variance↗
PubMed2002

Outcomes of surgical management of total HIP replacement in patients aged 65 years and older: cemented versus cementless femoral components and lateral or anterolateral versus posterior anatomical approach.

This observational study compared the outcomes of 271 cases of hip osteoarthritis receiving primary total hip replacement (patients 65 years of age and older) from numerous surgeons in 12 Baltimore region hospitals from 1991-1993. The independent variables studied were: (a) totally non-cemented prostheses (non-cemented femoral component, non-cemented acetabular component) versus hybrid prostheses (cemented femoral component, non-cemented acetabular component), and (b) lateral or anterolateral surgical approach versus posterior surgical approach. Outcomes included complications during the initial hospitalization, hospital length of stay, hospital cost, readmission, and reported and/or observed physical, instrumental, neuromuscular and affective functioning and pain at 2, 6, and 12 months post surgery. Results indicated that, while the totally non-cemented prosthesis was more costly, there were no statistically significant differences in clinical or functional outcomes between the non-cemented and the hybrid prostheses up to 12 months post surgery. Also, while the posterior surgical approach was associated with a non-statistically significant higher rate of dislocation, overall, there was improved function and reduced pain in the first 12 months post-surgery associated with this approach.

Aged↗
PubMed2002

Fatigue crack growth rate does not depend on mantle thickness: an idealized cemented stem construct under torsional loading.

Retrieval studies indicate that cemented stem loosening in femoral components of total hip replacement can initiate at the stem-cement interface. The etiology of the crack propagation process from the stem-cement interface is not well understood, but cracks are typically associated with thin cement mantles. In this study, a combination of experimental and computational methods was used to investigate the fatigue crack propagation process from the stem-PMMA cement interface using a novel torsional loading model. Constructs with thin (1 mm), medium (3 mm) or thick (7 mm) cement mantles were evaluated. Crack growth was stable for all cases and the rate of crack growth diminished with increasing crack length. Crack growth rate did not depend on mantle thickness (p > 0.05) over the first 1 mm of crack length, but cracks in thin mantles reached the full thickness of the mantle in the fewest number of loading cycles. The fracture mechanics-based finite element models indicated decreased stress intensity factors with increasing crack length and were consistent with the experimental findings. When combined with a fatigue crack growth Paris-law for PMMA cement, the finite element models provided reasonable predictions of the crack growth process.

Arthroplasty, Replacement, Hip↗