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PubMed2005

Segmental cement extraction system (SEG-CES) and the Ilizarov method in limb salvage procedure after total knee cemented prosthesis removal in a former osteosarcoma patient.

Survival of osteosarcoma has greatly improved in the past few decades. Knee prosthesis is a well-recognized limb salvage procedure for osteosarcoma of the distal end of the femur. One drawback is that prostheses have a limited life and prosthetic failure with the inherent high rate of reoperations remains a serious long-term problem for former osteosarcoma patients. The segmental cement extraction system (SEG-CES) is a technique to remove cement in arthroplasty revision, based on a cement-bone interface with a lower strength compared to the old cement-new cement interface. We report the case of a 32-year-old former osteosarcoma patient in whom the SEG-CES was applied to remove a long-stemmed total knee cemented prosthesis. The prosthesis was placed 17 years before for a recurrent telangiectatic osteosarcoma of the left femur. Thirteen years after the prosthesis implantation, the patient complained of knee instability, pain, and complete failure of the extensor apparatus. The extraction of the prosthesis was performed using cylindrical batters of diameter corresponding to the diameter of the axle, two hammer extractors clamping the prosthesis components between two jaws. Extraction of the periprosthetic cement in the femoral and tibial components was done using the SEG-CES technique. The successful prosthesis removal performed in this patient allowed us to perform an external fixation with bone lengthening and reconstruction by the Ilizarov method.

Adult↗
PubMed2006

Cement venogram--a risk of satisfactory cement pressurization.

Longevity of cemented femoral components is dependent upon many factors. It is certainly related to the cementing technique. A dilemma exists between adequate cement pressurization and risk of embolic events. A cementation pressure above bleeding pressure, to allow optimum cement bone interdigitation but not high enough to produce embolic or cardiorespiratory events, is the ideal situation. We present a case where cement pressurization resulted in the appearance of a cement venogram on the routine postoperative x-ray.

Aged↗
PubMed1996

Cemented revision total hip arthroplasties in patients younger than 55 years old. A multicenter evaluation of second-generation cementing technique.

The results of all cemented first-time revisions in Sweden performed in patients younger than 55 years of age, during the period 1984-1986, are reported. The revisions were performed by the average orthopaedic surgeon in 25 hospitals distributed throughout Sweden. Second-generation femoral cementing technique was used. One third of the acetabular revisions were performed with pressurized cement. The reason for revision was aseptic loosening. Seventy hips in 68 patients were reviewed at an average follow-up period of 7 years (range, 4-10 years). The average age of the patients at the time of revision surgery was 47 years. Forty-eight cups and 57 stems were revised using cement. Survival analysis, with revision for aseptic loosening as the endpoint, suggests an overall 76% survival rate after 8 years. The survival rate for the cup was 80%, and for the stem, 85%. The radiographic evaluation revealed that the cement mantle was inadequate in many revisions. Localized osteolysis was rare. Clinical data were reported for 55 (53 patients) non-revised hips. Thirty-five hips were without pain or slightly painful. Forty patients limped when walking. Forty-three patients were satisfied with the revised hip. These results using second-generation femoral cementing technique are better than those reported with first-generation technique, but the failure rate in this young patient population is too high. The search for a more durable fixation in revision total hip athroplasty for young patients with long life expectancy is ongoing. These results emphasize that there is a need for centralization to gain experience in extended clinical research and to further improve surgical and cementing techniques.

Adult↗
PubMedDate not supplied

The effects of acetabular cup temperature and duration of cement pressurization on cement porosity in a canine total hip replacement model.

OBJECTIVE: To determine the effect of acetabular cup temperature and duration of cement pressurization on porosity of the acetabular cement mantel. STUDY DESIGN: In vitro study. METHODS: Twenty-four polyurethane foam blocks prepared for acetabular prosthetic implantation were implanted with polyethylene acetabular cups using four combinations and variations of temperature and pressure: (1) high temperature/short-term pressurization; (2) high temperature/long-term pressurization; (3) low temperature/long-term pressurization; and (4) low temperature short-term pressurization. Five 1-mm-thick slices were taken from the center of each block using a tissue processing system. The slices were scanned into a personal computer using a photo slide scanner. Imaging software was used to determine cement surface area and size, number, and distribution of pores. The quality of the cement-implant interface was subjectively evaluated. Statistical analysis of relative cement porosity was performed by a Kruskal-Wallis analysis of variance comparing the four groups individually and combining the short-term pressurization groups versus the long-term pressurization groups. RESULTS: There were no significant differences in cement porosity between the four test groups (P =.11). There were no significant differences in porosity between the combined groups (P =.48). CONCLUSIONS: There is no benefit in prewarming acetabular cups before implantation. There are no deleterious effects of short-term pressurization of the cement during implantation.

Acetabulum↗
PubMed2004

A comparison of the in vitro retentive strength of glass-ionomer cement, zinc-phosphate cement, and mineral trioxide aggregate for the retention of prefabricated posts in bovine incisors.

The purpose of this study was to compare the retentive strength of zinc-phosphate cement, glass-ionomer cement, and mineral trioxide aggregate (MTA) cement in the retention of prefabricated posts. The root canals of 60 bovine incisors were prepared and obturated with warm gutta-percha. Post space was prepared, the smear layer removed, and posts were luted with zinc-phosphate cement, glass-ionomer cement, or MTA. The specimens were stored at 37 degrees C and 100% humidity for 2 weeks, and then subjected to increasing axial tensile forces by an Instron machine until bond failure occurred. Data were analyzed by a one-way ANOVA and a Tukey-Kramer multiple comparison test. The retentive strengths of zinc phosphate and glass-ionomer cements were statistically equivalent, and significantly greater than MTA (p < 0.001), which suggests that zinc phosphate or glass-ionomer cement may be superior to MTA when used as luting agents for posts in endodontically treated teeth.

Aluminum Compounds↗
PubMed1993

The Miller-Galante knee prosthesis for the treatment of osteoarthrosis. A comparison of the results of partial fixation with cement and fixation without any cement.

In a prospective, non-randomized study of 344 patients who had 392 primary total knee replacements with a Miller-Galante I prosthesis for the treatment of osteoarthrosis, the results of partial fixation with cement (insertion of the tibial and patellar components with cement and of the femoral component without cement) were compared with those of fixation without any cement. Of the 392 knees, 183 (163 patients) had fixation without cement (Group I) and 209 (181 patients), with and without cement (Group II). The average duration of follow-up was three years (range, two to five years). Nine patients died during the follow-up period, but no others were lost to follow-up. Analysis of the knee scores, range of motion of the knee, radiographs, and rates of complications revealed no differences between the outcomes in the two groups during the follow-up period. The rate of complications due to problems related to the extensor mechanism was high in both groups: a reoperation was performed in fifteen (8 per cent) of the knees that had had fixation without cement and in nineteen (9 per cent) of those that had had both types of fixation. Thirteen patients had additional operative treatment for recurrent patellar dislocations; twelve patients, for abnormal wear of the polyethylene of the patellar component: two patients, for avulsion of the patellar ligament from the tibia; and two patients, for unexplained pain in the knee. In addition, there were eight patellar fractures (two of which led to a reoperation) and three deep infections (all of which led to a reoperation).

Adult↗
PubMedDate not supplied

Shear bond strengths of orthodontic brackets cemented to bovine enamel with composite and resin-modified glass ionomer cements.

PURPOSE: The purpose of this in vitro study was to determine the effects of short- and long-term storage on the shear bond strength of metal, polycarbonate, and ceramic orthodontic bracket bases using autopolymerizing resin composite and resin-modified glass ionomer cements (RMGIC). The glass ionomer cement was applied in both a wet and a dry environment. METHODS: With a method developed in the authors' laboratory, orthodontic brackets were cemented under constant pressure to embedded bovine incisor enamel. All cements were mixed and applied in accordance with the manufacturer's instructions. The specimens were stored in water at 37 degrees C for 24 hours, 7 days, or 180 days. After the lapse of each time interval, they were shear tested to failure. The shear bond strengths (SBSs) were converted to megapascals (MPa). An adhesive remnant index (ARI) was used to record the site of the residual cement. RESULTS: There were no precipitous increases or decreases in SBS over a lapsed time of 180 days, although some variations occurred between 24 hours and 7 days. Similar findings were recorded for ARI. CONCLUSIONS: The bracket base-cement combinations produce clinically sustainable SBSs over time. Selection of the cement may be important in patients who exhibit a high risk for caries.

Analysis of Variance↗
PubMed2006

Cytotoxicity of a calcium aluminate cement in comparison with other dental cements and resin-based materials.

The objective of this study was to compare the cytotoxic effects of a calcium aluminate cement with several currently used direct restorative materials. Specimens of three composites (QuiXfil, Tetric Ceram, Filtek Supreme), one zinc phosphate cement (Harvard Cement), one glass ionomer cement (Ketac Molar), and one calcium aluminate cement (DoxaDent), were used fresh or after 7-days' preincubation in cell culture medium at 37 degrees C, pH 7.2. PVC strips for ISO 10993-5 cytotoxicity test were used as positive control and glass specimens as negative control. L-929 fibroblasts (5-ml aliquots, containing 3 x 10(4) cells/ml), cultivated in DMEM with 10% FCS, 1% glutamine, and 1% penicillin/streptomycin at 37 degrees C/5% CO2 and trypsinized, were exposed to the specimens for 72 h. The cells were harvested, centrifuged, and resuspended in 500 microl DMEM and then counted in 500 microl DMEM for 30 s with a flow cytometer at 488 nm. The analysis of variance comparing the six materials showed different influences on L-929 fibroblast cytotoxicity (p <0.0001). The cytotoxicity of all specimens diminished with increasing preincubation time (p <0.0001). Fresh DoxaDent exhibited the lowest cytotoxicity, followed by QuiXfil. Ketac Molar showed the highest cytotoxicity. After 7 days of preincubation, Harvard Cement and Filtek Supreme demonstrated more cytotoxicity than the other materials (p <0.005).

Aluminum Compounds↗
PubMed1977

Clinical study of dental cements. VI. A study of zinc phosphate, EBA-reinforced zinc oxide eugenol and polyacrylic acid cements as luting agents in fixed prostheses.

A clinical trial for the final cementation of crowns and bridges with a reinforced zinc oxide and eugenol cement, a polyacrylic acid cement and a zinc phosphate cement was made over a 3-year period. The study involved 441 patients for whom 547 bridges and 162 single restorations were cemented. The patients were recalled at 6-month intervals for the duration of the study and the restorations were examined for looseness. Of the 547 bridges 520 remained firmly cemented to the abutment teeth. Of 1,082 bridge retainers, 1,049 remained in position; success and failure by types of retainer will be the subject of a subsequent paper. Of the 162 single restorations 159 remained in place.

Acrylates↗
PubMed2000

Relative roles of cement molecular weight and mixing method on the fatigue performance of acrylic bone cement: Simplex P versus Osteopal.

The weight-average molecular weight (MW(w)) of a cement and the method used to mix its powder and liquid monomer constituents have been identified in the literature as key variables that affect mechanical properties of the fully polymerized cement that are relevant to its performance as a grouting agent in cemented arthroplasties. The goal of the present work was to identify which of these two variables exerts the greater effect in the case of fully reversed tension-compression fatigue performance. A judicious choice of cement brands, Surgical Simplex P and Osteopal, and the use of hand versus vacuum mixing, permitted this identification to be achieved. Three key observations were made in this work. First, for a given cement, the fatigue performance of vacuum-mixed specimens is far superior to that of hand-mixed ones, which may be a consequence of the substantially lower percentage areal porosity of the former specimens. Second, regardless of the mixing method, the fatigue performance of Osteopal outstrips that of Simplex P, a result that is attributed to the much higher MW(w) of the former cement. Third, hand-mixed Osteopal outperforms vacuum-mixed Simplex P (especially at low alternating stress levels), indicating that MW(w) of a bone cement is more influential than mixing method on its fatigue performance.

Arthroplasty, Replacement↗
PubMed2007

Influence of the activator in an acrylic bone cement on an array of cement properties.

In all but one of the acrylic bone cement brands used in cemented arthroplasties, N,N-dimethyl-4-toluidine (DMPT) serves as the activator of the polymerization reaction. However, many concerns have been raised about this activator, all related to its toxicity. Thus, various workers have assessed a number of alternative activators, with two examples being N,N-dimethylamino-4-benzyl laurate (DMAL) and N,N-dimethylamino-4-benzyl oleate (DMAO). The results of limited characterization of cements that contain DMAL or DMAO have been reported in the literature. The present work is a comprehensive comparison of cements that contain one of these three activators, in which the values of a large array of their properties were determined. These properties range from the setting time and maximum exotherm temperature of the curing cement to the variation of the loss elastic modulus of the cured cement with frequency of the applied indenting force in dynamic nanoindentation tests. The present results, taken in conjunction with those presented in previous reports by the present authors and co-workers on other properties of these cements, indicate that both DMAL and DMPT are suitable alternatives to DMPT.

Acrylic Resins↗
PubMed1994

A novel skeletal drug delivery system using a self-setting calcium phosphate cement. 5. Drug release behavior from a heterogeneous drug-loaded cement containing an anticancer drug.

A novel drug delivery device based on a self-setting bioactive calcium phosphate cement formed from tetracalcium phosphate and dicalcium phosphate has been developed and tested in vitro using the anticancer agent 6-mercaptopurine (6-MP) as a model compound. X-ray diffraction results suggest that equimolar mixtures of the calcium phosphate salts were transformed into hydroxyapatite after being mixed with a dilute phosphoric acid solution, even in the presence of various amounts of 6-MP powder. The inclusion of 6-MP in the reaction mixture resulted in the formation of a homogeneous drug-containing cement. Alternatively, the drug was loaded after cement formation to produce a heterogeneous drug-containing pellet. In vitro drug release from both the homogeneous and heterogeneous drug-loaded cement pellets into simulated body fluid (pH 7.25, 37.0 degrees C) was measured using the rotating-disk method. Release from the homogeneous 5% drug-loaded cements did not obey the Higuchi equation. The release rate from the heterogeneous drug-loaded cements of different thicknesses (1, 2, and 3 mm) was a function of thickness, indicating that release kinetics could be controlled by the design of the cement formulation.

Antineoplastic Agents↗
PubMed1996

Advantage of the transprosthetic drainage system (TDS) for application in cemented hip arthroplasty--a standardized experimental comparison with other cementing techniques.

We constructed a computer-assisted implantation device to compare different cementing techniques of stem implantation in total hip arthroplasty, thus avoiding any manual influence during implantation. We used an intramedullary plug in each case. Conventional cementing techniques, employing an additional lateral drain for the femoral canal or applying the cement by hand, did not lead to a satisfyingly reproducible quality of the cement mantle. With the vacuum cementing technique, in which an additional cannulated screw is inserted into the plug from the lateral side of the femur for the application of the vacuum, the cement mantle improved in quality, but there was still a relatively high number of bubbles incorporated in the cement. We think that, even under improved experimental circumstances, it is not always possible to place the cannulated screw correctly into the plug in order to achieve a satisfying drainage of the femoral canal with this procedure. The transprosthetic drainage system showed the best results due to the optimized position and working capacity of the drain.

Biomechanical Phenomena↗
PubMed2004

Ionic modification of calcium phosphate cement viscosity. Part I: hypodermic injection and strength improvement of apatite cement.

A broadening of the indications for which calcium phosphate cements (CPC) can be used, for example, in the field of vertebroplasty, would require injectable and higher strength materials. Unmodified CPC are not injectable due to a filter-pressing effect during injection. In this work we demonstrated that an effective method for improving the injection properties of CPC was by the use of sodium citrate solution as a liquid component. Cement consisting of tetracalcium phosphate (TTCP) and monetite (DCPA) mixed with water up to a powder:liquid ratio (P:L) of 3.3 g/ml had an injectability of approximately 60%. The use of 500 mM trisodium citrate solution instead of water decreased the viscosity of the cement paste to a point, where complete injectability (>95%) through an 800 microm diameter hypodermic needle could be achieved at low loads. The reduction in water demand of the cement effected by the use of sodium citrate enabled high P:L mixes to be formed which were 400% stronger than cements made with water. The effect was less pronounced with compacted cements such that at 9 MPa applied pressure, 58% improvement was obtained and at 50 MPa 36% improvement was measured yielding a cement with a compressive strength of 154 MPa. The liquefying effect of sodium citrate was thought to derive from a strong increase in the surface charge of both the reactants and the product as determined by zeta-potential measurement.

Biocompatible Materials↗
PubMed2004

Ionic modification of calcium phosphate cement viscosity. Part II: hypodermic injection and strength improvement of brushite cement.

Brushite-forming calcium phosphate cements are of great interest as bone replacement materials because they are resorbable in physiological conditions. However, their short setting times, low mechanical strengths and limited injectability limit broad clinical application. In this study, we showed that a significant improvement of these properties of brushite cement could be achieved by the use of sodium citrate or citric acid as setting retardants, such that workable cement pastes with a powder to liquid ratio of up to 5 could be manufactured. The cement used in this study consisted of an equimolar powder mixture of beta-tricalcium phosphate and monocalcium phosphate hydrate The use of 500 mM-1M retardant solutions as liquid phase enabled initial setting times of 8-12 min. Wet compressive strength were found to be in the range between 12-18 MPa after immersion of uncompacted cement samples in serum for 24 h. A further strength improvement to 32 MPa was obtained by compaction of the cement paste during samples preparation. This is significant because high-temperature processes cannot be used to fabricate hydrated calcium phosphate materials. Cement pastes were injectable through a hypodermic needle at a powder to liquid ratio of 3.3 g/ml when a 1M citric acid was used as liquid phase, thus enabling precise controlled delivery to small defects.

Biocompatible Materials↗
PubMed2005

Influence of the method of blending an antibiotic powder with an acrylic bone cement powder on physical, mechanical, and thermal properties of the cured cement.

Two variants of antibiotic powder-loaded acrylic bone cements (APLBCs) are widely used in primary total joint replacements. In the United States, the antibiotic is manually blended with the powder of the cement at the start of the procedure, while, in Europe, pre-packaged commercially-available APLBCs (in which the blending is carried out using an industrial mixer) are used. Our objective was to investigate the influence of the method of blending gentamicin sulphate with the powder of the Cemex XL formulation on a wide collection of properties of the cured cement. The blending methods used were manual mixing (the MANUAL Set), use of a small-scale, easy-to-use, commercially-available mechanical powder mixer, OmoMix 1 (the MECHANICAL Set), and use of a large-scale industrial mixer (Cemex Genta) [the INDUSTRIAL Set]. In the MECHANICAL and MANUAL Sets, the blending time was 3 min. In preparing the test specimens for each set, the blended powder used contained 4.22 wt% of the gentamicin powder. The properties determined were the strength, modulus, and work-to-fracture (all obtained under four-point bending), plane-strain fracture toughness, Weibull mean fatigue life (fatigue conditions: +/-15 MPa; 2 Hz), activation energy and frequency factor for the cement polymerization process (both determined using differential scanning calorimetry, at heating rates of 5, 10, 15, and 20 Kmin(-1)), the diffusion coefficient for the absorption of phosphate buffered saline, PBS, at 37 degrees C, and the rate of elution of the gentamicin into PBS, at 37 degrees C (E). Also determined were the particle size, particle size distribution, and morphology of the blended powders and of the gentamicin. For each of the cured cement properties (except for E), there is no statistically significant difference between the means for the 3 cements, a finding that parallels the observation that there are no significant differences in either the mean particle size or the morphology of the blended cement powders. Notwithstanding these results, it is suggested that when the powder mixture is blended in the operating room, using the OmoMix 1 is more likely to produce a more consistent and reproducible mixture than when manual mixing is used.

Absorption↗
PubMed1995

In vitro enamel remineralization at orthodontic band margins cemented with glass ionomer cement.

Demineralization adjacent to orthodontic bands remains a clinical concern. The release of fluoride from glass ionomer cement has been shown to inhibit demineralization. The purpose of this study was to examine the remineralization effects of a glass ionomer cement adjacent to orthodontic bands. Forty extracted molars were painted with an acid-protective varnish, excluding a 2 x 6 mm window on the buccal surfaces. Artificial caries-like lesions were created in the exposed enamel with an acidified gel. Half the lesion on each tooth was then painted with an acid-protective varnish. An orthodontic band was cemented with a glass ionomer cement or zinc phosphate cement, the gingival margin of the band located at the level of the artificial carious lesion. The teeth were placed in separate closed environments of a nonfluoridated artificial saliva for 3 months. The teeth were then sectioned and photographed with polarized light microscopy in imbibition medias of water and Thoulet's (R.I.: 1.41, 1.47), representing a minimum of 5%, 10%, and 25% pore volume, respectively. With a sonic digitizer, the area of the body of the lesion was measured in each imbibition media, comparing the maintained varnished out lesions to the lesions exposed to the cement. Results demonstrated a statistically significant reduction in the body of the lesions (p < 0.005) for those exposed to the glass ionomer cement.

Dental Caries↗
PubMed1983

Investigation of hydrostatic pressure changes during cementation of screw-retained posts, and posts with integral cement release channels.

Intra-radicular pressures during the cementation of screw-retained posts have been found to reach 1.5 x 10(4) KN/m2 when cement is inserted into the prepared post hole or no pressure, indicating that an incomplete cement lute had developed, when the post was coated with cement. The effectiveness of cement channels was investigated and for the traditional single channel, using the cement 'insertion' method, there was an intra-radicular pressure of 8.5 x 10(4) KN/m2, compared with 1.1 x 10(4) KN/m2 for the corresponding round post. Multiple cement release channels gave an enhanced pressure reduction to 2.0 x 10(3) KN/m2.

Cementation↗