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 199 records · Page 11Linked to original sources
PubMed1993

A novel skeletal drug delivery system using self-setting bioactive glass bone cement. IV: Cephalexin release from cement containing polymer-coated bulk powder.

A novel device consisting of Eudragit-coated cephalexin as a model drug and a self-setting bioactive cement based upon CaO-SiO2-P2O5 glass was investigated. The glass cement hardened within 5 min of mixing with a phosphate buffer. After setting, in vitro drug release from homogeneous or heterogeneous drug-loaded cement pellets in a simulated body fluid (SBF) at pH 7.25 and 37 degrees C continued for over 2 weeks. The hardened cement gradually formed low-crystallinity hydroxyapatite and decreased in volume by about 5% during drug release in SBF. Consequently, 30% of the loaded drug was initially released from the homogeneous cement system, and thereafter it was released more slowly. Since the heterogeneous system consisting of the cement and a 50% polymer coated, drug-loaded pellet avoided this drug's burst, the drug was released over a longer period than that in the homogeneous system. The heterogeneous system released the polymer-coated drug very slowly, because it completely avoided the initial burst, and sustained the release over a long period.

Biocompatible Materials↗
PubMed1976

Monomer leakage from polymerizing acrylic bone cement. An in vitro study on the influence of speed and duration of mixing, cement volume and surface area.

An in vitro study was dthesigned to measure the effects of variable cement volumes and modified mixing techniques on the monomer leakage after simulated implantation. The cement volume as such was found to be an irrelevant parameter for calculations of the monomer loss from bone cement. The leakage was directly related to the surface area of the cement. Variations in the thickness of the cement mantle from 1 to 5 mm did not affect the leakage. Late cement insertion should reduce the total monomer leakage into the tissues. It is doubtful whether an increased stirring speed during mixing reduces the monomer leakage after implantation.

Bone Cements↗
PubMed1995

A novel skeletal drug delivery system using self-setting calcium phosphate cement. 9: Effects of the mixing solution volume on anticancer drug release from homogeneous drug-loaded cement.

The effects of mixing solution volume (0.25-0.65 mL/g) on in vitro drug release from a self-setting bioactive calcium phosphate cement containing the anticancer agent 6-mercaptopurine (6-MP) as a model compound were investigated. The drug release profiles from isolated planar surfaces as well as the entire surfaces of cement systems containing 5% 6-MP were measured in simulated body fluid at pH 7.25 and 37.0 degrees C. The drug release rate from both cement system geometries increased with increasing mixing solution volume. Drug release profiles from the planar-release and entire-surface-release cement matrix systems were analyzed by and found to agree with the Higuchi and Cobby equations, and the kinetic parameters were estimated with a nonlinear least-squares computer program. Linear relationships were found between the mixing solution volume and the drug release rate constants or time required for 50% drug release for both cement release geometries. Furthermore, the total pore volume of the cements, as measured by mercury porosimetry, increased with increasing mixing solution volume.

Antineoplastic Agents↗
PubMed2006

An alternative to Portland Cement for waste encapsulation--the calcium sulfoaluminate cement system.

Currently, Portland Cement (PC) is used extensively in the solidification/stabilisation of a wide variety of wastes. In the nuclear industry, low and intermediate level radioactive wastes are encapsulated or immobilised within composite PC cement systems based on high replacement with blast furnace slag or fly ash. However, the high alkalinity of these PC-based systems will corrode reactive metals found in some wastes releasing hydrogen and forming expansive corrosion products. Alternative cement systems could provide a different hydration chemistry, which would allow wastes containing these metals to be encapsulated with lower reactivity. Calcium sulfoaluminate (CS A) cement is one such cement. It combines economy of cost and low emission of CO(2) with rapid strength gain and compatibility with other construction materials. Hydration provides an internal pore solution where the pH is considerably lower than that of PC. The main hydration product, ettringite, can incorporate a number of ions into its crystal structure, making it an ideal candidate for waste immobilisation. This paper details some results from a commercial CS A system that examines aspects of mixing, hydration of different formulations and aluminium corrosion behaviour. The fluidity of mixes can be adjusted by changing the formulations. All designed mixes were set within 24 h with little bleeding and the pH values were in the range of 10-11.5. In addition, a significant reduction in Al corrosion was observed compared to a composite OPC system. Although these results provide encouragement for the idea that CS A cement can provide a possible alternative to PC in the immobilisation of difficult and reactive wastes, further investigation is needed.

Aluminum↗
PubMed1999

Hydroxyapatite coating versus cemented fixation of the tibial component in total knee arthroplasty: prospective randomized comparison of hydroxyapatite-coated and cemented tibial components with 5-year follow-up using radiostereometry.

Fifty-three consecutive patients (57 knees; mean age, 69 years) entered a prospective randomized study to compare the fixation of hydroxyapatite (HA)-coated (29 knees) with cemented (28 knees) tibial components in the Tricon II total knee arthroplasty. The quality of the fixation during 5 years postoperatively was evaluated with radiostereometric analysis (RSA). Three HA-coated implants were revised: 2 owing to infection, and 1 owing to early delamination of the coating and clinical loosening. Eight patients (9 knees) died, 1 patient sustained a stroke, and 1 patient refused investigations after 1 year. In the 40 patients (19 HA-coated, 21 cemented) remaining at 5 years, the magnitude of the micromotion between the HA-coated and cemented groups did not differ. The HA-coated implants displayed most of the migration within the initial 3 months then stabilized, whereas the cemented implants showed an initially lower, but over time continuously increasing migration. Between 1 and 2 years, 4 of 24 HA-coated and 10 of 23 cemented implants migrated >0.2 mm and were categorized unstable, which has been shown to have a prognostic value as regards future aseptic loosening. Progressive radiolucent lines developed in 2 cemented knees, which both were categorized unstable. If HA-coated implants can sustain the forces that threaten the fixation in the early period after implantation, a strong and enduring fixation may be obtained.

Adult↗
PubMed2006

Dose response effect of cement dust on respiratory muscles competence in cement mill workers.

Electromyography (EMG) of respiratory muscles is a reliable method of assessing the ventilatory muscle function, but still its use has not been fully utilized to determine the occupational and environmental hazards on respiratory muscles. Therefore, EMG of intercostal muscles was performed to determine the dose response effect of cement dust on respiratory muscles competence. Matched cross-sectional study of EMG in 50 non-smoking cement mill workers with an age range of 20 - 60 years, who worked without the benefit of cement dust control ventilation or respiratory protective devices. EMG was performed by using surface electrodes and chart recorder. Significant reduction was observed in number of peaks (p < 0.0005), maximum peak amplitude (p < 0.0005), peak-to-peak amplitude (p < 0.0005) and duration of response (p < 0.0005) in cement mill workers compared to their matched control. Cement dust impairs the intercostal muscle competence and stratification of results shows a dose-effect of years of exposure in cement mill.

Adult↗
PubMed1989

Calcium phosphate cements: action of setting regulators on the properties of the beta-tricalcium phosphate-monocalcium phosphate cements.

Various additives were tested as setting retarders of the beta-tricalcium phosphate-monocalcium phosphate monohydrate (beta-TCP-MCPM) cements. Calcium pyrophosphate (CPP), calcium sulphate dihydrate (CSD) and calcium sulphate hemihydrate (CSH) were found to increase the setting time from 30 s to about 10 min. Moreover, the use of CSH resulted in a marked increase of the final diametral strength of the cement, which could be raised from 1 MPa to about 3 MPa. The best results were obtained when CSH and CPP were added together to the cement, while the addition of CSD and CPP alone only retarded the setting, without improving the final strength. A particular cement composition (64 wt% beta-TCP, 16 wt% MCPM, 15 wt% CSH and 5 wt% CPP), selected for its optimum final strength, was aged in vitro for 8 d at 37 degrees C in saline solution (0.9 wt% NaCl in water). After a moderate decrease, the diametral strength of the specimen was found to level off at about 60% of its initial value (3.2 MPa), for ageing times beyond 1 d. This behaviour has been ascribed to the progressive dissolution of the CSD fraction of the hardened cement, compensated by the crystallization of further amounts of DCPD.

Bone Cements↗
PubMed1996

Effect of dowel lubrication on resistance to dislodgment of dowels cemented with a 4-META resinous cement.

Dentatus stainless steel dowels were cemented 5 mm into prepared canals of extracted human teeth with C&B Metabond cement. One half the dowels were lubricated before cementation to ensure easy subsequent retrieval. Significantly less tensile force was required to dislodge the lubricated dowels (p = 0.0209). Retrievable lubricated dowels could provide dentists the option of nonsurgical endodontic retreatment in lieu of endodontic surgery. However, lubrication cannot be recommended for clinical use at this time because of the potential for the dowel to unscrew during normal oral function. Further studies are required to determine the effects of rotational forces on the lubricated dowel, surface design of the dowel on retention, and chemical interaction of the lubricant on the resinous cement. Long-term effects of the lubricant on the cement are unknown.

Acrylic Resins↗
PubMed2005

All-polyethylene vs. metal-backed tibial component in total knee arthroplasty-a randomized RSA study comparing early fixation of horizontally and completely cemented tibial components: part 1. Horizontally cemented components: AP better fixated than MB.

BACKGROUND: Controversy still exists as to whether to mount the tibial bearing on a metal baseplate or not. Furthermore, the tibial component can be either horizontally or completely cemented. We evaluated metal backing versus all-polyethylene using horizontal cementing technique. PATIENTS AND METHODS: We randomized 40 patients with knee arthrosis (40 knees) to 2 groups: cemented total knee arthroplasty (AGC, Biomet) using either all-polyethylene (AP) or metal-backed (MB) tibial components (n = 20 for each group). All tibial implants had a total thickness of 8 mm. We used proximal cement-ing, including only the horizontal part of the tibia with avoidance of the stem-bone interface. RESULTS: The positioning of the implants, as judged by the HKA angle, showed an average neutral alignment in both groups. Preoperatively and after 2 years, there was no statistically significant difference between the HSS scores in both groups (p = 0.6 and 0.4). After 2 years, the metal-backed components had rotated more around the longitudinal axis, median 0.5 degrees vs. 0.2 degrees (internal or external rotation, p = 0.002), and showed increased maximum total point motion, median 1.0 vs. 0.4 mm (maximum migration or MTPM, p = 0.003). INTERPRETATION: Our study indicates that better fixation can be obtained with the all-polyethylene design if proximally cemented thin components are used.

Aged↗
PubMed2005

All-polyethylene vs. metal-backed tibial component in total knee arthroplasty-a randomized RSA study comparing early fixation of horizontally and completely cemented tibial components: part 2. Completely cemented components: MB not superior to AP components.

BACKGROUND: Uncertainty exists as to whether metal backing (MB) of the tibial component is better than an all-polyethylene component (AP). This is valid for both horizontally and completely cemented components. We evaluated completely cemented MB vs. AP (Part 2). PATIENTS AND METHODS: In a randomized study, 39 patients (40 knees) with knee arthrosis were operated with cemented low-conforming total knee arthroplasty (AGC, Biomet) with a tibial component of uniform thickness (8 mm), cemented both beneath the tibial tray and around the stem. 20 patients had an all-polyethylene (AP) tibial component and 20 patients had an identical but metal-backed (MB) tibial component. We used clinical examination and radiostereometric analysis (RSA) to evaluate the hypothesis that MB improves component fixation. Fixation was evaluated using RSA up to 2 years after surgery. Clinical assessment was performed preoperatively and after 2 years using the Hospital for Special Surgeons (HSS) score. RESULTS: We found no differences in micromotion, and no differences in clinical scores could be detected between the groups at any time point. INTERPRETATION: Our findings indicate that there was equal initial fixation of the AP and MB stemmed monobloc components when they were cemented beneath the tibial plateau and around the stem.

Aged↗
PubMedDate not supplied

[Traction resistance of cast metal posts with and without retention, cemented with zinc phosphate cement in smooth and rough canals].

The purpose of this research was to test the traction resistance of cast posts and cores with and without roughness cemented with zinc phosphate cement in cuspids roots, with smooth and roughness canals walls. From the results of the tests and statistical analysis there was significant difference between roughness posts cemented in root canals with roughness walls and smooth posts cemented in smooth root canals. It was also analyzed, the retention of cast crows cemented on roughness posts and canals and it was concluded that posts are responsible for crows retention, when the cores were done at the correct way.

Cementation↗
PubMed1997

Microleakage of glass ionomer cement composite resin and glass ionomer resin cement.

An in vitro dye leakage study was performed to compare the sealing ability of glass ionomer, composite resin and glass ionomer/resin cement when used as restorative materials for G.V. Black class V cavities. In this research, standard Class V cavities were prepared in sound premolar teeth extracted for orthodontic reasons. The cavities were randomly divided into 3 groups. After filling the cavities with glass ionomer cement, composite resin and light curing glass ionomer/resin cement, the specimens were immersed in silver nitrate solution. Marginal microleakage at the interface between the cavity wall and restoration was evaluated. The results were analyzed by using Kruskal-Wallis and Mann Whitney U tests. Result of this in vitro study indicate that composite resin and glass ionomer/resin cement provide a better seal than glass ionomer cement.

Aluminum Silicates↗
PubMedDate not supplied

Fracture resistance of metal- and galvano-ceramic crowns cemented with different luting cements: in vitro comparative study.

This study aimed to compare the fracture resistance of galvano-ceramic crowns with metal-ceramic crowns cemented to natural premolar teeth with different luting cements. Sixty intact maxillary premolars were prepared to receive full-coverage crown restorations and were divided into 2 equal groups (n = 30): galvano-ceramic crowns and metal-ceramic crowns. Each group was further subdivided into 3 equal subgroups (n = 10) according to the luting cement used: zinc-phosphate, glass-ionomer, or adhesive-resin cement. The specimens were then compressively loaded until failure in a universal testing machine. The metal-ceramic crowns exhibited higher resistance to fracture compared to galvano-ceramic crowns, but both exceeded the normal documented values of occlusal masticatory forces.

Bicuspid↗
PubMed2003

Antibiotic bone cement for the treatment of Pseudomonas aeruginosa in joint arthroplasty: comparison of tobramycin and gentamicin-loaded cements.

One hundred clinical isolates of Pseudomonas aeruginosa were collected from 22 medical centers throughout Europe and were challenged with two aminoglycoside-loaded bone cements, employing a modified in vitro Kirby-Bauer susceptibility model. The results of this study show that Simplex P with tobramycin exhibits antibacterial activity against 98% of the strains tested, compared to 93% for Palacos with gentamicin. Additionally, for strains that were susceptible to the antibiotic bone cement formulations, the average zone of inhibition produced around the tobramycin-loaded cement disks was approximately 25% greater than that seen around the gentamicin-loaded cement disks. This difference was statistically significant (p << 0.01). Tobramycin-loaded bone cement is therefore the preferred formulation when addressing Pseudomonas aeruginosa in septic joint arthroplasty.

Anti-Bacterial Agents↗
PubMed1995

Heat generation and heat protection in methylmethacrylate cementation of vertebral bodies. A cadaver study evaluating different clinical possibilities of dural protection from heat during cement curing.

For metastatic disease of the spine, anterior operations on the vertebral bodies often include methylmethacrylate cementation. The cement curing process may produce high temperatures in the surroundings, as demonstrated in joint replacement surgery, and there is a risk of thermal injury to the spinal nerves. In cadavers, we studied the heat arising during curing of cement on the dural sac, and the temperature of the cement surface was measured when the vertebral body was reconstructed using acrylic cement in the same way as in tumor surgery. The temperature increase on the surface of the dural sac during polymerization was between 4 degrees and 12 degrees C, depending on the amount of protection. Only a moderate temperature elevation was measured on the surface of the dural sac, provided that the posterior cortex of the vertebra was retained together with 0.5 cm of the spongious bone or a silicone membrane.

Bone Cements↗
PubMed2001

Cement removal with an endoscopically controlled ballistically driven chiselling system. A new device for cement removal and preliminary clinical results.

In this paper, we introduce a newly developed miniaturised chiselling system (Swiss OrthoClast) which allows endoscopically controlled cement removal even from deep within the femur in hip revision arthroplasty. The intraoperative handling is demonstrated and illustrated. The device consists of a control unit, a handpiece, a set of chisels of different lengths, shape, and tip geometry, a set of plug extraction tools, and a special intrafemoral endoscope. It uses simple ballistic principles to effect fracturing of the bone cement. Inside the handpiece the projectile is accelerated and strikes the chisel head. The tip moves at high speed and with a small excursion towards the cement, which is fragmented mechanically by the movement of the chisel tip without generating heat. The device is being validated in a prospective, international, multicenter study, and we include here the results of the first 28 clinical procedures of cement removal. The duration of the procedure varied from 13 to 75 min, with an average of 32 min. In all but one case, the cement was completely removed. We noted one case of cortical fissuring.

Aged↗