Application Of Cement Research Articles

Osteogenic effect of polymethyl methacrylate bone cement with surface modification of lactoferrin

Polymethyl methacrylate (PMMA) bone cement is a commonly used filling material in orthopedic surgery. Its good and stable performances make it the most widely used in all kinds of bone cement. With the advancement of the application and research of PMMA bone cement by surgeons, its disadvantages such as non-degradation and non-bioactivity are gradually exposed. In recent years, the biological functions of lactoferrin (LF) have been gradually explored, especially its role in promoting osteogenesis. In this study, LF was modified on the surface of solidified PMMA bone cement (LF/PMMA bone cement) by physical/chemical mixed modification and verified by cytological experiments invitro. Invitro studies have implicated that PMMA bone cement modified with LF can improve the attachment, expansion, proliferation, extracellular matrix secretion and osteogenic differentiation of mouse preosteoblasts (MC3T3-E1) cells, indicating biocompatibility. This experiment provides a novel insight for improving the biological activity of PMMA bone cement and lays a foundation for broadening the clinical application of PMMA bone cement.

Strength and Microstructure of Clay Geopolymer Non-Load-Bearing Masonry Units Using Fine-Clay Brick Waste and Palm Oil Fuel Ash

This research studies the applicability of alkali-activated cement with a mixture of fine-clay brick waste (FCBW) and palm oil fuel ash (POFA) to manufacture environmentally friendly masonry units. FCBW and POFA were used as a precursor, while a dredged soft clay (SC) was used as aggregate. Sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) solutions were used as the liquid alkaline activator. Effects of NaOH concentration, initial SiO2/Al2O3 mole ratio, Na2SiO3/NaOH ratio, and curing conditions on the strength and microstructure of the FCBW-POFA-SC geopolymers were evaluated. The FCBW-POFA-SC geopolymers had a lower total unit weight than compacted SC because NaOH in the geopolymer binder caused a flocculated soil structure. It was found that Na2SiO3/NaOH=70/30, 10 M NaOH, and FCBW/POFA=70/30 were the best ingredients providing the rigid network of the geopolymer structures. The suitable heat duration of 48 h at 80°C accelerated the dissolution rate of the Si and Al and polycondensation in the geopolymer structure, resulting in denser geopolymer gels and early strength gain. With this optimum ingredient and suitable heat condition, 7-day unconfined compressive strength (UCS) of the FCBW-POFA-SC geopolymers achieved the requirement of the Thailand industrial standard for non-load-bearing masonry units (UCS>2.5 MPa). The geopolymer products were found to be sodium aluminum silicate hydrate (N─ A─ S─ H) and calcium aluminum silicate hydrate (C─ A─ S─ H). The research outcome will promote the usage of waste materials for manufacturing environmentally friendly infrastructure in Thailand and other countries.

Preparation and Characterization of Cellulose Nanocrystals from Typha sp. as a Reinforcing Agent

ABSTRACT In this study, Typha latifolia (Typha sp.) was investigated as a new raw material for the isolation of cellulose nanocrystals (CNCs) for future application in geopolymer cement. Cellulose was extracted from the stem fibers by carrying out alkali and bleaching treatments. CNCs were then isolated from the extracted cellulose using the acid hydrolysis method. The chemical composition of cellulose, hemicellulose, and lignin was 60.9%, 7.0%, and 5.7%, respectively. Transmission electron microscopy showed a reduction in particle size due to the loss of the amorphous portion of the Typha sp. fiber. Thermogravimetric analysis showed that CNCs in the acid hydrolysis treatment have good thermal stability at 240 °C which is higher than raw ones. Based on the characteristics of a Typha sp. CNCs, it can be concluded that CNCs have the potential to be used as a reinforcement in geopolymer cement.

Water expansion performance standard for cement stabilized phosphogypsum soil

The application of cement stabilized phosphogypsum soil (CSPS) in highway engineering has great economic and social benefits. There are few corresponding classification standards for water swelling during long-term use and so a test method for water swelling of CSPS is designed. Unconfined compressive strength (UCS), dry shrinkage (DS), and temperature shrinkage (TS) of CSPS at three cement contents and eight phosphogypsum (PG) contents were measured. This paper analyzes the reasons for the poor early mechanical strength of CSPS. Based on the water expansion tests, ultimate expansion without load (δe) is proposed as the evaluation index for water expansion. Combined with the relationship between the shear strength of the CSPS after the termination of water expansion, δe, and PG content, a water swelling classification standard for CSPS is established. The results show that be is negatively correlated with cement content, and positively correlated with PG content. In combination with direct shear test results, CSPS is divided into mild water expansion (0 <δe ≤15), moderate water expansion (15 < δe ≤80), and severe water expansion (δe > 80).

Pull-out strength evaluation of cement augmented iliac screws in osteoporotic spino-pelvic fixation

IntroductionSpino-pelvic fixation has been widely accepted for surgical treatment of sacral tumor, scoliosis surgery and pelvic fractures. Cement augmentation of screws is an option to improve implant stability in osteoporotic bone quality. Aim of the present study is to compare iliac screw fixation without cement fixation and two cement application options in a biomechanical testing. HypothesisCement augmentation of iliac screws leads to superior pull-out strength. Material and methodsThirty female and osteoporotic human iliac bones were used. Three operation treatment groups were generated: Screw fixation (cannulated screws) without cement augmentation [Operation treatment (OT) A], screw fixation with cement augmentation before screw placement (cannulated screws) (OT B) and screw fixation with perforated screws and cement augmentation after screw placement (OTC). Pull-out tests were performed with a rate of 6mm/min. A load versus displacement curve was generated. Maximum pull-out force (N) was measured in the load-displacement curve. ResultsPaired group 1 (OT A vs. OT B): Screw fixation without cement augmentation: 592.6N±335.07 and screw fixation with cement augmentation before screw placement: 996N±287.43 (p=0.0042). Paired group 2 (OT A vs. OT C): screw fixation without cement augmentation: 716.2N±385.86 and fenestrated screw fixation with cement augmentation after screw placement: 1324.88N±398.76 (p=0.0489). Paired group 3 (OT B vs. OT C): Screw fixation with cement augmentation before screw placement: 1077.2±486.66 and fenestrated screw fixation with cement augmentation after screw placement: 1298.2N±726.19 (p=0.3286). DiscussionRegarding iliac screw fixation for spino-pelvic ostesynthesis in osteoporotic bone, cement augmentation is significantly superior to solid iliac screw fixation respecting pull-out-strength. Nevertheless, further biomechanical studies are needed to verify these findings. Level of evidenceNot applicable; biomechanical cadaver study.

Effect of Cement Replacement with Carbide Waste on the Strength of Stabilized Clay Subgrade

Cement is commonly used for soil stabilization and many other ground improvement techniques. Cement is believed to be very good to improve the compressive and split-tensile strength of clay subgrades. In some application cement could be partly or fully replaced with carbide waste. This research is to study the effectiveness of the cement replacement and to find the maximum carbide waste content to be allowed for a clay subgrade. The quantities of cement replaced with the carbide waste were 30, 50, 70, 90, and 100% by its mass. The results show that replacing the cement with carbide waste decreased both the compressive and split tensile strength. Replacing cement content with carbide waste reduced its ability for stabilization. The carbide waste content should be less than 70% of the cement to provide a sufficient stabilizing effect on a clay subgrade.

Bone Cement Formulation with Reduced Heating of Bone Cement Resin

Bone cement material is one of the key materials in bone surgery and orthopedic medicine. In this study, commercial polymethyl-methacrylate bone cement was mixed with boric acid and zinc borate to reduce the reaction temperature of the bone cement. The observation of temperature changes during the polymerization using laser thermometer and thermal camera showed that the use of boron compounds decreased the temperature of the bone cement at least 10 °C which is very critical for the biomaterial uses as it affects the biocompatibility of the material. Besides temperature monitoring, microbiological tests showed that the materials have certain antibacterial effect. Water contact angle studies also supported the biocompatibility studies. In the last part, mechanical tests showed that there was not significant change in the tensile strength and tensile modulus values. Antibacterial tests exhibited that zinc borate addition shows antimicrobial activity against S.epidermidis as well as boric acid addition over %5 concentration. According to the cell culture studies, boric acid can be interpreted as non-toxic up to 10%, while 10% and 20% zinc borate has toxic effect. This is the first study to use boron compounds in bone cement and it is proved that boric acid at low concentrations can be used for bone cement applications but zinc borate would not be suitable to use in medical applications due to toxic effects.

Exposure of calcined clay and low calcium flyash-based mortar on moderate acid environment

The resource management is one of the crucial issues in managing the various natural resources available. Presently, the application of cement in construction industry is very frequent in producing different structural elements. Such use of cement in preparing structural formworks emits a reasonable amount of carbon dioxide and other hazardous gases into the atmosphere during the manufacturing of cement. As a result, these mechanisms pollute the environment and degrade the thickness of the protective layer of ozone. Several concerns and measures have been taken to lower the footprint of carbon emission. One of them is the adoption of pozzolana. In the present study, Class F fly ash and calcined clay is taken as the substitute for ordinary Portland cement in 4%, 8%, 12%, 16%, and 20% for making mortar cubes cured up to 90 days. The cubes were subjected to the analysis of consistency, initial and final setting times, compressive strength, and acid attacks. The study revealed the interaction of pozzolans with the properties of the mortars and dependencies of the present proportions in forming the strength of the mortar cubes.

Factors Related to Instrumentation Failure in Titanium Mesh Reconstruction for Thoracic and Lumbar Tumors: Retrospective Analysis of 178 Patients.

PurposeTo investigate risk factors for instrumentation failure (IF) in titanium (Ti) mesh reconstruction for thoracic and lumbar tumors.Patients and MethodsThe clinical data of patients with thoracic or lumbar tumors who received Ti mesh reconstruction via the posterior approach in our hospital from 2013 to 2018 were analyzed retrospectively. The observation indexes included sex, age, BMI, the vertebra resection mode, the number of resected vertebral segments, application of bone cement, radiotherapy, chemotherapy, revision or primary surgery, and primary tumor metastasis. Correlations between these factors and IF were analyzed by Kaplan–Meier survival and logistics regression analyses.ResultsThe 178 patients included 108 males and 70 females with a mean age of 48.09±16.21 (6–78) years and a mean follow-up period of 51.18 (24–90) months. The data showed that 17 patients (9.55%) were inflicted with IF, involving the thoracic vertebra in 11 cases, thoracolumbar vertebrae (T12–L1) in 2 cases, and lumbar vertebrae in 4 cases. The mean interval between surgery to IF was 35.18±14.17 (14–59) months. Univariate analysis showed that total vertebral body resection, the number of resected vertebral segments, radiotherapy and multiple tumor resection were potential factors for IF, while multivariate analysis showed that only total vertebral body resection, the number of resected vertebral segments and radiotherapy were independent factors.ConclusionTotal vertebra resection, the number of resected vertebral segments (≥2) and radiotherapy before and after operation were significant risk factors related to IF.

Lumbar Intervertebral Spacer With Cement Augmentation of Endplates and Integrated Screws as a Fixation Device in an Osteoporotic Model: An In Vitro Kinematic and Load-to-Failure Study

Integrated lateral lumbar interbody fusion (LLIF) devices have been shown to successfully stabilize the spine and avoid complications related to posterior fixation. However, LLIF has increased subsidence risk in osteoporotic patients. Cement augmentation through cannulated pedicle screws enhances pedicle fixation and cage-endplate interface yet involves a posterior approach. Lateral application of cement with integrated LLIF fixation has been introduced and requires characterization. The present study set out to evaluate kinematic and load-to-failure properties of a novel cement augmentation technique with an integrated LLIF device, alone and with unilateral pedicle fixation, compared with bilateral pedicle screws and nonintegrated LLIF (BPS + S). Twelve specimens (L3-S1) underwent discectomy at L4-L5. Specimens were separated into 3 groups: (1) BPS + S; (2) polymethyl methacrylate (PMMA) augmentation, integrated LLIF, and unilateral pedicle screws (PMMA + UPS + iS); and (3) PMMA and integrated LLIF (PMMA + iSA) without posterior fixation. Flexion-extension, lateral bending, and axial rotation were applied. A compressive load was applied to L4-L5 segments until failure. An analysis was performed (P < .05). Operative constructs significantly reduced motion relative to intact specimens in all motion planes (P < .05). BPS + S provided the most stability, reducing motion by 71.6%-86.4%, followed by PMMA + UPS + iS (68.1%-79.4%) and PMMA + iSA (62.9%-81.9%); no significant differences were found (P > .05). PMMA + UPS + iS provided the greatest resistance to failure (2290 N), followed by PMMA + iSA (1970 N) and BPS + S (1390 N); no significant differences were observed (P > .05). Cement augmentation of vertebral endplates via the lateral approach with integrated LLIF moderately improved cage-endplate strength compared to BPS + S in an osteoporotic model; unilateral pedicle fixation further improved failure load. Reconstruction before and after application of unilateral pedicle screws and rods was biomechanically equivalent to anteroposterior reconstruction. Overall, initial results suggest that integrated LLIF with cement augmentation may be a viable alternative in the presence of osteoporosis.

The technique of cement application has no influence on cement intrusion in total knee arthroplasty: randomized study comparing three different techniques

The technique of cement application has no influence on cement intrusion in total knee arthroplasty: randomized study comparing three different techniques

Preparation and characterization of high-strength and water-resistant waterborne epoxy resin/magnesium oxychloride composite based on cross-linked network structure

To expand the application of magnesium oxychloride cement (MOC) as a kind of engineering materials in the construction field, organic–inorganic hybrid modifications were performed. Waterborne epoxy resin/magnesium oxychloride composites (WER/MOC) with high-strength and water-resistance were prepared using a simple and green method with MOC as matrix and WER as reinforcement. The effects of WER on the resulting composite’s viscosity, mechanical strength, water resistance, phase composition, thermal stability, and micromorphology were discussed. The results demonstrated that WER reduced the viscosity of the WER/MOC complex system, and the composite water resistance and compressive strength were improved, which were mainly attributed to chemical reactions between WER and MOC to form a crosslinked network structure. Meanwhile, XRD analysis results showed that the intensity of the diffraction peak of the 3-phase decreased and 5-phase increased with WER addition to the composite and no new crystal phase appeared. The compressive strength, water resistance, thermal stability, and porosity of these WER/MOC composites reached the best values when the WER mass proportion was 4.8%. Here, the composite water absorption rate decreased to 8.7%, softening coefficient increased to 17.8%, middle compressive strength (sealed for 7 d) at 48.0 MPa, and dry bulk density increased to 1.34 g/cm3. Thus, these WER/MOC composites were suitable for use as engineering materials in the construction and road industries.

Closed Reduction and Percutaneous Pinning for Treatment of Proximal Interphalangeal Joint Pilon Fractures.

Proximal interphalangeal (PIP) joint pilon fractures are among the challenging hand injuries, which are often associated with a wide range of complications. This study aimed to report the clinical and radiological outcomes of closed reduction and percutaneous Kirschner wire (KW) insertion with or without bone cement application (for the fabrication of an external fixator) in the treatment of PIP joint pilon fractures. Twenty pilon fractures underwent closed reduction and percutaneous KW fixation through a modified technique. At the end of the follow-up period, 3 questionnaires-Quick Disabilities of the Arm, Shoulder, and Hand (Quick DASH), Visual Analogue Scale for pain, and Patient-Rated Wrist Evaluation-were completed. The radiological outcome was assessed by radiography. Range of motion, and grip and pinch strength were measured. The mean follow-up period was 14.57 ± 4.03 months (range, 12-20 months). The mean range of motion of PIP at the end of the follow-up period was 89.64° ± 10.82° (range, 65°-100°). The mean difference in the range of motion in the contralateral side was 21.4° ± 13°. The mean of the Quick DASH score was 13.50 ± 2.92 (range, 11-21). Two patients had residual articular malalignment, and 3 patients had angular or rotational malunion. By treating pilon fractures with the proposed technique, we achieved a satisfactory outcome. The acceptable articular and axial alignment was achieved in 75% of patients, and complications were low. The flexibility of percutaneous KW insertion and handmade external fixators makes these approaches convenient for treating PIP joint pilon fractures.

Resistance Reduction Scheme for Tower Grounding with Conductive Cement

The construction conditions of transmission lines are becoming more and more difficult. It is necessary to find new ways to reduce the grounding resistance of poles and towers at high soil resistivity and small construction area. Conductive cement samples with graphite, stainless steel fibers, and their mixtures as conductive phases materials were prepared, the resistivity, flexural strength and compressive strength were tested, compared and analyzed. The graphite and stainless steel fiber conductive cement with better comprehensive performance was selected out for tower grounding. The application schemes of conductive cement for tower grounding were designed and compared, the partial wrapping scheme was selected and its application methods under different soil resistivity was analyzed. The analysis results can provide theoretical basis and guidance for the application of conductive cement in transmission tower grounding, the feasibility of scheme is proved by the field application.

Experimental and Numerical Investigation of PMMA Based Composites used for Bone Cement Application

Polymethylmethacrylate PMMA is considered a generally famous bone cement base material. Most failures that take place during function, are due to its weakness and lack of mechanical resistance. The clear limitations of PMMA are not enough ductility, strength, and viscoelastic behavior. Current research is an attempt to numerically using finite element and experimentally investigate of flexural and compression behaviour of PMMA bone cement strengthen and improve by adding modified TiO2 nanoparticles (m-TiO2 NPs). Therefore, the neat TiO2 nanoparticles were modified by silane coupling agent and then added by different ratios (0.5, 1, 1.5, and 2 wt %) to the PMMA bone cement. Fourier transform infrared spectroscopy (FTIR) technique used to investigate the modification process, as well as to specify the bonding type between the m-TiO2NPs and the PMMA bone cement matrix. (SEM) technique used to study the morphologies of the prepared samples. Properties were measured bending strength, compression strength and modulus of elasticity. Results proved the successes of TiO2NPs modification by silane coupling agent and the absence of any chemical bonding between this modified filler and other PMMA bone cement ingredients. The mechanical properties increased by m-TiO2NPs addition up to 1 wt% ratio then decreased. For the purpose of making sure of the possibility of using the proposed composite materials in the application of bone cement, numerical simulation was used using the ANSYS (16.1) program for the femur model, and the results showed good agreement with the practical results. The morphology and numerical results supported the mechanical properties trends.

Effect of Different Surface Treatment Methods on Bond Strength of Dental Ceramics to Dental Hard Tissues: A Systematic Review.

For long-term successful use of ceramic materials in dental procedures, it is necessary to ensure reliable bonding of restorations to dental substrates. This can be achieved by the application of a proper luting cement and through additional surface conditioning. The present systematic review summarizes the most up-to-date evidence on the use of different surface modification methods to enhance the bond strength of dental ceramics to the hard tissues of the teeth. The authors of the review searched the Web of Science, Scopus, and MEDLINE databases to identify relevant articles published between 1 January 2010 and 1 January 2020. A total of 4892 records were identified, and after screening, the full text of 159 articles was evaluated, which finally resulted in the inclusion of 19 studies. The available reports were found to be heterogeneous in terms of materials and methodology, and therefore, only within-studies comparison was performed instead of comparison between studies. A statistically significant difference in the bond strength between the samples treated with different methods of surface conditioning, or between conditioned and nonconditioned samples, was revealed by most of the studies. Predominantly, the studies showed that a combination of mechanical and chemical methods was the most effective way of enhancing bond strength. Artificial aging and luting cement were also identified as the factors significantly influencing bond strength.

Early age hydration and application of blended magnesium potassium phosphate cements for reduced corrosion of reactive metals

Magnesium potassium phosphate cements (MKPC) were investigated to determine their efficacy towards retardation of reactive uranium metal corrosion. Optimised low-water content, fly ash (FA) and blast furnace slag (BFS) blended MKPC formulations were developed and their fluidity, hydration behaviour, strength and phase assemblage investigated. In-situ time resolved synchrotron powder X-ray diffraction was used to detail the early age (~60 h) phase assemblage development and hydration kinetics, where the inclusion of BFS was observed to delay the formation of struvite-K by ~14 h compared to FA addition (~2 h). All samples set within this period, suggesting the possible formation of a poorly crystalline binding phase prior to struvite-K crystallisation. Long-term corrosion trials using metallic uranium indicated that MKPC systems are capable of limiting uranium corrosion rates (reduced by half), when compared to a UK nuclear industry grout, which highlights their potential application radioactive waste immobilisation.

Synthesis of star PMMA via ARGET ATRP towards application in acrylic bone cements

AbstractIn this study, we attempted to apply a four‐arm star poly(methyl methacrylate) (4sPMMA) as a prepolymer of acrylic bone cement. The 4sPMMA with viscosity average molecular weight of about 45 kDa was synthesized via Atom Transfer Radical Polymerization method using Activators Regenerated by Electron Transfer (ARGET ATRP). In practical use, the fine powder of precipitated 4sPMMA was changed to rigid beads followed by making sheet and pulverizing. Proton nuclear magnetic resonance (HNMR), Fourier transform infrared (FTIR) spectra of 4sPMMA beads indicated the star structure of 4sPMMA with bromide end groups (C‐Br). Scanning electron microscopy (SEM) image of 4sPMMA beads showed their random shapes with size in the range of 10‐100 μm, no traces of residual metal catalysts (Cu and Sn) were detected by Energy Dispersive X‐Ray (EDX) analysizer equipped with SEM instrument. Bone cement from 4sPMMA beads had been prepared manually and curing in rectangular and cylindrical molds. The setting characterization results showed that 4sPMMA bone cements exhibited lower maximum temperature (63.9 °C), lower setting temperature (45.6 °C), than those required in ISO 5833:2002. Other properties of 4sPMMA bone cement, such as bending strength, bending modulus and setting time met the requirements of above ISO standard.

Tooth Discoloration Using Calcium Silicate-Based Cements For Simulated Revascularization in Vitro.

The endodontic revascularization may be an alternative treatment for necrotic immature teeth, however, several treatment steps may cause tooth discoloration. This study evaluated the use of three calcium silicate-based cements with different radiopacifying agents on the color alteration (∆E) of extracted premolars after simulation of revascularization. Forty single rooted extracted premolars were shaped with #1-6 gates Glidden drills, rinsed with sodium hypochlorite, and filled with fresh human blood. Three calcium silicate-based cements with different radiopacifying agents (bismuth oxide - CSBi, calcium tungstate - CSW, and zirconium oxide - CSZr) were applied over the blood clot (n=10). The control group received the application of a temporary zinc oxide-based cement (TFZn) (n=10). ∆E was measured with a spectrophotometer, using the L*a*b* color system of the International Commission on Illumination (CIELab), in different times: prior to the preparation of the access cavity (t0); right after treatment (t1); and after one (t2), two (t3), three (t4) and four (t5) months. The tooth site for color evaluation was standardized by silicon matrix, the color reading was performed 3 times per tooth, and the teeth were stored in 37º water between evaluations. ∆E, whiteness (WID index) and yellowness (b*) were evaluated. Data were subjected to one-way ANOVA and repeated measures ANOVA, followed by Tukey's post hoc test (α=0.05). All groups were similar in ∆E1 (t0-t1). The ∆E was the lowest and constant in the control group. In all evaluation times, CSBi presented the highest ∆E (p<0.01). CSW and CSZr were similar in all evaluated times and presented intermediate ∆E values. WID index from CSBi and CSW presented more distancing from 'white' reference. CSBi presented the greatest decrease in yellowness (b* value). The cement containing bismuth oxide presented the highest color alteration values. All tested calcium silicate-based cements presented clinically perceptible discoloration. Calcium tungstate and zirconium oxide may be used as alternative radiopacifiers to decrease tooth discoloration after endodontic tooth revascularization.

The influence of calcined mixture cooling method on hydration products composition of blended cement stone

Complex additives based on combinations of calcined clays, including kaolinite with limestone, due to the synergetic effect play a major role in the creation of blended cements. Usually carbonate rocks contain clay impurities with adverse effects on the properties of the resultant cements and concretes. At the same time calcium carbonate contained in marl clays during calcination allows getting high-quality pozzolanic material. The effective complex additive based on the calcined mixture of clay and limestone was created. The aim of the study is to determine the effect of fast and slow cooling methods of the artificial mixture after calcination on the hydration products composition of blended cement stone with complex additives of calcined mixtures of clays and carbonates. Obtained results allow determining the conditions for obtaining effective complex additives based on calcined mixtures of ubiquitous clays and carbonate rocks for their application in blended Portland cement, and thus to expand the range of the latter. It is found that the preferred method is the fast cooling of the resulting mixture, which contributes to obtaining a complex additive with higher pozzolanic properties, compared with the additive obtained by the slow cooling method.