Clinical Efficacy of Polycaprolactone β-Calcium Triphosphate Composite for Osteoconduction in Rabbit Bone Defect Model

The combination of β-tricalcium phosphate (β-TCP) with polycaprolactone (PCL) has been considered a promising strategy for designing scaffolds for bone grafting. This study incorporated PCL with commercially available β-TCP (OsteoceraTM) to fabricate an injectable bone substitute and evaluate the effect of PCL on compressive strength and setting time of the hydraulic cement. The mechanical testing was compliant with the ASTM D695 and ASTM C191-13 standards. Results showed that PCL-TCP composite presented a well-defined architecture with uniform pore distribution and a significant increase in compressive strength compared with β-TCP alone. Eighteen rabbits, each with two surgically created bone defects, were treated using the PCL-TCP composites. The composite materials were resorbed and replaced by newly formed bone tissue. Both PCL-TCP and β-TCP demonstrated equivalent clinical effects on osteoconduction property in terms of the percentage of newly formed bone area measured by histomorphometric analysis. PCL-TCP was proven to be as effective as the commercially available β-TCP scaffold (OsteoceraTM).

Download Full-text

In Vivo Efficacy of Neutrophil-Mediated Bone Regeneration Using a Rabbit Calvarial Defect Model

International Journal of Molecular Sciences ◽

10.3390/ijms222313016 ◽

2021 ◽

Vol 22 (23) ◽

pp. 13016

Author(s):

Thanuja D. K. Herath ◽

Leonardo Saigo ◽

Benoit Schaller ◽

Anis Larbi ◽

Swee Hin Teoh ◽

...

Keyword(s):

Bone Regeneration ◽

Volume Fraction ◽

Bone Defects ◽

Bone Volume ◽

Surgical Removal ◽

Calvarial Defect ◽

Bone Area ◽

Defect Model ◽

In Vivo Efficacy

Reconstruction of bone due to surgical removal or disease-related bony defects is a clinical challenge. It is known that the immune system exerts positive immunomodulatory effects on tissue repair and regeneration. In this study, we evaluated the in vivo efficacy of autologous neutrophils on bone regeneration using a rabbit calvarial defect model. Methods: Twelve rabbits, each with two surgically created calvarial bone defects (10 mm diameter), were randomly divided into two groups; (i) single application of neutrophils (SA-NP) vs. SA-NP control, and (ii) repetitive application of neutrophils (RA-NP) vs. RA-NP control. The animals were euthanized at 4 and 8 weeks post-operatively and the treatment outcomes were evaluated by micro-computed tomography, histology, and histomorphometric analyses. Results: The micro-CT analysis showed a significantly higher bone volume fraction (bone volume/total volume) in the neutrophil-treated groups, i.e., median interquartile range (IQR) SA-NP (18) and RA-NP (24), compared with the untreated controls, i.e., SA-NP (7) and RA-NP (14) at 4 weeks (p < 0.05). Similarly, new bone area fraction (bone area/total area) was significantly higher in neutrophil-treated groups at 4 weeks (p < 0.05). Both SA-NP and RA-NP had a considerably higher bone volume and bone area at 8 weeks, although the difference was not statistically significant. In addition, immunohistochemical analysis at 8 weeks revealed a higher expression of osteocalcin in both SA-NP and RA-NP groups. Conclusions: The present study provides first hand evidence that autologous neutrophils may have a positive effect on promoting new bone formation. Future studies should be performed with a larger sample size in non-human primate models. If proven feasible, this new promising strategy could bring clinical benefits for bone defects to the field of oral and maxillofacial surgery.

Download Full-text

Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽

10.3390/ma14071611 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1611

Author(s):

Gintautas Skripkiūnas ◽

Asta Kičaitė ◽

Harald Justnes ◽

Ina Pundienė

Keyword(s):

Compressive Strength ◽

Cement Paste ◽

Setting Time ◽

Calcium Nitrate ◽

Curing Temperature ◽

Hardened Concrete ◽

Cement Pastes ◽

Initial Setting Time ◽

Initial Setting ◽

Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

Download Full-text

Effect of Waste Glass on the Properties and Microstructure of Magnesium Potassium Phosphate Cement

Materials ◽

10.3390/ma14082073 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2073

Author(s):

Qiubai Deng ◽

Zhenyu Lai ◽

Rui Xiao ◽

Jie Wu ◽

Mengliang Liu ◽

...

Keyword(s):

Compressive Strength ◽

Glass Powder ◽

Setting Time ◽

Potassium Phosphate ◽

Heat Of Hydration ◽

Waste Glass ◽

Hydration Heat ◽

Magnesium Potassium Phosphate Cement ◽

The Matrix ◽

Powder Content

Waste glass is a bulk solid waste, and its utilization is of great consequence for environmental protection; the application of waste glass to magnesium phosphate cement can also play a prominent role in its recycling. The purpose of this study is to evaluate the effect of glass powder (GP) on the mechanical and working properties of magnesium potassium phosphate cement (MKPC). Moreover, a 40mm × 40mm × 40mm mold was used in this experiment, the workability, setting time, strength, hydration heat release, porosity, and microstructure of the specimens were evaluated. The results indicated that the addition of glass powder prolonged the setting time of MKPC, reduced the workability of the matrix, and effectively lowered the hydration heat of the MKPC. Compared to an M/P ratio (MgO/KH2PO4 mass ratio) of 1:1, the workability of the MKPC with M/P ratios of 2:1 and 3:1 was reduced by 1% and 2.1%, respectively, and the peak hydration temperatures were reduced by 0.5% and 14.6%, respectively. The compressive strength of MKPC increased with an increase in the glass powder content at the M/P ratio of 1:1, and the addition of glass powder reduced the porosity of the matrix, effectively increased the yield of struvite-K, and affected the morphology of the hydration products. With an increase in the M/P ratio, the struvite-K content decreased, many tiny pores were more prevalent on the surface of the matrix, and the bonding integrity between the MKPC was weakened, thereby reducing the compressive strength of the matrix. At less than 40 wt.% glass powder content, the performance of MKPC improved at an M/P ratio of 1:1. In general, the addition of glass powders improved the mechanical properties of MKPC and reduced the heat of hydration.

Download Full-text

Role of Autologous Platelet Gel (APG) in Bone Healing: A Rabbit Study

Applied Sciences ◽

10.3390/app11010395 ◽

2021 ◽

Vol 11 (1) ◽

pp. 395

Author(s):

Antonio Scarano ◽

Francesco Inchingolo ◽

Biagio Rapone ◽

Alberta Greco Lucchina ◽

Erda Qorri ◽

...

Keyword(s):

Critical Size ◽

Bone Defects ◽

New Bone Formation ◽

Platelet Gel ◽

Woven Bone ◽

Rapid Healing ◽

Rabbit Bone ◽

Autologous Platelet ◽

New Zealand Rabbits

Purpose: The aim of the present study is to evaluate the influence and efficacy of autologous platelets on bone regeneration in a rabbit defects model. Materials and Methods: A total of 12 critical size tibial defects were produced in six New Zealand rabbits: A total of six defects were filled with autologous platelet gel (APG) and six defects were maintained as untreated controls. No membranes were used to cover the bone osteotomies. The histology and histomorphometry were performed at four weeks on retrieved samples of both groups. Results: No complications were reported in any of the animals nor for the defects produced. A significantly higher lamellar and woven bone percentage was reported for the APG group with a lower level of marrow spaces (p < 0.05). Evidence of newly formed bone was found in the superficial portion of the bone defect of APG samples where no aspects of bone resorption were observed. Conclusions: The evidence of the present research revealed that APG increases new bone formation restricted to the cortical portion and induces more rapid healing in rabbit bone defects than in untreated defects.

Download Full-text

Cement-Based Renders Manufactured with Phase-Change Materials: Applications and Feasibility

Advances in Materials Science and Engineering ◽

10.1155/2016/7254823 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6 ◽

Cited By ~ 10

Author(s):

Luigi Coppola ◽

Denny Coffetti ◽

Sergio Lorenzi

Keyword(s):

Compressive Strength ◽

Phase Change ◽

Phase Change Materials ◽

Residential Buildings ◽

Setting Time ◽

Drying Shrinkage ◽

Hydration Kinetics ◽

Mechanical Performances ◽

Entrapped Air ◽

Kinetics Of

The paper focuses on the evaluation of the rheological and mechanical performances of cement-based renders manufactured with phase-change materials (PCM) in form of microencapsulated paraffin for innovative and ecofriendly residential buildings. Specifically, cement-based renders were manufactured by incorporating different amount of paraffin microcapsules—ranging from 5% to 20% by weight with respect to binder. Specific mass, entrained or entrapped air, and setting time were evaluated on fresh mortars. Compressive strength was measured over time to evaluate the effect of the PCM addition on the hydration kinetics of cement. Drying shrinkage was also evaluated. Experimental results confirmed that the compressive strength decreases as the amount of PCM increases. Furthermore, the higher the PCM content, the higher the drying shrinkage. The results confirm the possibility of manufacturing cement-based renders containing up to 20% by weight of PCM microcapsules with respect to binder.

Download Full-text

Enhancing the mechanical properties and cytocompatibility of magnesium potassium phosphate cement by incorporating oxygen-carboxymethyl chitosan

Regenerative Biomaterials ◽

10.1093/rb/rbaa048 ◽

2020 ◽

Author(s):

Changtian Gong ◽

Shuo Fang ◽

Kezhou Xia ◽

Jingteng Chen ◽

Liangyu Guo ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Physicochemical Properties ◽

Bone Cement ◽

Ph Value ◽

Setting Time ◽

Potassium Phosphate ◽

Carboxymethyl Chitosan ◽

Bioactive Substances ◽

Magnesium Potassium Phosphate Cement

Abstract Incorporating bioactive substances into synthetic bioceramic scaffolds is challenging. In this work, oxygen-carboxymethyl chitosan (O-CMC), a natural biopolymer that is nontoxic, biodegradable and biocompatible, was introduced into magnesium potassium phosphate cement (K-struvite) to enhance its mechanical properties and cytocompatibility. This study aimed to develop O-CMC/magnesium potassium phosphate composite bone cement (OMPC), thereby combining the optimum bioactivity of O-CMC with the extraordinary self-setting properties and mechanical intensity of the K-struvite. Our results indicated that O-CMC incorporation increased the compressive strength and setting time of K-struvite and decreased its porosity and pH value. Furthermore, OMPC scaffolds remarkably improved the proliferation, adhesion and osteogenesis related differentiation of MC3T3-E1 cells. Therefore, O-CMC introduced suitable physicochemical properties to K-struvite and enhanced its cytocompatibility for use in bone regeneration.

Download Full-text

Optimization of Gypsum Composition Against Setting Time And Compressive Strength In Clinker For PCC (Portland Composite Cement)

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1053/1/012116 ◽

2021 ◽

Vol 1053 (1) ◽

pp. 012116

Author(s):

Herliati ◽

Anggi Sagitha ◽

A. Dyah Puspita ◽

R. Puput Dwi ◽

Akhirudin Salasa

Keyword(s):

Compressive Strength ◽

Setting Time ◽

Composite Cement

Download Full-text

Bone formation and bioresorption after implantation of injectable ?-tricalcium phosphate granules-hyaluronate complex in rabbit bone defects

Journal of Biomedical Materials Research ◽

10.1002/jbm.a.30094 ◽

2004 ◽

Vol 70A (4) ◽

pp. 542-549 ◽

Cited By ~ 113

Author(s):

Masaaki Chazono ◽

Takaaki Tanaka ◽

Hirokazu Komaki ◽

Katsuyuki Fujii

Keyword(s):

Bone Formation ◽

Tricalcium Phosphate ◽

Bone Defects ◽

Rabbit Bone

Download Full-text

Treated Effluent in Concrete Technology

Jurnal Teknologi ◽

10.11113/jt.v34.648 ◽

2012 ◽

Author(s):

Soon Lee Ooi ◽

Mohd Razman Salim ◽

Mohammad Ismail ◽

Md. Imtiaj Ali

Keyword(s):

Compressive Strength ◽

Potable Water ◽

Setting Time ◽

Sewage Treatment ◽

Concrete Technology ◽

Water Quality Control ◽

Treated Effluent ◽

Compressive Strength Test ◽

Direct Discharge ◽

Mixing Water

In this paper, the feasibility of using treated effluent for concrete mixing was studied. Treated effluent from sewage treatment plants in Malaysia is currently being wasted through direct discharge into waterways. With proper water quality control, this treated effluent can also be considered as a potential water resource for specific applications. Two tests were carried out namely compressive strength test and setting time to determine the feasibility of using treated effluent for concrete mixing. The results were compared against the test conducted on control specimens which used potable water. The results showed that treated effluent increases the compressive strength and setting time when compared with potable water. Key words: treated effluent; mixing water; compressive strength; setting time; concrete technology.

Download Full-text