Mixture Of Tricalcium Phosphate Research Articles

Effect of heat treatment on the synthesis of hydroxyapatite from Indian clam seashell by hydrothermal method

Hydroxyapatite (HA) powder has been successfully synthesized from low-cost Indian clam seashells by using hydrothermal method. The mixture of tri-calcium phosphate [Ca3(PO4)2], heat-treated ball-milled clam seashell, and demineralized water are heat-treated at several temperatures (700 °C, 800 °C, 900 °C, 1000 °C, and 1100 °C) for various time periods (1 h, 2 h, and 3 h) to perform the hydrothermal reactions. The phases and microstructure of the solid-state reaction products are analyzed through X-ray diffraction (XRD) method and field emission scanning electron microscopy (FESEM) respectively. The crystallite size of all the synthesized powders is calculated by using Scherrer's model. Mainly HA phase is obtained in all the different reaction products. However, these HAs are found to be non-stoichiometric in nature. As per the literature, non-stoichiometric HA is a more biologically active material compared to the stoichiometric one. Almost pure HA is formed with any selected reaction temperature applied for 2 h time duration. The crystallinity and Ca/P ratio of the synthesized pure HA are estimated by using standard model and energy-dispersive X-ray spectroscopy (EDS) analysis, respectively. The highest amount of near stoichiometric crystalline HA has been obtained at 900 °C of reaction temperature applied for 2 h time duration. With raising reaction temperature, the grain size of pure HA is found to be increased. Needle/rod shaped nano grains are noticed to form at lower reaction temperature whereas; beyond 1000 oC of temperature globular/spherical shaped grains are also observed to form. At 3 h reaction time agglomeration of grains is found to occur in all the synthesized powders.

Microsphere-based scaffolds encapsulating tricalcium phosphate and hydroxyapatite for bone regeneration.

Bioceramic mixtures of tricalcium phosphate (TCP) and hydroxyapatite (HAp) are widely used for bone regeneration because of their excellent cytocompatibility, osteoconduction, and osteoinduction. Therefore, we hypothesized that incorporation of a mixture of TCP and HAp in microsphere-based scaffolds would enhance osteogenesis of rat bone marrow stromal cells (rBMSCs) compared to a positive control of scaffolds with encapsulated bone-morphogenic protein-2 (BMP-2). Poly(D,L-lactic-co-glycolic acid) (PLGA) microsphere-based scaffolds encapsulating TCP and HAp mixtures in two different ratios (7:3 and 1:1) were fabricated with the same net ceramic content (30 wt%) to evaluate how incorporation of these ceramic mixtures would affect the osteogenesis in rBMSCs. Encapsulation of TCP/HAp mixtures impacted microsphere morphologies and the compressive moduli of the scaffolds. Additionally, TCP/HAp mixtures enhanced the end-point secretion of extracellular matrix components relevant to bone tissue compared to the "blank" (PLGA-only) microsphere-based scaffolds as evidenced by the biochemical, gene expression, histology, and immunohistochemical characterization. Moreover, the TCP/HAp mixture groups even surpassed the BMP-2 positive control group in some instances in terms of matrix synthesis and gene expression. Lastly, gene expression data suggested that the rBMSCs responded differently to different TCP/HAp ratios presented to them. Altogether, it can be concluded that TCP/HAp mixtures stimulated the differentiation of rBMSCs toward an osteoblastic phenotype, and therefore may be beneficial in gradient microsphere-based scaffolds for osteochondral regeneration.

Histomorphometric outcomes after lateral sinus floor elevation procedure: a systematic review of the literature and meta-analysis.

The aim of the present systematic review of the literature was to evaluate biomaterials performances considering new bone formation estimated through histomorphometric analysis of bone biopsies from human subjects after maxillary sinus floor elevation. An electronic and manual search was performed to retrieve articles showing histomorphometric data of bone biopsies performed after sinus floor elevation surgery. Recorded data were statistically analyzed evaluating percentage of new bone volume, residual biomaterial, and connective/soft tissues in the biopsies. A meta-analysis of comparative studies was also performed. After article selection process, 84 articles were included in the quantitative synthesis and 16 of them in the meta-analysis of comparative studies. The use of autogenous bone (AB) alone led to a significantly higher new bone formation if compared with bovine bone (BB) alone (P=0.04), while no significant difference was found when the latter was compared with a mixture of AB and BB (P=0.52). Grafts composed of BB showed significantly greater new bone formation as compared to hydroxyapatite (HA) (P<0.001) while a mixture of tricalcium phosphate (TCP) and HA achieved better outcomes than BB (P<0.001). Based on histomorphometric evaluation, AB should still be taken into consideration when the highest possible new bone formation is the primary aim in maxillary sinus surgery. When donor site morbidity is a concern, BB and a mixture of TCP and HA could be considered as predictable, showing promising results. More comparative histologic studies are needed to confirm such results.

Mechanism of calcium phosphate deposition in a hydrothermal coating process

Hydrothermal process is a useful method for deposition of corrosion protective calcium–phosphate (Ca–P) coating on magnesium alloy (AZ31) substrate. Since the deposition mechanism determines the coating properties to a considerable extent, the present work studied the key steps in the formation of Ca–P during the hydrothermal process. Ca–P was deposited on four different metallic substrates: AZ31, zinc (Zn), titanium (Ti) and stainless steel (SS). The Ca–P coatings were studied by means of Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) to determine the various steps in the coating formation and growth. The deposition of Ca–P layer was found to strongly depend on the substrate material. Little or no deposition took place on corrosion resistant SS and Ti substrates while thick layers formed on more reactive AZ31 and Zn substrates. The deposition mechanism changed with increasing temperature in the case of the AZ31 substrate. At lower temperature, the coatings consisted of tricalcium phosphate and monetite phases. Increase in deposition temperatures resulted in the formation of an additional thick magnesium hydroxide layer below a mixture of tricalcium phosphate and monetite layer when magnesium substrate was used.

The copolymer of ε-caprolactone-lactide and tricalcium phosphate does not enhance bone growth in mandibular defect of sheep

In the field of craniomaxillofacial and orthopaedic surgery there is a constant need for bone or bone substitute. At the present, the most effective way to enhance bone healing clinically is to use autogenous bone grafts. The problems associated with the use of these autografts are donor site morbidity, limited supply and need for a second operative site. Currently there are several different synthetic products commercially available in the market; nevertheless, none of them is ideal for filling bone defects. Therefore, search for new synthetic materials for bone replacement is necessary. A mixture of tricalcium phosphate (TCP) and epsilon-caprolactone-lactide copolymer P(epsilon -CL/DL-LA) was prepared and implanted in critical size mandibular bone defects in twelve sheep. Contralateral side was used as a control. Follow-up times for histological and radiological studies were 9, 14, 24 and 52 weeks. We found that the implanted material did not enhance bone formation compared to control site. We also confirmed that defect size was of critical size, since there was no complete healing of the control site either. The results do not encourage us to continue our studies with the mixture of TCP and P(epsilon-CL/DL-LA) as a filling material for bone defects. Therefore the search for the ideal material is still ongoing.

Mixture of epsilon-caprolactone-lactide copolymer and tricalcium phosphate: a histological and immunohistochemical study of tissue reactions.

In cranio-maxillofacial surgery, bone transplantation is needed for treatment of bony defects. An autograft, allograft or biomaterial can be used. Autogenous bone grafts are considered to be the best materials available, but there are some disadvantages in their use including donorsite morbidity, need for a second operative site and limited graft supply. A search for new bone-graft materials therefore remains necessary. We prepared a mixture of tricalcium phosphate (TCP), which is a resorbable, non-toxic, osteoconductive ceramic material and epsilon-caprolactone-lactide copolymer P(epsilon-CL/DL-LA), a resorbable polymer, and placed it in the dermis and in mandibular bone defects in 13 rabbits. Follow-up times were two, three, seven, eight, 12, 15 and 18 weeks, tissue reactions were assessed, histologically and immunohistochemically. Times of resorption of the material from tissues were reported. We found that the mixture caused a mild inflammatory reaction when placed in bone and severe inflammation when placed in dermis. No highly fluorescent layer of tenascin or fibronectin was found surrounding the implant area. The mixture was excellent to handle and very easy to place into bone defects. The results are promising and have led us to continue development of the mixture.