Calcium phosphate ceramics

TCP is an osteoconductive and resorbable material, with a resorption rate dependent on its chemical structure, porosity, and particle size [10]. 

Composites of polyhydroxy butyrate, a natural biodegradable thermoplastic P-hydroxy add, with TCP have been prepared by conventional melt processing technologies (extrusion, injection, or compression molding) [2, 17, 18]. In vitro experiments in SBF produced an apatite like stmcture on the composite surface suggesting bioactivity. When immersion in SBF was extended to 2 months or more, the onset of matrix degradation could be followed by the decrease in storage modulus. 

Composites of chitosan and P-TCP with improved compressive modulus and strength have been prepared by a soUd-Uquid phase separation of the polymer solution and evaporation of the solvent [8]. The composites exhibited bioactivity when immersed in SBF. Variation of polymer/filler ratio and development of different macroporous structures resulted in products with potential applications in tissue engineering. 

An application of calcium carbonate as a bioactive filler was discussed by Kasuga et al. [19], who incorporated vaterite powders prepared by a carbonation process in methanol into a polylactic acid matrix. Composites containing 20-30 wt% vaterite 

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X. Miao, Y. Hu, J. Liu, A.P. Wong, Porous calcium phosphate ceramics prepared by coating polyurethane foams with calcium phosphate cements. Mater. Lett. 58 (2004) 397 02. 

Lavemia, C., and J. M. Schoenung, Calcium phosphate ceramics as bone substitutes, Ceram. Bull, 70(1), 95 (1991). 

Shirkhanzadeh, M. 2005. Microneedles coated with porous calcium phosphate ceramics Effective vehicles for transdermal delivery of solid trehalose. J Mater Sci 16 37. 

In spite of these investigations, many reports in the literature demonstrate that these nanoapatite ceramics are not always osteoinductive and, furthermore, do not possess mechanical properties similar enough to bone for sustained osseointegration (Muller-Mai el al., 1995 Doremus, 1992 Du et al., 1999 Weng et al., 1997), criteria necessary for increased orthopedic and dental implant efficacy. Moreover, mechanisms of osteoinduction of calcium phosphate ceramics are not clear and seem to depend on specific nanoapatite material properties (such as surface properties and crystallinity) and the animal tested (i.e., dog versus rabbit). Undoubtedly, the incidental cases of calcium phosphate biomaterial-induced osteogenesis indicate promise in... 

Flately, T. J., Lynch, K. L., and Benson, M., Tissue response to implants of calcium phosphate ceramics in the rabbit spine. Clinical Orthop. 179,246-252 (1983). 

Klein, C, de Groot, K., Chen, W., Li, Y., and Zhang, X., Osseous substance formation in porous calcium phosphate ceramics in soft tissues. Biomaterials 15, 31-34 (1994). 

Passuti, N., Daculsi, G, Rogez, J. M., Martin, S., and Bainvel, J. V., Macroporous calcium phosphate ceramic performance in human spine fusion. Clinical Orthop. 248, 169-176 (1989). 

Radin, S. R., and Ducheyne, P, The effect of calcium phosphate ceramic composition and structure on in vitro behavior. II. Precipitation. J. Bone and Mineral Res. 27, 35 45 (1993). 

Yang, Z., Yuan, H., Zou, P., Tong, W., Qu, S., and Zhang, X., Osteogenic responses to extraskele-tally implanted synthetic calcium phosphate ceramics an early stage histomorphological study in dogs. J. Mater. Sci. Med. 8, 697-701 (1997). 

Yuan, H., Li, Y., Yang, Z., Feng, X, and Zhang, X., Calcium phosphate ceramic induced osteogenesis in rabbits, in Biomedical Materials Research in the Far East (III), (X. Zhang and Y. Ikada, Eds.), pp. 228-229. Kobunshi Kankokai, Kyoto, Japan, 1997c. 

A number of spectacular applications in structural studies of glasses were reported employing the INADEQUATE experiment.174 175 The basic sequence and different modifications were discussed in Section 2.2.2. Smith and coworkers176 used 31P refocused INADEQUATE MAS NMR experiment for searching the length of phosphate chain and quantification of crystalline phases in ternary sodium calcium phosphate ceramic of composition (CaO)0.4(Na20)0.i(P205)o.5. 

One great advantage with phosphate bonded ceramics in biomaterial or dental applications is the phosphate ions in their structure. Bones contain calcium phosphate, and hence phosphate bonded ceramics are generally biocompatible with bones. While chemically bonded calcium phosphate ceramics have been difficult to produce, magnesium and zinc based phosphate bonded ceramics have been more easily synthesized and used as structural and dental cements. 

Naturally occurring phosphate cements are also known. Krajewski [3] cites calcium-based phosphate cements in the Albeian condensed Glauconitic Limestone of the Tatra Mountains in Western Carpathians. In recent years methods have been developed to fabricate calcium phosphate ceramics by direct reaction of calcium compounds and either phosphoric acid or an acid phosphate. The mineralogy of the products has also been well studied. Most of these efforts are directed towards development of calcium-based bioceramics containing calcium phosphate compounds, such as hydroxyapatite. These developments are discussed below. 

Note in Fig. 13.2 that the solubility of monocalcium silicate is higher than that of the corresponding aluminate at any pH > 3. In the acidic region that is of interest for forming CBPCs, both may be considered as sparsely soluble, and if they are reacted with a phosphate salt, ceramics may be formed. Thus, monocalcium silicate and aluminate are starter minerals to form calcium phosphate ceramics. 

Jarcho, M. (1981) Calcium phosphate ceramics as hard tissue prosthetics. Clin. Orthop. Relat. Res., 157, 259-278. 

While properties and applications of calcium phosphate ceramics will be treated in much detail, only a short account on the composition and functionality of bioglasses will be given below. More information on bioglasses and their in vitro and in vivo reactions can be found in Hench (1991, 2008, 2014), Gross et al. (1988), Kokubo (1991), Ducheyne, El-Ghannam and Shapiro (1997), Cerutti (2004) or Ben-Nissan and Ylanen (2006). 

De Groot, K. (1988) Effect of porosity and physicochemical properties on the stability, resorption, and strength of calcium phosphate ceramics. Ann. N.Y. Acad. Sci., 523, 227-233. 

Ducheyne, P. and Healy, K.E. (1988) The effect of plasma-sprayed calcium phosphate ceramic coatings on the metal ion release from porous titanium and cobalt-chromium alloys. J. Biomed. Mater. Res.,... 

To answer the question whether heterotopically formed bone, induced by hydroxyapatite, oc- and [3-TCP and biphasic HAp/TCP (BCP), would disappear over time due to the absence of mechanical stresses and whether this heterotopically formed bone would give rise to uncontrolled growth, a long-time investigation over 2.5 years was conducted (Yuan et al., 2001). Porous hydroxyapatite ceramic (HAp), porous biphasic calcium phosphate ceramic (TCP/HAp, BCP), porous a-TCP ceramic and porous P-TCP ceramic were implanted in the dorsal muscles of dog with an observation time of 2.5 years. Histological observation, backscattered scanning electron microscopy observation and histomorphometric analysis were performed on thin non-decalcified sections of retrieved samples. Normal compact bone with bone marrow was found in... 

Radin, S.R. and Ducheyne, P. (1992) Plasma spraying induced changes of calcium phosphate ceramic characteristics and the effect on in vitro stability. /. Mater. Sci. - Mater. Med., 3, 33-42. 

Material-dependent bone induction by calcium phosphate ceramics a 2.5-year study in dog. Biomaterials, 22, 2617 - 2623. 

Development of nano-structured alumina and zirconia ceramics and composites as well as nano-structured calcium phosphate ceramics and porous bioactive glasses, possibly as composites with organic constituents, will provide desired properties for bone substitution and tissue engineering for the next 20 years (Chevalier and Gremillard, 2009). 

Fujibayashi S, Shikata J, Tanaka C, Matsnshita M, Nakamura T (2001) Lumbar posterolateral fusion with biphasic calcium phosphate ceramic. J Spinal Disord 14 214-221 Fulmer MT, Brown PW (1998) Hydrolysis of dicalcium phosphate dihydrate to hydroxylapatite. J Mater Sci Mater in Med 9 197-202... 

Heymann D, Guicheux J, Rouselle AV (2001) Ultrastractural evidience in vitro of osteoclast-induced degradation of calcium phosphate ceramic by simultaneous resorption and phagacytosis mechanisms. Histol Histopath 16 37-44... 

Kim TN, Feng QL, Kim JO, Wu J, Wang H, Chen GC, Cui FZ (1998) Antimicrobial effects of metal ions (Ag, Cu, Zn ) in hydroxylapatite. J Mater Sci Mater in Med 9 129-134 Klein CP AT, Driessen AA, de Groot K (1984) Relationship between the degradation behaviour of calcium phosphate ceramics and their physical chemical characteristics and trltrastractrrral geometry. Biomaterials 5 157-160... 

Le Geros RZ (1993) Biodegradation and bioresorption of calcium phosphate ceramics [Review]. Clin Materials 14 65-88... 

Momoe ZA, Votawa W, Bass DB, McMullen J (1971) New calcium phosphate ceramic material for bone and tooth implants. J Dent Res 50 860... 

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