Biomedical Engineering Reference
In-Depth Information
18
Elaboration and Characterization
of Calcium Phosphate Biomaterial
for Biomedical Applications
Foued Ben Ayed
Laboratory of Industrial Chemistry, National School of Engineering, Box 1173, 3038 Sfax
Tunisia
1. Introduction
Calcium phosphates constitute an important family of biomaterials resembling the part of
calcified tissues. This study is based on calcium phosphate such as hydroxyapatite
(Ca
10
(PO
4
)
6
(OH)
2
, Hap), fluorapatite (Ca
10
(PO
4
)
6
F
2
, Fap) and tricalcium phosphate
(Ca
3
(PO
4
)
2
, TCP) phases because their chemical composition is similar to that of bone
mineral (Hench, 1991; Legeros, 1993; Uwe et al.,1993; Elliott, 1994; Landi et al., 2000; Varma
et al., 2001; Destainville et al., 2003; Wang et al., 2004; Ben Ayed et al., 2000, 2001a, b; 2006a,
b; 2007; 2008a, b; Bouslama et al., 2009; Chaari et al., 2009). The most frequent is β-TCP
because it is resorbable and osteoinductive (Gaasbeek et al., 2005; Steffen et al., 2001). β-TCP
is resorbed in vivo by osteoclasts and replaced by new bone (Schilling et al., 2004). The
tricalcium phosphate has been used clinically to repair bone defects for many years.
However, mechanical properties of calcium phosphates are generally inadequate for many
load-carrying applications. The tricalcium phosphate has a low density decreasing the
mechanical properties. But, the efficiency of bi-phasic calcium phosphate (BCP) has been
fully importantly efficiency its clinical efficacy to combat the chronic osteomyelitis in the
long term. To our knowledge, if it is possible to vary the composition of bioceramic
materials (composed of Hap and -TCP) with its inherent porosity, it could be a solution
owing to the faster resorption of this BCP together with the sustained release of the
antibiotic.
In the literature Hap, -TCP or the combination of both (Hap/TCP) was the most commonly
used synthetic augments in high tibial osteotomy (Haell et al., 2005; Koshino et al., 2003;
Gaasbeek et al., 2005; Van Hemert et al., 2004; Gutierres et al., 2007). The use of bone cement
as a temporary spacer for bone defects has been described, but secondary biological
reconstruction was performed after cement removal (DeSilva et al., 2007). However,
permanent acrylic bone cement has been used as an interface in the postero-medial part of
high tibial osteotomy to maintain the opening angle and good results have been achieved
(Hernigou et al., 2001). However, due to the different biomechanical features between bone
and bone cement and missing bony remodelling and incorporation, the use of bone cement
as a permanent spacer was not recommended, if one aims to achieve biological regeneration.
Recently, Jensen and colleagues described that rapid resorption of -TCP might impair the
regenerative ability of local bone, especially in the initial stage of bone healing (Jensen et al.,
