Abstract: β-tricalcium phosphate (β-TCP) based cement features unique biodegradability and mild
temperature rise as a material for bone reconstruction. However, the bone cement often raises a shelf
life issue and therefore study was made focusing on the temperature and humidity during storage.
With the increase of storing days, the density and compressive strength of hardened cement were
found to drastically decrease for the cement powder stored in a mixed state. In addition, the setting
property was finally lost at the same time. Such a degradation was more evident at higher temperature
and was the result of the formation of dicalcium phosphate anhydrous (DCP) instead of dicalcium
phosphate dehydrate (DCPD) during the storage. On the contrary, for the cement stored in an
unmixed state, very slight changes were detected in density, compressive strength and setting time
with the increase of storing days even if the powders were kept in a humid environment. In the
unmixed ones, DCP was not precipitated regardless of the storing temperature. Discussion was made
on the condition for precipitating either DCPD or DCP in terms of the amount of water supplied
during setting. Practically the work suggested that the β-TCP based cement needs to be conserved at
lower temperature and in dry environment as possible to effectively increase the shelf life.
Abstract: It is well known that calcium phosphate compounds are widely used as bone substitute due to their
biocompatibility and bioactivity. Furthermore, recent studies have shown that slight changes in morphology
or crystal structure can lead to several in vivo behaviours. Therefore, the purpose of this study was to
investigate two different β-TCP synthesis routes (solid state reaction and aqueous solution precipitation) and
their consequences on the final cement properties. It was found out that both routes are equivalent as there
were no significant differences on their cement properties, except for mechanical resistance. The latter
difference can also be attributed to the difference on the particle size distributions of the obtained β-TCP.
These facts indicate that solid state reaction route is more interesting given its simplicity and yield.
Abstract: Injectable calcium phosphate (CaP) biomaterial is considered as an injectable bone
substitute (IBS). It was developed to minimize invasive surgery in various applications in
orthopedic and dental surgery. The IBS considered of a polymer solution mixed with biphasic
calcium phosphate (BCP) ceramic particles. Two particle sizes of BCP (40-80 and 80-200μm) were
used and the weight ratio was 40%. This study investigated the influence of polymer solution on the
BCP particles stability. Effects of particles size and limiting viscosity of polymer on the
sedimentation were studied. The polymer concentration and particles size can be adapted to provide
the best stability and storage of IBS.
Abstract: Two different injectable materials, intended for use in vertebroplasty (VP) treatments of
fractured vertebras, were tested in an in vitro bone model. The materials tested were an
experimental bioceramic material based on calcium aluminate manufactured by Doxa AB, and
Vertebroplastic, a PMMA based material manufactured by DePuy Acromed. The model was earlier
developed by others and has been found valid for testing of materials intended for PVP. The model
offers alternative data to traditional compressive and diametral tensile testing by adding the
infiltration of material into synthetic cancellous bone. Five different synthetic bones with different
porosity and pore structure were tested. The results show that for the PMMA the infiltration pattern
of the different bones tested seems to have no influence. The material deforms plastically and
displays about the same strength in all bones tested. For the bioceramic, linear elastic, material
however there is a difference. In the more porous bones, where the material infiltrate the pores and
creates a test body with a large amount of crack initiation points, the material displays lower
strength compared to that of the more solid bones.
Abstract: Vertebral compression fractures were simulated by making a hole into sheep vertebrae
and by injecting a stabilizing material. The injectable bio-ceramic Xeraspine™ was evaluated
together with a commercially available PMMA (Vertebroplastic™) as the reference material. The
Vertebrae were harvested after 7 days and prepared for microscopy. The samples were deposited
with gold on the surface and thereafter subjected to SEM and EDX analysis. It was found that the
Xeraspine-bone interface was composed of a mixture of elements. The Vertebroplastic implant was
embedded in a carbon containing tissue, likely a soft tissue capsule. The Xeraspine sample was
subjected to high resolution analysis in the TEM combined with EDX measurements. The TEM
sample was prepared with a novel technique for preparation of the tissue-material interface (FIB). In
the TEM analysis it was found that the interface region consists of ZrO2 together with a mixture
possibly consisting of katoite and apatite formed during setting and/or originating from the boneapatite.
Abstract: We performed vertebroplasty on goat model by injecting a new macroporous calcium
phosphate cement MCPC®. The mechanical property of the cement is about 12MPa after 24 hours
(compression test). The cement matrix is totally transformed into poorly crystallized apatite in 48
hours. This study demonstrates that MCPC cement was suitable and efficient for a spine
application. Its injectability allows to be used in mini invasive surgery and its mechanical properties
are compatible to support spine strength. In addition, a bone ingrowth onto the BCP granules
occurred with time.
Abstract: Calcium alkyl phosphates and their strontium and magnesium analogues were synthesised
by the reaction of aqueous metal salts with a range of alkyl phosphates of varying chain length and
were characterised by X-ray diffraction, thermogravimetric and FTIR analyses. These hybrid
structures are based on alternating organic/metal phosphate regions and were found to exhibit a
linear increase in interlayer separation upon increasing the length of the alkyl chain. Our analysis
suggests a general formula for these phases of M(ROPO3).nH2O (where M = Ca, Sr, Mg and R =
alkyl group), containing alkyl bilayers reminiscent of phospholipid bilayers found in biological
Abstract: A comparative study of the in situ interactions between different maleic anhydride based
copolymers and calcium phosphates is presented in this paper. The ability of functional groups of
the organic polymers to form under high pressure and low temperatures chemical bonds with the
inorganic phase leading to improved properties of hybrid nanostructured material is discussed. The
open challenges of new hybrid nanocomposites in the field of biomedical materials are evaluated.
The challenge to use these nanostructured materials in medical field was evaluated by mapping the
interface reactions between hybrid active layers and cells.
Abstract: Pure calcium sulfate (CS) is an excellent bone graft material because it is biocompatible,
completely biodegradable, osteoconductive, safe, nontoxic and angiogenic. It also has barrier
properties. However, its rapid degradation limits its use as a bone graft material. A nanocomposite of
CS and poly (l lactic acid) (PLLA) in a ratio of 96:4 was developed to overcome this problem. This
composite underwent slower degradation. It took 16 weeks for complete degradation whereas pure CS
takes only 4 weeks. When implanted in bone defects in rabbits, it underwent complete degradation and
stimulated vigorous bone formation.