Barbieri Thesis - BioMedical Materials program (BMM)

CChapter
3 – Instructive
composit tes: effect of filller
content on osteoinduction
Table 5. Bone
incidence, histoomorphometry
an nd fluorescent reesults
after 12–we eek implantation in dogs.
0% Ca aP 10% CaP 20% CaP 40% CaP
Bone iincidence
0/7 0/7 0/7 7/7
Bone iin
available space
[%] 0±0 0±0 0±0 4.9±4.5
Time ffor
bone formatioon
no bone formmation
between 3–6 weeks w
Figure 9. Byy
comparing micrrographs
of the same s region of ann
unstained sect tion under fluores scent (a) and
transmitted ligght
(b), correlatioons
between the composite (40% CaP) and the zo one coloured in green g (calcein,
C, 3 weeks), , and between thhe
bone tissue ( Bone) with the zzones
coloured in
red (xylenol orange,
XO, 6
weeks) and yyellow
(tetracyclinne,
T, 9 weeks) are a possible. Thiis
leads to the co onclusion that bo one started to
form after 3 wweeks
but beforee
6 weeks from th he implantation, wwhile
surface mineralization
may have started
to occur durinng
the first 3 weeeks.
The resultss
showed thatt
titanium imp
induced boone
formation in vivo. Conve
not trigger any bone formmation.
mineralizattion
and bone
vitro in SBF,
only the su
that apatitte–based
mat
formation oof
mineralized
its surface,
40% CaP h
here studieed.
We canno
mineralize: : it might be th
time to mmineralize.
O
hydroxyapaatite/poly(L–la
mineralizedd
layer onto
observed ppreviously
with
the startingg
of bone form
have enhanced
surface
allowed boone
induction
[234] We
e induction in o
urface of 40%
terials contai
d layers onto t
ad the fastest
ot now conclu
hat, by virtue
Our results a
actide) comp
their surface
h polyHEMA, [
lants capable of forming ap
ersely, those tthat
did not m
e showed a similar
relation
our compositees.
Amongst t
CaP composiites
could min
n functional groups that
heir surfaces. .
t surface mine
de that 0, 10
of their lower
are in line w
posites rapid
es when imm
[221] 40% CaP
mation (Figure 9). Thus, hig
mineralization n of the 40% C
n. This is in n line with th
[245] patite layers in
ineralize in vit
between in vi
the composite
neralize. It is w
allow the sp
Having more m apatite ex
eralization tha an the other c
and 20% CaP
composites
r apatite conte ents, they req
with the find dings that m
ly formed (within one
mersed in SBF.
may have m
h contents of
CaP composit
he suggestio
[320] n SBF also
tro also did
tro surface
es tested in
well–known
pontaneous
xposure on
composites
s will never
uire longer
micro–sized
week) a
Similarly
to what
ineralized in vivo v before
nano–sized apatite a may
tes in vivo, and d therefore
n that in viv vo surface
65