1. Universidade Federal de
Bioactive Glass and Glass Ceramics:
Oscar Peitl, Murilo Crovace, Marina Trevelin,
Clever Chinaglia
Universidade Federal de
São Carlos
BRAZIL

2. To Develop new BIOACTIVE Glass
Multidisciplinarity
To Develop new BIOACTIVE Glass
It demands INTENSIVE COLLABORATION with other diverse areas of knowledge
Material
In Vitro
In vivo
Human
Veterinary
Physician
Dentist
Physiotherapist
Physician
Dentist
Engineer
Chemist
Physicist
Biologist
Biomedical

3. Outline Bioactive glasses Bioglass-ceramics Backgraund, Oscar
Scaffolds, Murilo *
Biofunctionalization, Clever *
In vitro, in vivo and Clinical ,Marina*
Exemples:
BioSilicateR and F18R
* - VETRA (spin-off)

4. Bioactive Materials
A material which is able to REACT inside a living being
Promotes tissue regeneration

5. Why glasses First important issue: Should be used for
Tissue Regeneration
Are there advantages in relation to traditional HYDROXYAPATITE CERAMICS ??

6. Glasses show a huge range of solubility from INERT to SOLUBLE
It is necessary to control their solubility
Glasses show a huge range of solubility from INERT to SOLUBLE
Hench, Pantano, had proposed 5 types behavior glass surfaces
Glass Sample
Water
Solution
INTERFACE
WINDOW
INERT- Protective Film PARTIALLY SOLUBLE SOLUBLE-Non Stable Interface

7. Control Solubility is related to glass chemical composition
Glass Component
Window
(wt%)
Bioglass
45S5 (wt%)
TYPE 2 4
SiO2
74,0
45.0
CaO
10,0
24.5
Na2O
14,0
P2O5 #
6.0
In biological environment :
Glass Type II - The cells face the glass as a foreign body but it is not
harmful. Therefore, they isolate the glass implant
with a fibrous capsule
Glass Type IV – It is much more interesting. The Cells and Body Fluid
have a strong INTERACTION with the glass, so it is
possible to stimulate their proliferation and to REPAIR
the tissue

8. GLASSES Schematic Interface INERT to BIOACTIVE
Type II
Fibrous Tissue
INERT
Andersson et al J Mater Sci Mater Med 1 (1990)

9. Bioactive Glasses Compositions Stage II happens even in neutral pH
I- Fast ION Exchange Na+ and Ca+2
With H+ from SOLUTION pH
OH- H+
Stage II
II- Breaking Si-O-Si Bonds
Si(OH)4 to SOLUTION
Bioactive Glasses Compositions Stage II happens even in neutral pH
Ordinary glasses, Type II, experiment these SURFACE
chemical reactions : Stage I and Stage II (to pH>9)
Clark, Hench, Pantano,: “Corrosion of Glass”,1979

10. HYDROXY-CARBONATE-APATITE (HCA)
Stage III
III- Repolymerization
of a SiO2-rich layer
H2O
Si-0-Si
H2O to solution and
Si-0-Si Net regenaration in
Silica GEL form
Stage IV
IV- Migration Ca+2 and PO43-
to surface SiO2-rich layer
Forming Amorphous
CaO-P2O5- rich film (ACP)
Stage V
V- Crystallization ACP film by
Incorporation OH-, C032-
from solution forming
HYDROXY-CARBONATE-APATITE (HCA)
Hench “An Introdution to Bioceramics” 2ed, 2013

11. Type IV BIOACTIVE Glass - Bone Bonding Interface
The bioactive glasses run through the stages 1 and 2 and
continue with other surface chemical reactions
Glass - Bone Bonding
Interface
Two distinguish LAYERS
Silica Rich
HCA
BIOACTIVE

13. Five steps Reactions Result
DOUBLE LAYER formation
SiO2-rich
HCA

14. Compositional Dependence of Bioactive Glasses Constant - 6% P2O5.
CaO.SiO2
A/W-
Inert
NON Glass Forming
BIOACTIVES
RESORBABLE
High P2O5
IB=2
IB=0
IB=8
IB=5
IB=10
45S5
IB=12
Ceravital
IB = Bioactivity Index = 100/t0,5
t0,5; time in days (In vivo) to 50%
of the interface to be bone bonded
IB> 8 Soft-tissue Bonding
(Dashed line)

15.  Level of bioactivity IB for several Bioceramics
IB = 100/t0,5
Bioglass 45S5
12,5
Ceravital
5,6
A/W
3,2
Hydroxyapatite
3,1
Ceravital KGX
2,3
Al2O3

16. Interface Evolution by Implantation Time
According to Hench´s book “ An Introdution to Bioceramics” 2ed, 2013
Bioglass 45S5 it is ABLES to bond to SOFT tissue

17. Interfacial Thickness (mm) – Commercial Bio-Ceramics
1000
100 10 1
Bioglass - 45S5
Ceravital
A/W Glass-Ceramic
Hidroxyapatite
Al203
Fibrous
Tissue
Porous Hidroxyapatite
Inicial
Interface
Material
Bone
Machineable Glass-Ceramic (Bioverit)

18. Modulus of Elasticity of prosthetic materials compared with BONE
What kind of problem can be introduced when we bond two distinguish materials such as Bone with a Higher Elastic Modulus implant??

19. STRESS SHIELDING
Health Bone MUST BE under Stress => Piezoeletric Message
If the stress level is LOW, our Biologiacal System judges
to be Unnecessary to keep BONE at the Implant Interface
Bone at the interface will be absorbed

20. Nothing is perfect
BIOGLASSES present
1 Highest Bioactivity
2 Lowest Elastic Modulus
3 Thicker Layers.
4 Soft Tissue bonding
Bioactive Glass-Ceramics, such as
Cerabone(A/W), Ceravital, Bioverit, exhibit
better mechanical properties than Bioglasses

21. Bending strength (MPa)
Mechanical Properties of Bioglass-ceramics
Bioceramics
Bending strength (MPa)
KC MPa.m1/2
Cerabone A/W
215
2,0
Bioverit I
1,2-2,1
Hydroxyapatite
40-70
not specified
Bioglass 45S5 70
0,6
45S5 Mechanical Properties are their “Achilles Heel”

22. Failure Loads of Some Bioceramics at 8 Weeks after Implantation
Material
Failure Load (kg|)
Location of Fracture
Dense alumina
0,13 ± 0,02
Interface
Bioglass 45S5
2.75 ± 1.80
Within material
Ceravital (GC)
3.52 ± 1.48
Cerabone A-W (GC)
7.43 ± 1.19
Within bone
Hydroxyapatite
6.28 ± 1.58
Conclusion:
Bioceramics with higher Bioactivity as Bioglass and Ceravital, have
lower strength than bone.

23. BIOSILICATE After 12 Years
To Solve 45S5 Bioglass Mechanical Proprerties problems
Peitl and Zanotto had changed 45S5 composition and .....
It was possible to obtain a GLASS CERAMIC
With similar Biological Behavior but with Much Better Mechanical Properties
First Patent
After 12 Years
About 10 Patents
More 28 thesis
50 researchers

24. 4-point bending
Crystal size ~13 um

25. Surface fracture after indentation + flexural test
Indentation Fracture Toughness (KC)
Crack deflection at
Crystal - Glass Matrix
interface
Micrographs:
Surface fracture after
indentation + flexural
test

26. On Set Time HCA formation ( Stage V)
Even to Fully
Crystall ized
Glass Ceramic
exhibits High Bioactivity
AW GC takes 170h to show HCA on the surface

27. Modulus of Elasticity
Lower when compared with other CGs

28. Typical properties of bioglass-ceramics
Flexural
Strength
(MPa)
KIC
MPa.m1/2 E
(GPa)
Bioativity
IB=100/t50
Load to
Failure
(kg)
Fracture Location
Machinability
Biosilicate
210
1,0 60 12 *
BONE
FAIR
45S5 70
0.6 50
2.8
Material
POOR
Cerabone (A/W)
215
2.0
220 3
7.4
LOW
CERAVITAL
150 ? 6
3.5
Hydroxyapatite
40-70
<1
120
2.5
6.2
Bioverit
160
1-2 90 ??
GOOD
Biosilicate still UNABLE to be used as in Load Bearing implants
He does not have enough Mechanical Properties