2. INTRODUCTION
Greek term "keramos" which means pottery.
an article having a glazed or unglazed body of crystalline or
partly crystalline structure, or of glass, which body is produced
from essentially inorganic, non-metallic substances and either is
formed from a molten mass which solidifies on cooling, or is
formed and simultaneously or subsequently matured by the
action of the heat.
BIOCERAMICS.
3. I GENERATION BIOCERAMICS
In 1960’s
BIO-INERTNESS
Interaction with the living tissue as low as possible.
Alumina & Zirconia
4. II GEN BIOCERAMICS
1980’s
BIOACTIVE or BIO-RESORBABLE
Favorable interaction with body
Able to form strong interaction with living tissue
crystalline calcium phosphates, bioactive glasses and glass-ceramics
bone tissue augmentation, bone cements or the coating of metallic
implants
5. III GEN BIOCERAMICS
Start of 21st
century
concept replacement of tissues is been substituted with
regeneration of tissues.
Able to induce regeneration and repair of living tissues based
on genes
porous second generation bioceramics
Organic & inorganic hybrids, mesoporous of silica, stargels,
templated glasses.
6. CERAMICS IN ARTHROPLASTYoxide ceramics
formed by closely packed crystals of Very small and very pure
crystals oxides of aluminum or zirconium metals
Sliding ceramics
1930 Rock, 1st
person to consider the possibility of ceramics in
A’plasty.
1970 French surgeon Boutin implanted the first ceramic-on-
ceramic cemented total hip joint in France
7. MANUFACTURING PROCESS
Particulates of C. + H20 + organic binder
Moulding
Hot isostatic pressure.
Evaporation of water, burning the binder by thermal
treatment
Sintering with Cao / Mgo
Final ceramic structure.
9. HARDNESS:
very resistant to scratches from the tiny particles
harder the surfaces coupled together, the less wear the coupling
system produces
WETTABILITY:
Self lubricating, because of ionic structure which produces
hydrophilic surface.
Synovial fluids gets attracted & spreads out which minimizes
adhesive wear.
10. BIO-COMPATABILITY
Exist in highly oxidative state
Chemically inert, resistant to oxidative degradation.
Insoluble in water, hydrative degradation not possible.
Results in less wear, smaller wear particle size, decreased
cytotoxity & osteolysis.
11. TRIBOLOGICAL PROPERTY
wear rate of alumina-alumina bearing coupling is extremely
low (0.001 mm/year). If compared with metal-polyethylene
(0.2 mm/ yr)
4000 times less
fluid film lubrification - reduces the coefficient of clutch.
14. ALUMINA
Old A. ceramic materials the crystals of aluminum oxides
were large, not assembled closely; there were many
impurities and voids between them [5%].
impurities - weak points for propagation of fracture cracks.
The coarse structure and impurities were the cause of the
frequent fractures
15. Modern alumina [0.5% impurity]: HIPing process extrudes
impurities out off the material and packs the crystals very close
together.
very tough structure, tougher than the metallic stem on which it is
seated, and even more tough then the natural thighbone.
disadvantage of the modern alumina ceramic is lower toughness
16.
17. high alumina ceramics : materials that have the minimal
content of 97% of alumina.
high purity alumina ceramics: percentage of minimal alumina
is of 99%.
HPA: commonly used for arthroplasty.
Biolax forte.
18. Zirconia Toughened Alumina
(ZTA) ceramic
Mixed-oxide ceramics.
75% of alumina and the rest are zirconium, Yttrium and chrome
oxides.
superior strength and resistance to wear.
Biolax delta
bending strength around 1000 MPa, more than the double of the
alumina standard (400 MPa).
Burst strength - 100 KN
19. Zirconia ceramic
one of the stronger ceramics
introduced to reduce the risk of fracture.
Pure zirconia is an unstable
material showing three different crystalline phases
Stabilisation of zirconia by adding oxides to maintain the tetragonal
phase
Smaller Femoral heads [22 mm]
20. More smoother finish
Zirconia femoral heads should articulate only against
polyethylene sockets
It ages in the body’s temperature and the surface of the
zirconia ball roughens
21. Advantages as bearing material
Smoother surface & less co-efficient of friction & wear.
Superior lubrication property.
Harder & less susceptible to third body wear
Inert with no ion release.
best used in young and active patients who have a high risk of
loosening and osteolysis in the mid to long term.
22. Oxinium materials
Zirconium is a strong and biocompatible metal similar to
titanium
Thin layer of zirconium oxide is coated on the surface of the
solid zirconium metal
femoral head made out of Oxinium that articulates with a
polyethylene cup
23. combines the benefits of metals and ceramics.
It offers superior wear resistance on its surface
zirconium metal itself, with characteristics close to titanium, is a
material without the risk of brittle fracture.
oxidized zirconium is black
24. Ceramics for total knees
The total knee joints doesn’t have congruent joint surfaces.
Thus, in a total knee joint with both joint surfaces made from
ceramic materials, there would appear large localized stresses that
would destroy components made from the contemporary ceramics
difficult to fabricate such a large yet thin ceramic component as is
the form of the femoral component
26. Bioactive ceramics
Osteoconductive property
acting as a scaffold to enhance bone formation on their surface
used either as a coating on various substrates or to fill bone defects.
Calcium phosphate ceramics.
hydroxyapatite (HA) and tricalcium phosphate (TCP).
In solid form, neither of these materials exhibits adequate fatigue
resistance for use as a load-bearing implant
27. Hydroxyapatite (Ca10(PO4)6(OH)2)
Synthetic apatite
Most similar material from structural & chemical point of view to
the mineral component of bone.
bone-graft substitute, HA coating to prosthesis.
bonding mechanism - attachment at the surface of the HA of
osteogenically-competent cells which differentiate into osteoblasts
28. A cellular bone matrix is then formed at the surface of the HA.
An amorphous area is present between the surface and the bone
tissue containing thin apatite crystals.
As maturation occurs, this bonding zone shrinks HA becomes
attached to bone through a thin epitaxial layer, resulting in a strong
interface with no layer of fibrous tissue interposed between the
bone and HA.
29. Such integration rarely, if ever, occurs with porous or smooth
metal implants
hot plasma spray technique.
optimal thickness of the coating- 50 microns
Thinner coatings may not supply sufficient Ca and P long enough to
be effective,
Thicker layers can experience sufficient stress under implant cyclic
bending and shear and tensile loads to be subject to fatigue failure
30. Tricalcium phosphate (Ca3(PO4)2)
exists in either alpha or beta crystalline forms.
The beta form is the most stable.
The rate of biodegradation is higher when compared with HA.
Degradation occurs by combined dissolution and osteoclastic
resorption.
to stimulate early bone in-growth into porous surfaces.
31. Bone graft substitutes
Porous coraline ceramics
Chiroff et al, first recognised that, corals made from marine
invertebrates have a structure similar to both cortical & cancellous
bone.
Exoskeleton of genus porite [ICF- 190mm], structure similar to
cortical bone.
Genus gonipora – similar to cancellous bone
32. Hydrothermal exchange process converts delicate coral
carbonate in to hydroxyapatite without altering the internal
structure.
Invaded & converted to mature lamellar B.
Only surface resorption & no remodeling.
Reconstruct metaphyseal defects.
33. Bioactive glasses.
Bioglass 45S5
bonding mechanism to bone - series of surface reactions ultimately
leading to the formation of a hydroxycarbonate apatite layer at the
glass surface.
Greater production of bone, compared with HA.
poor mechanical properties
34. wollastonite (CaOSiO2)
glass ceramic developed by Kokubo et al
osteoconductive properties similar to Bioglass 45S5
increased mechanical strength.
It has been used as a spacer at the iliac crest, for vertebral
prostheses and as a shelf in procedures about the shoulder
35. Bioactive bone cement
Explored in order to avoid complications related to PMMA debris
and to enhance fixation of the prosthesis.
calcium-phosphate based bone cement and glass-ceramic bone
cement.
36. Calcium phosphate cements
Biocompatible & resorbable cement
Injectable cements
Replaced by creeping substitution with host bone.
As bone void fillers with uniform & predictable drug eluding
property.
Deliver the antibiotics.
N-SRS, ETEX alpha - BSM
37. Norian SRS
N. skeletal repair system.
Augmentation of fracture repair.[DHS, pedicle screw]
Combination of monocalcium phosphate, tricalcium
phosphate, calcium carbonate & a sodium phosphate solution
in to inj. Paste
Hardens with in minutes into dahllite [carbonated HA] in a
nonexothermic reaction.
38. ETEX alpha BSM
Calcium orthophosphate cement
Dicalciumphosphate dihydrate, octocalcium P & many
precipitating apatites.
Poorly crystalline apatite which will mimic bone, aiming
superior resorption & osteointegration.
Easy intraop handling characteristics..
39. OSTEOSETMedical grade calcium sulphate
High tech processing [retains all biological adv & consistent mech /
resorption profile]
Provide structural support & is bioabsorbable and biocompatible.
Resorption profile matches with the rate at which host
environment can lay down bone around the compound.
Available as pellets
Antibiotic delivery – aminoglycosides/ ideal.
40. FUTURE
Scaffold fabricated with a synthetic bioceramic which after
being supplemented with moieties of biological activity is
implanted in a living organism to induce tissue regeneration,
