Ceramics have been used in joint replacements since the 1970s. First generation bioceramics from the 1960s aimed to be bioinert. Second generation from the 1980s sought to actively bond with bone tissue. Modern bioceramics can induce tissue regeneration through genes. Alumina and zirconia ceramics are commonly used in hip replacements due to their hardness, biocompatibility and low wear rates. Newer ceramics include calcium phosphates for bone grafts and bioactive glasses that bond to bone. Future biomaterials could regenerate tissues using scaffolds and biological supplements.

1. CERAMICS

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 ARTHROPLASTYoxide 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.

8. MATERIAL PROPERTIES
Hardness
Wettability
Biocompatiblity
Excellent tribological properties
Chemical & corrosion resistant
Good surface finish

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.

12. Evaluation
 I GENERATION:
1974-1988
Grain size – 4.5 micrometers
burst strength of 46 KN
Impurities
high rate of #

13. II GENERATION:
1990-1993
Grain size – 3.2 micro
burst strength – 58
 III GENERATION:
From 1994
grain size – 1.8 micro
burst strength – 65 KN
Improved mech, HIP, Laser etching.

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

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

25. Oxinium total knee prosthesis

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. OSTEOSETMedical 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,