Bioceramic dental implant coatings (Deposited and converted coatings ). This presentation discusses the different techniques used to coat dental implants to enhance osseointegration .

1. BIO-CERAMIC
IMPLANT COATINGS
Dr. Mohamed Mahmoud Abdul-Monem
Spring 2020
Applied Biomedical glasses & ceramics

2. Dental Implants
Titanium Zirconia PEEK

3. Osseointegration
◦ Osseointegration as a concept was
introduced by Per-Ingvar
Branemark (1969), Professor at the
Institute of Applied Biotechnology,
University of Goteborg.
◦ He defined it as “A direct structural
and functional connection
between ordered living bone and
the surface of the implant.”

4. Requirements of osseointegration
◦Design.
◦Chemical composition.
◦Surface roughness.
◦Surface chemistry.

5. Implant
coatings
Bio-ceramic Polymer Metallic Growth factors

6. Bio-ceramic
implant coatings
Materials Techniques

7. Bioceramic implant coatings
◦ Those ceramics intended to be in contact with living tissues are called bioceramics.
HA: hydroxyapatite, HCA: hydroxycarbonate apatite, A-W: apatite–wollastonite,TCP: tricalcium
phosphate, OCP: octacalcium phosphate, DCPA: dicalcium phosphate anhydrous, DCPD:
dicalcium phosphate dihydrate, TetCP: tetracalcium phosphate monoxide

8. Types of bioceramic implant coatings
Bioactive ceramic coatings
◦ Ability to induce bone regeneration
and bone ingrowth at the
tissue/implant interface without an
intermediate fibrous tissue layer.
◦ Examples :
◦ Calcium phosphate bioceramics
◦ Bioglasses
Bioinert ceramic coatings
◦ Protective coatings when deposited
onto substrates, prevent the release
of ions.
◦ Examples :
◦ Alumina
◦ zirconia

9. Implant coating fabrication techniques
1.Deposited coatings
◦ A ceramic film, deposited
onto the surface, which can be
totally different from the
substrate.
◦ That is, coating the surface
with a new material without
modifications to the substrate
material.
2.Conversion coatings
◦ Chemical surface modification of
a metallic substrate resulting in
slight increase in thickness.
◦ In this case, the substrate material
components are involved in the
modified layer formation.

10. The advantage of the surface-modified layer is :
◦ Graded composition.
◦ Absence of a clearly defined interface between the surface layer
and substrate, making surface delamination less of a problem.

11. Deposited coatings

12. Deposited coatings
I. Physical methods
1. Plasma spraying
2.Physical vapor deposition (PVD)

13. What is plasma ?
◦ One of the four fundamental states of matter.
◦ It consists of a gas of ions or atoms which have some of
their orbital electrons removed and free electrons.
◦ Plasma can be artificially generated by heating or subjecting
a neutral gas to a strong electromagnetic field to the point
where an ionized gaseous substance becomes
increasingly electrically conductive.

14. I.Physical methods
1.Plasma spraying
◦ Thermal plasma spraying is a process in which materials are thermally
melted into liquid droplets and introduced energetically to the surface of
the substrate on which the individual particles stick and condense.
◦ Thermal spraying requires a device that creates a high temperature flame
or a plasma jet.
◦ It uses electrical energy as the source to create the plasma and can
provide a very high temperature that is determined by the energy input.

15. ◦ An electric arc is struck between two electrodes whereas a stream of
gases (mostly Ar, He, H2, N2, or a mixture of them) passes through
this arc.
◦ The arc turns these gases into a high speed, high temperature plasma
(10 000−300 000 K).

16. 1.Plasma spraying
Advantages
◦ High deposition rates.
◦ Ability to coat large areas.
◦ Thick deposits.
◦ Low cost .
Disadvantages
◦ Non-homogenous coat.
◦ High temperature , if not
controlled can affect the
dental implant .

17. I.Physical methods
2.Physical vapor deposition (PVD)
◦ PVD is a general term used to
describe a variety of vacuum
techniques to deposit thin
films by the condensation of a
vaporized form of the solid
material onto a surface.

18. 2.Physical vapor deposition (PVD)
A.Cathodic arc deposition
B.Sputtering deposition
C.Pulse laser deposition (Laser ablation)

19. A. Cathodic arc deposition
◦ Which an electric arc is used
to vaporize material from
a cathode target.
◦ The vaporized material then
condenses on a substrate, forming
a thin film.
◦ Filtered cathodic arc deposition (FCA):
before coating the substrate, all
particles pass through a filtering electric
field and focusing magnetic field , to
eliminate any macroparticles .

20. A. Cathodic arc deposition
Advantages Disadvantages
Enhancing adhesion and allow
deposition of dense films.
Formation of macroparticles which
have a negative effect on the
properties of the coatings.

21. B. Sputtering deposition
◦ Sputtering is the process whereby atoms
or molecules of a target material are
ejected in a vacuum chamber by
bombardment with high-energy ions (ion
beam sputtering) and the ejected atoms
must be able to move freely toward the
substrate.
◦ A magnetron sputtering system works on
the principle of applying a specially
shaped magnetic field to a diode
sputtering target. The magnetic field
allows an increase in the ionization
efficiency and the ion current density.

22. B. Sputtering deposition
1. Ion beam sputtering
Advantages
Facilitates the deposition of
dense and well-adhered films
with controlled elemental
composition
Disadvantages
In the preparation of
bioinert coatings, it
produces coatings with
low crystallinity, requiring
post-deposition annealing
treatment

23. B. Sputtering deposition
2. Magnetron sputtering
Advantages
◦ Control the deposition
parameters in order to
obtain biocompatible
uniform thin films
without defects
◦ High adhesion to the
substrates
Disadvantages
◦ Deposition of calcium
phosphate by magnetron
sputtering remains at a
low deposition rate.

24. C. Pulse Laser deposition (Laser Ablation)
◦ This technique is based on the
irradiation of a solid target by a
focused pulsed laser beam resulting in
a gaseous cloud, formed by electrons,
atoms, molecules, and so on.
◦ Laser ablation or photoablation is the
process of removing material from a
solid (or occasionally liquid) surface
by irradiating it with a laser beam

25. C. Pulse Laser deposition (Laser Ablation)
Advantages
◦ Obtaining stoichiometric and adherent HA
coatings over titanium substrate.
◦ Improve bonding strength of HA coating onto
titanium substrate.
◦ Simple: a laser beam vaporizes a target
surface, producing a film with the same
composition as the target.
◦ Flexible: many materials can be deposited in a
wide variety of gases.
◦ Cost-effective: one laser can serve many
vacuum systems.
◦ Fast: high quality samples can be grown in 10
or 15 minutes.
Disadvantages
◦ The size of particulates may be
as large as a few micrometers
which affect the growth of the
subsequent layers as well as
properties of the films.

26. Deposited coatings
II. Chemical methods
A.Chemical vapor deposition
B.Sol-Gel technique
C.Electrophoretic deposition (EDP)
D.Biomimetic deposition

27. A. Chemical vapor deposition
◦ Chemical vapor deposition (CVD) is a
process which involves heterogeneous
chemical reactions of gaseous
reactants on or near the surface of a
heated substrate, thereby coating the
substrate.
◦ Types:
◦ Conventional CVD (Atm. Pressure)
◦ Low pressure CVD
◦ Plasma enhanced CVD

28. B. Sol-Gel technique
Spin-coating
• A solution is
dropped at the
center of the
spinning
substrate and is
spread by
centrifugal force.
Dip-coating
• The sample is
dipped in a
solution
containing the
precursors and
then withdrawn
at a constant rate
Spray-coating
• The solution is
pulverized onto
the surface of the
substrate using
an aerosol
generator or an
atomizer

29. C. Electrophoretic deposition (EDP)
This is based on the movement
of electrically charged particles
under an electric field applied to
a stable colloid suspension, and
the subsequent deposition onto
a conductive substrate surface of
opposite charge.

30. D. Biomimetic Deposition
Substrates are immersed in
simulated body fluid (SBF) for
several days at 37°C, resulting in
a bone-like biologically active
layer formation on the substrates

31. Conversion coatings
lead to the formation of ceramic oxides on the surface
A. Passivation
B. Oxidation
C. Chemical immersion
D. Anodization

32. ◦It is used for obtaining a uniformly oxidized
surface to improve corrosion resistance.
◦Immersion of the titanium for a minimum of 30
minutes in 20-40 vol.% solution of nitric acid at
room temperature.
A.Passivation

33. ◦After the passivation, surface of the implant should
be neutralized, rinsed and dried.
◦Nitric acid passivation has no major influence on
the overall surface topography of titanium
surfaces

34. A.Passivation
Advantages
◦ Simple
Disadvantages
◦ Although the converted layer
provides protection during the
initial phases of corrosion in a
living body, the protective ability is
reported to be inadequate.
◦ These treatments do not show
major changes in the overall
surface topography.

35. ◦ The surface of Ti is naturally covered by a thin oxide layer that is
formed as the metal surface is exposed to air.
◦ The deposition of TiO2 thin-films on dental implants is a way to
improve the surface biological properties by controlling the structure,
morphology and thickness of the TiO2 layer exposed to the peri-
implant tissues.
B.Oxidation

36. ◦Other oxides, such as ZrO2 have also been
tested as alternatives to TiO2 to improve the
properties of dental implants, reduce the
bacterial adhesion, improve the
biocompatibility or protect from the corrosion
exerted by the body fluids.

37. ◦This oxides are usually grown by sputtering,
plasma enhanced chemical vapor deposition
or cathodic arc deposition, since these
techniques allow the deposition of compact
layers and allow a good coating adhesion
even at low temperature.

38. ◦Methods of surface modification of titanium
and its alloys by chemical treatment are based
on chemical reactions occurring at the
interface between titanium and a solution.
C.Chemical immersion

39. Types of chemical immersion
1. Acid treatment
2. Alkali treatment
3. Hydrogen peroxide treatment

40. Advantages of Chemical surface
modification of titanium
◦Alter surface roughness and composition
◦Enhance wettability/surface energy

41. ◦ The process of acid treatment removes the surface oxide and
contamination which leads to a clean and homogenous surface.
◦ The acids commonly used include hydrochloric acid, sulfuric acid,
hydrofluoric acid, and nitric acid.
◦ Acid treatment of the surfaces of titanium implants results in
uniform roughness with micro pits ranging in size from 0.5-2 µm
1. Acid treatment

42. 1. Acid treatment
Advantages
◦ Increase in surface area .
◦ Improvement in bioadhesion.
◦ Enhances osseointegration as these
implants can facilitate migration and
retention of osteogenic cells at the
implant surface
Disadvantages
◦ Creates microcracks on the surface of the
implants that reduce the fatigue resistace
of the implants

43. ◦ It involves immersion of the implants in either sodium or potassium
hydroxide followed by heat treatment by rinsing in distilled water.
◦ This results in the growth of a bioactive, nanostructured sodium
titanate layer on the implant surface.
◦ This involves an initial formation of Ti-OH by release of sodium ions
from the sodium titanate layer by the process of ion exchange.
2. Alkali treatment

44. ◦ This is followed by formation of calcium titanate as a
of reaction with the calcium ions from the fluid.
◦ Phosphate and calcium ions get incorporated into this
calcium titanate and get transformed into apatite which
provide favorable conditions for bone marrow cell
differentiation.

45. ◦ Chemical treatment of implant surfaces with hydrogen peroxide
results in chemical dissolution and oxidation of the titanium surface.
◦ When titanium surfaces react with hydrogen peroxide, Ti-peroxy
gels are formed.
◦ The thickness of titania layer formed can be controlled by
adjusting the treatment time.
3. Hydrogen peroxide treatment

46. ◦It is a process by which oxide films are deposited on
the surface of the titanium implants by means of an
electrochemical reaction.
◦In this process, titanium surface to be oxidized serves
as the anode in an electrochemical cell with diluted
solution of acids serving as the electrolyte.
D.Anodization

47. ◦Usually carried out in strong acids, such as
H2SO4, H3PO4 or HF.
◦As a result of this process, a thick porous layer
of titanium oxide is formed on the implant
surface, which substitutes the very thin and
compact native oxide layer.

48. D.Anodization
Advantages
◦Improve adhesion and
bonding
Disadvantages
◦Create moderate
roughness on the
surface of the implant

49. Key properties of bioactive coatings
1.Bioactivity and osseointegration
2.Cellular response
3.Ion dissolution and osteogenesis
4.Mechanical performance
5.Good adhesion to implant surface