BIOCOMPATIBILITY AND
BIOMATERIALS FOR
IMPLANTS
• (Part 1)
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www....
• INTRODUCTION
• HISTORY
• PHYSICAL AND MECHANICAL, AND CHEMICAL REQUIREMENTS FOR IMPLANT MATERIALS
• METALS AND ALLOYS
• ...
INTRODUCTIONINTRODUCTION
• The disciplines of biomaterials and
biomechanics are complementory to the
undersatanding of dev...
• Dr. John Autian regards biocompatible
as meaning that no significant harm
comes to the host.
• Another world leader in t...
• (Weiss) Biocompatibility can be defined as “
the capacity of a material to exist in harmony
with the surrounding biologi...
HISTORYHISTORY
• The first evidence of the use of implants
dates back to 600 A.D in the Mayan
population. A fragment of a ...
• In 1809, Maggiolo described the process of
fabricating and inserting gold roots to support teeth.
• In 1911, Greenfield ...
• Venable & Stuck in 1936 Their studies
indicated that cobalt-chromium molybdenum
alloy (vitallium) was the only metal uti...
In 1970, Roberts and Roberts
developed Ramus blade endosseous
implant. This ‘blade’ types of implant was
constructed of su...
• Vitreous carbon implants were first
placed in canines in early 1970 by
Grenoble based upon biocompatibility
and efficacy...
• In early 80’s Calcitek corporation
began manufacturing and marketing its
synthetic poly crystalline ceramic
hydroxyapati...
• BraneMark devoted the next 13 years
conducting animal studies, determine the
parameters under which osseo-integration
wo...
PHYSICAL, MECHANICAL, ANDPHYSICAL, MECHANICAL, AND
CHEMICAL REQUIREMENTS FORCHEMICAL REQUIREMENTS FOR
IMPLANT MATERIALSIMP...
Physical and MechanicalPhysical and Mechanical
PropertiesProperties
• Forces exerted on the implant
material consist of te...
• All fatigue failures obey mechanical laws
correlating the dimensions of the material
to the mechanical properties of sai...
• Limitations of the relevance of these
properties are mainly caused by the
variable shape and surface features of
implant...
• The higher the applied load, the higher
the mechanical stress, and the greater
the possibility for exceeding the fatigue...
• Ceramic materials are weak under shear forces
because of the combination of fracture strength
and no ductility, which ca...
• The modifying elements in metallic
systems may be metals or nonmetals.
• A general rule is that mechanical process
harde...
• Most all consensus standards for metals
• [ASTM], [ISO], [ADA]) require
• a minimum of 8% ductility to minimize
brittle ...
Corrosion and BiodegradationCorrosion and Biodegradation
Corrosion is defined as
‘the loss of measurable substance
within ...
• Corrosion is a special concern for metallic
materials in dental implantology
• Galvanic processes depend on the
passivit...
• The passive layer is made of oxides or
hydroxides of the metallic elements that
have greatest affinity for oxygen.
• Wil...
Stress Corrosion CrackingStress Corrosion Cracking
• The combination of high magnitude of
applied mechanical stress plus
s...
• Lemons and others hypothesized that it
may be responsible for some implant
failures in view of high concentrations of
fo...
• This tends to support potential SCC at the
implant interface area (i.e., a transition
zone for altered chemical and mech...
Galvanic corrosion (GG)Galvanic corrosion (GG)
• occurs when two dissimilar metallic
materials are in contact and are
with...
Fretting corrosion (FC)Fretting corrosion (FC)
• occurs when there is a micro motion
and rubbing contact within a corrosiv...
Toxicity and ConsiderationToxicity and Consideration
• Toxicity is related to primary
biodegradation products (simple and
...
• Factors to be considered include
(1)the amount dissolved by biodegradation
per time unit,
(2) the amount of material rem...
• The electrochemical behavior of
implanted materials has been
instrumental in assessing their
biocompatibility.
• Charge ...
• Passive layers along the surfaces of
titanium, niobium, zirconium, and
tantalum increase resistance to change
transfer p...
METALS AND ALLOYSMETALS AND ALLOYS
INTRODUCTION
• The most common metallic objects are in the
shape of nails, screws, nuts...
So far three kinds of metal substrates
have been used for prosthetic purposes:
• Iron-based
• Cobalt-based
• Titanium-base...
• Several organizations have provided
guidelines for the standardization of
implant materials
• ASTM Committee F4 and ISO ...
The most widely used nonmetallic implants
are
• Oxidic
• carbonitic, or
• graphitic oxide like materials.
www.indiandental...
The major groups of implantable
materials for dentistry are:
• titanium and alloys,
• cobalt chromium alloys,
• austenitic...
Titanium and Titanium-6Titanium and Titanium-6
Aluminum-4 VanadiumAluminum-4 Vanadium
• Titanium oxidizes (passivates) upo...
• In situations where the implant would be
placed within a closely fitting receptor
site in bone, areas scratched or abrad...
• Titanium is a highly reactive metal.
• An oxide layer 100A thick forms on the
cut surfaces of pure titanium within a
mil...
• high dielectric properties of titanium
oxide, which exceed those of most
metal oxides, - is responsible for the
positive...
• The alloy of titanium most often used is
titanium-aluminium-vanadium.
• The wrought alloy condition is 6 times
stronger ...
• The emerging techniques to cast Ti and Ti
alloys remain limited for dental implant
application because of high melting
p...
Cobalt-Chromium-Cobalt-Chromium-
Molybdenum Based AlloyMolybdenum Based Alloy
• The cobalt-based alloys are most often
use...
• The elemental composition of this alloy
includes cobalt, chromium, and
molybdenum as the major elements.
• Cobalt provid...
• chromium provides corrosion resistance
through the oxide surface;
• molybdenum provides strength and bulk
corrosion resi...
• the cobalt alloys are the least ductile of
the alloy systems used for dental
surgical implants, and bending should be
av...
Iron-Chromium-Nickel-Iron-Chromium-Nickel-
Based AlloysBased Alloys
• Is used most often in a wrought and
heat-treated met...
• Of the implant alloys, this alloy is most subject
to crevice and pitting biocorrosion and care
must be taken to utilize ...
Other Metals and AlloysOther Metals and Alloys
• Many other metals and alloys have been
used for dental implant device
fab...
• More recently, devices made from
zirconium, hafnium, and tungsten
have been evaluated.
• Gold, platinum, and palladium a...
Other MaterialsOther Materials
 Biomedical PolymersBiomedical Polymers
 Ceramic and polymeric carbonsCeramic and polymer...
• Biomedical polymers are presently being
considered the best materials for soft-
tissue implantation in the cardiovascula...
The molecular structure of polymers
can belong to four different classes:
• Linear chains
• Branched chains
• Lattice thre...
COLLAGENCOLLAGEN
• Among natural biopolymers,
collagen deserves special attention.
• Its fundamental building block is
bel...
RESORBABLE POLYMERSRESORBABLE POLYMERS
• Polyactide (PLA) polyglycolide (PGA)
coprolactone and their relative
copolymers a...
• other polymeric substances are
polyglycolide, poly hydroxybutyric
acid and polyester amides.
• The only polymers fit for...
CERAMIC AND POLYMERICCERAMIC AND POLYMERIC
CARBONS:CARBONS:
• It is represented by polymeric
carbons with either ceramic o...
VITREOUS CARBONVITREOUS CARBON
• It is now possible to manufacture dental
implants and heart valves based on
vitreous carb...
Properties:
• It is prepared by controlled thermal degradation
of some organic polymers, for example phenol-
formaldehyde....
CARBON-COATED IMPLANTSCARBON-COATED IMPLANTS
• In order to eliminate the use of PMMA
cement to achieve prosthesis fixation...
PYROLYTIC CARBONSPYROLYTIC CARBONS
• High resistance, pyrolytic carbons
are prepared by decomposition of
hydrocarbon gases...
GRAPHITEGRAPHITE
• Graphite is the stablest phase of solid-
state carbon.
• Graphite occurs in two distinct phases a
dihex...
BIOLOGICAL GLASSESBIOLOGICAL GLASSES
• Most of the vitreous systems reveal in
their composition the presence of
phosphates...
LOADED BIOLOGICALLOADED BIOLOGICAL
GLASSGLASS
• In order to improve their quality and
preserve their elastic properties in...
CERAMICSCERAMICS
• In the field of material science the term
‘ceramic’ includes all non-metallic
inorganic materials.
• A ...
There follows a list of assets and defects,
as well as specific characteristics of
advanced ceramics:
1.Resistance to heat...
ZIRCONIUM OXIDEZIRCONIUM OXIDE
• The zirconium oxide is not suitable for use as
the only material from which a body is
man...
ALUMINAALUMINA
• It was a ceramic material widely used for
porcelains
• The methods used for the production of
A1203 powde...
TITANIATITANIA
With respect to Titania, at present no
prosthesis in bulk form has been
experimented with.
www.indiandental...
SILICON NITRIDESILICON NITRIDE
• For some time silicon nitride (Si3N4) has
been in the forefront of the development
of hig...
CALCIUM ALUMINATECALCIUM ALUMINATE
• Used in a variety of prosthetic forms, for
example to build bridges able to ensure
lo...
• Application of calcium aluminates will be
possible when there is no need for
particular qualities of mechanical
strength...
BIOLOGICAL RESPONSESBIOLOGICAL RESPONSES
OF CALCIUM ALUMINATEOF CALCIUM ALUMINATE
• In invitro tests it appeared that
unfo...
COMPOSITESCOMPOSITES
• A composite material is an association of
intimately linked substances.
• It is made up of a matrix...
• With respect to the ceramic sector
various kinds of composites can be
distinguished.
1. The CERMET ones, consisting of a...
PHOSPHATE CERAMICSPHOSPHATE CERAMICS
• Phosphatic substances, notably calcium salts,
are particularly interesting as mater...
APATITESAPATITES
• Apatite, or more precisely calcium
hydroxyapatite {Ca10 (PO4) 6 (OH) 2},
is the main constituent of har...
BIOACTIVE AND BIODEGRADABLEBIOACTIVE AND BIODEGRADABLE
CERAMICS BASED ON CALCIUMCERAMICS BASED ON CALCIUM
PHOSPHATESPHOSPH...
Bone Augmentation andBone Augmentation and
ReplacementReplacement
• The calcium phosphate (Ca.PO4) ceramics used
in dental...
• The laboratory and clinical results for
these particulates were most promising
and led to implant expansions, including
...
Endosteal andEndosteal and
Subperiosteal ImplantsSubperiosteal Implants
• The first series of structural forms for dental
...
• The coatings of metallic surfaces using
flame or plasma spraying (or other
techniques) increased rapidly for the
Ca*PO4 ...
The recognized advantagesThe recognized advantages
associated with the Ca*PO4associated with the Ca*PO4
ceramic biomateria...
disadvantages associated withdisadvantages associated with
these types of biomaterials are:these types of biomaterials are...
Ca.PO4 Ceramic PropertiesCa.PO4 Ceramic Properties
Chemical AnalysisChemical Analysis
Forms, Microstructures, andForms, Mi...
Chemical AnalysisChemical Analysis
 TheThe crystalline monolytic hydroxylapatitecrystalline monolytic hydroxylapatite
(HA...
These two compositions have been usedThese two compositions have been used
most extensively asmost extensively as
 - Part...
 One of the more important aspects ofOne of the more important aspects of
the Ca.PO4 ceramics relates to thethe Ca.PO4 ce...
 Steam or water autoclavingSteam or water autoclaving couldcould
significantly change the basic structure andsignificantl...
Forms, Microstructures, andForms, Microstructures, and
Mechanical PropertiesMechanical Properties
• Particulate HA, provid...
• The macro- (i > 50 µm), or micro- (i <
50 µm) porous particulates have an
increased surface area per unit volume.
• This...
• The coatings of Ca.PO4 ceramics onto
metallic (cobalt- and Ti-based)
biomaterials have become a routine
application for ...
Density Conductivity andDensity Conductivity and
SolubilitySolubility
• Bioactive ceramics are especially interesting
for ...
• Dissolution characteristics of
bioactive ceramics have been
determined for both particulates and
coatings.
• , the large...
• The purity of the HA bone substitutes
may also affect the resorption rate.
• The resorption of the bone substitute
may b...
• Cell-mediated resorption requires
processes associated with living cells to
resorb the material, similar to the
modeling...
• The pH in the region in which the bone
substitutes are placed also affects the
rate of resorption.
• As the pH decreases...
Current Status andCurrent Status and
Developing TrendsDeveloping Trends
• The CaPO4 ceramics have proved to be
one of the ...
FUTURE AREAS OFFUTURE AREAS OF
APPLICATIONAPPLICATION
• Synthetic substances for tissue
replacement have evolved from sele...
• Devices that function through bone or
soft tissue interfaces along the force
transfer regions could be systems of
choice...
Thank you
For more details please visit
www.indiandentalacademy.com
www.indiandentalacademy.co
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Biomaterials / diploma in orthodontics in delhi

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Indian Dental Academy: will be one of the most relevant and exciting

training center with best faculty and flexible training programs

for dental professionals who wish to advance in their dental

practice,Offers certified courses in Dental

implants,Orthodontics,Endodontics,Cosmetic Dentistry, Prosthetic

Dentistry, Periodontics and General Dentistry.

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Biomaterials / diploma in orthodontics in delhi

  1. 1. BIOCOMPATIBILITY AND BIOMATERIALS FOR IMPLANTS • (Part 1) INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.comwww.indiandentalacademy. com
  2. 2. • INTRODUCTION • HISTORY • PHYSICAL AND MECHANICAL, AND CHEMICAL REQUIREMENTS FOR IMPLANT MATERIALS • METALS AND ALLOYS • OTHER METALS AND ALLOYS • OTHER MATERIALS • FUTURE AREAS OF APPLICATION • BIOACTIVE AND BIODEGRADABLE CERAMICS BASED ON CAL.PHOSPHATES • SURFACE CHARACTERIZATION AND TISSUE INTERACTION • OTHER SURFACE MODIFICATIONS • PASSIVATION AND CHEMICAL CLEANING • BIOCOMPATIBILITY • STERILIZATION • CONCLUSION www.indiandentalacademy.co m
  3. 3. INTRODUCTIONINTRODUCTION • The disciplines of biomaterials and biomechanics are complementory to the undersatanding of device- based function • The physical, mechanical, chemical, and electrical properties of the basic material components must always be fully evaluated for any biomaterial application, as these properties provide key inputs into the interrelated biomechanical and biologic analysis of function www.indiandentalacademy.co m
  4. 4. • Dr. John Autian regards biocompatible as meaning that no significant harm comes to the host. • Another world leader in the field of biomaterials, Dr. Jonathan Black. Has suggested that the term “biologic performance” is more appropriate than biocompatibility to represent the various interactions between the host and the material. www.indiandentalacademy.co m
  5. 5. • (Weiss) Biocompatibility can be defined as “ the capacity of a material to exist in harmony with the surrounding biologic environment ; not having toxic or injurious effects on biologic functions.” Currently the most popular implant designs are subperiosteal implants, endosteal implants and endosteal root form or cylindrical implants. But other implant designs such as the ramus frame, mandibular staple bone plate, fiber mesh are being utilized successfully as well. www.indiandentalacademy.co m
  6. 6. HISTORYHISTORY • The first evidence of the use of implants dates back to 600 A.D in the Mayan population. A fragment of a mandible illustrates the implantation of pieces of shell to replicate three lower incisor teeth. • Implant designs are tracable to early egyptians and central / south American cultures and have evolved into current implant designs that are now experiencing an explosive popularity. www.indiandentalacademy.co m
  7. 7. • In 1809, Maggiolo described the process of fabricating and inserting gold roots to support teeth. • In 1911, Greenfield described the fabrication and insertion of an endosseous implant. The recipient site was prepared utilising a trephine. An irridio platinum basket, soldered with 24 carat gold, was then inserted into prepared site. • In 1939, Strock described a method of placing of first cobalt chromium molybdenum alloy (Vitalium) screw to provide anchorage for replacement of a missing tooth. A radiograph of Vitalium screw implant in the maxillary anterior segment eight months post placement was taken. It demonstrated that the tissue response after eight months was excellent, although the implant could be rotated in its socket. www.indiandentalacademy.co m
  8. 8. • Venable & Stuck in 1936 Their studies indicated that cobalt-chromium molybdenum alloy (vitallium) was the only metal utilized at the time that produced no electrolytic action when buried in tissues • In the mid 50’s, Lew introduced the use of an endosseous implant with a central post to circumferential extension, made of Cobalt chromium molybdenum screw. • In the mid 1960’s Sandhaus developed crystalline bone screw consisting mainly of aluminium oxide. www.indiandentalacademy.co m
  9. 9. In 1970, Roberts and Roberts developed Ramus blade endosseous implant. This ‘blade’ types of implant was constructed of surgical grade 316 stainless steel • By early 1970’s animal studies began on the use of non-metallic types of endosseous implant. www.indiandentalacademy.co m
  10. 10. • Vitreous carbon implants were first placed in canines in early 1970 by Grenoble based upon biocompatibility and efficacy studies. • In early 1980’s, Tatum introduced the Omni R implant. This is a titanium alloy root form implant with horizontal fins, designed to be placed into a prepared or expanded and osseous receptor site. • In 1980 Core-vent was introduced by Niznick the screw vent implant was later introduced as an endosseous screw type implant www.indiandentalacademy.co m
  11. 11. • In early 80’s Calcitek corporation began manufacturing and marketing its synthetic poly crystalline ceramic hydroxyapatite, hydroxyapatite – coated cylindrical post titanium alloy implant. • In 1985, Straumann Company, unique in plasma sprayed cylinders and screws are designed to be inserted in a one- stage operation. www.indiandentalacademy.co m
  12. 12. • BraneMark devoted the next 13 years conducting animal studies, determine the parameters under which osseo-integration would predictably occur. • Based on his study and others, titanium was the material of choice. • Many dental implants now available make use of commercially pure or extra – low interstitial titanium. • Recently there has been a trend towards coated implants, including plasma-spray, porous-www.indiandentalacademy.co m
  13. 13. PHYSICAL, MECHANICAL, ANDPHYSICAL, MECHANICAL, AND CHEMICAL REQUIREMENTS FORCHEMICAL REQUIREMENTS FOR IMPLANT MATERIALSIMPLANT MATERIALS www.indiandentalacademy.com
  14. 14. Physical and MechanicalPhysical and Mechanical PropertiesProperties • Forces exerted on the implant material consist of tensile, compressive, and shear components. • compressive strengths of implant materials are usually greater than their shear and tensile counterparts www.indiandentalacademy.co m
  15. 15. • All fatigue failures obey mechanical laws correlating the dimensions of the material to the mechanical properties of said material. • Para function (nocturnal and/or diurnal) can be greatly detrimental to longevity because of the mechanical properties, such as maximum yield strength, fatigue strength, creep deformability, ductility, and fracture. www.indiandentalacademy.co m
  16. 16. • Limitations of the relevance of these properties are mainly caused by the variable shape and surface features of implant designs. • A different approach to match more closely the implanted material and hard tissues properties led to the experimentation of polymeric, carbonitic, and metallic materials of low modulus of elasticity. www.indiandentalacademy.co m
  17. 17. • The higher the applied load, the higher the mechanical stress, and the greater the possibility for exceeding the fatigue endurance limit of the material. • In general, the fatigue limit of metallic implant materials reaches approximately 50% of their ultimate tensile strength. www.indiandentalacademy.co m
  18. 18. • Ceramic materials are weak under shear forces because of the combination of fracture strength and no ductility, which can lead to brittle fracture. • Metals can be heated for varying periods to influence properties, modified by the addition of alloying elements or altered by mechanical processing such as drawing, swaging, or forging, followed by age or dispersion hardening, until the strength and ductility of the processed material are optimized for the intended application. www.indiandentalacademy.co m
  19. 19. • The modifying elements in metallic systems may be metals or nonmetals. • A general rule is that mechanical process hardening procedures result in an increased strength but also invariably correspond to a loss of ductility. www.indiandentalacademy.co m
  20. 20. • Most all consensus standards for metals • [ASTM], [ISO], [ADA]) require • a minimum of 8% ductility to minimize brittle fractures. www.indiandentalacademy.co m
  21. 21. Corrosion and BiodegradationCorrosion and Biodegradation Corrosion is defined as ‘the loss of measurable substance within a metallic structure and the diffusion of chemical elements in the surrounding tissue under the effects of the environment.’ www.indiandentalacademy.co m
  22. 22. • Corrosion is a special concern for metallic materials in dental implantology • Galvanic processes depend on the passivity of oxide layers, which are characterized by a minimal dissolution rate and high regenerative power for metals such as titanium. www.indiandentalacademy.co m
  23. 23. • The passive layer is made of oxides or hydroxides of the metallic elements that have greatest affinity for oxygen. • Williams suggested that three types of corrosion were most relevant to dental implants: • stress corrosion cracking, • galvanic corrosion, and • fretting corrosion. www.indiandentalacademy.co m
  24. 24. Stress Corrosion CrackingStress Corrosion Cracking • The combination of high magnitude of applied mechanical stress plus simultaneous exposure to a corrosive environment can result in the failure of metallic materials by cracking, where neither condition alone would cause the failure. (William) www.indiandentalacademy.co m
  25. 25. • Lemons and others hypothesized that it may be responsible for some implant failures in view of high concentrations of forces in the area of the abutment-to- implant body interface. • Most traditional implant body designs under three dimensional finite element stress analysis show a concentration of stresses at the crest of the bone support and cervical one-third of the implant. www.indiandentalacademy.co m
  26. 26. • This tends to support potential SCC at the implant interface area (i.e., a transition zone for altered chemical and mechanical environmental conditions). • This has also been described in terms of corrosion fatigue (i.e. cyclic load cycle failures accelerated by locally aggressive medium). www.indiandentalacademy.co m
  27. 27. Galvanic corrosion (GG)Galvanic corrosion (GG) • occurs when two dissimilar metallic materials are in contact and are within an electrolyte resulting in current to flow between the two. • The metallic materials with the dissimilar potentials can have their corrosion currents altered, thereby resulting in a greater corrosion rate. www.indiandentalacademy.co m
  28. 28. Fretting corrosion (FC)Fretting corrosion (FC) • occurs when there is a micro motion and rubbing contact within a corrosive environment (such as the perforation of the passive layers and shear- directed loading along adjacent contacting surfaces). • FC has been shown to occur along implant body / abutment / superstructure interfaces. www.indiandentalacademy.co m
  29. 29. Toxicity and ConsiderationToxicity and Consideration • Toxicity is related to primary biodegradation products (simple and complex cations and anions), particularly those of higher atomic weight metals. www.indiandentalacademy.co m
  30. 30. • Factors to be considered include (1)the amount dissolved by biodegradation per time unit, (2) the amount of material removed by metabolic activity in the same time unit, and (3) quantities of solid particles and ions deposited in the tissue and any associated transfers to the systemic system. www.indiandentalacademy.co m
  31. 31. • The electrochemical behavior of implanted materials has been instrumental in assessing their biocompatibility. • Charge transfer appears to be a significant factor specific to the biocompatibility of metallic biomaterials. www.indiandentalacademy.co m
  32. 32. • Passive layers along the surfaces of titanium, niobium, zirconium, and tantalum increase resistance to change transfer processes by isolating the substrate from the electrolyte, in addition to providing a higher resistance to ion transfers. • On the other hand, metals based on iron, nickel, or cobalt is not as resistant to transfers through the oxide like passive surface zones.www.indiandentalacademy.co m
  33. 33. METALS AND ALLOYSMETALS AND ALLOYS INTRODUCTION • The most common metallic objects are in the shape of nails, screws, nuts and bolts, staples, bone plates, intramedullary pegs, wires, bands, and joint prostheses. • These are ordinarily used for repairing bone injuries, or may serve as either adjuvant to promote natural bone maturation or substitutes for removed bony parts. www.indiandentalacademy.co m
  34. 34. So far three kinds of metal substrates have been used for prosthetic purposes: • Iron-based • Cobalt-based • Titanium-based www.indiandentalacademy.co m
  35. 35. • Several organizations have provided guidelines for the standardization of implant materials • ASTM Committee F4 and ISO (ISO TC 106, ISOTR 10541) have provided the basis for such standards. • To date a multinational survey by ISO indicated that titanium and its alloy are mainly used. www.indiandentalacademy.co m
  36. 36. The most widely used nonmetallic implants are • Oxidic • carbonitic, or • graphitic oxide like materials. www.indiandentalacademy.co m
  37. 37. The major groups of implantable materials for dentistry are: • titanium and alloys, • cobalt chromium alloys, • austenitic Fe-Cr-Ni-Mo steels, • tantalum, niobium and zirconium alloys, • precious metals, ceramics, and polymeric materials. www.indiandentalacademy.co m
  38. 38. Titanium and Titanium-6Titanium and Titanium-6 Aluminum-4 VanadiumAluminum-4 Vanadium • Titanium oxidizes (passivates) upon contact with room temperature air or normal tissue fluids. • This reactivity is favorable for dental implant devices. • In the absence of interfacial motion or adverse tissue conditions, this passivated surface condition minimizes biocorrosion phenomena. www.indiandentalacademy.co m
  39. 39. • In situations where the implant would be placed within a closely fitting receptor site in bone, areas scratched or abraded during placement would repassivate in vivo. • This characteristic is one important property consideration related to the use of titanium for dental implants.www.indiandentalacademy.co m
  40. 40. • Titanium is a highly reactive metal. • An oxide layer 100A thick forms on the cut surfaces of pure titanium within a millisecond. • Thus, any scratch or nick in the oxide coating is essentially self-healing. • Typically, titanium is further passivated by placement in a bath of nitric acid to form a thick, durable oxide coating.www.indiandentalacademy.co m
  41. 41. • high dielectric properties of titanium oxide, which exceed those of most metal oxides, - is responsible for the positive biologic response to these implants because they make the surface more reactive to bio molecules via enhanced electrostatic forces. • Any contamination or adulteration of this surface before placement will surely have a negative effect on the success of the implant. www.indiandentalacademy.co m
  42. 42. • The alloy of titanium most often used is titanium-aluminium-vanadium. • The wrought alloy condition is 6 times stronger than compact bone and thereby affords more opportunities for designs with thinner sections (e.g., plateaus, thin interconnecting regions, rectangular scaffolds, porosities). • The modulus of elasticity of the alloy is slightly greater than that of titanium, being about 5.6 times that of compact bone. www.indiandentalacademy.co m
  43. 43. • The emerging techniques to cast Ti and Ti alloys remain limited for dental implant application because of high melting points of the elements • and propensity for absorption of oxygen, nitrogen, and hydrogen, which may cause metallic embrittlement. • Typical strengths of cast commercially pure (CP)-Ti grade 2 and Ti-6A1-4V after heat treatment and annealing can be in the range of those of wrought Ti alloys used for dental implants. www.indiandentalacademy.co m
  44. 44. Cobalt-Chromium-Cobalt-Chromium- Molybdenum Based AlloyMolybdenum Based Alloy • The cobalt-based alloys are most often used in an as-cast or cast-and- annealed metallurgical condition. • This permits the fabrication of implants as custom designs such as subperiosteal frames. www.indiandentalacademy.co m
  45. 45. • The elemental composition of this alloy includes cobalt, chromium, and molybdenum as the major elements. • Cobalt provides the continuous phase for basic properties; • secondary phases based on cobalt, chromium, molybdenum, nickel, and carbon provide strength (4 times that of compact bone) and surface abrasion resistance; www.indiandentalacademy.co m
  46. 46. • chromium provides corrosion resistance through the oxide surface; • molybdenum provides strength and bulk corrosion resistance. • Nickel has been identified in biocorrosion products, and • carbon must be precisely controlled to maintain mechanical properties such as ductility. www.indiandentalacademy.co m
  47. 47. • the cobalt alloys are the least ductile of the alloy systems used for dental surgical implants, and bending should be avoided. • When properly fabricated, implants from this alloy group have shown excellent biocompatibility profiles. www.indiandentalacademy.co m
  48. 48. Iron-Chromium-Nickel-Iron-Chromium-Nickel- Based AlloysBased Alloys • Is used most often in a wrought and heat-treated metallurgical condition, which results in a high-strength and high- ductility alloy. • The ramus blade, ramus frame, stabilizer pins (old), and some mucosal insert systems have been made from the iron- based alloy. www.indiandentalacademy.co m
  49. 49. • Of the implant alloys, this alloy is most subject to crevice and pitting biocorrosion and care must be taken to utilize and retain the passivated (oxide) surface condition. • Because this alloy contains nickel as a major element, use in patients allergic to nickel should be avoided. • The iron-based alloys have galvanic potentials and corrosion characteristics that make them subject to galvanic coupling biocorrosion if interconnected with titanium, cobalt, zirconium, or carbon implant biomaterials www.indiandentalacademy.co m
  50. 50. Other Metals and AlloysOther Metals and Alloys • Many other metals and alloys have been used for dental implant device fabrication. • Early spirals and cages included tantalum, platinum, iridium, gold, palladium, and alloys of these metals. www.indiandentalacademy.co m
  51. 51. • More recently, devices made from zirconium, hafnium, and tungsten have been evaluated. • Gold, platinum, and palladium are metals of relatively low strength, which places limits on design. www.indiandentalacademy.co m
  52. 52. Other MaterialsOther Materials  Biomedical PolymersBiomedical Polymers  Ceramic and polymeric carbonsCeramic and polymeric carbons www.indiandentalacademy.com
  53. 53. • Biomedical polymers are presently being considered the best materials for soft- tissue implantation in the cardiovascular, respiratory, digestive, and genitourinary and nervous systems. • Today some polymers are replacing aluminium and a number of other structural metals in certain applications in the course of which they must endure high temperatures and considerable stress. www.indiandentalacademy.co m
  54. 54. The molecular structure of polymers can belong to four different classes: • Linear chains • Branched chains • Lattice three-dimensional chains • Star-like chains www.indiandentalacademy.co m
  55. 55. COLLAGENCOLLAGEN • Among natural biopolymers, collagen deserves special attention. • Its fundamental building block is believed to be the triple-helical, dipolar tropo-collagen unit. www.indiandentalacademy.co m
  56. 56. RESORBABLE POLYMERSRESORBABLE POLYMERS • Polyactide (PLA) polyglycolide (PGA) coprolactone and their relative copolymers are promising implant materials. • They are presently used as bioabsorbable fibers widely employed as suture materials for avoiding any post operative adhesion or in growth of injured defective tissue. www.indiandentalacademy.co m
  57. 57. • other polymeric substances are polyglycolide, poly hydroxybutyric acid and polyester amides. • The only polymers fit for contact with blood proved to be Mylar and Silastic, which after 17 months did not appear to have been affected significantly by the action of the physiological environment. www.indiandentalacademy.co m
  58. 58. CERAMIC AND POLYMERICCERAMIC AND POLYMERIC CARBONS:CARBONS: • It is represented by polymeric carbons with either ceramic or fibrous structure, used in a variety of biomedical applications. www.indiandentalacademy.co m
  59. 59. VITREOUS CARBONVITREOUS CARBON • It is now possible to manufacture dental implants and heart valves based on vitreous carbons. • These materials for example carbon reinforced with carbon fibers, can be manufactured in the shape of rigid forms for the substitution of the facial mandible bone. www.indiandentalacademy.co m
  60. 60. Properties: • It is prepared by controlled thermal degradation of some organic polymers, for example phenol- formaldehyde. • One of the major differences between the physical properties of vitreous carbon and those of graphite is the extremely low permeability of vitreous carbon to gases. • It is much stable than a variety of other carbons or graphites. • It is very inert www.indiandentalacademy.co m
  61. 61. CARBON-COATED IMPLANTSCARBON-COATED IMPLANTS • In order to eliminate the use of PMMA cement to achieve prosthesis fixation, systems of direct biological coupling have been examined over the past few years. • some metal prostheses made of Ti-6A1- 4V were studied and provided with a porous surface a combination that has the advantage of enabling bone in growth on the carbon surface in association with bone tissue expansion within the porosity of the substrate.www.indiandentalacademy.co m
  62. 62. PYROLYTIC CARBONSPYROLYTIC CARBONS • High resistance, pyrolytic carbons are prepared by decomposition of hydrocarbon gases. • Characterized by high compatibility with blood and exhibiting a close and extremely adhesive epithelium/coal interface was also prepared www.indiandentalacademy.co m
  63. 63. GRAPHITEGRAPHITE • Graphite is the stablest phase of solid- state carbon. • Graphite occurs in two distinct phases a dihexagonal dipyramidal one and a ditrigonal disphenoidal one. • The latter is metastable as compared with the hexagonal phase. • As far as its use as a biomaterial is concerned, graphite, or heparin-coated graphite, has revealed a highly thromboresistant surface.www.indiandentalacademy.co m
  64. 64. BIOLOGICAL GLASSESBIOLOGICAL GLASSES • Most of the vitreous systems reveal in their composition the presence of phosphates, and all of them contain either silica or silicates. • The function of silica is to give rise to a low-solubility molecular matrix whose network of silicate chains acts as a container for those elements in ionic form whose role is to stimulate the biochemical environment surrounding the bioactive glass. www.indiandentalacademy.co m
  65. 65. LOADED BIOLOGICALLOADED BIOLOGICAL GLASSGLASS • In order to improve their quality and preserve their elastic properties in time, biological glass compositions can be loaded with inert materials • refractory oxides and nitrides in the form of grains or whiskers, or metal whiskers, or Pt powders able to induce crystallization from bioactive glasses to bioactive glass-ceramics, or nets of either metallic or polymeric fiber. www.indiandentalacademy.co m
  66. 66. CERAMICSCERAMICS • In the field of material science the term ‘ceramic’ includes all non-metallic inorganic materials. • A number of new ceramics have emerged which have given remarkable performance in terms of hardness, thermal resistance, corrosion resistance, and electrical properties. www.indiandentalacademy.co m
  67. 67. There follows a list of assets and defects, as well as specific characteristics of advanced ceramics: 1.Resistance to heat, wear, corrosion 2.Unsurpassed properties of electric insulation 3.Good magnetic permeability 4.Particular optical properties 5.Great hardness 6.High dielectric constant 7.High mechanical strength at high temperatures 8.High melting point www.indiandentalacademy.co m
  68. 68. ZIRCONIUM OXIDEZIRCONIUM OXIDE • The zirconium oxide is not suitable for use as the only material from which a body is manufactured because, in the transition from tetragonal to monoclinic during cooling, tensions are generated inside the ceramic body by the different contraction relationships between the granules, which can cause fractures. • The most common zirconium oxide is often contaminated, particularly the oxides of the lanthanide elements, which are present as minerals and which diminish the mechanical properties of the ceramics that will be obtained.www.indiandentalacademy.co m
  69. 69. ALUMINAALUMINA • It was a ceramic material widely used for porcelains • The methods used for the production of A1203 powders are: the Bayer process pyrogenic process kaolinite clay process chemical method www.indiandentalacademy.co m
  70. 70. TITANIATITANIA With respect to Titania, at present no prosthesis in bulk form has been experimented with. www.indiandentalacademy.co m
  71. 71. SILICON NITRIDESILICON NITRIDE • For some time silicon nitride (Si3N4) has been in the forefront of the development of high-strength high-temperature materials able to replace metal alloys in a great number of applications. • As a covalent substance, however, silicon nitride presents a very small concentration of vacancies and cannot be sintered to high densities by heat application alone. www.indiandentalacademy.co m
  72. 72. CALCIUM ALUMINATECALCIUM ALUMINATE • Used in a variety of prosthetic forms, for example to build bridges able to ensure locking to bone, and for mastoid cavities, long-bone prostheses, and tracheal or dental implantations. • Its biocompatibility has proved acceptable, and so has its great capacity for growth into the porous mass of both soft and hard tissue has been ascertained. www.indiandentalacademy.co m
  73. 73. • Application of calcium aluminates will be possible when there is no need for particular qualities of mechanical strength, such as when the purpose is to either fill hollows or remedy skeleton malformation. • The biocompatibility of a material such as this is clearly high and wettability is also reasonably good. It is therefore possible for other substances to filter through its pores. www.indiandentalacademy.co m
  74. 74. BIOLOGICAL RESPONSESBIOLOGICAL RESPONSES OF CALCIUM ALUMINATEOF CALCIUM ALUMINATE • In invitro tests it appeared that unfortunately its biodegradability by the tissues into which it was inserted was excessive so much so as to compromise the stability of the prosthesis introduced • On account of its poor characteristic calcium aluminates was abandoned both as bulk and as a coating material. www.indiandentalacademy.co m
  75. 75. COMPOSITESCOMPOSITES • A composite material is an association of intimately linked substances. • It is made up of a matrix, which builds the main body of the composite and constitutes a homogeneous phase of this, and of one, or more than one, added substances, which form inclusions connected to the matrix. www.indiandentalacademy.co m
  76. 76. • With respect to the ceramic sector various kinds of composites can be distinguished. 1. The CERMET ones, consisting of an association of a ceramic matrix with metallic threads, plates, or grains. 2. The CERFIB ones, ceramic matrix and load-bearing component consist of vitreous fibers in this case the fibers may be short or long and may be arranged either orderly or randomly. www.indiandentalacademy.co m
  77. 77. PHOSPHATE CERAMICSPHOSPHATE CERAMICS • Phosphatic substances, notably calcium salts, are particularly interesting as materials for surgical grafts. • These materials provide the appropriate surface for cell bonding. • The behaviour in vivo of calcium phosphate implants depends on a variety of factors, among which the Ca/P relationship, the crystallographic structure, and the amount of porosity appear particularly important.www.indiandentalacademy.co m
  78. 78. APATITESAPATITES • Apatite, or more precisely calcium hydroxyapatite {Ca10 (PO4) 6 (OH) 2}, is the main constituent of hard tissues such as bone, dentin, and enamel. • In reality we classify apatite as a whole family of substances who’s Ca2- can be replaced by other alkaline-earth ions, for example Sr2+ or Ba2+ to obtain strontium hydroxyapatite (SrHA) and barium hydroxyapatite (BaHA) respectively. www.indiandentalacademy.co m
  79. 79. BIOACTIVE AND BIODEGRADABLEBIOACTIVE AND BIODEGRADABLE CERAMICS BASED ON CALCIUMCERAMICS BASED ON CALCIUM PHOSPHATESPHOSPHATES www.indiandentalacademy.com
  80. 80. Bone Augmentation andBone Augmentation and ReplacementReplacement • The calcium phosphate (Ca.PO4) ceramics used in dental reconstructive surgery include a wide range of implant types and thereby a wide range of clinical applications. • Micro structural and chemical properties of these particulates were controlled to provide forms that would either dissolve or remain intact for structural purposes after implantation. www.indiandentalacademy.co m
  81. 81. • The laboratory and clinical results for these particulates were most promising and led to implant expansions, including larger implant shapes (such as rods, cones, blocks, H-bars) for structural support under relatively high magnitude loading conditions • Mixtures of particulates with collagen and subsequently with drugs and active organic compounds such as Bone Morphogenic Protein (BMP) increased the range of applications.www.indiandentalacademy.co m
  82. 82. Endosteal andEndosteal and Subperiosteal ImplantsSubperiosteal Implants • The first series of structural forms for dental implants included rods and cones for filling tooth root extraction sites (ridge retainers) and, in some cases, load-bearing endosteal implants. • Limitations in mechanical property characteristics soon resulted in internal reinforcement of the Ca*PO4 ceramic implants through mechanical (central metallic rods) or physiochemical (coating over another substrate) techniques.www.indiandentalacademy.co m
  83. 83. • The coatings of metallic surfaces using flame or plasma spraying (or other techniques) increased rapidly for the Ca*PO4 ceramics. • The coatings have been applied to a wide range of endosteal and subperiosteal dental implant designs with an overall intent of improving implant surface biocompatibility profiles and implant longevities. www.indiandentalacademy.co m
  84. 84. The recognized advantagesThe recognized advantages associated with the Ca*PO4associated with the Ca*PO4 ceramic biomaterials are:ceramic biomaterials are: • Chemical compositions of high purity and of substances that are similar to constituents of normal biological tissue (calcium, phosphorus, oxygen, and hydrogen). • Excellent biocompatibility profiles within a variety of tissues when used as intended. • Opportunities to provide attachments between selected Ca*PO4 ceramics and hard and soft tissues. • Minimal thermal and electrical conductivity plus capabilities to provide a physical and chemical barrier to ion transport (e.g., metallic ions) www.indiandentalacademy.co m
  85. 85. disadvantages associated withdisadvantages associated with these types of biomaterials are:these types of biomaterials are: • Variations in chemical and structural characteristics for some currently available implant products. • Relatively low mechanical tensile and shear strengths under condition of fatigue loading • Relatively low attachment strengths for some coating-to-substrate interfaces • Variable solubilities depending on the product and the clinical application.www.indiandentalacademy.co m
  86. 86. Ca.PO4 Ceramic PropertiesCa.PO4 Ceramic Properties Chemical AnalysisChemical Analysis Forms, Microstructures, andForms, Microstructures, and Mechanical PropertiesMechanical Properties Density Conductivity and SolubilityDensity Conductivity and Solubility www.indiandentalacademy.comwww.indiandentalacademy.com
  87. 87. Chemical AnalysisChemical Analysis  TheThe crystalline monolytic hydroxylapatitecrystalline monolytic hydroxylapatite (HA) [fired ceramic Ca10 (PO4) 6(OH) 2] of(HA) [fired ceramic Ca10 (PO4) 6(OH) 2] of high density and purity (< 50 ppm impurities)high density and purity (< 50 ppm impurities) has provided one standard for comparisonhas provided one standard for comparison related to implant applications.related to implant applications.  TheThe crystalline tricalcium phosphatecrystalline tricalcium phosphate [[ββ Ca3 (PO4) 2] (TCP) ceramic has also providedCa3 (PO4) 2] (TCP) ceramic has also provided a high-purity (< 50 ppm impurities) biomateriala high-purity (< 50 ppm impurities) biomaterial for comparison with other products.for comparison with other products.www.indiandentalacademy.comwww.indiandentalacademy.com
  88. 88. These two compositions have been usedThese two compositions have been used most extensively asmost extensively as  - Particulates for bone augmentation and- Particulates for bone augmentation and replacementreplacement  - Carriers for organic products, and- Carriers for organic products, and  - As coatings for endosteal and subperiosteal- As coatings for endosteal and subperiosteal implants.implants. www.indiandentalacademy.comwww.indiandentalacademy.com
  89. 89.  One of the more important aspects ofOne of the more important aspects of the Ca.PO4 ceramics relates to thethe Ca.PO4 ceramics relates to the possible reactions with waterpossible reactions with water ..  For example, hydration can convert TCP toFor example, hydration can convert TCP to HA;HA;  also, phase transitions among the variousalso, phase transitions among the various structural forms can exist with any exposure tostructural forms can exist with any exposure to water.water. www.indiandentalacademy.comwww.indiandentalacademy.com
  90. 90.  Steam or water autoclavingSteam or water autoclaving couldcould significantly change the basic structure andsignificantly change the basic structure and properties of Ca.PO4 (or any bioactive surface)properties of Ca.PO4 (or any bioactive surface) and thereby provide an unknown biomaterialand thereby provide an unknown biomaterial condition at the time of implantation.condition at the time of implantation.  This is to be avoided through the use ofThis is to be avoided through the use of presterilized or clean, dry, heat-sterilizationpresterilized or clean, dry, heat-sterilization conditions.conditions. www.indiandentalacademy.comwww.indiandentalacademy.com
  91. 91. Forms, Microstructures, andForms, Microstructures, and Mechanical PropertiesMechanical Properties • Particulate HA, provided in a nonporous (<5% porosity) form as angular or spherically shaped particles, is an example of a crystalline, high-purity HA biomaterial. • These particles can have relatively high compressive strengths (>500 MPa), with tensile strengths in the range of 50 to 70 MPa.www.indiandentalacademy.co m
  92. 92. • The macro- (i > 50 µm), or micro- (i < 50 µm) porous particulates have an increased surface area per unit volume. • This provides more surface area for dissolution under static conditions and a significant reduction in compressive and tensile strengths. • The porous materials also provide additional regions for tissue in growth and integration (mechanical stabilization) and thereby a minimization of interfacial motion and dynamic (wear-associated) interfacial breakdown.www.indiandentalacademy.co m
  93. 93. • The coatings of Ca.PO4 ceramics onto metallic (cobalt- and Ti-based) biomaterials have become a routine application for dental implants. • These coatings, for the most part, are applied by flame or plasma spraying; have average thicknesses between 20 and 100 µm; www.indiandentalacademy.co m
  94. 94. Density Conductivity andDensity Conductivity and SolubilitySolubility • Bioactive ceramics are especially interesting for implant dentistry because the inorganic portion of the recipient bone is more likely to grow next to a more chemically similar material. • Under the bioactive (bioreactive) categorization are included calcium phosphate materials such as TCP, HA, calcium carbonate (corals), and calcium sulfate-type compounds and ceramics. www.indiandentalacademy.co m
  95. 95. • Dissolution characteristics of bioactive ceramics have been determined for both particulates and coatings. • , the larger the particle size, the longer the material will remain at an augmentation site. • The crystallinity of HA also affects the resorption rate of the material. The highly crystalline structure is more resistant to alteration and resorption www.indiandentalacademy.co m
  96. 96. • The purity of the HA bone substitutes may also affect the resorption rate. • The resorption of the bone substitute may be cell or solution mediated. www.indiandentalacademy.co m
  97. 97. • Cell-mediated resorption requires processes associated with living cells to resorb the material, similar to the modeling / remodeling process of living bone, which demonstrates the coupled resorption / formation process. • A solution mediated resorption permits the dissolution of the material by a chemical process. • Impurities or other compounds in bioactive ceramics, such as calcium carbonate, permit more rapid solution mediated resorption, which then increases the porosity of the bone substitute. www.indiandentalacademy.co m
  98. 98. • The pH in the region in which the bone substitutes are placed also affects the rate of resorption. • As the pH decreases the components of living bone, primarily the calcium phosphates, resorb by a solution- mediated process. • The CaPO4 coatings are nonconductors of heat and electricity. www.indiandentalacademy.co m
  99. 99. Current Status andCurrent Status and Developing TrendsDeveloping Trends • The CaPO4 ceramics have proved to be one of the more successful high technology-based biomaterials that have evolved within the past decades. • Their advantageous properties strongly support the expanding clinical applications and the enhancement of the biocompatibility profiles for surgical implant uses. www.indiandentalacademy.co m
  100. 100. FUTURE AREAS OFFUTURE AREAS OF APPLICATIONAPPLICATION • Synthetic substances for tissue replacement have evolved from selected industrial grade materials such as metals, ceramics, polymers, and composites. • Knowledge of tissue properties and computer-assisted modeling and analyses also support the present developments. • and control of all aspects of manufacturing, packaging, delivering, placing, and restoring enhance the opportunities for optimal application and, it is hoped, device treatment longevities. www.indiandentalacademy.co m
  101. 101. • Devices that function through bone or soft tissue interfaces along the force transfer regions could be systems of choice, depending on the clinical situation. • Unquestionably, the trend for conservative treatment of oral diseases will continue. Thus it can be anticipated that dental implants will frequently be a first-treatment option. www.indiandentalacademy.co m
  102. 102. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.co m

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