Surface Characteristics Implants

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IMPLANT MATERIALS ANDIMPLANT MATERIALS AND

SURFACE COATINGS ON IMPLANTSSURFACE COATINGS ON IMPLANTS



Definition :Definition :

A prosthetic device of alloplastic material(s) implanted A prosthetic device of alloplastic material(s) implantedinto the oralinto the oral tissues beneath the mucosal and/ortissues beneath the mucosal and/orperiosteal layer, and on/or within the bone to provideperiosteal layer, and on/or within the bone to provideretention and support for a fixed or removableretention and support for a fixed or removableprosthesis ;prosthesis ;

a substance that is placed into and/or upon the jawa substance that is placed into and/or upon the jawbone to support a fixed or removable prosthesis.bone to support a fixed or removable prosthesis.



A biocompatible material is defined as being harmonious A biocompatible material is defined as being harmoniouswith life and not having toxic or injurious effects onwith life and not having toxic or injurious effects onbiologic function.biologic function.

A biomaterial can be defined as any substance other A biomaterial can be defined as any substance otherthan a drug, that can be used for any period as a part of than a drug, that can be used for any period as a part of a system that treats, augments, or replaces any tissuea system that treats, augments, or replaces any tissueorgan or function of the body.organ or function of the body.



The body is a harsh chemical environment for foreign materials.The body is a harsh chemical environment for foreign materials.

An implanted material can have its properties altered by body fluids. An implanted material can have its properties altered by body fluids.

Degradation mechanisms such as corrosion or leaching can beDegradation mechanisms such as corrosion or leaching can beaccelerated by ion concentrations and pH changes in body fluids.accelerated by ion concentrations and pH changes in body fluids.

The bodys response to an implant can range from benign to aThe bodys response to an implant can range from benign to achronic inflammatory reaction, with the degree of biologic responsechronic inflammatory reaction, with the degree of biologic responselargely dependent on the implanted material.largely dependent on the implanted material.

The physical, mechanical, chemical and electrical properties of theThe physical, mechanical, chemical and electrical properties of thebasic materials components must always be fully evaluated for anybasic materials components must always be fully evaluated for anybiomaterial application as these properties provide key inputs intobiomaterial application as these properties provide key inputs intothe interrelated biomechanical and biologic analyses of function.the interrelated biomechanical and biologic analyses of function.



oo Replacing lost teeth with aReplacing lost teeth with a bonebone--anchored deviceanchored device is not a newis not a new

concept at all.concept at all.

oo Archeological findings showed that the ancient Egyptian and South Archeological findings showed that the ancient Egyptian and South American civilizations already experimented with American civilizations already experimented with rere--implantingimplanting lost lost teeth with handteeth with hand--shaped ivory or wood substitutes.shaped ivory or wood substitutes.

HISTORY

In the 18th century lost teeth wereIn the 18th century lost teeth weresometimes replaced with extractedsometimes replaced with extractedteeth of other humanteeth of other human donorsdonors..

The implantation process wasThe implantation process wasprobably somewhat crude and theprobably somewhat crude and thesuccess rates extremely low due tosuccess rates extremely low due tothe strong immune reaction of thethe strong immune reaction of thereceiving individual.receiving individual.

Allergy???



500 BC used gold wire tostabilize the periodontally weak teeth

First evidence of use of implants

implantation of pieces of shell



In 1809, Maggiolo fabricated a goldIn 1809, Maggiolo fabricated a gold implant implant

In 1887, a physician named Harris attemptedIn 1887, a physician named Harris attemptedthe same procedure with a platinum post, instead of a gold post.the same procedure with a platinum post, instead of a gold post.



oo In 1886 Edmunds was the first in theIn 1886 Edmunds was the first in theUS to implant a platinum disc intoUS to implant a platinum disc into

the jawbone, to which a porcelainthe jawbone, to which a porcelaincrown was fixated.crown was fixated.

Strock placed the first somewhat Strock placed the first somewhat successful oral implants in 1937 at successful oral implants in 1937 at

Harvard University.Harvard University.

Strock published a paper on theStrock published a paper on thephysiological effects of cobalt physiological effects of cobalt--chromiumchromium--molybdenum alloymolybdenum alloy

(vitallium) in bone, and thus placed a(vitallium) in bone, and thus placed aseries of vitallium implants into test series of vitallium implants into test animals and humans.animals and humans.



Modern Historical Developments:Modern Historical Developments:

The first Subperiosteal Implant was placed in 1948 by Gustav DahlThe first Subperiosteal Implant was placed in 1948 by Gustav Dahl

TheThe Endosteal Blade Implant Endosteal Blade Implant , introduced independently in 1967 by Leonard, introduced independently in 1967 by LeonardLinkow and Ralph and Harold RobertsLinkow and Ralph and Harold Roberts



Types of endosseous implantsTypes of endosseous implants



The quantum leap in Oral Implantology wasThe quantum leap in Oral Implantology was

achieved in 1952 in Sweden by Per Ingvar Branemarkachieved in 1952 in Sweden by Per Ingvar Branemark

He founded the phenomenon of He founded the phenomenon of OsseointegrationOsseointegration

Dr. Branemark's research shifted more towards the use of titaniumDr. Branemark's research shifted more towards the use of titaniumappliances in human bone, including the use of titanium screws asappliances in human bone, including the use of titanium screws asbone anchors for lost teeth.bone anchors for lost teeth.

In 1982, the Toronto Conference on Osseointegration in ClinicalIn 1982, the Toronto Conference on Osseointegration in ClinicalDentistry laid down the first parameters on what is to be consideredDentistry laid down the first parameters on what is to be consideredsuccessful implant treatment within the stringent confines of thesuccessful implant treatment within the stringent confines of thescientific community.scientific community.



BIOLOGIC CLASSIFICATION OF IMPLANT M ATERIALS

DEGREE OF DEGREE OF COMP ATIBILITYCOMP ATIBILITY

CHARACTERISTICS CHARACTERISTICS OF REACTIONS OF OF REACTIONS OF BONY TISSUEBONY TISSUE

M ATERIALSM ATERIALS

biotolerant biotolerant characterized by a thincharacterized by a thin

fibrous tissue interface:fibrous tissue interface:distance osteogenesisdistance osteogenesis

Stainless Steel, PMMA,Stainless Steel, PMMA,

CoCo--CrCr--Mo,Mo,CoCo--CrCr--MoMo--NiNi

bioinert bioinert are characterized byare characterized bydirect bone contact:direct bone contact:

contact osteogenesiscontact osteogenesis

Alumina, Titanium, Alumina, Titanium,Tantalum, CarbonTantalum, Carbon

bioactivebioactive direct chemical bondingdirect chemical bondingof the implant with theof the implant with thesurrounding bone :surrounding bone :

bonding osteogenesisbonding osteogenesis

Calcium phosphateCalcium phosphate--containing glasses,containing glasses,glassglass--ceramics,ceramics,ceramics, titanium?ceramics, titanium?

Biologic classification based on tissue response and systemic toxicity effects of implant







Implant Material Common name or abbreviation

MetalsTitaniumTitanium AlloyStainless SteelCobalt Chromium AlloyGold AlloysTantalum

CeramicsAluminaHydroxyapatiteBeta-Tricalcium Phosphate

Carbon

Carbon-Silicon

BioglassPolymers

PolymethylmethacrylatePolytetrafluoroethylenePolyethelenePolysulfone

Polyurethane

cpTiTi6Al4vSS, 316, L SSVitallium, Co-Cr-Mo

TaAl2O3, amorphous or single crystalsapphire (Kyocera)HA, Ca10(PO4) (OH)2

B-TCP, Ca3(PO4)2

C, vitreous, low temperature isotropic(LT1), ultra-low temperature isotropicC-Si

SiO2 / CaO / Na2O / P2O3

PMMAPTFEPEPSF

PU



PHYSICAL, MECHANICAL,AND CHEMICAL REQUIREMENTS for IMPLANT M ATERIALS



Forces exerted on the implant material consists of tensile,compressive and shear components.

For most of the implant materials compressive strengths areusually greater than their shear bond tensile counterparts

A recurring problem occurs between the mechanical strength anddeformability of the material and the recipient bone

different approach to match more closely the implanted materialand hard tissue properties led to the experimentation of polymeric

carbonitic and metallic materials because of low modulus of elasticity



The higher the applied load, the higher the mechanical stress and

the greater the possibility for exceeding the fatigue limit of the

material.

In general the fatigue limit of metallic implant materials reachesapproximately 50% of their ultimate tensile strength

Ceramic materials are weak under shear forces because of thecombination of fracture strength and low ductility which can lead tobrittle facture.

Metals are Modified by the addition of alloying elements or alteredMetals are Modified by the addition of alloying elements or altered

by mechanical processing such as drawing , swaging or forgingby mechanical processing such as drawing , swaging or forgingfollowed by age or dispersion hardening until the strength of followed by age or dispersion hardening until the strength of material is optimized for the intended application.material is optimized for the intended application.



A general rule is that constitution of mechanical process hardening A general rule is that constitution of mechanical process hardening

procedures result in an increased strength but also invariably correspondprocedures result in an increased strength but also invariably correspond

to a loss of ductility. This especially is relevant for dental implants. Most to a loss of ductility. This especially is relevant for dental implants. Most

of all consensus standards for metal are given by American Society forof all consensus standards for metal are given by American Society for

Testing and Materials (ASTM), International standardization organizationTesting and Materials (ASTM), International standardization organization

(ISO). American dental association (ADA) require a minimum of 8% (ISO). American dental association (ADA) require a minimum of 8%

ductility to minimize brittle fractures.ductility to minimize brittle fractures.



Material

NominalAnalysis

(w/o)

Modulus of

Elasticit

yGN/m2

(psix106)

Ultimatetensile

strengthMN/m2 (ksi)

Elongation to

fracture(%)

Surface

Titanium (T1) 99+Ti97 (14)

240-550 (25-70)

> 15Tioxide

Titanium-aluminiumvanadium (Ti-Al-V)

90Ti-6A1-4V 117 (34)

869 ² 896(125 ² 130) > 12

Tioxide

Cobalt-Chromiummolybdenum (casting) (Co-Cr-Mo)

66Co -27Cr-7Mo 235 (34)

655 (95)

> 8

Croxide

Stainless Steel (316L) 70Fe ²18Cr ² 12Ni

193 (28)

480 ² 1000(70 - 145) > 30

Croxide

Tantalum (Ta) 99+Ta-

690 (100)11

Ta

oxide



CORROSION AND BIODEGRAD ATIONCORROSION AND BIODEGRAD ATION

Corrosion is a special concern for metallic materials in dental

implantology because implants must be placed in oral cavity andoxygen compositions differ from that of tissue fluids

In addition the pH can vary significantly in areas below plaque andwithin the oral cavity.

The effect of galvanic corrosion is greater in case of dentalimplants. Galvanic processes depends on the passivity of oxidelayers.

The passive layer is usually made of oxides or hydroxides of themetallic elements that have greatest affinity for oxygen.

In reactive group metals such as titanium, niobium, zirconium,tantalum and related alloys, the base materials determine theproperties of the passive layer.



Three types of corrosion are most relevant toThree types of corrosion are most relevant todental implantsdental implants::

stress corrosionstress corrosion

cracking, galvanic corrosion andcracking, galvanic corrosion and

fretting corrosion.fretting corrosion.



STRESS CORROSION CRACKINGSTRESS CORROSION CRACKING

The combination of high magnitudes of applied mechanical stressThe combination of high magnitudes of applied mechanical stressplus simultaneous exposure to a corrosive environment can result inplus simultaneous exposure to a corrosive environment can result inthe failure of metallic materials by crackingthe failure of metallic materials by cracking

Most traditional implant body designs under three dimensional finiteMost traditional implant body designs under three dimensional finiteelement stress analysis show a concentration of stresses at the crest element stress analysis show a concentration of stresses at the crest of the bone support and cervical one third of the implant.of the bone support and cervical one third of the implant.

This tends to support potential stress corrosion at the implant This tends to support potential stress corrosion at the implant interface areasinterface areas



GALVANIC CORROSIONGALVANIC CORROSION

Galvanic corrosion occurs when two dissimilar metallic materials areGalvanic corrosion occurs when two dissimilar metallic materials are

in contact and are within an electrolyte resulting in current to flowin contact and are within an electrolyte resulting in current to flowbetween the two.between the two.

FRETTING CORROSIONFRETTING CORROSION

Fretting corrosion occurs when there is a micromotion and rubbingFretting corrosion occurs when there is a micromotion and rubbingcontact within a corrosive environment contact within a corrosive environment

Fretting corrosion has been shown to occur along implant abutment Fretting corrosion has been shown to occur along implant abutment

superstructure interfaces.superstructure interfaces.



CLINICAL SIGNIFICANCE of CORROSIONCLINICAL SIGNIFICANCE of CORROSION passive oxide layers on metallic substrates dissolves at much slowerpassive oxide layers on metallic substrates dissolves at much slower

ratesrates

more critical problem is irreversible local perforation of the passivemore critical problem is irreversible local perforation of the passivelayer that is often caused by chloride ions which may result inlayer that is often caused by chloride ions which may result inlocalized pitting corrosion.localized pitting corrosion.

This is observed for iron chromium nickel molybdenum (Fe-Cr-Ni-Mo) steels

ceramic oxide materials are not fully degradation resistant.

corrosion resistance of synthetic polymers on the other hand,depends not only on their composition and structural from but alsoon the degree of polymerization.

polymers are not only dissolved but also penetrated by water andsubstance from biologic environment.



TOXICITY CONSIDERATIONSTOXICITY CONSIDERATIONS

Toxicity is related to primary biodegradation product Toxicity is related to primary biodegradation product

Factors to be considered include :Factors to be considered include :

1.1. The amount dissolved by biodegradation per time unit The amount dissolved by biodegradation per time unit

2.2. The amount of material removed by metabolic activity in the sameThe amount of material removed by metabolic activity in the sametime unit time unit

3.3. Quantities of solid particles and ions deposited in the tissueQuantities of solid particles and ions deposited in the tissue

The transformation of harmful primary products is dependent The transformation of harmful primary products is dependent

on their level of solubility and transfer.on their level of solubility and transfer.

electrochemical behaviour of implanted materials has beenelectrochemical behaviour of implanted materials has beeninstrumental in assessing their biocompatibilityinstrumental in assessing their biocompatibility



Charge transfer appear to be a significant factor specific to theCharge transfer appear to be a significant factor specific to thebiocompatibility of metallic biomaterials.biocompatibility of metallic biomaterials.

passive layers along the surfaces of niobium, titanium, zirconiumpassive layers along the surfaces of niobium, titanium, zirconiumand tantalum increase resistance to charge transfer processes byand tantalum increase resistance to charge transfer processes by

isolating the substrate from the electrolyte in addition to providing aisolating the substrate from the electrolyte in addition to providing ahigher resistance to ion transfers.higher resistance to ion transfers.

On the other hand, metals of iron, nickel or cobalt are not asOn the other hand, metals of iron, nickel or cobalt are not asresistant to transfer through the oxide the passive surface zones.resistant to transfer through the oxide the passive surface zones.



Commonly used biomaterials for dental implants areCommonly used biomaterials for dental implants are

Commercially pure (CP) titanium and titaniumCommercially pure (CP) titanium and titanium aluminiumaluminium vanadium (Tivanadium (Ti--6Al6Al--4V) alloy are most often used for endosseous4V) alloy are most often used for endosseousimplantsimplants

whereas cobalt whereas cobalt chromium molybedenum (Cochromium molybedenum (Co--CrCr--Mo) alloy is most Mo) alloy is most often used for subperiosteal implants.often used for subperiosteal implants.

Calcium phosphate ceramics, particularly hydroxyapatite (HA), haveCalcium phosphate ceramics, particularly hydroxyapatite (HA), havebeen used in monolithic form as augmentation material for alveolarbeen used in monolithic form as augmentation material for alveolarridges and as coating on metal devices for endosseous implantation.ridges and as coating on metal devices for endosseous implantation.



TITANIUM AND TITANIUM 6 ALUMINIUM TITANIUM AND TITANIUM 6 ALUMINIUM --44 VANDIUM (Ti VANDIUM (Ti 6 Al6 Al 4 V)4 V) Titanium appears on the periodicTitanium appears on the periodic

table as element, 22,table as element, 22,a fourth row transition metal witha fourth row transition metal withan atomic weight of 47.88.an atomic weight of 47.88.

An extremely reactive metal, An extremely reactive metal,titanium forms a tenacious oxidetitanium forms a tenacious oxidelayer that contributes to itslayer that contributes to its

electrochemical passivity.electrochemical passivity.

The element was discovered byThe element was discovered byWilheim Gregor, a clergyman whoWilheim Gregor, a clergyman whofound the metal in a blackfound the metal in a blackmagnetic sand in cornwall inmagnetic sand in cornwall in1791.1791.

K laproth has named titanium afterK laproth has named titanium afterthe Greek Titans.the Greek Titans.

In 1930s K rol developedIn 1930s K rol developedcommercially extractioncommercially extractionprocedures that are still usedprocedures that are still used

today.today.



Commercially pure (Commercially pure (CP)CP)titanium and titaniumtitanium and titanium--based alloysbased alloysare low density metals that haveare low density metals that havechemical properties suitable forchemical properties suitable forimplant applicationsimplant applications

Titanium has a high corrosionTitanium has a high corrosionresistanceresistance

Titanium oxidizes or passivatesTitanium oxidizes or passivatesupon contact with roomupon contact with roomtemperature air and normal tissuetemperature air and normal tissuefluids. This activity is favourablefluids. This activity is favourablefor dental implant devices in thefor dental implant devices in theabsence of interfacial motion orabsence of interfacial motion or

adverse environmental conditions.adverse environmental conditions.

This passivated surface conditionThis passivated surface conditionminimizesminimizes biocorrosionbiocorrosionphenomena.phenomena.





Among these two general groups, however, are six distinct Among these two general groups, however, are six distinct materials defined by the American Society for Testing andmaterials defined by the American Society for Testing andMaterials (ASTM).Materials (ASTM).

All six of these materials, which include four grades of CP titanium All six of these materials, which include four grades of CP titaniumand two titanium alloys, are commercially available.and two titanium alloys, are commercially available.

The mechanical and physical properties of these materials differsThe mechanical and physical properties of these materials differssignificantly.significantly.

The two alloys are TiThe two alloys are Ti--6Al6Al 4V and Ti4V and Ti--6Al6Al-- 4V extra low interstitial4V extra low interstitial(ELI).(ELI).

The commercially pure titanium materials areThe commercially pure titanium materials are

1.1. commercially pure grade I titanium,commercially pure grade I titanium,

2.2. commercially pure grade II titaniumcommercially pure grade II titanium

3.3. commercially pure grade III titaniumcommercially pure grade III titanium

4.4. and commercially pure grade I V titaniumand commercially pure grade I V titanium



Titanium N C H Fe O Al V Ti

Cp Grade I

Cp Grade II

Cp Grade III

Cp Grade IV

Ti-6AL-4Valloy

Ti-6AL-4V-ELIalloy

0.03

0.03

0.03

0.03

0.05

0.05

0.10

0.10

0.10

0.10

0.08

0.08

0.015

0.015

0.015

0.015

0.015

0.012

0.02

0.03

0.03

0.05

0.30

0.10

0.18

0.25

0.35

0.40

0.20

0.13

-

-

-

-

5.50-6.7

-

-

-

-

3.50-4.50

3.50-4.50

Bal.

Bal.

Bal.

Bal.

Bal.

Bal.



Cp Ti is available in different grades which vary mostly in theCp Ti is available in different grades which vary mostly in theoxygen content oxygen content

Grade 4 cp Ti has the most oxygen at 0.40%.Grade 4 cp Ti has the most oxygen at 0.40%.

Iron is added for corrosion resistanceIron is added for corrosion resistance

Aluminium increases the strength of the alloy and decreases its Aluminium increases the strength of the alloy and decreases itsdensity.density.

Vanadium acts to inhibit corrosion by acting as an aluminium Vanadium acts to inhibit corrosion by acting as an aluminiumscavenger.scavenger.

Vanadium stabilizes the beta phase of Ti Vanadium stabilizes the beta phase of Ti--6Al6Al--4V alloys4V alloys

This combination of phases gives the alloy strengthThis combination of phases gives the alloy strength



Extra low interstitial describes the low levels of oxygen dissolved inExtra low interstitial describes the low levels of oxygen dissolved in

interstitial sites in the metal.interstitial sites in the metal.

With lower amounts of oxygen and ironWith lower amounts of oxygen and ironresiduals in the ELI alloy, ductility isresiduals in the ELI alloy, ductility isimproved slightly.improved slightly.



MaterialModulus

(Gpa)

UltimateTensile

Strength(MPa)

YieldStrength

MPa)

Elongation(%)

Density(G / cc)

Cp grade I TiCp grade II TiCp grade III TiCp grade IV TiTi-6Al-4V ELI

Ti-6Al-4VCo-Cr-Mo316L steelCortical BoneDentinEnamel

102102102104113

11324020018

18.384

240345450550860

9307009651405210

170275380483795

860450690n/an/an/a

2420181510

10820100

4.54.54.54.54.4

4.48.57.90.72.2

3

Mechanical Properties of CP Titanium and Alloys



Strength is beneficial because materials better resist occlusal forceswithout fracture or failure.

Lower modulus is desirable because the implant biomaterialbetter transmits forces to the bone.

The addition of aluminium and vanadium, which make up 10% of titanium alloys, raises the modulus about 10%.



Surface PropertiesSurface Properties

The surface properties of implants are important to the biologicalThe surface properties of implants are important to the biologicalresponse that the material will elicit from the body.response that the material will elicit from the body.

Thus, the surface oxide which forms on the titanium alloys is of Thus, the surface oxide which forms on the titanium alloys is of paramount importance to its favorable biological properties.paramount importance to its favorable biological properties.

In air, the oxide begins to form in nanoseconds and reachesIn air, the oxide begins to form in nanoseconds and reaches

2020--100 A thickness by 1 sec100 A thickness by 1 sec

The oxide thickness of Ti alloy (83 A) has been reported to beThe oxide thickness of Ti alloy (83 A) has been reported to bethicker than that of cp Ti (32 A)thicker than that of cp Ti (32 A)

The composition of oxide is primarily TiO2, but also contains TiOThe composition of oxide is primarily TiO2, but also contains TiOand Ti2O3 among other oxide , depending on the position of theand Ti2O3 among other oxide , depending on the position of theoxide within the oxide layer.oxide within the oxide layer.

The surface oxide layer protects against corrosion, it cannot The surface oxide layer protects against corrosion, it cannot completely prevent release of elements into the body.completely prevent release of elements into the body.





Biological ResponseBiological Response

Evidence suggests that the oxide layer is first hydrated then coveredEvidence suggests that the oxide layer is first hydrated then coveredby molecular layers of water.by molecular layers of water.

The molecules which occur are probably the proteins andThe molecules which occur are probably the proteins andcarbohydrates of the ground substance of bone.carbohydrates of the ground substance of bone.

in the osseointegrated implant, the layer is probably onlyin the osseointegrated implant, the layer is probably only20 20 50 A thick.50 A thick.

The final layer before the mineralized tissue is that of collagenThe final layer before the mineralized tissue is that of collagenfibrils in the ground substance which are continuous with thefibrils in the ground substance which are continuous with the

organic phase of the bone itself.organic phase of the bone itself.

The favourable biological response to Ti materials is most likely toThe favourable biological response to Ti materials is most likely tothe limited release of ions from the material, the stability of the limited release of ions from the material, the stability of complexes which form when release does occur, and the limitedcomplexes which form when release does occur, and the limitedbiological effects of the ionsbiological effects of the ions





The interface of titanium implants with the gingival tissue is also important The interface of titanium implants with the gingival tissue is also important because in the natural tooth the junctional epithelium creates a barrierbecause in the natural tooth the junctional epithelium creates a barrier

to chemical, mechanical and biological penetration.to chemical, mechanical and biological penetration.

The connective tissue fibers below the epithelium form a tight cuff aroundThe connective tissue fibers below the epithelium form a tight cuff aroundthe implant which may act as a seal. It prevent the apical migration of the implant which may act as a seal. It prevent the apical migration of the epithelium and subsequent bone loss.the epithelium and subsequent bone loss.

The Titanium alloy is approximately 6 times stronger than compact boneThe Titanium alloy is approximately 6 times stronger than compact boneand thus affords more opportunities for design with thinner sections.and thus affords more opportunities for design with thinner sections.

Any residues of surface changes must be removed before implantation to Any residues of surface changes must be removed before implantation toensure mechanically and chemically cleaned conditions.ensure mechanically and chemically cleaned conditions.





The cobalt based alloys are most often used in as cast or cast and annealedmetallurgic dentition.

The elemental composition of this alloy includes cobalt , Chromium andmolybdenum as major elements.

Cobalt provide the continuous phase for basic properties

Chromium provides corrosion resistance through theChromium provides corrosion resistance through the oxide surface.oxide surface.

While molybdenum provides strength and bulk corrosion resistance.While molybdenum provides strength and bulk corrosion resistance.

Minor concentrations of nickel, manganese and carbon are also included inMinor concentrations of nickel, manganese and carbon are also included inthis alloy.this alloy.

COBALT CHROMIUM MOLYBDENUM BASED ALLOY



Nickel has been identified as biocorrosion products.Nickel has been identified as biocorrosion products.

The carbon content must be precisely controlled to maintain mechanicalThe carbon content must be precisely controlled to maintain mechanicalproperties such as ductility.properties such as ductility.

In general the cast cobalt alloys are the least ductile alloy systems used forIn general the cast cobalt alloys are the least ductile alloy systems used fordental surgical implants.dental surgical implants.

Thus bending of the finished implants should be avoided.Thus bending of the finished implants should be avoided.

when properly fabricated implant from this alloy groups have shownwhen properly fabricated implant from this alloy groups have shownexcellent biocompatibility profiles.excellent biocompatibility profiles.



IRON CHROMIUM NICKEL B ASED ALLOYSIRON CHROMIUM NICKEL B ASED ALLOYS

This alloy, as with titanium systems is used most often in a wrought This alloy, as with titanium systems is used most often in a wrought and heat treated metallic condition which results in a high strengthand heat treated metallic condition which results in a high strengthductility alloy.ductility alloy.

The ramus blade ,ramus frame stabilizer pins (old) and someThe ramus blade ,ramus frame stabilizer pins (old) and somemucosal insert systems have been made from the iron basedmucosal insert systems have been made from the iron based alloys.alloys.

OF the implant alloys this alloy is most subject to crevice and pittingOF the implant alloys this alloy is most subject to crevice and pittingbiocorrosion.biocorrosion.

So care must be taken to use and retain the passivated surfaceSo care must be taken to use and retain the passivated surface

condition.condition.

This alloy contains nickel as a major element. Hence its use inThis alloy contains nickel as a major element. Hence its use inpatients allergic or hypersensitive to nickel should be avoidedpatients allergic or hypersensitive to nickel should be avoided



The iron based alloys have galvanic potentials and corrosion characteristicsThe iron based alloys have galvanic potentials and corrosion characteristicsthat cause concern about galvanic coupling and biocorrosion if that cause concern about galvanic coupling and biocorrosion if

interconnected with titanium, cobalt, zirconium or carbon implant interconnected with titanium, cobalt, zirconium or carbon implant biomaterialsbiomaterials

If used independently, where the alloys are not in contact or not electricallyIf used independently, where the alloys are not in contact or not electricallyinterconnected, the galvanic couple would not exist, and each device wouldinterconnected, the galvanic couple would not exist, and each device wouldfunction independentlyfunction independently





CERAMICS :CERAMICS :

Ceramics are inorganic, non metallic, non polymeric materialCeramics are inorganic, non metallic, non polymeric materialmanufactured by compacting and sintering at elevated temperatures .manufactured by compacting and sintering at elevated temperatures .

Oxide ceramics were introduced for surgical implant devices because of theirOxide ceramics were introduced for surgical implant devices because of theirinertness to biodegradation, high strength, physical characteristics suchinertness to biodegradation, high strength, physical characteristics suchas colour and minimal thermal and electrical conductivity and wideas colour and minimal thermal and electrical conductivity and widerange of material specific elastic properties.range of material specific elastic properties.

Ceramics may be used in bulk forms and more recently as coatings onCeramics may be used in bulk forms and more recently as coatings onmetals and alloysmetals and alloys



ALUMINIUM TITANIUM AND ZIRCONIUM OXIDES: ALUMINIUM TITANIUM AND ZIRCONIUM OXIDES:

High ceramics form aluminium , titanium and zirconium oxides haveHigh ceramics form aluminium , titanium and zirconium oxides have

been used for root form, endosteal plate form and pin type dentalbeen used for root form, endosteal plate form and pin type dentalimplant.implant.

The compressive, tensile, and bending strengths exceed theThe compressive, tensile, and bending strengths exceed thestrength of compact bone by 3 to 5 times.strength of compact bone by 3 to 5 times.

These properties combined with a high modulus of elasticity andThese properties combined with a high modulus of elasticity andwith high fracture and fatigue strengths have resulted in specializedwith high fracture and fatigue strengths have resulted in specializeddesign requirements for these classes of biomaterials.design requirements for these classes of biomaterials.

Minimal thermal and electrical conductivity, minimumMinimal thermal and electrical conductivity, minimum

biodegradation and minimal reactions with bone, soft tissue and thebiodegradation and minimal reactions with bone, soft tissue and theoral environment also recognized as beneficial when compared withoral environment also recognized as beneficial when compared withother types of synthetic biomaterials.other types of synthetic biomaterials.

Ceramics have exhibited direct interfaces similar to anCeramics have exhibited direct interfaces similar to anosseointegrated condition with titanium.osseointegrated condition with titanium.



care must be taken in the handling and placement of thesecare must be taken in the handling and placement of thesebiomaterials.biomaterials.

Exposure to steam sterilization results in a measurable decrease inExposure to steam sterilization results in a measurable decrease instrength for some ceramicsstrength for some ceramics

Scratches or notches many introduce fracture initiation sites,Scratches or notches many introduce fracture initiation sites,chemical solutions may leave residueschemical solutions may leave residues

Dry heat sterilization within a clear and dry atmosphere isDry heat sterilization within a clear and dry atmosphere is

recommended for most ceramicsrecommended for most ceramics



GLASS CERAMICSGLASS CERAMICS

Glass ceramics such as bioglass and polycrystalline ceramicsGlass ceramics such as bioglass and polycrystalline ceramicsproduced by the controlled crystallization of glassesproduced by the controlled crystallization of glasses

Glass ceramicGlass ceramic made up of crystalline oxyapatite and flourapatite &made up of crystalline oxyapatite and flourapatite & wollastonite (Si O2 wollastonite (Si O2 CaO) in MgOCaO) in MgO CaOCaO SiO2 glassy matrixSiO2 glassy matrix

Bio glassBio glass is synthesis of several glasses containing mix of silica,is synthesis of several glasses containing mix of silica,phosphates, calcia and sodaphosphates, calcia and soda

Glass ceramics have poor mechanical properties for load carryingGlass ceramics have poor mechanical properties for load carryingapplications because they are extremely brittle.applications because they are extremely brittle.

A calcium phosphate layer forms on the surface. A calcium phosphate layer forms on the surface.

The ability of bioglass to bond depends on this layer.The ability of bioglass to bond depends on this layer.

thisthis surface layer develops on the bioglass when its silica contentsis greater than 60 mol%.



BIOACTIVE AND BIODEGRAD ABLE CERAMICS BIOACTIVE AND BIODEGRAD ABLE CERAMICS B ASED ON CALCIUM PHOSPHATESB ASED ON CALCIUM PHOSPHATES

Calcium phosphate ceramics classified as polycrystalline ceramicCalcium phosphate ceramics classified as polycrystalline ceramicsimilar to mineral phase of bone (Ca5[PO4]3OH)similar to mineral phase of bone (Ca5[PO4]3OH)

Hydroxyapatite commonly called tribasic calcium phosphate is aHydroxyapatite commonly called tribasic calcium phosphate is ageologic mineral that closely resembles the natural mineral ingeologic mineral that closely resembles the natural mineral in

vertebrate bone tissue.vertebrate bone tissue.

Hydroxyapatite forms non resorbable form of calcium phosphateHydroxyapatite forms non resorbable form of calcium phosphate

Tribasic calcium phosphate should not be confused with otherTribasic calcium phosphate should not be confused with other

calcium phosphate ceramics especially tricalcium phosphatecalcium phosphate ceramics especially tricalcium phosphate[(Ca(PO4)2] which is chemically similar to hyroxyapatite but is not a[(Ca(PO4)2] which is chemically similar to hyroxyapatite but is not anatural bone mineral.natural bone mineral.

--TCP is an non crystalline amorphous material, which is resorbableTCP is an non crystalline amorphous material, which is resorbable



Used in wide range of implant typesUsed in wide range of implant types

The coatings of metallic surfaces using flame or plasma sprayingThe coatings of metallic surfaces using flame or plasma spraying

have increased rapidly for the calcium phosphate ceramics.have increased rapidly for the calcium phosphate ceramics.

The coatings have been applied to a wide range of endosteal andThe coatings have been applied to a wide range of endosteal andsubperiosteal dental implant designs with an overall indent of subperiosteal dental implant designs with an overall indent of improving implant surface biocompatibility profiles and implant improving implant surface biocompatibility profiles and implant

longevities.longevities.

Mixtures of particulates with collagen, and subsequently with drugsMixtures of particulates with collagen, and subsequently with drugsand active organic compounds such as BMP increases the range of and active organic compounds such as BMP increases the range of applicationsapplications

ADVANTAGES and DISADVANTAGES OF CALCIUMADVANTAGES and DISADVANTAGES OF CALCIUM



AD V ANTAGES and DISAD V ANTAGES OF CALCIUM AD V ANTAGES and DISAD V ANTAGES OF CALCIUMPHOSPHATE CERAMICSPHOSPHATE CERAMICS

AD V ANTAGES AD V ANTAGES DISAD V ANTAGESDISAD V ANTAGES

Chemistry mimics normalChemistry mimics normalbiological tissues (Ca,P,O,H)biological tissues (Ca,P,O,H)

Excellent biocompatibilityExcellent biocompatibility

Attachment between cpc Attachment between cpc

and hard and soft tissuesand hard and soft tissues

Minimal thermal and electricalMinimal thermal and electricalconductivityconductivity

Moduli of elasticity closer to boneModuli of elasticity closer to bone

Colour similar to hard tissuesColour similar to hard tissues

Variable chemical and structural Variable chemical and structuralcharacteristicscharacteristics

Relatively low mechanical, tensileRelatively low mechanical, tensile

and shear strength under fatigueand shear strength under fatigueloadingloading

Low attachment between coatingLow attachment between coatingand substrateand substrate

Variable solubility Variable solubility

variable mechanical stability of variable mechanical stability of coatings under load bearing conditionscoatings under load bearing conditions

overuseoveruse



classes of bioceramics have low strength, hardness and moduli of classes of bioceramics have low strength, hardness and moduli of elasticity than the more chemically inert forms.elasticity than the more chemically inert forms.

The calcium phosphate ceramics have proved to be one of the moreThe calcium phosphate ceramics have proved to be one of the moresuccessful high technology based biomaterials that has evolvedsuccessful high technology based biomaterials that has evolved

with the past decades.with the past decades.

Their advantages properties strongly support the expanding clinicalTheir advantages properties strongly support the expanding clinicalapplications and the enhancement of the biocompatibilityapplications and the enhancement of the biocompatibilityprofiles for surgical implant uses.profiles for surgical implant uses.



CARBON AND CARBON SILICON CARBON AND CARBON SILICON

COMPOUNDSCOMPOUNDS

Carbon compounds are often classified as ceramics because of theirCarbon compounds are often classified as ceramics because of theirchemical inertness and absence of ductility.chemical inertness and absence of ductility.

They are conductors of heat and electricity.They are conductors of heat and electricity.

Their excellent biocompatibility and moduli of elasticity close to that Their excellent biocompatibility and moduli of elasticity close to that of bone have resulted in clinical trials of these compounds in dentalof bone have resulted in clinical trials of these compounds in dentalprostheses.prostheses.

combination of design, material and application limitations resultedcombination of design, material and application limitations resultedin a significant number of clinical failures and its subsequent in a significant number of clinical failures and its subsequent withdrawal from clinical use.withdrawal from clinical use.



The possible limitation areThe possible limitation are ::

1.1. Those relating to mechanical strength properties along the substrateThose relating to mechanical strength properties along the substrateto coating interface.to coating interface.

2.2. Biodegradation that could adversely influence tissue stability.Biodegradation that could adversely influence tissue stability.

3.3. Minimal resistance to scratching or scarping procedures, associatedMinimal resistance to scratching or scarping procedures, associatedwith oral hygiene.with oral hygiene.

4.4. Susceptibility to standard handling, sterilizing or placingSusceptibility to standard handling, sterilizing or placingmethodologies.methodologies.



POLYMER AND COMPOSITESPOLYMER AND COMPOSITES ::

Fiber reinforced polymers offer advantages in that they can be designed toFiber reinforced polymers offer advantages in that they can be designed tomatch tissue properties, and can be coated for attachment to tissues.match tissue properties, and can be coated for attachment to tissues.

STRUCTURAL BIOMEDICAL POLYMERSSTRUCTURAL BIOMEDICAL POLYMERS

The more inert polymeric biomaterials includeThe more inert polymeric biomaterials include

Polytetra fluoroethylene (PTFE)Polytetra fluoroethylene (PTFE) Polyethylene tetraphthalate (PET)Polyethylene tetraphthalate (PET) Polymethyl methacrylate (PMMA)Polymethyl methacrylate (PMMA)

Ultrahigh molecular weight polyethylene (UHMWUltrahigh molecular weight polyethylene (UHMW--PE)PE) Polypropylene (PP)Polypropylene (PP) Polysulfone (PSF) andPolysulfone (PSF) and Poly dimethyl siloxane (PDS) or silicone rubber (SR)Poly dimethyl siloxane (PDS) or silicone rubber (SR)



In general the polymers have lower strengths and elastic moduli andIn general the polymers have lower strengths and elastic moduli andhigher elongations to fracture compared with others.higher elongations to fracture compared with others.

They are thermal and electrical insulators,They are thermal and electrical insulators,

They are relatively resistant to biodegradation.They are relatively resistant to biodegradation.

Compared with bone most polymers have lower elastic moduli withCompared with bone most polymers have lower elastic moduli withmagnitudes closer to soft tissue.magnitudes closer to soft tissue.

Polymers have been fabricated in porous and solid forms for tissuePolymers have been fabricated in porous and solid forms for tissueattachment, replacement and augmentation and as coatings for forceattachment, replacement and augmentation and as coatings for force

transfer to soft tissue and hard tissue regions.transfer to soft tissue and hard tissue regions.



Extremly tough and fatigue cycle resistant (PP,UHMAExtremly tough and fatigue cycle resistant (PP,UHMA--PE,PTFE)PE,PTFE) --

for mechanical force transfer within selected implant designs.for mechanical force transfer within selected implant designs.

Internal force distribution connectors for osseointegratedInternal force distribution connectors for osseointegratedimplants where the connector is intended to better stimulateimplants where the connector is intended to better stimulatebiomechanical conditions for normal tooth functions.biomechanical conditions for normal tooth functions.

PTFE has a low resistance to contact abrasion and wearPTFE has a low resistance to contact abrasion and wearphenomenaphenomena



COMPOSITES :COMPOSITES :

Combinations of polymers and other categories of syntheticCombinations of polymers and other categories of syntheticbiomaterials continuesbiomaterials continues

Biodegradable polymers such as polyvinyl alcohol (P V A) polylactidesBiodegradable polymers such as polyvinyl alcohol (P V A) polylactidesor glycolides, cyanoacrylates or other hydratable forms have beenor glycolides, cyanoacrylates or other hydratable forms have beencombined with calcium phosphate particulate or fibres.combined with calcium phosphate particulate or fibres.

polymers and composite of polymers are especially sensitive topolymers and composite of polymers are especially sensitive tosterilization and handling techniques.sterilization and handling techniques.

If intended for implant use most cannot be sterilized by steam orIf intended for implant use most cannot be sterilized by steam orethylene oxideethylene oxide



Extreme care must be taken to maintain quality surface conditions of Extreme care must be taken to maintain quality surface conditions of

the implant.the implant.

Porous polymers can be deformed by elastic deformation , which canPorous polymers can be deformed by elastic deformation , which canclose open regions intended for tissue in growth.close open regions intended for tissue in growth.

Cleaning of contaminated porous polymers is not possible without aCleaning of contaminated porous polymers is not possible without alaboratory environment .laboratory environment .

Talc or starch on surgical gloves, contact with a towel or gauze pad,Talc or starch on surgical gloves, contact with a towel or gauze pad,or the touching of any contaminated area must be avoided.or the touching of any contaminated area must be avoided.



Osseo integrationOsseo integration ::

IT is DEFINED as direct structural and functional contact of orderedIT is DEFINED as direct structural and functional contact of orderedliving bone to the surface of loaded implant materialsliving bone to the surface of loaded implant materials

this contact helps in direct transfer of forces onto the surroundingthis contact helps in direct transfer of forces onto the surrounding

bone , prevents mobility of the implant and stimulates the growth of bone , prevents mobility of the implant and stimulates the growth of bonebone

Thus reduces the incidence of implant failureThus reduces the incidence of implant failure

is dependent on material biocompatibility implant surface, status of is dependent on material biocompatibility implant surface, status of bone, surgical technique, healing conditions, and biting forces.bone, surgical technique, healing conditions, and biting forces.





Metallic oxides dictate type of cellular and protein binding at implant Metallic oxides dictate type of cellular and protein binding at implant surfacesurface

Progression of surface from the lowest implant tissue strength toProgression of surface from the lowest implant tissue strength tothe highest: smooth, textured, screw threaded plasma sprayed andthe highest: smooth, textured, screw threaded plasma sprayed andporous coatedporous coated

Surface coatings enhance the bond of bone to the implantsSurface coatings enhance the bond of bone to the implants

Roughness and porosities of the surface conducive to cellRoughness and porosities of the surface conducive to cellattachment attachment

Surface roughening can be done by sand blastingSurface roughening can be done by sand blasting

Titanium implants may be etched with a solution of nitric acid andTitanium implants may be etched with a solution of nitric acid andhydroflouric acid to chemically alter the surfacehydroflouric acid to chemically alter the surface

Alumina grit blasting and glass bead blasting Alumina grit blasting and glass bead blasting



SURFACE COATINGSSURFACE COATINGS

The implant surface may be covered with a porousThe implant surface may be covered with a porouscoating.coating.

These may be titanium or ceramicsThese may be titanium or ceramics





Plasma spray coating process:Plasma spray coating process:

a thermal spraying process in which ana thermal spraying process in which an arc is utilized as a source of arc is utilized as a source of

heat that ionizes a gas which melts and propels the coating materialheat that ionizes a gas which melts and propels the coating material

to the work piece.to the work piece.

powders are injected into the plasma stream thus melting the materialpowders are injected into the plasma stream thus melting the material



powders are injected into the plasma stream thus melting the material.powders are injected into the plasma stream thus melting the material.

Powder is carried at the velocity of the gas to the substrate where it isPowder is carried at the velocity of the gas to the substrate where it isquenched and bonds to the substrate.quenched and bonds to the substrate.

both thermal and kinetic energy in the particles bring out the highboth thermal and kinetic energy in the particles bring out the highbond strengthbond strength

Plasma is generated by passing the gas between 2 concentricPlasma is generated by passing the gas between 2 concentricelectrodes (water cooled) where it is heated by sustained highelectrodes (water cooled) where it is heated by sustained high current current





Titanium Plasma Sprayed:

Porous or rough titanium surfaces have been fabricated by plasma

spraying at high temperatures of 15,000 degree C at very highat high temperatures of 15,000 degree C at very highvelocity 600 m/secvelocity 600 m/sec

The plasma sprayed layer after solidification (fusion) is oftenThe plasma sprayed layer after solidification (fusion) is oftenprovided with a 0.04 to 0.05 mm thickness.provided with a 0.04 to 0.05 mm thickness.

These types of surface were first developed by Hahn and PalichThese types of surface were first developed by Hahn and Palich

rough and porous surfaces showed a threerough and porous surfaces showed a three--dimensionaldimensionalinterconnected configuration likely to achieve boneinterconnected configuration likely to achieve bone--implant implant attachment for stable anchorageattachment for stable anchorage

P tit i f f i f b i tiP tit i f f i f b i ti



Porous titanium surface from various fabricationPorous titanium surface from various fabricationmethods maymethods may

increase the total surface area,increase the total surface area,

produce attachment by osteoformation,produce attachment by osteoformation, enhance attachment by increasing ionic interactions,enhance attachment by increasing ionic interactions, introduce a dual physical and chemical anchor systems andintroduce a dual physical and chemical anchor systems and increase the loadincrease the load bearing capacity 25% to 30%.bearing capacity 25% to 30%.

oo In 1981 Clemow et al showed that the rate and percentage of In 1981 Clemow et al showed that the rate and percentage of bone ingrowth into the surface was inversely proportional to thebone ingrowth into the surface was inversely proportional to thesquare root of the pore size for sizes greater than 100 square root of the pore size for sizes greater than 100 QQmm

oo porous surfaces can result in an increase in tensile strength.porous surfaces can result in an increase in tensile strength.

oo Bone forms within the porosities even in the presence of someBone forms within the porosities even in the presence of somemicromovement during the healing phase.micromovement during the healing phase.

oo The basic theory was based on increased area for bone contact.The basic theory was based on increased area for bone contact.

H d i C iH d i C i ::



Hydroxyapatite CoatingHydroxyapatite Coating ::

oo Hydroxyapatite coating by plasma spraying was brought to theHydroxyapatite coating by plasma spraying was brought to thedental profession by deGroot.dental profession by deGroot.

oo HA coating can also lower the corrosion rate of the alloy.HA coating can also lower the corrosion rate of the alloy.

oo The bone adjacent to this implant shows better organized then withThe bone adjacent to this implant shows better organized then withother implant materials and with a higher degree of mineralization. .other implant materials and with a higher degree of mineralization. .

oo HA to bone attachment is superior to the HA to implant interface.HA to bone attachment is superior to the HA to implant interface.

oo Implants of solid sintered hydroxyapatite have been shown to beImplants of solid sintered hydroxyapatite have been shown to besusceptible to fatigue failure. This situation can be altered by thesusceptible to fatigue failure. This situation can be altered by theuse of CPC coatings, along metallic substrate.use of CPC coatings, along metallic substrate.



The bond between CPC and metal should be dense, more tenaciousThe bond between CPC and metal should be dense, more tenaciousand thinnerand thinner

this minimize the problem of poor shear strength and fatigue at thethis minimize the problem of poor shear strength and fatigue at thecoating substrate interface.coating substrate interface.

CPC coatings may resorb in infected or chronic inflammation areas.CPC coatings may resorb in infected or chronic inflammation areas.

One advantage of CPC coatings is that they can act as a protectiveOne advantage of CPC coatings is that they can act as a protectiveshield to reduce potential slow ion release from the Tishield to reduce potential slow ion release from the Ti--6AI6AI--4V 4V

substratesubstrate..



BIOCOMPATIBILITY OF PLASMA SPRAYED BIOMEDICAL COATINGSBIOCOMPATIBILITY OF PLASMA SPRAYED BIOMEDICAL COATINGS

Osteoblasts grows better on hydroxyapatite and wollastonite coatingOsteoblasts grows better on hydroxyapatite and wollastonite coating

than on zirconium dioxide coatings and alumina oxide coatingsthan on zirconium dioxide coatings and alumina oxide coatings

Biocompatibility of bio active ceramic coatings is better than of bioBiocompatibility of bio active ceramic coatings is better than of bioinert ceramic coatings.inert ceramic coatings.

Bone like apatite can form on bio active coatingsBone like apatite can form on bio active coatings

Plasma spray Al2O3 coatings is harmful because of existence of Plasma spray Al2O3 coatings is harmful because of existence of alumina in the coatingalumina in the coating

alumina forms when stable Al2O3 is plasma sprayedalumina forms when stable Al2O3 is plasma sprayed

The compatibility of wollastonite is similar to that of bio active glass.The compatibility of wollastonite is similar to that of bio active glass.it forms tight bond to Ti alloy substrate as its T.E is close to Ti alloysit forms tight bond to Ti alloy substrate as its T.E is close to Ti alloys

HyroxyapatiteHyroxyapatite -- thin film coatingthin film coating



HyroxyapatiteHyroxyapatite thin film coatingthin film coating

Adhesive strength of coating to implant surface are maximized by: Adhesive strength of coating to implant surface are maximized by:

incorporation of bio compatible bond coats such as titaniumincorporation of bio compatible bond coats such as titanium

use of radio frequency sputtering technique for the deposition of HA thinuse of radio frequency sputtering technique for the deposition of HA thinfilm coatingsfilm coatings

These coatings can be applied on complex shapes and provide completeThese coatings can be applied on complex shapes and provide completecoverage.coverage.

This deposition forms graded micro structure for selective dissolution of This deposition forms graded micro structure for selective dissolution of

coating i.e. sub layer with high crystallanity (low dissolution rate) andcoating i.e. sub layer with high crystallanity (low dissolution rate) andamorphous layer on topamorphous layer on top



The drawback of Ti 6The drawback of Ti 6-- Al Al-- 4V is its poor strength4V is its poor strength

HA coated Ti 6HA coated Ti 6-- Al Al-- 4V of the corrosion of underlying material4V of the corrosion of underlying material

HA coatings have tendency of cracking or peeling off under theHA coatings have tendency of cracking or peeling off under theinfluence of bending or shearing forcesinfluence of bending or shearing forces

These drawbacks have led to the invention of HA and Ti 6These drawbacks have led to the invention of HA and Ti 6-- Al Al-- 4V 4V composite powder and its deposition by plasma spraying.composite powder and its deposition by plasma spraying.

The composite powder improves bonding between HA andThe composite powder improves bonding between HA and

underlying substrate and prevents oxidation and corrosion of Ti 6underlying substrate and prevents oxidation and corrosion of Ti 6-- Al Al-- 4V 4V

Other Surface Modifications:Other Surface Modifications:



Other Surface Modifications:Other Surface Modifications: Surface modification methods include controlled chemical reactionsSurface modification methods include controlled chemical reactions

with nitrogen or other elements or surface ion implantationwith nitrogen or other elements or surface ion implantationprocedures.procedures.

The reaction of nitrogen with titanium alloys at elevatedThe reaction of nitrogen with titanium alloys at elevatedtemperatures results in titanium nitride compounds being formedtemperatures results in titanium nitride compounds being formedalong the surface.along the surface.

These nitride surface compounds are biochemically inert and alterThese nitride surface compounds are biochemically inert and alter

the surface mechanical properties to increase hardness and abrasionthe surface mechanical properties to increase hardness and abrasionresistance.resistance.

The element most commonly used is nitrogen.The element most commonly used is nitrogen.

electrochemically, the titanium nitrides are similar to the oxideselectrochemically, the titanium nitrides are similar to the oxides

(TiO2) and(TiO2) and

no adverse electrochemical behaviour has been noted if the nitrideno adverse electrochemical behaviour has been noted if the nitrideis lost regionally.is lost regionally.

the titanium substrate reoxidizes when the surface layer of nitride isthe titanium substrate reoxidizes when the surface layer of nitride is

removed.removed.

The local treatment of sol gel derived coatings with CO2 laser is aThe local treatment of sol gel derived coatings with CO2 laser is a



The local treatment of sol gel derived coatings with CO2 laser is aThe local treatment of sol gel derived coatings with CO2 laser is apromising technique for implants with varying properties to interfacepromising technique for implants with varying properties to interfacedifferent tissues both hard and soft tissuesdifferent tissues both hard and soft tissues

CHITOSAN is a biopolymer that exhibits osteoconductive, enhancedCHITOSAN is a biopolymer that exhibits osteoconductive, enhancedwound healing and antimicrobial properties which make it attractivewound healing and antimicrobial properties which make it attractivefor use as a bioactive coating to improve osseointegration of for use as a bioactive coating to improve osseointegration of orthopaedic and craniofacial implant devices.orthopaedic and craniofacial implant devices.

Coatings made from 91.2% deCoatings made from 91.2% de--acetylated chitosan were chemicallyacetylated chitosan were chemicallybonded to titanium coupons via silanebonded to titanium coupons via silane--glutaraldehyde moleculesglutaraldehyde molecules

the bond strengths were not affected by gas sterilization.the bond strengths were not affected by gas sterilization.



CHEMICALCHEMICAL--MADE APATITE LAYERMADE APATITE LAYER

Commercially pure titanium plates were heated and chemicallyCommercially pure titanium plates were heated and chemicallytreated to deposit crystalline apatite on their surface.treated to deposit crystalline apatite on their surface.

dense bonedense bone--like apatite layer was formed on the surface of thelike apatite layer was formed on the surface of thetitanium by a simple chemical methodtitanium by a simple chemical method

This chemical apatite layer also bonded tighter to the titanium thanThis chemical apatite layer also bonded tighter to the titanium than

the plasmathe plasma--sprayed apatite. This chemically made apatite coating issprayed apatite. This chemically made apatite coating isexpected to provide a longexpected to provide a long--term implant term implant--bone fixation.bone fixation.



PLASMPLASM-- PPulsedulsed LLaseraser A Assistedssisted SSurfaceurface MModificationodification

Ultra fine layers of polymers are deposited through non aqueous, nonUltra fine layers of polymers are deposited through non aqueous, nonsolvent techniques near atmospheric pressuresolvent techniques near atmospheric pressure

Advantages: control of both thickness and uniformity of polymer Advantages: control of both thickness and uniformity of polymercoating on any surfacecoating on any surface



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Surface Characteristics Implants