biomaterials ent 311/4 lecture 5 ceramic material prepared by: nur farahiyah binti mohammad date: 3...
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BIOMATERIALSBIOMATERIALSENT 311/4ENT 311/4
Lecture 5 Lecture 5
Ceramic MaterialCeramic Material
Prepared by: Nur Farahiyah Binti Mohammad
Date: 3rd August 2008
Email : [email protected]
Teaching PlanTeaching Plan
BIOCERAMIC•Describe, discuss and evaluate types o ceramic biomaterials.•Define and describe biomedical application of each ceramic biomaterial.•Evaluate effect of the physiological environment on ceramic biomaterials.
DELIVERYMODE•Lecture
LEVEL OF COMPLEXITY•Knowledge•Repetition•Evaluation
COURSE OUTCOMECOVERED•Ability to describe the concept of biocompatibility & basic concepts of materials used in medical application•Ability to select biomaterials that can be used for different medical applications and explain the criteria that will lead to a successful implants
1.0 INTRODUCTION1.0 INTRODUCTION•Ceramics are inorganic materials Ceramics are inorganic materials
composed of non-directional ionic composed of non-directional ionic bonds between electron donating bonds between electron donating and electron –accepting elements.and electron –accepting elements.
•Mechanical properties of ceramics:Mechanical properties of ceramics:– HardHard– BrittleBrittle
•Allow for little deformation before Allow for little deformation before failurefailure
– Can withstandCan withstand high compression high compression stressstress
• WHY CHOOSE CERAMIC AS WHY CHOOSE CERAMIC AS BIOMATERIALS?BIOMATERIALS?– Have an appropriate mechanical Have an appropriate mechanical
properties for particular medical properties for particular medical application such as dental crowns.application such as dental crowns.
– Biocompatible:Biocompatible:•Relative inertness to the body fluid.Relative inertness to the body fluid.•More resistant to degradation. More resistant to degradation.
– Have a similar chemistry and mechanical Have a similar chemistry and mechanical properties with natural bone → more often properties with natural bone → more often used as a part of orthopaedic implant used as a part of orthopaedic implant (coating material) or as dental materials (coating material) or as dental materials (crowns, dentures). (crowns, dentures).
– High wear resistanceHigh wear resistance
1.0 INTRODUCTION1.0 INTRODUCTION
2.0 STRUCTURE OF 2.0 STRUCTURE OF CERAMICCERAMIC•Ceramic may contain crystal Ceramic may contain crystal
or non-crystalline glassessor non-crystalline glassess
2.02.0 ATOMIC STRUCTURE ATOMIC STRUCTURE OF CERAMICOF CERAMIC
2.12.1 ATOMIC ATOMIC STRUCTURE OF STRUCTURE OF CERAMICCERAMIC• FACE CENTERED CUBICFACE CENTERED CUBIC
2.12.1 ATOMIC ATOMIC STRUCTURE OF STRUCTURE OF CERAMICCERAMIC• BODY CENTERED CUBICBODY CENTERED CUBIC
2.12.1 ATOMIC ATOMIC STRUCTURE OF STRUCTURE OF CERAMICCERAMIC• HEXAGONAL CLOSED PACK (HCP)HEXAGONAL CLOSED PACK (HCP)
2.2 MICROSTRUCTURE 2.2 MICROSTRUCTURE OF CERAMICOF CERAMIC
2.2 MICROSTRUCTURE 2.2 MICROSTRUCTURE OF CERAMICOF CERAMIC• MICROSTRUCTURAL FEATURESMICROSTRUCTURAL FEATURES
3.0 BIOMEDICAL 3.0 BIOMEDICAL APPLICATIONAPPLICATION
• DENTISTRY DENTISTRY – Dental filling, Dental crown, Dental filling, Dental crown,
denturesdentures– Why widely used in dentistryWhy widely used in dentistry
•Relatively inert to body fluidRelatively inert to body fluid•High compressive strengthHigh compressive strength•Aesthetically pleasing apparentAesthetically pleasing apparent
• ORTHOPAEDIC IMPLANTORTHOPAEDIC IMPLANT•Femoral head/ball of hip implantFemoral head/ball of hip implant•Coating of hip stemCoating of hip stem•Acetabular inner cup of hip Acetabular inner cup of hip
implantimplant•Bone plates and screwBone plates and screw
Femoral component
• femoral stem (metal)
• neck (metal)
• head/ball (metal or ceramic)
Acetabular component
• Inner cup (Polymer or ceramic)
• Outer cup (Metal)
4.04.0DESIRED PROPERTIES OF DESIRED PROPERTIES OF BIOCERAMICSBIOCERAMICSIn orderIn order to be classified as a to be classified as a bioceramic, the ceramic material bioceramic, the ceramic material must exceed such properties:must exceed such properties:
1.1. Should be nontoxicShould be nontoxic
2.2. Should be noncarcinogenicShould be noncarcinogenic
3.3. Should be nonallergicShould be nonallergic
4.4. Should be non inflammatoryShould be non inflammatory
5.5. Should be biocompatibleShould be biocompatible
6.6. Should be biofunctional for its Should be biofunctional for its lifetime in hostlifetime in host
5.05.0 TYPE OF TYPE OF BIOCERAMICSBIOCERAMICS5.15.1 RELATIVELY INERT (NON-RELATIVELY INERT (NON-
ABSORBABLE) BIOCERAMICSABSORBABLE) BIOCERAMICS
5.25.2 NON-INERT BIOCERAMICS NON-INERT BIOCERAMICS (RESORBABLE) BIOCERAMICS(RESORBABLE) BIOCERAMICS
5.35.3 SURFACE REACTIVE (SEMI-SURFACE REACTIVE (SEMI-INERT) BIOCERAMICSINERT) BIOCERAMICS
Notes
Absorbable : Capable of being absorbed or taken in through the pores of a surface
•Relative reactivity of Relative reactivity of bioceramics in physiological bioceramics in physiological enviroments: enviroments:
5.05.0 TYPE OF TYPE OF BIOCERAMICSBIOCERAMICS
Non-inert bioceramicSurface reactive bioceramic
•Some typical room Some typical room temperature properties of temperature properties of bioceramics and corticol bone bioceramics and corticol bone
5.05.0 TYPE OF TYPE OF BIOCERAMICSBIOCERAMICS
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICS BIOCERAMICS • Maintain their physical and mechanical Maintain their physical and mechanical
properties while in host.properties while in host.• Resist corrosion and wearResist corrosion and wear• Have all the six (6) desired properties Have all the six (6) desired properties
of implantable bioceramics.of implantable bioceramics.• Have a reasonable fracture toughness.Have a reasonable fracture toughness.• Typically used as structural-support Typically used as structural-support
implant such as bone plates, bone implant such as bone plates, bone screw and femoral heads.screw and femoral heads.
5.1.15.1.1 ALUMINA (AlALUMINA (Al220033))• The main source of alumina or aluminium The main source of alumina or aluminium
oxide is bauxite and native corundum. oxide is bauxite and native corundum. • Highly stable oxide – very chemically Highly stable oxide – very chemically
inertinert• Low fracture toughness and tensile Low fracture toughness and tensile
strength – high compression strengthstrength – high compression strength• Very low wear resistance Very low wear resistance • Quite hard material, varies from 20 to 30 Quite hard material, varies from 20 to 30
GPa. GPa.
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICS BIOCERAMICS
Notes
Bauxite and corundum is type of minerals
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICS BIOCERAMICS • Mechanical properties Mechanical properties
requirement:requirement:– Compressive strength: 4 -5 GpaCompressive strength: 4 -5 Gpa– Flexural strength : > 400MPaFlexural strength : > 400MPa– Elastic modulus: 380 GPaElastic modulus: 380 GPa– Density : 3.8 – 3.9 g/cmDensity : 3.8 – 3.9 g/cm33
– Generally quite hard : 20 to 30 GPaGenerally quite hard : 20 to 30 GPa
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICSBIOCERAMICSALUMINAALUMINA
High hardness + low friction + low wear+ High hardness + low friction + low wear+ inert to in vivo environment inert to in vivo environment
Ideal material for use in:Ideal material for use in:• Orthopaedic joint replacement component, Orthopaedic joint replacement component,
e.g. femoral head of hip implante.g. femoral head of hip implant• Orthopaedic load-bearing implantOrthopaedic load-bearing implant
• Implant coatingImplant coating• Dental implantsDental implants
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICSBIOCERAMICS5.1.25.1.2 ZIRCONIA (ZrZIRCONIA (Zr220022))
• Pure zirconia can be obtained Pure zirconia can be obtained from chemical conversion of from chemical conversion of zircon, which is an abundant zircon, which is an abundant mineral deposit.mineral deposit.
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICSBIOCERAMICS•Has a high melting Has a high melting
temperature and temperature and chemical stability.chemical stability.
•The bending The bending strength and strength and fracture toughness fracture toughness are 2-3 and 2 are 2-3 and 2 times greater than times greater than alumina.alumina.
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICSBIOCERAMICS•The improved mechanical The improved mechanical
properties plus excellent properties plus excellent biocompatibility and wear biocompatibility and wear properties make this material the properties make this material the best choice the new generation of best choice the new generation of orthopaedic implant.orthopaedic implant.
•Has already widely use to replace Has already widely use to replace alumina and metals.alumina and metals.
5.1 RELATIVELY INERT 5.1 RELATIVELY INERT (NON-ABSORBABLE) (NON-ABSORBABLE)
BIOCERAMICSBIOCERAMICS5.1.35.1.3 CARBON CARBON • Carbon can be made in many Carbon can be made in many
allotropic allotropic forms:forms:– Crystalline diamondCrystalline diamond– Graphite Graphite – Nanocrystalline glassy carbonNanocrystalline glassy carbon– Quasicrystalline pyrolitic carbonQuasicrystalline pyrolitic carbon
• Only pyrolitic carbon is widely Only pyrolitic carbon is widely utilized for implant fabrication. utilized for implant fabrication.
• Normally used as surface coatingNormally used as surface coating
5.25.2NON-INERT NON-INERT BIOCERAMICS BIOCERAMICS (RESORBABLE) (RESORBABLE) BIOCERAMICSBIOCERAMICS
• Chemically broken down by the body and Chemically broken down by the body and degradedegrade
• The resorbed material is replaced by The resorbed material is replaced by endogenous tissue endogenous tissue
• Chemicals produced as the ceramic is Chemicals produced as the ceramic is resorbed must be able to be processed resorbed must be able to be processed through the normal metabolic pathways of through the normal metabolic pathways of the body without evoking any deleterious the body without evoking any deleterious effect.effect.
• Synthesize from chemical (synthetic ceramic) Synthesize from chemical (synthetic ceramic) or natural sources (natural ceramic)or natural sources (natural ceramic)
5.25.2NON-INERT BIOCERAMICS NON-INERT BIOCERAMICS (RESORBABLE) BIOCERAMICS(RESORBABLE) BIOCERAMICS• Examples of Resorbable BioceramicsExamples of Resorbable Bioceramics
1.1. Calcium phosphateCalcium phosphate
2.2. Calcium sulfate, including plaster of Calcium sulfate, including plaster of ParisParis
3.3. HydroxyapatiteHydroxyapatite
4.4. Tricalcium phosphateTricalcium phosphate
5.5. Ferric-calcium-phosphorous oxidesFerric-calcium-phosphorous oxides
6.6. CoralsCorals
5.25.2NON-INERT BIOCERAMICS NON-INERT BIOCERAMICS (RESORBABLE) BIOCERAMICS(RESORBABLE) BIOCERAMICS5.2.15.2.1 Synthetic ceramicSynthetic ceramic5.2.1.1 5.2.1.1 Calcium phosphate and Calcium phosphate and
HydroxyapatiteHydroxyapatite• Can be crystallized into salts such as Can be crystallized into salts such as
Hydroxyapatite.Hydroxyapatite.• Hydroxyapatite (HAP) has a similar Hydroxyapatite (HAP) has a similar
properties with mineral phase of bone properties with mineral phase of bone and teeth.and teeth.
• Important properties of HAP:Important properties of HAP:– Excellent biocompatibilityExcellent biocompatibility– Form a direct chemical bond with hard tissueForm a direct chemical bond with hard tissue
5.25.2NON-INERT BIOCERAMICS NON-INERT BIOCERAMICS (RESORBABLE) BIOCERAMICS(RESORBABLE) BIOCERAMICS
• Low values of mechanical strength Low values of mechanical strength and fracture toughness, thus and fracture toughness, thus cannot be used in load bearing cannot be used in load bearing materials.materials.
5.25.2NON-INERT NON-INERT BIOCERAMICS BIOCERAMICS (RESORBABLE) (RESORBABLE) BIOCERAMICSBIOCERAMICS• Application:Application:
– Bone substitute in a granular or a solid Bone substitute in a granular or a solid block.block.
– Temporary scaffold which is gradually Temporary scaffold which is gradually replaced by tissuereplaced by tissue
– Orthopaedic and dental implant coatingOrthopaedic and dental implant coating– Dental implant materialsDental implant materials
• Drawback:Drawback:– Complicated fabrication process and Complicated fabrication process and
difficult to shapedifficult to shape
5.25.2NON-INERT BIOCERAMICS NON-INERT BIOCERAMICS (RESORBABLE) BIOCERAMICS(RESORBABLE) BIOCERAMICS5.2.1.2 5.2.1.2 Tricalcium phosphateTricalcium phosphate• Composition similar to Composition similar to
hydroxyapatitehydroxyapatite• Degrades faster than calcium Degrades faster than calcium
phosphatephosphate• More soluble than synthetic HAP More soluble than synthetic HAP • Allow good bone in growth and Allow good bone in growth and
eventually is replaced by eventually is replaced by endogenous tissue.endogenous tissue.
5.25.2NON-INERT NON-INERT BIOCERAMICS BIOCERAMICS (RESORBABLE) (RESORBABLE) BIOCERAMICSBIOCERAMICS5.2.25.2.2 Natural ceramic Natural ceramic
5.2.2.1 5.2.2.1 BiocoralBiocoral• Corals transformed into HAPCorals transformed into HAP• BiocompatibleBiocompatible• Facilitate bone growthFacilitate bone growth• Used to repair traumatized bone, Used to repair traumatized bone,
replaced disease bone and correct replaced disease bone and correct various bone defect.various bone defect.
• Bone scaffold Bone scaffold
5.35.3SURFACE REACTIVE SURFACE REACTIVE (SEMI-INERT) BIOCERAMICS(SEMI-INERT) BIOCERAMICS
• Direct and strong chemical bond with Direct and strong chemical bond with tissuetissue
• Fixation of implants in the skeletal Fixation of implants in the skeletal systemsystem
• Low mechanical strength and fracture Low mechanical strength and fracture toughnesstoughness
• Examples:Examples:– Glass ceramicsGlass ceramics– HydroxyapatiteHydroxyapatite– Dense nonporous glassesDense nonporous glasses
5.35.3SURFACE REACTIVE SURFACE REACTIVE (SEMI-INERT) BIOCERAMICS(SEMI-INERT) BIOCERAMICS5.3.15.3.1 Glass ceramicsGlass ceramics• Glass-ceramics are crystalline
materials obtained by the controlled crystallization of an amorphous parent glass.
• Controlled crystallisation requires:– specific compositions– usually a two-stage heat-treatmen– Controlled nucleation
• Controlled crystallization will growth of crystal of small uniform size
5.35.3SURFACE REACTIVE SURFACE REACTIVE (SEMI-INERT) BIOCERAMICS(SEMI-INERT) BIOCERAMICS
• Type of glass ceramicType of glass ceramic– BioglassBioglass– CeravitalCeravital
• Both are SiOBoth are SiO22, CaO, Na, CaO, Na22O and PO and P22OO5 5
systemssystems• Bioglass composition manipulated to Bioglass composition manipulated to
induce direct bonding with the boneinduce direct bonding with the bone– Must simultaneously form a calcium Must simultaneously form a calcium
phosphate and SiOphosphate and SiO2 2 – rich film layer on – rich film layer on surface of ceramic for this to happensurface of ceramic for this to happen
– With correct composition will bond with With correct composition will bond with bone in approximately 30 daysbone in approximately 30 days
Bioglass structureBioglass structure
5.35.3SURFACE REACTIVE SURFACE REACTIVE (SEMI-INERT) BIOCERAMICS(SEMI-INERT) BIOCERAMICS
• Glass ceramic propertiesGlass ceramic properties
5.35.3SURFACE REACTIVE SURFACE REACTIVE (SEMI-INERT) BIOCERAMICS(SEMI-INERT) BIOCERAMICS
5.35.3SURFACE REACTIVE SURFACE REACTIVE (SEMI-INERT) BIOCERAMICS(SEMI-INERT) BIOCERAMICS
5.35.3SURFACE REACTIVE SURFACE REACTIVE (SEMI-INERT) (SEMI-INERT) BIOCERAMICSBIOCERAMICS
• Application of Glass Ceramic Application of Glass Ceramic – Orthopaedic and dental implant Orthopaedic and dental implant
coatingcoating– Dental implantDental implant– Facial reconstruction componentsFacial reconstruction components– Bone graft substitute materialBone graft substitute material
• Main limitation:Main limitation:– BrittlenessBrittleness– Cannot be used for making major load Cannot be used for making major load
bearing implant such as joint implant bearing implant such as joint implant
6.06.0BIODEGRADATION OF BIODEGRADATION OF CERAMICCERAMICDEFINITIONDEFINITION• Biodegradation: chemical breakdown of a Biodegradation: chemical breakdown of a
material mediated by any component of material mediated by any component of the physiological environment ( such as the physiological environment ( such as water, ions, cells, proteins, and bacteria).water, ions, cells, proteins, and bacteria).
• Bioerosion is breakdown including Bioerosion is breakdown including chemical degradation or other process in chemical degradation or other process in which bond cleavage is not required (e.g. which bond cleavage is not required (e.g. physical dissolution), of a material physical dissolution), of a material mediated by any component of mediated by any component of physiological environment.physiological environment.
BIODEGRADATION
Uncontrolled degradation
Controlled degradation
ceramic degrade primarily via dissolution,
this because ceramic formulation are highly soluble in aqueous environment
6.16.1 UNCONTROLLED UNCONTROLLED DEGRADATIONDEGRADATION•DEPEND ON TWO FACTORDEPEND ON TWO FACTOR
– Mechanical environmentMechanical environment•Stress induced degradation can Stress induced degradation can occur in ceramics under tension.occur in ceramics under tension.
•If crack is formed in these If crack is formed in these materials, the tensile stress may materials, the tensile stress may lead to further dissolution at the lead to further dissolution at the crack tip and material fracture.crack tip and material fracture.
– Ceramic porosityCeramic porosity•Pores are stress raiser thus may Pores are stress raiser thus may increase the formation of cracks or increase the formation of cracks or the rate of their propagation.the rate of their propagation.
6.16.1 UNCONTROLLED UNCONTROLLED DEGRADATIONDEGRADATION
Uncontrolled degradation
Mechanical environment
Ceramic porosity-stress raiser
Stress induced degradation
Wear-main problem
Produces biologically active particles
Lead to inflammation and implant loosening
6.16.1 UNCONTROLLED UNCONTROLLED DEGRADATIONDEGRADATION• Uncontrolled degradation will Uncontrolled degradation will
cause WEAR.cause WEAR.• WEAR WEAR → → the generation of fine the generation of fine
wear particles that can lead to wear particles that can lead to inflammation and implant inflammation and implant loosening.loosening.
6.26.2 CONTROLLED CONTROLLED DEGRADATIONDEGRADATION•Degradation is desirable.Degradation is desirable.•Controlled biomaterial degradation can Controlled biomaterial degradation can
be used as an important part of tissue be used as an important part of tissue engineering and drug delivery engineering and drug delivery therapies.therapies.
•For these application, the temporary For these application, the temporary nature of the material is ideal to nature of the material is ideal to promote localized tissue healing or promote localized tissue healing or release of a bioactive agent without release of a bioactive agent without the need for second surgery to remove the need for second surgery to remove implant.implant.
6.26.2 CONTROLLED CONTROLLED DEGRADATIONDEGRADATION• Biodegradable ceramics are usually Biodegradable ceramics are usually
type of calcium phosphate, such astype of calcium phosphate, such as– Hydroxyapatite, HA (CaHydroxyapatite, HA (Ca1010(PO(PO44))66(OH)(OH)22))
– Tricalcium phosphate, TCP (CaTricalcium phosphate, TCP (Ca33(PO(PO44))22))
• Biodegradable ceramic generally Biodegradable ceramic generally degrade by dissolution (influenced by degrade by dissolution (influenced by the solubility of the ceramic the solubility of the ceramic formulation in media and the pH of formulation in media and the pH of the media) coupled with physical the media) coupled with physical disintegration.disintegration.
6.26.2 CONTROLLED CONTROLLED DEGRADATIONDEGRADATION6.2.16.2.1 FACTOR THAT INFLUENCE FACTOR THAT INFLUENCE
DEGRADATION RATEDEGRADATION RATE
1.1. Chemical susceptibility of the Chemical susceptibility of the materialmaterial
• Hydrated form forms such as Hydrated form forms such as hydrated calcium sulphate hydrated calcium sulphate degrade faster than their degrade faster than their nonhydrated counterparts. nonhydrated counterparts.
6.2.16.2.1 FACTOR THAT FACTOR THAT INFLUENCE DEGRADATION INFLUENCE DEGRADATION RATERATE2.2. Amount of crystallinity Amount of crystallinity • Ceramic degradation depend on water Ceramic degradation depend on water
penetration.penetration.• A more tightly packed crystalline material is A more tightly packed crystalline material is
less susceptible to dissolution than a less susceptible to dissolution than a ceramic that is mainly amorphous ceramic that is mainly amorphous (unstructured). (unstructured).
• Polycrystalline ceramics degrade more quickly Polycrystalline ceramics degrade more quickly than single crystal ceramic due to presence of than single crystal ceramic due to presence of grain boundaries.grain boundaries.
• Ceramic contain many smaller crystals is more Ceramic contain many smaller crystals is more susceptible to dissolution than one with fewer, susceptible to dissolution than one with fewer, larger crystal. larger crystal.
6.2.16.2.1 FACTOR THAT FACTOR THAT INFLUENCE DEGRADATION INFLUENCE DEGRADATION RATERATE3.3. Amount of media (water) availableAmount of media (water) available• High amount of water → increase High amount of water → increase
degradation ratedegradation rate• Low amount of water → slower Low amount of water → slower
degradation ratedegradation rate
4.4. Material surface area to volume ratioMaterial surface area to volume ratio• Highly porous ceramic will dissolve Highly porous ceramic will dissolve
more quickly than the same ceramic more quickly than the same ceramic with fewer pores due to increase in with fewer pores due to increase in area for interaction with the area for interaction with the environment.environment.
6.2.16.2.1 FACTOR THAT FACTOR THAT INFLUENCE DEGRADATION INFLUENCE DEGRADATION RATERATE
Highly porosity Low porosity
6.2.16.2.1 FACTOR THAT FACTOR THAT INFLUENCE DEGRADATION INFLUENCE DEGRADATION RATERATE5.5. Mechanical environmentMechanical environment• Ceramic degradation is encouraged Ceramic degradation is encouraged
in areas with high mechanical in areas with high mechanical stress, either due tostress, either due to
– Implant site locationImplant site location– Presence of stress raiser in the devicePresence of stress raiser in the device– Production of wear particles will Production of wear particles will
caused inflammatory response → pH caused inflammatory response → pH drop → accelerate degradation of drop → accelerate degradation of materialmaterial
Extra: Bone scaffoldExtra: Bone scaffold
Perfection regained: the perfect fit of the Sandia ceramic scaffolding in the model jaw also recreates the upper line of the original jawbone. The scaffold layering, which cross each other like a child's Lincoln Logs, are approximately 500 microns apart to expedite passage of new bone and blood vessels.
The milled implant from a wax-embedded scaffold of hydroxyapatite.
Once the device is milled, the wax is melted out, and the implant is finished. The porous structure of the scaffold allows bone to grow into it, providing the future basis for the growth of new bone in a patient.
The final implant scaffold fit tested in the patients jaw.
The underside of the final implant scaffold, showing the modeled canal for the nerve path.
AttachmentAttachment• Allotropy is the property of some Allotropy is the property of some
chemical elementschemical elements to be able to take two or to be able to take two or more different forms, where the more different forms, where the atomsatoms are are arranged differently by arranged differently by chemical bondschemical bonds. .
• The forms are known as The forms are known as allotropesallotropes of that of that element.element.[1][1] The phenomenon of allotropy is The phenomenon of allotropy is sometimes also called allotropism. sometimes also called allotropism.
• For example, For example, carboncarbon has two common has two common allotropes: allotropes: diamonddiamond, where the carbon atoms , where the carbon atoms are bonded together in a are bonded together in a tetrahedraltetrahedral lattice lattice arrangement, arrangement,
• and and graphitegraphite, where the carbon atoms are , where the carbon atoms are bonded together in sheets of a hexagonal bonded together in sheets of a hexagonal lattice.lattice.
