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Massachusetts Institute of TechnologyMassachusetts Institute of TechnologyHarvard Medical SchoolHarvard Medical School
Brigham and Women’s HospitalBrigham and Women’s HospitalVA Boston Healthcare SystemVA Boston Healthcare System
2.79J/3.96J/BE.441/HST522J2.79J/3.96J/BE.441/HST522J
FORMATION OF SOFT TISSUE AND BONE FORMATION OF SOFT TISSUE AND BONE AROUND IMPLANTS:AROUND IMPLANTS:
The Chronic Response to ImplantsThe Chronic Response to Implants
I.V. Yannas, Ph.D. and M. Spector, Ph.D.I.V. Yannas, Ph.D. and M. Spector, Ph.D.
RESPONSE TO IMPLANTS:RESPONSE TO IMPLANTS:WOUND HEALINGWOUND HEALING
Surgical ImplantationSurgical Implantation
Vascular ResponseVascular ResponseClottingClotting
PhagocytosisPhagocytosisNeovascularizationNeovascularization
New Collagen SynthesisNew Collagen Synthesis
Tissue of Labile and Stable CellsTissue of Labile and Stable Cells Tissue of Permanent CellsTissue of Permanent Cells
FrameworkFramework FrameworkFramework ScarringScarringIntact DestroyedIntact Destroyed (fibrous encapsulation;(fibrous encapsulation;
synovium)synovium)RegenRegen. . ScarringScarring Chronic InflammationChronic Inflammation
((incorpincorp. . (fibrous encapsulation;(fibrous encapsulation;of implant)of implant) synovium)synovium)
Chronic InflammationChronic Inflammation
Acute Acute InflammationInflammation GranulationGranulation
TissueTissue
Implant MovementImplant Movement
Inc. timeInc. time
Photo removed due to copyright considerations.
I. Metchnikoff
In 1923 a piece of glass was removed from a patient’s back; it had been there for a year. It was surrounded by a minimal amount of fibrous tissue, lined by a glistening synovial sac, containing a few drops of clear yellow fluid.
Photo removed due to copyright considerations.
Smith-Peterson
J. Bone Jt. Surg., 30-B:59 (1948)
Four pages removed due to copyright considerations.
I. Silver
CHRONIC RESPONSE TO IMPLANTSCHRONIC RESPONSE TO IMPLANTS
•• Persistence of macrophages* at the implant Persistence of macrophages* at the implant surfacesurface
•• Presence of fibroblasts*Presence of fibroblasts*•• Proliferation and increased matrix synthesis of Proliferation and increased matrix synthesis of
fibroblasts can result from mechanical fibroblasts can result from mechanical perturbation by the implant or by agents perturbation by the implant or by agents released by the implant, leading to an increase in released by the implant, leading to an increase in the thickness and density of the scar tissue.the thickness and density of the scar tissue.
•• Fibroblast contraction can result in scar Fibroblast contraction can result in scar contracture.contracture.
* Constituents of synovium* Constituents of synovium
MACROPHAGE AND FIBROBLAST MACROPHAGE AND FIBROBLAST INTERACTIONS IN SYNOVIUMINTERACTIONS IN SYNOVIUM
Macrophage + Part. Sol. Part +Macrophage + Part. Sol. Part + RegReg..EndocytosisEndocytosis
Fibroblast + ECM +Fibroblast + ECM + RegReg..
Fibroblast + ECM +Fibroblast + ECM + RegReg..
Fibroblast + ECM +Fibroblast + ECM + RegReg..
Fibroblast + ECM +Fibroblast + ECM + RegReg..
MitosisMitosis
MigrationMigration
SynthesisSynthesis
ContractionContraction
IonsIons Mechanical forceMechanical force
RESPONSE TO IMPLANTS:RESPONSE TO IMPLANTS:WOUND HEALINGWOUND HEALING
Surgical ImplantationSurgical Implantation
Vascular ResponseVascular ResponseClottingClotting
PhagocytosisPhagocytosisNeovascularizationNeovascularization
New Collagen SynthesisNew Collagen Synthesis
Tissue of Labile and Stable CellsTissue of Labile and Stable Cells Tissue of Permanent CellsTissue of Permanent Cells
FrameworkFramework FrameworkFramework ScarringScarringIntact DestroyedIntact Destroyed (fibrous encapsulation;(fibrous encapsulation;
synovium)synovium)RegenRegen. . ScarringScarring Chronic InflammationChronic Inflammation
((incorpincorp. . (fibrous encapsulation;(fibrous encapsulation;of implant)of implant) synovium)synovium)
Chronic InflammationChronic Inflammation
Acute Acute InflammationInflammation GranulationGranulation
TissueTissue
Implant MovementImplant Movement
Inc. timeInc. time
IMPLANT MATERIALS/BIOMATERIALSIMPLANT MATERIALS/BIOMATERIALSTISSUE RESPONSETISSUE RESPONSE
Soft Tissue (that does not regenerate)Soft Tissue (that does not regenerate)•• Fibrous capsule (scar)Fibrous capsule (scar)
Synovium: fibrous tissue interspersed with Synovium: fibrous tissue interspersed with macrophagesmacrophages
Wound healing response of repair (scar formation) Wound healing response of repair (scar formation) coupled with macrophage accretion at the “dead coupled with macrophage accretion at the “dead space” space” -- chronic inflammationchronic inflammation
BoneBone•• Tissue integration and tissue bondingTissue integration and tissue bonding
TISSUE INTEGRATION TISSUE INTEGRATION TISSUE BONDINGTISSUE BONDING
•• Tissue Integration (Osseointegration)Tissue Integration (Osseointegration)Apposition of tissue (bone) to the implant (contact of Apposition of tissue (bone) to the implant (contact of
bone with the surface but not necessarily bonding); bone with the surface but not necessarily bonding); no macrophage layer?no macrophage layer?
Regeneration of tissue up to the surface of the implantRegeneration of tissue up to the surface of the implant•• Tissue Bonding (Bone Bonding)Tissue Bonding (Bone Bonding)
Chemical bonding of tissue (Chemical bonding of tissue (vizviz., bone) to the surface., bone) to the surfaceProtein adsorption and cell adhesionProtein adsorption and cell adhesionBiomaterials: calcium phosphates and titanium (?)Biomaterials: calcium phosphates and titanium (?)
Dental Implant Designs and Materials
Carbon
TitaniumAlumina
Images removed due to copyright considerations.
Alumina AluminaCarbon
Blade Implant
Photos removed due to copyright considerations.
“Commercially pure” Titanium
Two-Stage Design;to shield the artificial
root from loading during the initial stage of healing
Images removed due to copyright considerations.
Osseointegration
Images removed due to copyright considerations.
T. Albrektsson, et al., Ann. Biomed. Engr., 11:1 (1983) T. Albrektsson, CRC Crit. Rev. Biocompat., 1:53 (1984)
Osseointegration:Control of Surgical Trauma
Image removed due to copyright considerations.
T. Albrektsson, CRC Crit. Rev. Biocompat., 1:53 (1984)
Implants with Porous Coatings in Bone
Bone
Metal stemBone
Beaded porous coating
Image removed due to copyright considerations.
Image removed due to copyright considerations.
Image removed due to copyright considerations. Bone
Hydroxyapatite-Coated Implants
Images removed due to copyright considerations.
Plasma-sprayedHA coating, 40 µm thick
3 hrMetal
Image removed due to copyright considerations.
Bone Image removed due to copyright considerations.
Cylindrical implant in canine
prox. femur
6 da Plasma-Sprayed Hydroxyapatite
Coating
Image removed due to copyright considerations.
14 daImage removed due to
copyright considerations.
Bone regeneration in the gap between the implant surface and surrounding bone.
Plasma-Sprayed Hydroxyapatite Coating14 days
Photo removed due to copyright considerations.
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