Osseointegration1/endodontic courses

INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.comwww.indiandentalacademy.com

 INTRODUCTIONINTRODUCTION
 HISTORYHISTORY
 PROCESS OF OSSEOINTEGRATIONPROCESS OF OSSEOINTEGRATION
 TISSUE-IMPLANT INTERFACETISSUE-IMPLANT INTERFACE
 TRANSMUCOSAL ATTACHMENTTRANSMUCOSAL ATTACHMENT
 FACTORS INFLUENCINGFACTORS INFLUENCING
OSSEOINTEGRATIONOSSEOINTEGRATION
 - IMPLANT RELATED FACTORS- IMPLANT RELATED FACTORS
 - HOST RELATED FACTORS- HOST RELATED FACTORS

 FIBROOSSEOUS RETENSIONFIBROOSSEOUS RETENSION VSVS
 OSSEOINTEGRATIONOSSEOINTEGRATION VSVS
OSSEOCOALESCENCEOSSEOCOALESCENCE
 LOADING AND OSSEOINTEGRATIONLOADING AND OSSEOINTEGRATION
 DEVICES TO MEASURE OSSEOINTEGRATIONDEVICES TO MEASURE OSSEOINTEGRATION
 MEASURES TO ENHANCEMEASURES TO ENHANCE
 CONCLUSIONCONCLUSION
 BIBLIOGRAPHYBIBLIOGRAPHY

 INTRODUCTIONINTRODUCTION
 Dental implant (endosteal) is an alloplastic materialDental implant (endosteal) is an alloplastic material
surgically inserted into residual bony ridge primarily tosurgically inserted into residual bony ridge primarily to
serve as a prosthodontic foundation.serve as a prosthodontic foundation.
 Implants are used to –Implants are used to –
 Replace missing teethReplace missing teeth
 Rebuild the craniofacial skeletonRebuild the craniofacial skeleton
 Provide anchorage during orthodontic treatmentProvide anchorage during orthodontic treatment
 Help form new bone in the process of distractionHelp form new bone in the process of distraction
osteogenesisosteogenesis

 Osseointegration is defined as a relationship whereOsseointegration is defined as a relationship where
bone is in direct contact with the implant,without anybone is in direct contact with the implant,without any
intermediate connective tissue.intermediate connective tissue. (Branemark 1952)(Branemark 1952)
 A revised definition describes it as structural andA revised definition describes it as structural and
functional connection between ordered living bone andfunctional connection between ordered living bone and
the surface of a load carrying implant.the surface of a load carrying implant.

 A process where by clinically asymptomatic rigidA process where by clinically asymptomatic rigid
fixation of alloplastic material is achieved andfixation of alloplastic material is achieved and
maintained in bone during functional loading.maintained in bone during functional loading.
(Zarb & Alberktsson 1991)(Zarb & Alberktsson 1991)

 HistoryHistory
 In 1952 Per-Ingvar Brånemark used a titanium implantIn 1952 Per-Ingvar Brånemark used a titanium implant
chamber to study blood flow in rabbit bone and notedchamber to study blood flow in rabbit bone and noted
that the chambers could not be removed at the end ofthat the chambers could not be removed at the end of
the experiment. He called the discoverythe experiment. He called the discovery
“osseointegration.”“osseointegration.”
 In the early 1960’s branemark and coworkers at theIn the early 1960’s branemark and coworkers at the
university of Goteborg first developed a novel implantuniversity of Goteborg first developed a novel implant
for clinical function.for clinical function.

 Animal experiments performed by Branemark in 1969Animal experiments performed by Branemark in 1969
clearly demonstrated that it is possible to establish aclearly demonstrated that it is possible to establish a
direct bone anchorage.direct bone anchorage.
 Schroeder was the first investigator to clearlySchroeder was the first investigator to clearly
demonstrate osseointegration in mid 1970’s.demonstrate osseointegration in mid 1970’s.
 He used the new techniques to cut through theHe used the new techniques to cut through the
decalcified bone and implant without separation ofdecalcified bone and implant without separation of
anchorage.anchorage.

 Alberktsson (1981)Alberktsson (1981) presented the background factorspresented the background factors
needed for osseointegration-needed for osseointegration-
 Bio- compatibilityBio- compatibility
 DesignDesign
 Surface conditions of implantSurface conditions of implant
 Status of host bedStatus of host bed
 Surgical techniqueSurgical technique
 Loading conditionsLoading conditions

 Biological basis of osseointegration-Biological basis of osseointegration-
 The ability of the living(vital) bone tissue to developThe ability of the living(vital) bone tissue to develop
and maintain,in physiological function, a direct interfaceand maintain,in physiological function, a direct interface
and dynamic union with implants.and dynamic union with implants.

 Mechanism of osseointegrationMechanism of osseointegration
 The damage caused during the surgical procedure andThe damage caused during the surgical procedure and
the press fit of the implant to the hard and soft tissuesthe press fit of the implant to the hard and soft tissues
initiate the process of healing.initiate the process of healing.
 This ultimately allows –This ultimately allows –
 The implant to become anchylotic with boneThe implant to become anchylotic with bone
 Establishment of delicate mucosal attachment orEstablishment of delicate mucosal attachment or
barrier to the titanium device.barrier to the titanium device.

 The wound healing at the implant site depends on the –The wound healing at the implant site depends on the –
 Presence of adequate cellsPresence of adequate cells
 Their adequate nutritionTheir adequate nutrition
 Adequate stimulus for bone repairAdequate stimulus for bone repair

 The three main phases of bone healing necessary forThe three main phases of bone healing necessary for
osseointegration are –osseointegration are –
 Phase 1 InflammationPhase 1 Inflammation
 Phase 2 ProliferationPhase 2 Proliferation
 Phase3 MaturationPhase3 Maturation

 InflammationInflammation

 The cytokines released at the inflammatory siteThe cytokines released at the inflammatory site
regulate-regulate-
 Adhesion molecule productionAdhesion molecule production
 Increase vascularization rateIncrease vascularization rate
 Enhance collagen synthesisEnhance collagen synthesis
 Regulate bone metabolismRegulate bone metabolism
 Activate osteoclastsActivate osteoclasts
 Neutrophil aggregation occurs during the first 3-4 daysNeutrophil aggregation occurs during the first 3-4 days
following surgeryfollowing surgery
 At 5-6 days following surgery the inflammatoryAt 5-6 days following surgery the inflammatory
response becomes more specific.response becomes more specific.

 Proliferative phase:Proliferative phase:
 The growth factors released by the macrophages andThe growth factors released by the macrophages and
undifferentiated mesenchymal cells stimulateundifferentiated mesenchymal cells stimulate
fibroplasias through which undifferentiated connectivefibroplasias through which undifferentiated connective
tissue forms at the apical trabecular regions of thetissue forms at the apical trabecular regions of the
implant site and in the furcation regions of screwimplant site and in the furcation regions of screw
shaped implants.shaped implants.
 During this phaseDuring this phase
neovascularisation,proliferation,activation of cells andneovascularisation,proliferation,activation of cells and
production of immature connective tissue occurs.production of immature connective tissue occurs.

 The provisional connective tissue is rich in –The provisional connective tissue is rich in –
 Newly formed vesselsNewly formed vessels
 FibroblastsFibroblasts
 Undifferentiated mesenchymal cellsUndifferentiated mesenchymal cells
 The undifferentiated mesenchymal cells differentiateThe undifferentiated mesenchymal cells differentiate
into fibroblasts,osteoblasts and chondroblasts ininto fibroblasts,osteoblasts and chondroblasts in
response to local hypoxia and cytokine release.response to local hypoxia and cytokine release.
 The connective tissue matures into osteoid from whichThe connective tissue matures into osteoid from which
woven bone forms to fill the void with bone tissue.woven bone forms to fill the void with bone tissue.

 Woven bone with primary osteons seen at the base ofWoven bone with primary osteons seen at the base of
the surgical site and in the furcation sitesthe surgical site and in the furcation sites

 Reversal lines seen in the bone tissue next to theReversal lines seen in the bone tissue next to the
implantimplant

 4 weeks of wound healing4 weeks of wound healing
 Shows remnants of old bone replaced by woven boneShows remnants of old bone replaced by woven bone

 Phase of RemodellingPhase of Remodelling (8 weeks)(8 weeks)

 At 4 months of implant placementAt 4 months of implant placement

 TISSUE IMPLANT INTERFACETISSUE IMPLANT INTERFACE
 Events leading to success or failure of the implant takeEvents leading to success or failure of the implant take
place at the implant tissue interface.place at the implant tissue interface.
 Numerous factors involved at the development of thisNumerous factors involved at the development of this
interface are-interface are- (Alberktsson et al 1981)(Alberktsson et al 1981)
 Implant related factorsImplant related factors
 Patient variablesPatient variables

 Events on the implant side:Events on the implant side:
 Electrochemical events take place on the surface of theElectrochemical events take place on the surface of the
implants and cause the oxide layer to double or triple inimplants and cause the oxide layer to double or triple in
thickness. (Lekovic et al)thickness. (Lekovic et al)
 Electrochemical reactions also lead to incorporation ofElectrochemical reactions also lead to incorporation of
biological ions such as calcium,phosphorous,sulfur.biological ions such as calcium,phosphorous,sulfur.
 Analysis of tissues around dental implants showedAnalysis of tissues around dental implants showed
titanium at levels upto tens of ppm immediatelytitanium at levels upto tens of ppm immediately
adjacent to device.adjacent to device.

 On biological side:On biological side:
 Water molecules and hydrated ions associate withWater molecules and hydrated ions associate with
implant surface within nano second.implant surface within nano second.
 Implant surface acts as a substrate and alters theImplant surface acts as a substrate and alters the
organization of water molecules.organization of water molecules.
 Smaller affinity molecules are replaced by larger andSmaller affinity molecules are replaced by larger and
greater affinity molecules for the biomaterial.greater affinity molecules for the biomaterial.
 With time the cells encounter an implant surface that isWith time the cells encounter an implant surface that is
preconditioned with a variety of biomolecules.preconditioned with a variety of biomolecules.

 Phenomena of bone formation:Phenomena of bone formation:
 Distance osteogenesis:Distance osteogenesis:
 Osteogenesis occurs from the bone towards theOsteogenesis occurs from the bone towards the
implant.implant.
 The bone surface provides a layer of osteogenic cellsThe bone surface provides a layer of osteogenic cells
that deposit a new matrix which approaches thethat deposit a new matrix which approaches the
implant.implant.

 Contact osteogenesis:Contact osteogenesis:
 Osteogenesis occurs in a direction away from theOsteogenesis occurs in a direction away from the
implant as the osteogenic cells are recruited onto theimplant as the osteogenic cells are recruited onto the
implant surface and begin secreting bone matrix.implant surface and begin secreting bone matrix.
 The relative significance of the two processes dependsThe relative significance of the two processes depends
on the type of implant and its surface characteristics.on the type of implant and its surface characteristics.

 TRANSMUCOSAL ATTACHMENT:TRANSMUCOSAL ATTACHMENT:
 Berglundh et al 1991Berglundh et al 1991 in a study evaluated the healthyin a study evaluated the healthy
gingiva and periiplant mucosa and found manygingiva and periiplant mucosa and found many
similarities between the two.similarities between the two.
 The radiographs of the implant site showed marginalThe radiographs of the implant site showed marginal
bone termination at the implant fixture interface.bone termination at the implant fixture interface.
 The barrier epithelium was seen terminating aboutThe barrier epithelium was seen terminating about
2mm from the soft tissue margin.2mm from the soft tissue margin.
 Connective tissue is 1-1.5mm thick and is in directConnective tissue is 1-1.5mm thick and is in direct
contact with the TiO2 layer of implant.contact with the TiO2 layer of implant.

 Identical transmucosal attachments were seen withIdentical transmucosal attachments were seen with
different implant systems(shapes) and it wasdifferent implant systems(shapes) and it was
independent of whether the implant is submerged orindependent of whether the implant is submerged or
not.not.
 The profile of implant was recorded on the adjacentThe profile of implant was recorded on the adjacent
tissues.tissues.
 The material used in the abutment part of the implantThe material used in the abutment part of the implant
was of decisive importance for the quality ofwas of decisive importance for the quality of
attachment that occurredattachment that occurred.(Abrahamsson et al 1996).(Abrahamsson et al 1996)
 When the mucosal thickness prior to implantWhen the mucosal thickness prior to implant
connection was <2mm a consistent marginal boneconnection was <2mm a consistent marginal bone
resorption was seen as a result C.T attachment in suchresorption was seen as a result C.T attachment in such
cases occurred at the fixture level.cases occurred at the fixture level.

 Composition of connective tissue :Composition of connective tissue :
 The collagen fiber bundles are oriented parallel to theThe collagen fiber bundles are oriented parallel to the
implant surface.implant surface.

 The connective tissue at the attachment zone containsThe connective tissue at the attachment zone contains
more collagen,fewer fibroblasts and blood vessels thanmore collagen,fewer fibroblasts and blood vessels than
corresponding location at teeth.corresponding location at teeth.

 There was no difference in the composition of theThere was no difference in the composition of the
connective tissue when implant abutments withconnective tissue when implant abutments with
different surface roughness were used. (Abrahamssondifferent surface roughness were used. (Abrahamsson
et al)et al)
 Vascular supply:Vascular supply:
 supra periosteal blood vessels (Berglundh et al)supra periosteal blood vessels (Berglundh et al)

 Initial implant stabilization:Initial implant stabilization:
 It is achieved primarily by friction acting at implant-It is achieved primarily by friction acting at implant-
bone interface.bone interface.
 In order to achieve adequate initial stability by frictionIn order to achieve adequate initial stability by friction
significant torsional and axial forces have to be imposedsignificant torsional and axial forces have to be imposed
during implant placement.during implant placement.
 F fr = µf x FnF fr = µf x Fn
 During the initial phases of healing the resoprtion ofDuring the initial phases of healing the resoprtion of
the necrotic bone causes a decrease of frictionalthe necrotic bone causes a decrease of frictional
resistance, this forms the critical basis for limited orresistance, this forms the critical basis for limited or
ideally no loading during the healing phase.ideally no loading during the healing phase.

 The initial stability is independent of the implant toThe initial stability is independent of the implant to
bone contact and so not dependent on the length andbone contact and so not dependent on the length and
diameter of implant.diameter of implant.
 Increasing the implant to bone contact –Increasing the implant to bone contact –
 Helps to maintain stabilityHelps to maintain stability
 To resist significant transverse forces acting on implantTo resist significant transverse forces acting on implant

 Factors influencing osseointegration:Factors influencing osseointegration:
 Implant related factors:Implant related factors:
 Implant materialImplant material
 Implant designImplant design
 Surface topographySurface topography

 Host related factors-Host related factors-
 Systemic conditions and medicationsSystemic conditions and medications
 Hosts ability to healHosts ability to heal
 Ability to adapt to loading conditionsAbility to adapt to loading conditions
 Possibility to respond to peri-implant infection.Possibility to respond to peri-implant infection.
 Surgical techniqueSurgical technique
 Time of loadingTime of loading

 Implant material:Implant material:
 Titanium and titanium alloysTitanium and titanium alloys
 Cobalt –chromium –molybdenum alloysCobalt –chromium –molybdenum alloys
 Stainless steelStainless steel
 ZirconiumZirconium
 TantalumTantalum
 GoldGold
 Ceramics and carbonCeramics and carbon

 Advantages of titanium –Advantages of titanium –
 Passivates upon contact with air and normal tissuePassivates upon contact with air and normal tissue
fluids,this aids in osseointegration.fluids,this aids in osseointegration.
 Titanium is more ductile and helps in blending theTitanium is more ductile and helps in blending the
implant to receive straight abutmentsimplant to receive straight abutments
 Better resistance to corrosionBetter resistance to corrosion
 The modulus of elasticity is 5 times greater thanThe modulus of elasticity is 5 times greater than
bone ,which emphasizes the importance of design inbone ,which emphasizes the importance of design in
proper distribution of stress transfer.proper distribution of stress transfer.
 High bio-compatibilityHigh bio-compatibility

 SURFACE TOPOGRAPHY:SURFACE TOPOGRAPHY:
 The surface topography describes –The surface topography describes –
 1. The degree of roughness that the surface exhibits1. The degree of roughness that the surface exhibits
measured in perpendicular and parallelmeasured in perpendicular and parallel
directionsdirections
 2. Orientation of the irregularities on the surface2. Orientation of the irregularities on the surface
Isotropic and AnisotropicIsotropic and Anisotropic
Devices used –Devices used –
Confocal laser scanning ProfilometerConfocal laser scanning Profilometer
InterferometersInterferometers

Wennenberg indicated that for
threaded implants 9 measurements
are sufficient for proper
characterization
3D measurements are
more reliable

 Topography of a surface is defined in terms of –Topography of a surface is defined in terms of –
 FormForm
 WavinessWaviness
 RoughnessRoughness

 Surface roughness is further described in terms of –Surface roughness is further described in terms of –
 Sa-Sa- amplitudeamplitude – vertical height of irregularities– vertical height of irregularities
 Scx –Scx – spacingspacing – space between irregularities– space between irregularities
 Sdr –Sdr – hybridhybrid – (spacing and amplitude)– (spacing and amplitude)
 For proper characterization atleast one parameter fromFor proper characterization atleast one parameter from
each 3 groups must be included in the topographiceach 3 groups must be included in the topographic
evaluation of top,flank and valley.evaluation of top,flank and valley. (Wennenberg &(Wennenberg &
Alberktsson)Alberktsson)

 Experimental studies investigating surface roughnessExperimental studies investigating surface roughness
and osseointegration:and osseointegration:
 Invivo experiments showed better bone fixation withInvivo experiments showed better bone fixation with
enlarged isotropic surface when compared to turnedenlarged isotropic surface when compared to turned
anisotropic surface.anisotropic surface. (Wennenberg 1996)(Wennenberg 1996)
 A positive correlation was seen between the implantA positive correlation was seen between the implant
roughness and the degree of implant incorporationroughness and the degree of implant incorporation
(Gotfredsen et al 2000)(Gotfredsen et al 2000)

 Ideal degree of osseointegration was given in implantsIdeal degree of osseointegration was given in implants
with –with –
 Sa value (amplitude 3D) – 1.45 µmSa value (amplitude 3D) – 1.45 µm
 Scx value(spacing 3D) – 11 µmScx value(spacing 3D) – 11 µm
 Sdr ratio (hybrid 3D) – 1.5Sdr ratio (hybrid 3D) – 1.5

 Modification of implant design to resist loads and forModification of implant design to resist loads and for
better bone ingrowth-better bone ingrowth-
 Finely threaded coronal region for bone ingrowthFinely threaded coronal region for bone ingrowth
 Use of implants with surface design that allows 3DUse of implants with surface design that allows 3D
interlockinginterlocking
 Use of implant design that allows tensile,compressiveUse of implant design that allows tensile,compressive
and shear force transfer at bone-implant interface.and shear force transfer at bone-implant interface.

 Influence of surface treating on osseointegration:Influence of surface treating on osseointegration:
 Surface roughness of commercially available implants-Surface roughness of commercially available implants-
 1. Blasted surface:1. Blasted surface: (Tioblast)(Tioblast)
Surface blasted with TiO2 particlesSurface blasted with TiO2 particles
results in isotropic surfaceresults in isotropic surface
Sa- 1.07µmSa- 1.07µm
Scx – 10.11µmScx – 10.11µm
Sdr – 29%Sdr – 29%

 2. Blasted & Etched:2. Blasted & Etched:
surface is blasted followed by acid etchingsurface is blasted followed by acid etching
Sa – 1.42Sa – 1.42
Scx – 16.60Scx – 16.60
Sdr – 33%Sdr – 33%
3. Etched surface:3. Etched surface: (osseotite)(osseotite)
Surface is etched in a two step procedureSurface is etched in a two step procedure
Results in a isotophic surface with high frequencyResults in a isotophic surface with high frequency
irregularitiesirregularities
Sdx- 20%Sdx- 20%

 Hydroxyapatite coated surfaceHydroxyapatite coated surface:( sterioss):( sterioss)
 creates rough isotrophic surfacecreates rough isotrophic surface
 Sa – 1.68Sa – 1.68
 Scx – 13.47Scx – 13.47
 Sdr – 55%Sdr – 55%

 Oxidized surface:Oxidized surface: Ti UniteTi Unite
Electrolytic oxidation of the surface increases theElectrolytic oxidation of the surface increases the
surface thickness of oxide layersurface thickness of oxide layer
Results in isotropic craterous surfaceResults in isotropic craterous surface
Sa- 1.08 Scx – 10.98 Sdr – 37%Sa- 1.08 Scx – 10.98 Sdr – 37%

 Titanium plasma sprayed surface: bonefit,steriossTitanium plasma sprayed surface: bonefit,sterioss
 SteriossSterioss(nobel biocare) is the roughest implant surface(nobel biocare) is the roughest implant surface
among all, with an increase in surface area by 134%among all, with an increase in surface area by 134%
Sa – 3.86 µmSa – 3.86 µm
Scx – 19.55 µmScx – 19.55 µm

 Rate of development of osseointegration-Rate of development of osseointegration-
 Is related to osseoconductivity of different surfacesIs related to osseoconductivity of different surfaces
 Ability to resist interfacial tensile forcesAbility to resist interfacial tensile forces
This is achieved by sintered porous surfaces withThis is achieved by sintered porous surfaces with
interconnected pores suitable for bone ingrowth.interconnected pores suitable for bone ingrowth.
(endopore)(endopore)
This helps in use of shorter implants in cases withThis helps in use of shorter implants in cases with
compromised bone quality and quantity.compromised bone quality and quantity.

 The surface modification of implants provides-The surface modification of implants provides-
(Carlsson et al, Feighan et al)(Carlsson et al, Feighan et al)
Better mechanical stability following installationBetter mechanical stability following installation
Surface configuration that properly retains blood clotSurface configuration that properly retains blood clot
Stimulates bone healing processStimulates bone healing process

 HOST DETERMINANTSHOST DETERMINANTS
 Age:Age:
 Increased parathyroid hormone secretionIncreased parathyroid hormone secretion
 Decreased calcitonin and vit-D absorption andDecreased calcitonin and vit-D absorption and
activationactivation
 Increased Ph in stomach which leads to decreasedIncreased Ph in stomach which leads to decreased
calcium absorptioncalcium absorption
 Decreased testosterone with age in menDecreased testosterone with age in men
 Thinning of cortical bone and increased trabecularThinning of cortical bone and increased trabecular
spacingspacing
 Increase in number of dead osteocytesIncrease in number of dead osteocytes
 Reduced vascular supplyReduced vascular supply

 Using patients of different age groups (BranemarkUsing patients of different age groups (Branemark
system) found that age as such even advanced doesnotsystem) found that age as such even advanced doesnot
have an impact on osseintegration.have an impact on osseintegration.
(Bass et al; Tiplett et al)(Bass et al; Tiplett et al)

Bone factors:Bone factors:
 Quality of boneQuality of bone
 Quantity of boneQuantity of bone

CLASSIFICATION OF BONE
QUALITY(Lekholm and Zarb et al 1985)
Type I: Jaw consists almost exclusively of
homogenous compact bone no cancellous
bone

Type II:Thick cortical compartment with varying
sized cancellous region

Type III:Thin cortical bone surrounding dense
cancellous portion.

Type IV: Thin cortical bone surrounds
loose, spongy core.

CLASSIFICATION OF BONE
QUALITY (Misch 1990)
DI : Thick compact bone
D2 : Thick porous compact bone
D3 : Thin porous compact bone –loosely
structured cancellous bone
D4 : Loose, thin cancellous bone.

Low bone density at the site implant placement
(Type IV bone) has been associated with
increased risk of implant failure.(Lang et al 1990,
Jaffin et al 1991).
They reported high number of losses of Branemark
implants in bone of reduced structural quality and
showed that less dense alveolar cancellous bone
correlates with loss of endosseous implants.

DIABETES MELLITUS.
Uncontrolled diabetes has been shown to be risk
factor for periodontal disease.(Nelson et al 1990).
 In a prospective study by Morris et al in 663 patients
using 2887 implants showed that significantly more
failures occurred in type II diabetics.
Shernoff et al reported that the failure rate of implants in
NIDDM is 7.3%.
This seems to indicate that osseointegration can be
obtained in diabetic patients but the medium to long
term prognosis is currently guarded.

 Osteoporosis/osteopenia:
 Studies by Friberg et al showed a survival rate of 97%
during an observation period of 6 months to 14 years in
patients with osteoporosis.
 However it is advisable to use implants with more
active surface and delay the loading.

 Hormone replacement(estrogen):
 Post menopausal women without HRT had nearly
twice the maxillary implant failure rate compared to
patients under replacement therapy. Chung et al 2001.
 Sjogrens syndrome:
 Isidor et al presented the outcome of implant therapy
in paients with sjogrens syndrome and found a overall
failure rate of 16.7% which is much heigher than in
healthy patients.

 HIV patients:
 To date only one case report described successful
placement of endosseous implant in immediate
extraction socket for single tooth replacement followed
for 18 months. Rajnay et al 1998.
 Hypophosphatasia and Vit –D deficiency:
 In a study by Bergendahl et al 2000 8 out of 10
implants showed failure in patients with Vit D
deficiency where as none of the implants failed in
hypophosphatasia group.

 Platelet and coagulation disorders:
 In patients with platelet and coagulation disorders such
as thrombocytopenia, Von willebrands
disease,hemphilia placement of dental implants is a
challenge and osseointegration is rarely achieved.

MEDICATIONS
A positive medical and medication history has been
associated with an increased risk of implant loss.
(Weyant et al 1994).
Isolated reports have associated implant failure
with the consumption of anti-osteoporotic drugs ,di-
phosphonate in particular. (Stark et al 1995)
Cyclosporine has a more challenging effect on
osseointegrating implants namely its well documented
effect of accelerating bone turnover and provoking a
negative bone balance.

 Chemotherapy and irradiation:
 Placement of implants in irradiated patients involves
the risk of inducing osteoradionecrosis as well as risk of
losing implants.
 Esposito et al in a meta analysis concluded that failure
rate is slightly higher in irradiated bone10% than
normal bone7%.
 Failure was also dependent on irradiation
dosage,implant failure was heigher above 55 Gy.
 In such cases implant survival can by enhanced by use
of hyperbaric oxygen.

 Microbiological state:
 There is no evidence that presence of previous
periodontal disease or periodontal pathogens is a
serious risk for osseontegration except immediate
implants. Rosequist et al
 However long term success of osseointegrated implants
can get effected due to increased number of P.gingivalis
and P. intermedia.

 Smoking:
Smoking has a negative influence on peripheral
microcirculation and wound healing.
Bain and Moy suggested that smoking influences bone
quality which inturn may lead to higher failure rate.
When potential confounding variables were assesed in
bivariate and multivariate survival analysis overall
implant failure was noted to be 7.72%
Smokers at the time of implant placement had failure
rate of 23.08%(early implant failure)
Late implant failure is associated with a positive history
of smoking more than 25 cigarette years.
Habsha et al 2000

Fibro-osseous Retention vsFibro-osseous Retention vs
OsseointegrationOsseointegration
 Fibroosseous retention is defined as interposition of
healthy,dense collagenous tissue between the implant
and bone.
 Weiss defends the presence of collagen fibers between
the implant and bone and interprets it as peri-implant
membrane with osteogenic potential.
 The piezoelectric effect created by the fibers has
osteogenic potential.
 The premise that peri-implant ligament is osteogenic
and exerts and piezoelectric effect is only a hypothesis.

Is there a fibrous tissue interface between
implant and bone?
 It must be realized that there is never a 100% bone to
implant interface.
 Johansson & Alberktsson reported a fibrous tissue
interface at 1 month following implantation,
 50% bone –implant contact at 3 months
 65% bone –implant contact at 6 months
 85% bone-implant contact at 1 year
 Using screw type implants in rabbits.

 Weiss hypothesis-
 Implant should be placed in hypofunctional mode from
the day of insertion and full function within 1-2 months
 Branemark hypothesis-(later proven in animal
experiments)
 Implant should be completely protected and
afunctional during a period of 0-12 months.
 Remodelling phase 3-18 months when exposed to
masticatory forces
 Steady state – after 18 months.

What may be the cause for connectiveWhat may be the cause for connective
tissue interface?tissue interface?
 Premature loading of implant system earlier than 3-6Premature loading of implant system earlier than 3-6
monthsmonths
 Apical migration of junctional epithelium into theApical migration of junctional epithelium into the
interface followed by connective tissue elementsinterface followed by connective tissue elements
 Placing the implant with too much of pressurePlacing the implant with too much of pressure
 Linkow & WertmanLinkow & Wertman
 Overheating the bone during site preparation (>116 F)Overheating the bone during site preparation (>116 F)
 Implant not fitting the site exactlyImplant not fitting the site exactly Carlsson et alCarlsson et al

Osseointegration vs OsseocoalescenceOsseointegration vs Osseocoalescence
 Osseointegration refers to pure mechanical interlockingOsseointegration refers to pure mechanical interlocking
between the implant and bonebetween the implant and bone
 This mechanical interlocking will not withstand tensileThis mechanical interlocking will not withstand tensile
forcesforces
 Osseocoalescence refers to chemical integration ofOsseocoalescence refers to chemical integration of
implants in the bone.implants in the bone.
 This is achieved by bio active materials such asThis is achieved by bio active materials such as
hydroxyapatite and bio active glasshydroxyapatite and bio active glass
 Physicochemical interaction between the bone and HAPhysicochemical interaction between the bone and HA
layer causes direct deposition of bone on the implantlayer causes direct deposition of bone on the implant
surfacesurface

 Devices to measure implant stability andDevices to measure implant stability and
osseointegration:osseointegration:
 1.1. PeriotestPeriotest Schulte & Lukas 1993Schulte & Lukas 1993
 Uses metal probe accelerated by an electromagnetUses metal probe accelerated by an electromagnet
 Contact time related to implant mobilityContact time related to implant mobility

 2.2. Resonance frequency analysisResonance frequency analysis:: MeredithMeredith
 A frequency rise was seen from 7473 Hz at the time ofA frequency rise was seen from 7473 Hz at the time of
implant placement to 7915 Hz 8 months later.implant placement to 7915 Hz 8 months later.
 The amplitude signals are used to caliculate implantThe amplitude signals are used to caliculate implant
stability ratio within a scale of 0-100.stability ratio within a scale of 0-100.


LOADING AND OSSEOINTEGRATIONLOADING AND OSSEOINTEGRATION
 Time of loading of an endosteal implant depends on-Time of loading of an endosteal implant depends on-
 Type of boneType of bone
 Characteristics of implant surfaceCharacteristics of implant surface
 Amount of bone to implant contactAmount of bone to implant contact

 Immediately following placement –
bone –implant contact
 D1 – 80%
 D2 - 70%
 D3 – 50%
 D4 – 25%
 Ideal bone for bone to implant prosthesis is lamellar
bone, it heals 50% faster than the cortical bone and is
highly organized.

Bone
density
Initial
healing
Reconst
ruction
Gap b/w
appointm
ents
Total
time
D-1D-1 55 66 11 6.56.5
D-2D-2 44 1010 22 6.56.5
D-3D-3 66 1414 33 9.59.5
D-4 8 18 4 12.5

 Pilliar et al poposed a value for critical relative
displacements =30µm to prevent bone ingrowth.
 However with surface modifications such as titanium
plasma spraying and hydroxyapatite coating on the
implants the relative displacement of the implants has
increased to 50-75µm without any interference with
osseointegration.
 But immediate loading when done in patients with
compromised bone quality will result in crestal bone
loss and fibrous encapsulation of implant and
subsequently implant failure.

 Adel et al 1981
 -Boneloss of 1-1.5mm occurs during the first year of
implant placement as a result of surgical trauma
 Marginal bone loss of 0.05-0.1mm occurs annually.
 Any overloading during the phase of remodelling
results in excessive crestal bone loss
 The use of a period of graduated loading is
recommended to avoid overloading failure of newly
formed bone.
 This graduated loading period should correlate with one
or more remodeling units to occur.

 Immediate loading and OsseointegrationImmediate loading and Osseointegration
 In a histologic study conducted in 5 patients using 9In a histologic study conducted in 5 patients using 9
implants 2 loaded immediately and 5 following 2implants 2 loaded immediately and 5 following 2
months of healing,retrieved after 5-9 months ofmonths of healing,retrieved after 5-9 months of
function showed bone –implant contact of 92% andfunction showed bone –implant contact of 92% and
81% respectively. (Antonio et al)81% respectively. (Antonio et al)

 In a 3 year retrospective study using 97 branemarkIn a 3 year retrospective study using 97 branemark
implants placed in 46 patients followed for 34 monthsimplants placed in 46 patients followed for 34 months
showed a cumulative survival rate of 91%showed a cumulative survival rate of 91%
 Nine implants in 8 patients failed during the first 8Nine implants in 8 patients failed during the first 8
weeks of loading and the remaining implants showedweeks of loading and the remaining implants showed
good long term prognosis.good long term prognosis.

 Measures to enhance osseointegration::Measures to enhance osseointegration::
 Maintain the periosteal supply as much possible at theMaintain the periosteal supply as much possible at the
implant siteimplant site
 Use implants with isotrophic surface with more porousUse implants with isotrophic surface with more porous
configurationconfiguration
 Use implants of large surface areaUse implants of large surface area
 Graduated loading of implantsGraduated loading of implants
 Using implants with mesenchymal stem cellsUsing implants with mesenchymal stem cells
incorporated with BMP’s on the surfaceincorporated with BMP’s on the surface
 Low level laser treatment –biostimulatory effect causesLow level laser treatment –biostimulatory effect causes
an increase in the number of viable osteoblasts.an increase in the number of viable osteoblasts.

CONCLUSIONCONCLUSION

 BIBLIOGRAPHYBIBLIOGRAPHY
1.1. Clinical Periodontology and Implant Dentistry
Jan Lindhe 4th
edition.
2.2. Implant therapy-Clinical approaches and Evidence of
success Vol II
–Nevins and Mellonig
3. Contemporary Implant Dentistry
Carl Misch 3rd
edition.
4. Ageing, Osteoporosis and Dental Implants
 Lekholm & Zarb
5. Dental Implants DCNA: (50);2006

6.6. Use of oral Implants in compromised patients
Periodontology 2000; vol 33.
7.7. Risk Factors in implant dentistry
Franck Renouard and Bo Rangert
8. Osseointegration in oral implantology
consensus development conference statement 1988
9. The long term efficacy of currently used dental
implants : A Review and proposed criteria of success
T.Alberktsson,P.Worthington,A.R.Eriksson
J Oral Maxillofac Implants 1986 vol 1 (11-25)

10.10. Histology of retrieved immediately and early loaded
oxidized implants: Light microscopic observations after
5-9 months of loading in the posterior mandible
Clinical Implant Dentistry 2003(5);88-97.
11. Immediate loading in the maxilla using flapless
surgery,implants placed in predetermined positions and
prefabricated restorations: A retrospective 3 year
clinical study. Clinical Implant Dentistry 2003(5);29-36..

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