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Implant quality scale :
Osseointegration, success
criteria and basic guides
Definitions
Mechanism of
osseointegration
Factors effecting
osseointegration
Methods of evaluation
of osseointegration
Oss...
HISTORICAL REVIEW
• The concept of osseointegration was developed
and the term was coined by Dr. Per-Ingvar
Branemark, Pro...
Definitions
“The apparent direct attachment or connection of osseous
tissue to an inert, alloplastic material without inte...
Histologically
Direct anchorage of an implant by the formation of
bone directly on the surface of an implant without
any i...
Clinically
Ankylosis of the implant bone interface.“Functional
ankylosis” -Schroeder and colleagues 1976
“It is a process ...
Biomechanically oriented definition
“Attachment resistant to shear as well as tensile forces”
- Steinmann et al (1986).
Bone physiology
Bone can be classified as
• Compact bone
• Spongy bone
Depending on age, developmental age, localization and
function, bone consists of three tissue types that differ in
collage...
Woven bone
• Formed by the osteoprogenitor cells in the vicinity
of blood vessels during prenatal development
,growth and ...
Woven bone
Lamellar bone
• Principle load-bearing tissue
• Predominant component of mature cortical and
trabecular bone
• Forms relat...
Lamellar bone
Bundle bone
• Found in the area of ligament and tendon attachment
along the bone-forming surfaces.
• Striation are extensi...
Bundle bone
Modelling
• A surface specific activity that produces a net change in
the size and/or shape of bone .
• An uncoupled proce...
Bone Remodeling
• It is the turnover or internal restructuring of previously
existing bone .
• Coupled tissue level phenom...
Bone to implant interface
There are two basic theories
Osseointegration
(Branemark 1985)
Fibro-osseous
integration
Linkow ...
FIBROINTEGRATION OSSEOINTEGRATION
In 1986, the American Academy of Implant Dentistry (AAID)
“Tissue-to-implant contact wit...
Fibro-osseous integration
 Presence of connective tissue between the implant and
bone
 Collagen fibers functions similar...
Weiss concept
 Collagen fibers at the interface - peri-implant membrane
with an osteogenic effect.
 Collagen fibers inve...
Failure of fibro-osseous theory
 No real evidence
 Forces are not transmitted through the fibers -
remodeling was not ex...
Natural teeth Implant
Oblique and horizontal
group of fibers
Parallel, irregular,
complete
encapsulation
Uniform distribut...
Osseointegration
American Academy of Implant Dentistry (AAID) defined it as
"contact established without interposition of ...
Mechanism of Osseointegration
• Healing process may be primary bone healing or
secondary bone healing.
• In primary bone h...
Blood between the
fixture and bone
Blood clot
Procallus
(contains fibroblast)
Callus (contains
osteoblast)
Bone
Remodellin...
Mechanism of osseointegration
Phase Timing Specific occurrence
1.Inflammatory
phase
Day 1-10 Adsorption of plasma proteins...
Phase Timing Specific occurrence
2. Proliferative
phase
Day 3 - 42 Neovascularization
Differentiation,
Proliferation and
a...
Phase Timing Specific occurrence
3.Maturation
phase
After
Day 28
Remodeling of the
immature bone matrix with
coupled resor...
Bone tissue response
• Distance Osteogenesis
A gradual process of bone healing inward from the edge
of the osteotomy towar...
• Contact Osteogenesis
The direct migration of bone-building cells through
the clot matrix to the implant surface. Bone is...
Mechanism of integration: (Davies - 1998)
Contact osteogenesis :
 Early phases of osteogenic cell migration
(Osteoconduct...
Osteoconduction
“Osteoconduction” refers to the migration of differentiating
osteogenic cells to the proposed site.
Migrat...
De novo bone formation
Differentiating osteogenic cells, which reach the implant
surface initially, secrete a collagen-fre...
Bone bonding in de novo bone formation
Bonding of de novo bone will occur by the fusion, or
micromechanical interlocking o...
Bone remodeling
During the long-term phase of peri-implant healing, it is
only through those remodeling osteons that actua...
Stages of Osseointegration
According to Misch there are two stages in
osseointegration, each stage been again divided into...
Stage 1: Woven callus
 0-6 weeks of implantation.
 Woven bone is formed at implant site.
 Primitive type of bone tissue...
Stage 2: Lamellar compaction
 6th week of implantation and continues till 18th week.
 The woven callus matures as it is ...
Stage 3: Interface remodeling
 This stage begins at the same time when woven callus is
completing lamellar compaction.
 ...
Stage 4: Compact bone maturation
 This occurs form 18th week of implantation and continues
till the 54th week.
 During t...
Six different factors known to be important for the
establishment of a reliable, long-term osseous anchorage
of an implant...
Implant Biocompatibility
 Chemical interaction determined – properties of surface
oxide
 Commercially pure (c.p.) Titani...
Other metals
 Niobium, tantalum
 Cobalt chrome molybdenum alloys
 Stainless steels
 Ceramics - calcium phosphate hydro...
Degree of
Compatibility
Characteristics of Reactions of
Bony Tissue
Materials
Biotolerant Implants separated from
adjacent...
Implant Design (Macrostructure)
Threaded or screw design implants
 Promote osseointegration
 More functional area for st...
Non threaded
•Tendency for slippage
•Bonding is required
•No slippage tendency
•No bonding is required
Threaded
Functional surface area per unit length of implant may be
modified by the three thread geometry parameters
• Thread shape
...
Grooves on the threads of all implants and on the collars,
wherever appropriate.
 Increase surface area
 Increase area f...
Implant Surface (Microstructure,Surface Topography)
“The extent of bone implant interface is positively
correlated with an...
• Roughness parameter (Sa)
0.04 –0.4 m - smooth
0.5 – 1.0 m – minimally rough
1.0 –2.0 m – moderately rough
 2.0 m – ...
Surface treatments
 Turned surface
 Sandblasted surface
 Acid etched surface
 Titanium plasma spray
 Sandblasting and...
Bone – implant contact area
Surface treatment 1 month 3 months 6 months
Machined/ truned 42% 44%
Machined/ sandblasted 54%...
State of the host bed
Ideal host bed
Healthy and with an adequate bone stock
 Bone height
 Bone width
 Bone length
 Bo...
Implant bed - Bone Quality
According to Lekholm and Zarb,1985
• Quality I
composed of homogenous compact
bone found in the...
 Quality III
Thin layer of cortical bone surrounding
dense
trabecular bone – upper anterior and
upper &
lower posterior r...
 Branemark system (5 year documentation)
 Mandible – 95% success
 Maxilla – 85-90% success
According to Branemark and M...
Surgical Considerations
 Promote regenerative type of the bone healing rather than
reparative type of the bone healing.
...
Recommendations
 Slow speed
 Graded series
 Adequate cooling
 Bone cutting speed of less than 2000 rpm
 Tapping at a ...
Progressive or two stage loading
Branemark et al to accomplish osseointegration
considered the following prerequisites
 C...
 Delayed loading:
- Two-stage surgical protocol
- One-stage surgical protocol
 Immediate loading:
1. Immediate occlusal ...
Frost’s mechanostat theory
Systemic factors
 Active chemotherapy
 Type 2 (late-onset) diabetes: This is especially the
case where this is not well ...
 Patients who were smokers at the time of implant
surgery had a significantly higher implant failure rate
(23.08%) than n...
Subjective criteria
 Adequate function
 Absence of discomfort
 Improved aesthetics
 Improved emotional and psychologic...
Objective criteria
 Bone loss no greater than 33% of vertical length of implant
 Gingival inflammation amenable to treat...
Possible criteria for success
 Mobility
 Peri-implant radiolucency
 Marginal bone loss
 Sulcus depth
 Gingival status...
Condition for application of criteria
 Only osseointegrated implants should be
evaluated with these criteria.
 The crite...
 Implants that are beneath the mucosa and in a
state of health in relation to the surrounding
bone should preferably not ...
Revised criteria - Albrektsson
 Individual implant is immobile clinically
 No evidence of peri-implant radiolucency is
p...
 No persistent pain, discomfort, or infection is
attributable to the implant.
 Implant design does not preclude placemen...
 Drago et al
anterior maxilla-89.1%
posterior maxilla-71.4%
anterior mandible-96.7%
posterior mandible-98.7%
Success rate
Moy et al –
maxilla-91.8% mandible-95.1%
Bass et al –
maxilla-93.4% mandible-97.2%
5-year survival
 conventional tooth-supported FDPs of 93.8%
 cantilever FDPs of 91.4%
 solely implant supported FDPs of...
After 10 years of function –
 89.2% -conventional FDPs
 80.3% -cantilever FDPs
 86.7%- implant-supported FDPs
 77.8% -...
Methods of evaluation of
Osseointegration
 Stability is a requisite characteristic of
osseointegration.
 Initial stability is a function of the
Bone quality,
Im...
Invasive Methods
 Histological sections (10 microns sections)
 Histomorphometric – To know the percentage of bone
contac...
Non-Invasive Methods
 Percussion test
 Tapping with a metallic instruments
Ringing sound- osseointegrated.
Dull sound ...
 Reliable method to determine implant stability
 Emg driven and electronically controlled
tapping head that hammers an o...
 Response to striking is measured by a small
accelerometer present in head
 Signals converted to periotest value
 Depen...
 Developed by Aoki and Hirakawa
 Mech is similar to periotest
 Microphone used as receiver and signals
transferred is p...
 Non invasive can be performed at any stage of
healing
 Bite wing-measure crestal bone level
 1.5 mm of CBL can be expe...
 Problems
Difficult for clinician to detect changes at 0.1mm
resolution
Can be measured when central ray of x-ray is
perf...
 Excellent method to assess health of natural teeth
 In implants little diagnostic value unless accompanied by
signs & s...
 Suggested by James, modified by Misch
 Group I
 Group II
 Group III
 Group IV
Misch CE, Perel ML, Wang HL, et al. Im...
 No pain or tenderness upon function
 0 Mobility
 Less than 2.0 mm crestal bone loss from initial
surgery
 No history ...
 No pain on function
 0 mobility
 Crestal bone loss – 2 to 4 mm
 No history of transient exudate
 Prognosis good to v...
 Slight to moderate peri-implantitis
 Sensitivity on function
 Radiographic bone loss > 4 mm (<1/2 of implant
body)
 N...
 Implant removed
 Pain
 mobility
 Uncontrolled progressive bone loss;
 Uncontrolled exudate
 50% bone loss
 surgica...
Rigid fixation
Scale Description
0 Absence of clinical mobility with 500g in any
direction
1 Slight detectable horizontal ...
 Cutting Torque resistance analysis (CRA)
 Reverse Torque test (RTV)
 Resonance Frequency analysis (RFA)
Other methods
 Johansson and strid and improved by Friberg et
al
 Energy required for a current fed electric motor
in cutting off a un...
 Torque guage-in drilling unit measures the
insertion torque in Ncm, gives idea about the
bone quality
 Gives more objec...
Advantages
a. Detect bone density
b. Identify bone density during surgery
c. Can be used in daily practice
Disadvantages
a...
 Measures the ‘critical’ torque threshold where
bone-implant contact (BIC) was destroyed
 Removal Torque value (RTV)-ind...
 Ranges from 45-48 Ncm
 RTV >20 Ncm accepted as criteria for
successful osseointegration
 Varies depending on bone qual...
Disadvantages
a. RTV only provide information as to “all or
none” outcome
b. Mainly used in experiments
 Non invasive method that measures implant stability
& bone density at various time points
 RFA utilizes a small L-shape...
 Transducer comprises of 2 piezoceramic
elements
 One for vibration, and other serves as a receptor
for the signal
 Res...
 Earlier hertz was used as measurement unit
now implant stability quotient (ISQ)
 RF values ranging from 3500-8500 Hz
tr...
 Higher value-greater stability
 Low value-instability
 Successful implant-ISQ >65
 ISQ <50 indicates potential failur...
 RFA can only give information regarding success
cannot provide information with respect to survival
or failure.
 ISQ is...
References
 Misch CE. Contemporary implant dentistry, 3rd edition,
Mosby Elsevier publication, St Louis, 2008, pp:27, 70,...
 Masuda T, Yliheikkilä PK, Felton DA, Cooper LF.
Generalizations Regarding the Process and
Phenomenon of Osseointegration...
 Davies JE. Understanding Peri-Implant Endosseous
Healing. J Dent Edu 2005;67(8):932-949
 Pye AD, Lockhart DEA, Dawson M...
 Palmer R. Introduction to dental implants. Brit Dent J
1999;187(3) 14:127-132
 DeLuca S, Habsha E, Zarb GA. The effect ...
 Pjetursson BE et al, Comparison of survival and
complication rates of tooth-supported fixed dental
prostheses (FDPs) and...
 Atsumi M et al, Methods used to Assess implant
stability: current status, Int J Oral Maxillafac
Implants 2007;22:743-54
...
Implant quality scale ; osseointegration, success criteria and basic guides
Implant quality scale ; osseointegration, success criteria and basic guides
Implant quality scale ; osseointegration, success criteria and basic guides
Implant quality scale ; osseointegration, success criteria and basic guides
Implant quality scale ; osseointegration, success criteria and basic guides
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Implant quality scale ; osseointegration, success criteria and basic guides

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dental implants,osseo integration and evaluation of osseointegration success criteria of implant quality scale

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Implant quality scale ; osseointegration, success criteria and basic guides

  1. 1. Implant quality scale : Osseointegration, success criteria and basic guides
  2. 2. Definitions Mechanism of osseointegration Factors effecting osseointegration Methods of evaluation of osseointegration Osseointegration Bone implant interface Fibro – osseous integration Success criteria Success Survival, And failure Evaluation of dental Implants
  3. 3. HISTORICAL REVIEW • The concept of osseointegration was developed and the term was coined by Dr. Per-Ingvar Branemark, Professor at the institute for Applied Biotechnology, University of Goteborg, Sweden .
  4. 4. Definitions “The apparent direct attachment or connection of osseous tissue to an inert, alloplastic material without intervening connective tissue”. - GPT 8 Structurally oriented definition “Direct structural and functional connection between the ordered, living bone and the surface of load carrying implants”. - Branemark and associates (1977)
  5. 5. Histologically Direct anchorage of an implant by the formation of bone directly on the surface of an implant without any intervening layer of fibrous tissue. - Albrektson and Johnson (2001)
  6. 6. Clinically Ankylosis of the implant bone interface.“Functional ankylosis” -Schroeder and colleagues 1976 “It is a process where by clinically asymptomatic rigid fixation of alloplastic material is achieved and maintained in bone during functional loading” - Zarb and T Albrektson 1991
  7. 7. Biomechanically oriented definition “Attachment resistant to shear as well as tensile forces” - Steinmann et al (1986).
  8. 8. Bone physiology
  9. 9. Bone can be classified as • Compact bone • Spongy bone
  10. 10. Depending on age, developmental age, localization and function, bone consists of three tissue types that differ in collagen fibril arrangement and mineral content. Woven bone Lamellar bone Bundle bone
  11. 11. Woven bone • Formed by the osteoprogenitor cells in the vicinity of blood vessels during prenatal development ,growth and healing . • Forms 30-50 µm /day • High cellular osseous tissue • Low mineral content • More pliable than mature lamellar bone • Capable of stabilizing an unloaded implant,woven bone lacks the strength to resist functional loads .
  12. 12. Woven bone
  13. 13. Lamellar bone • Principle load-bearing tissue • Predominant component of mature cortical and trabecular bone • Forms relatively slow (< 1.0µm/day) • Have highly organized matrix, and are densely mineralized • Orientation of the collagen fibrils differs from one layer to another .
  14. 14. Lamellar bone
  15. 15. Bundle bone • Found in the area of ligament and tendon attachment along the bone-forming surfaces. • Striation are extension of sharpey’s fibers composed of collagen bundles from adjacent connective tissue that insert directly into the bone • It is formed adjacent to the periodontal ligament of physiologically drifting teeth.
  16. 16. Bundle bone
  17. 17. Modelling • A surface specific activity that produces a net change in the size and/or shape of bone . • An uncoupled process, meaning that cell activation(A) proceeds independently to formation(F) or resorption(R) • Generalized change in overall dimension of a bone’s cortex or spongiosa • Modelling is a fundamental mechanism of growth , atrophy and reorientation.
  18. 18. Bone Remodeling • It is the turnover or internal restructuring of previously existing bone . • Coupled tissue level phenomenon
  19. 19. Bone to implant interface There are two basic theories Osseointegration (Branemark 1985) Fibro-osseous integration Linkow 1976 James 1975 Weiss 1986
  20. 20. FIBROINTEGRATION OSSEOINTEGRATION In 1986, the American Academy of Implant Dentistry (AAID) “Tissue-to-implant contact with healthy dense collagenous tissue between the implant and bone”
  21. 21. Fibro-osseous integration  Presence of connective tissue between the implant and bone  Collagen fibers functions similarly to Sharpey’s fibers found in natural dentition.  The fibers are arranged irregularly, parallel to the implant body, when forces are applied they are not transmitted through the fibers
  22. 22. Weiss concept  Collagen fibers at the interface - peri-implant membrane with an osteogenic effect.  Collagen fibers invest the implant, originating at the trabeculae of cancellous bone on one side, weaving around the implant, and reinserting into a trabeculae on the other side.  It was felt that, this membrane gave a cushion effect and acted as similar as periodontal membrane in natural dentition.
  23. 23. Failure of fibro-osseous theory  No real evidence  Forces are not transmitted through the fibers - remodeling was not expected  Forces applied resulted in widening fibrous encapsulation, inflammatory reactions, and gradual bone resorption there by leading to failure.
  24. 24. Natural teeth Implant Oblique and horizontal group of fibers Parallel, irregular, complete encapsulation Uniform distribution of load (Shock absorber) Difficult to transmit the load Failure : Inability to carry adequate loads - Infection
  25. 25. Osseointegration American Academy of Implant Dentistry (AAID) defined it as "contact established without interposition of non-bone tissue between normal remodeled bone and an implant entailing a sustained transfer and distribution of load from the implant to and within the bone tissue"
  26. 26. Mechanism of Osseointegration • Healing process may be primary bone healing or secondary bone healing. • In primary bone healing, there is well organized bone formation with minimal granulation tissue formation - ideal • Secondary bone healing may have granulation tissue formation and infection at the site, prolonging healing period. Fibrocartilage is sometimes formed instead of bone - undesirable
  27. 27. Blood between the fixture and bone Blood clot Procallus (contains fibroblast) Callus (contains osteoblast) Bone Remodelling Phagocytic cells PMNL
  28. 28. Mechanism of osseointegration Phase Timing Specific occurrence 1.Inflammatory phase Day 1-10 Adsorption of plasma proteins Platelet aggregation and activation Clotting cascade activation Cytokine release Specific cellular inflammatory response Macrophage mediated inflammation.
  29. 29. Phase Timing Specific occurrence 2. Proliferative phase Day 3 - 42 Neovascularization Differentiation, Proliferation and activation of cells. Production of immature connective tissue matrix.
  30. 30. Phase Timing Specific occurrence 3.Maturation phase After Day 28 Remodeling of the immature bone matrix with coupled resorption and deposition of bone. Bone remodeling in response to implant loading
  31. 31. Bone tissue response • Distance Osteogenesis A gradual process of bone healing inward from the edge of the osteotomy toward the implant. Bone does not grow directly on the implant surface.
  32. 32. • Contact Osteogenesis The direct migration of bone-building cells through the clot matrix to the implant surface. Bone is quickly formed directly on the implant surface.
  33. 33. Mechanism of integration: (Davies - 1998) Contact osteogenesis :  Early phases of osteogenic cell migration (Osteoconduction)  De novo bone formation  Bone remodeling at discrete sites.
  34. 34. Osteoconduction “Osteoconduction” refers to the migration of differentiating osteogenic cells to the proposed site. Migration of the connective tissue cells will occur through the fibrin that forms during clot resolution. The migration of cells through a temporary matrix such as fibrin - retraction of the fibrin scaffold.
  35. 35. De novo bone formation Differentiating osteogenic cells, which reach the implant surface initially, secrete a collagen-free organic matrix that provides nucleation sites for calcium phosphate mineralization Noncollagenous bone proteins - Osteopontin and bone Sialoprotein
  36. 36. Bone bonding in de novo bone formation Bonding of de novo bone will occur by the fusion, or micromechanical interlocking of the biologic cement line matrix with the surface reactive layer
  37. 37. Bone remodeling During the long-term phase of peri-implant healing, it is only through those remodeling osteons that actually impinge on the implant surface that de novo bone formation will occur at these specific sites on the implant
  38. 38. Stages of Osseointegration According to Misch there are two stages in osseointegration, each stage been again divided into two substages. They are: Surface modeling Stage 1: Woven callus (0-6 weeks) Stage 2: Lamellar compaction (6-18 weeks) Remodeling, Maturation Stage 3: Interface remodeling (6-18 weeks) Stage 4: Compact maturation (18-54 weeks)
  39. 39. Stage 1: Woven callus  0-6 weeks of implantation.  Woven bone is formed at implant site.  Primitive type of bone tissue and characterized Random, felt-like orientation of collagen fibrils Numerous irregularly shaped osteocytes Relatively low mineral density
  40. 40. Stage 2: Lamellar compaction  6th week of implantation and continues till 18th week.  The woven callus matures as it is replaced by lamellar bone.  This stage helps in achieving sufficient strength for loading.
  41. 41. Stage 3: Interface remodeling  This stage begins at the same time when woven callus is completing lamellar compaction.  During this stage callus starts to resorb, and remodeling of devitalized interface begins.  The interface remodeling helps in establishing a viable interface between the implant and original bone.
  42. 42. Stage 4: Compact bone maturation  This occurs form 18th week of implantation and continues till the 54th week.  During this stage compact bone matures by series of modeling and remodeling processes.  The callus volume is decreased and interface remodeling continues.
  43. 43. Six different factors known to be important for the establishment of a reliable, long-term osseous anchorage of an implanted device  Implant biocompatibility  Design characteristics  Surface characteristics  State of the host bed  Surgical technique and  Loading conditions
  44. 44. Implant Biocompatibility  Chemical interaction determined – properties of surface oxide  Commercially pure (c.p.) Titanium and Titanium alloy (Ti -6AL-4V)  Documented long term function  Covered with adherent, self- repairing oxide layer  Excellent resistance to corrosion – high dielectric constant  Load bearing capacity
  45. 45. Other metals  Niobium, tantalum  Cobalt chrome molybdenum alloys  Stainless steels  Ceramics - calcium phosphate hydroxyapatite (HA) and various types of aluminium oxides Biocompatible - insufficient documentation and very less clinical trials - less commonly used.
  46. 46. Degree of Compatibility Characteristics of Reactions of Bony Tissue Materials Biotolerant Implants separated from adjacent bone by a soft tissue layer along most of the interface: distance osteogenesis Stainless steels: CoCrMo and CoCrMoNi alloys Bioinert Direct contact to bony tissue contact osteogenesis Alumina ceramics, zirconia ceramics, titanium, tantalum, niobium, carbon. Bioactive Bonding to bony tissue: bonding osteogenesis Calcium phosphate- containing glasses, glass- ceramics, ceramics, titanium (?) Grouping of hard tissue replacement materials according to their compatibility to bony tissue
  47. 47. Implant Design (Macrostructure) Threaded or screw design implants  Promote osseointegration  More functional area for stress distribution than the cylindrical implants.  Minimal - <0.2 mm/year bone loss Cylindrical implants  Press fit root form implants depend on coating or surface condition to provide microscopic retention and bonding to the bone  Bone saucerization
  48. 48. Non threaded •Tendency for slippage •Bonding is required •No slippage tendency •No bonding is required Threaded
  49. 49. Functional surface area per unit length of implant may be modified by the three thread geometry parameters • Thread shape • Thread pitch • Thread depth
  50. 50. Grooves on the threads of all implants and on the collars, wherever appropriate.  Increase surface area  Increase area for bone-to-implant contact
  51. 51. Implant Surface (Microstructure,Surface Topography) “The extent of bone implant interface is positively correlated with an increasing roughness of the implant surface” Roughened surface   Greater bone to implant contact at histological level  Micro irregularities - cellular adhesion.  High surface energy - improved cellular attachment.
  52. 52. • Roughness parameter (Sa) 0.04 –0.4 m - smooth 0.5 – 1.0 m – minimally rough 1.0 –2.0 m – moderately rough  2.0 m – rough • Wennerberg (1996) – stated that moderately rough implants developed the best bone fixation. Smooth surface < 0.2 m will – soft tissue no bone cell adhesion  clinical failure. Moderately rough surface more bone in contact with implant  better osseointegration.
  53. 53. Surface treatments  Turned surface  Sandblasted surface  Acid etched surface  Titanium plasma spray  Sandblasting and surface etching  Hydroxyapatite coatings  Anodized surface
  54. 54. Bone – implant contact area Surface treatment 1 month 3 months 6 months Machined/ truned 42% 44% Machined/ sandblasted 54% Machined/ acid etched 42% 51% 49% Sandblasted and acid etched 58% 72% 52% 68% Oxidized 35% 43% Titanium plasma-sprayed 52% 78% Hydroxyapaptite 79% Ion implantation 68% 61% Laser treated 38%
  55. 55. State of the host bed Ideal host bed Healthy and with an adequate bone stock  Bone height  Bone width  Bone length  Bone density Undesirable host bed states for implantation  Previous irradiation  Ridge height resorption  Osteoporosis
  56. 56. Implant bed - Bone Quality According to Lekholm and Zarb,1985 • Quality I composed of homogenous compact bone found in the lower anterior • Quality II Thick layer of cortical bone surrounding dense trabecular bone found in the lower posterior
  57. 57.  Quality III Thin layer of cortical bone surrounding dense trabecular bone – upper anterior and upper & lower posterior region  Quality IV Very thin layer of cortical bone surrounding a core of low-density trabecular bone - very soft bone found in the upper anterior and posterior
  58. 58.  Branemark system (5 year documentation)  Mandible – 95% success  Maxilla – 85-90% success According to Branemark and Misch  D1 and D2 bone  initial stability / better osseointegration  D3 and D4  poor prognosis  D1 bone – least risk  D4 bone - most at risk Selection of implant  D1 and D2 – conventional threaded implants  D3 and D4 – HA coated or Titanium plasma coated implants
  59. 59. Surgical Considerations  Promote regenerative type of the bone healing rather than reparative type of the bone healing.  The critical time/ temperature - bone tissue necrosis - 47° for one minute.
  60. 60. Recommendations  Slow speed  Graded series  Adequate cooling  Bone cutting speed of less than 2000 rpm  Tapping at a speed of 15 rpm with irrigation  Using sharp drills  The optimal torque threshold – 35 N/cm.  Implant should gently engage the bone in order to avoid too much pressure at the bone interface which could jeopardize healing  Surgical skill / technical excellence
  61. 61. Progressive or two stage loading Branemark et al to accomplish osseointegration considered the following prerequisites  Countersinking the implant below the crestal bone  Obtaining and maintaining a soft tissue covering over the implant for 3 to 6 months  Maintaining a non loaded implant environment for 3 to 6 months
  62. 62.  Delayed loading: - Two-stage surgical protocol - One-stage surgical protocol  Immediate loading: 1. Immediate occlusal loading (placed within 48 hours) 2. Immediate non-occlusal loading (in single-tooth or short-span applications) 3. Early loading (within two months)
  63. 63. Frost’s mechanostat theory
  64. 64. Systemic factors  Active chemotherapy  Type 2 (late-onset) diabetes: This is especially the case where this is not well controlled  Treatment by an operator with limited surgical experience.
  65. 65.  Patients who were smokers at the time of implant surgery had a significantly higher implant failure rate (23.08%) than non-smokers (13.33%)  Short implants and implant placement in the maxilla were additional independent risk factors for implant failure. DeLuca S, Habsha E, Zarb GA. The effect of smoking on osseointegrated dental implants. Part I: implant survival. Int J Prosthodont 2006;19(5):491-8
  66. 66. Subjective criteria  Adequate function  Absence of discomfort  Improved aesthetics  Improved emotional and psychological wellbeing Harvard success criteria The dental implant must provide functional service for 5 years in 75% of cases
  67. 67. Objective criteria  Bone loss no greater than 33% of vertical length of implant  Gingival inflammation amenable to treatment  Mobility of less than 1mm in any direction  Absence of symptoms of infection  Absence of damage to surrounding structure  Healthy connective tissues
  68. 68. Possible criteria for success  Mobility  Peri-implant radiolucency  Marginal bone loss  Sulcus depth  Gingival status  Damage to adjacent teeth  Violation of maxillary sinus , mandibular canal or floor of nasal cavity  Appearance  Length of service
  69. 69. Condition for application of criteria  Only osseointegrated implants should be evaluated with these criteria.  The criteria apply to individual endosseous implants.  At the time of testing, the implants must have been under a functional load.
  70. 70.  Implants that are beneath the mucosa and in a state of health in relation to the surrounding bone should preferably not be included in the evaluations but reported as complications.  Complications of an iatrogenic nature that are not attributable to a problem with material or design should be considered separately when computing the percentage of success
  71. 71. Revised criteria - Albrektsson  Individual implant is immobile clinically  No evidence of peri-implant radiolucency is present as assessed on an undistorted radiograph.  Mean vertical bone loss is less than 0.2 mm annually after the first year of service.
  72. 72.  No persistent pain, discomfort, or infection is attributable to the implant.  Implant design does not preclude placement of a crown or prosthesis with an appearance that is satisfactory to the patient and dentist.  By these criteria, a success rate of 85% at the end of a 5-year observation period and 80% at the end of a 10 year period are minimum levels for success.
  73. 73.  Drago et al anterior maxilla-89.1% posterior maxilla-71.4% anterior mandible-96.7% posterior mandible-98.7% Success rate
  74. 74. Moy et al – maxilla-91.8% mandible-95.1% Bass et al – maxilla-93.4% mandible-97.2%
  75. 75. 5-year survival  conventional tooth-supported FDPs of 93.8%  cantilever FDPs of 91.4%  solely implant supported FDPs of 95.2%  combined tooth-implant-supported FDPs of 95.5%  implant supported SCs of 94.5% FDP vs Implants
  76. 76. After 10 years of function –  89.2% -conventional FDPs  80.3% -cantilever FDPs  86.7%- implant-supported FDPs  77.8% - combined tooth-implant-supported FDPs  89.4% - implant-supported SCs  Technical complications were (fractures of the veneer material, abutment or screw loosening and loss of retention)
  77. 77. Methods of evaluation of Osseointegration
  78. 78.  Stability is a requisite characteristic of osseointegration.  Initial stability is a function of the Bone quality, Implant design and Surgical technique.  During the osseointegration healing and maturation process , the initial stability changes with increases in bone- to –implant contact and osseous remodeling.
  79. 79. Invasive Methods  Histological sections (10 microns sections)  Histomorphometric – To know the percentage of bone contact  Transmission electron microscopy  By using Torque gauges
  80. 80. Non-Invasive Methods  Percussion test  Tapping with a metallic instruments Ringing sound- osseointegrated. Dull sound - fibrous integration.  Radiographs
  81. 81.  Reliable method to determine implant stability  Emg driven and electronically controlled tapping head that hammers an object at a rate of 4 times/sec Periotest
  82. 82.  Response to striking is measured by a small accelerometer present in head  Signals converted to periotest value  Depends on damping characteristic of tissues surrounding teeth or implant
  83. 83.  Developed by Aoki and Hirakawa  Mech is similar to periotest  Microphone used as receiver and signals transferred is processed by FFT for analysis Dental mobility checker
  84. 84.  Non invasive can be performed at any stage of healing  Bite wing-measure crestal bone level  1.5 mm of CBL can be expected in the Ist year of loading with 0.1 mm of subsequent annual bone loss Radiographic evaluation
  85. 85.  Problems Difficult for clinician to detect changes at 0.1mm resolution Can be measured when central ray of x-ray is perfectly ll with the structure of interest
  86. 86.  Excellent method to assess health of natural teeth  In implants little diagnostic value unless accompanied by signs & symptoms  Stable implants pocket depth- 2-6mm  Indicate bone loss but not necessarily disease  Sulcus depth greater than 5-6 mm-risk of anaerobic bacterial infection Probing depth
  87. 87.  Suggested by James, modified by Misch  Group I  Group II  Group III  Group IV Misch CE, Perel ML, Wang HL, et al. Implant success, survival, and failure: The International Congress of Oral Implantologists (ICOI) Pisa Consens Conference. Implant Dent 2008;17:5-15. Implant quality of health scale
  88. 88.  No pain or tenderness upon function  0 Mobility  Less than 2.0 mm crestal bone loss from initial surgery  No history of exudate Group I (Success)
  89. 89.  No pain on function  0 mobility  Crestal bone loss – 2 to 4 mm  No history of transient exudate  Prognosis good to very good Group II (survival-satisfactory health)
  90. 90.  Slight to moderate peri-implantitis  Sensitivity on function  Radiographic bone loss > 4 mm (<1/2 of implant body)  No mobility (IM-O)  Probing depth >7 mm  May have exudates history Group III (Survival-compromised health)
  91. 91.  Implant removed  Pain  mobility  Uncontrolled progressive bone loss;  Uncontrolled exudate  50% bone loss  surgically removed/ exfoliated Group IV (clinical or absolute failure)
  92. 92. Rigid fixation Scale Description 0 Absence of clinical mobility with 500g in any direction 1 Slight detectable horizontal movement 2 Moderate visible horizontal mobility up to 0.5 mm 3 Sever horizontal movement greater than 0.5 mm 4 Visible moderate to sever horizontal and any visible vertical movement
  93. 93.  Cutting Torque resistance analysis (CRA)  Reverse Torque test (RTV)  Resonance Frequency analysis (RFA) Other methods
  94. 94.  Johansson and strid and improved by Friberg et al  Energy required for a current fed electric motor in cutting off a unit volume of bone during surgery is measured.  Energy is correlated with bone density which influences the implant stability Cutting Torque resistance analysis (CRA)
  95. 95.  Torque guage-in drilling unit measures the insertion torque in Ncm, gives idea about the bone quality  Gives more objective assessment than clinician dependent evaluation
  96. 96. Advantages a. Detect bone density b. Identify bone density during surgery c. Can be used in daily practice Disadvantages a. can only be used during surgery b. longitudinal data cannot be collected to assess bone quality changes after implant placement
  97. 97.  Measures the ‘critical’ torque threshold where bone-implant contact (BIC) was destroyed  Removal Torque value (RTV)-indirect measurement of BIC/clinical osseointegration Reverse Torque test (RTV)
  98. 98.  Ranges from 45-48 Ncm  RTV >20 Ncm accepted as criteria for successful osseointegration  Varies depending on bone quality & quantity
  99. 99. Disadvantages a. RTV only provide information as to “all or none” outcome b. Mainly used in experiments
  100. 100.  Non invasive method that measures implant stability & bone density at various time points  RFA utilizes a small L-shaped transducer that is tightened to implant or abutment Resonance Frequency analysis (RFA)
  101. 101.  Transducer comprises of 2 piezoceramic elements  One for vibration, and other serves as a receptor for the signal  Resonance peaks from the received signal indicates the first RF of the measured object
  102. 102.  Earlier hertz was used as measurement unit now implant stability quotient (ISQ)  RF values ranging from 3500-8500 Hz translated into ISQ of 0-100
  103. 103.  Higher value-greater stability  Low value-instability  Successful implant-ISQ >65  ISQ <50 indicates potential failure/increased risk of failure
  104. 104.  RFA can only give information regarding success cannot provide information with respect to survival or failure.  ISQ is fairly reliable when implant has achieved osseointegration & the B-I interface is rigid.  ISQ tends to fluctuate when the interface is not rigid
  105. 105. References  Misch CE. Contemporary implant dentistry, 3rd edition, Mosby Elsevier publication, St Louis, 2008, pp:27, 70, 621  Hobkirk JA, Watson RM, Searson LJ. Introducing dental implants, 1st edition, Churchill Livingstone, London, 2003 pp:3 – 18  Smith DE, Zarb GA, Criteria for success of osseointegrated endosseous implants, J Prosthet Dent 1989;62:567-72
  106. 106.  Masuda T, Yliheikkilä PK, Felton DA, Cooper LF. Generalizations Regarding the Process and Phenomenon of Osseointegration. Part I. In Vivo Studies. Int J Oral Maxillofac Implants 1998;13:17–29  Esposito M, Hirsch JM, Lekholm U, Thomsen P, Biological factors contributing to failures of osseointegrated oral implants (I). Success criteria and epidemiology. Eur J Oral Sci 1998; 106: 527–551  Sadhvi KV. Implant surface characteristics – a review – Part I. Trends in prosthodontics and implantology 2011;2(2):45-48
  107. 107.  Davies JE. Understanding Peri-Implant Endosseous Healing. J Dent Edu 2005;67(8):932-949  Pye AD, Lockhart DEA, Dawson MP, Murray CA, Smith AJ. A review of dental implants and infection. J Hospital Infection 2009; 72:104-110  López AB, Martínez JB, Pelayo JL, García CC, Diago MP. Resonance frequency analysis of dental implant stability during the healing period. Med Oral Patol Oral Cir Bucal. 2008;13(4):E244-7.
  108. 108.  Palmer R. Introduction to dental implants. Brit Dent J 1999;187(3) 14:127-132  DeLuca S, Habsha E, Zarb GA. The effect of smoking on osseointegrated dental implants. Part I: implant survival. Int J Prosthodont 2006;19(5):491-8  Ehrenfest D M D, Coelho P, Kang B, Sul Y and Albrektsson T.Classification of osseointegrated implant surfaces: materials, chemistry and topography. Trends in Biotechnology  Osseointegration.ppt
  109. 109.  Pjetursson BE et al, Comparison of survival and complication rates of tooth-supported fixed dental prostheses (FDPs) and implant-supported FDPs and single crowns (SCs), Clin. Oral Impl. Res, 2007:97–113  Misch CE et al. Implant Success, Survival, and Failure: The International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference. Implant Dent 2008;17:5–15
  110. 110.  Atsumi M et al, Methods used to Assess implant stability: current status, Int J Oral Maxillafac Implants 2007;22:743-54  http://www.ecf.utoronto.ca/~bonehead/

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