Osseointegration of dental implants

1. OSSEOINTEGRATION
DR. THASLIM FATHIMA
DEPARTMENT OF PERIODONTOLOGY

2. CONTENTS
Introduction
Historical Review
Definitions
Mechanism & Biology of osseointegration
Fibrointegration Vs Osseointegration
Key factors responsible for successful
osseointegration
Success criteria of implants
Clinical evaluation of osseointegration
Failure of osseointegration
Future Directions
Conclusion
References

3. INTRODUCTION
A successful replacement of missing natural tooth by dental implant
supported prosthesis is a major clinical advance in dental science.
The successful outcome of the treatment depends upon the degree of
Osseointegration.
The concept of osseointegration has undergone a most extensive
understanding and research.
An implant is considered as osseointegrated when there is no progressive
movement between the implant and the bone surface.
OSTEON INTEGRARE
OSSEOINTEGRATION

4. DEFINITIONS
P.I. Branemark
“A direct structural and functional connection between ordered living bone and the
surface of a load carrying implant”.
American academy of implant dentistry
“Contact established without interposition of non bone tissue between normal
remodeled bone and on implant entailing a sustained transfer and distribution of load
from the implant to and within bone tissue”.

5. Zarb & albrektsson 1991
“Osseointegration is a process whereby clinically asymptomatic rigid fixation of
alloplastic materials is achieved and maintained in bone during functional loading.”
Schroeder et al.
Functional ankylosis: To describe the rigid fixation of the implant to the jaw bone, and
stated that “new bone is laid down directly upon the implant surface, provided that the
rules for atraumatic implant placement are followed and the implant exhibits primary
stability”.

6. HISTORICAL REVIEW
• 4000 years ago- China, carved bamboo pegs were used to replace missing teeth
• 3000 years- Egyptian king had a copper peg hammered into his upper jaw bone
• 2300-year- old iron tooth was recently found among real teeth in a celtic grave in
France.

7. During Mayan civilization, jaw with three carved, tooth-shaped
shells in the lower jaw of a human’s remains.
Bone structure around the shell showed signs of regeneration.

8. • Osseointegration was first observed in animals by Bothe, Beaton, and Davenport in 1940---
• In 1941, Swedish doctor - Gustav Dahl placed a metal structure below the periosteum
• Gottlieb Leventhal in 1951 placed titanium screws in rat femurs.
• Leonard I. Linkow - introduced a self-tapping titanium implant in 1964.

9. • Dr. Andre Schroeder - in-growth of bone into titanium plasma-sprayed endosseous implants.
• Professor Willi Schulte - success with immediate placement of vitreous carbon implants after
dental extraction.

10. Per Ingvar Brånemark
SWEDEN
Father of Modern Implantology
1952

11. Branemark named this phenomenon as
"osseointegration," and saw the possibilities
for human use.

12. • He and his team investigated the working and structure of human blood cells under a number of
conditions.
• This work yielded a great deal of information about the nature of blood.
• Titanium serving as lens casings appeared uniquely compatible with the human soft tissue and skin.
• No adverse immunological reactions.

13. • Branemark and his team - designed titanium screws and inserted them into the jaws of
beagle dogs
• By 1965 - felt ready to apply his findings to human patients.

14. Gösta Larsson (1931–2006) was the first recipient ever of
a modern dental implant, which occurred in 1965
o Larsson, a Swede who was edentulous at the time and had
been born with severe chin and jaw deformities, agreed to
the test because he wanted to have teeth again.[17] He
died in 2006, having used his implants for over 40 years
Branemark began training the first Swedish dental
experts in his techniques in October 1977.

15. Schroeder -
published his first
paper on bone -
anchored oral
implants in 1976.
Schulte -
published clinical
results for his
aluminum oxide
implants in the
late 1970s.
International
acceptance
followed the
Toronto
conference held in
1982…
(Schroeder 1982)
In sweden,
osseointegrated
implants became
acceptable in
1977 (Branemark
PI 1977)

16. DISCOVERY OF TITANIUM
• Titanium was first identified by a Cornish cleric, William Gregor in 1790 at Corn wall in
Germany.
• Originally called the new element as menaccine or menaccanite. but later in 1795, Klaproth
identified an element which he named “titanium.”
• Van Arkel refined the Ti ore in 1925.
• Krol developed commercial extraction procedures in 1930.

17. Metals and Alloys
The major groups of implantable materials
in dentistry are:
• Titanium and alloys
• Cobalt chromium alloys
• Austenitic Fe-Cr-Ni-Mo steels
• Other metals and alloys

18. MECHANISM OF OSSEOINTEGRATION
Inflammatory
phase
Proliferative
phase
Maturation
phase

19. INFLAMMATORY PHASE
• Vascular events: When platelets come in contact with synthetic surfaces, they release
serotonin and histamine causing further platelet aggregation and thrombosis.
• Cellular events: It is non-specific in the beginning consisting majorly of neutrophils that peak
during 3 to 4 days of surgery but towards the end of the first week, the generalized
inflammatory response becomes more specific in nature consisting majorly of increasing
numbers of thymus dependent lymphocytes (T cells), B cells, killer (K) cells, natural killer (NK)
cells and macrophages.

20. PROLIFERATIVE PHASE
• During this phase, vascular ingrowth occurs from the surrounding vital tissues, a process
called neovascularization.
• Metabolism of the local inflammatory cells, fibroblasts, progenitor cells and other local cells
creates an area of relative hypoxia in the wound area which triggers the local mesenchymal
cells to differentiate into fibroblasts, osteoblasts and chondroblasts.
• An extracellular matrix is laid down by these cells and eventually a fibro-cartilaginous callus
is formed that transforms to bone callus.
• The initial immature bone is called the woven bone.

21. MATURATION PHASE
• Appositional woven bone is laid down on the scaffold of necrotic bone in the peri-implant space
that resulted from operative trauma by differentiated mesenchymal cells in the advancing
granulation tissue mass.
• This process occurs concurrently with the ossification of the fibrocartilaginous callus noted
previously.
• Simultaneous resorption of these “composite” trabeculae and the newly formed bone, coupled
with the deposition of mature concentric lamellae eventually results in complete bone remodeling,
leaving a zone of living lamellar bone that is continuous with the surrounding basal bone.

22. TISSUE RESPONSE TO IMPLANTATION
• Bone healing around implants involves a cascade of cellular and extracellular biological
events that take place at the bone-implant interface until the implant surface appears
finally covered with a newly formed bone.
• These biological events include the activation of osteogenetic process similar to those of
the bone healing process.
• This cascade of biological events is regulated by growth and differentiation factors released
by the activated blood cells at the bone-implant interface.

23. • The host response after implantation is modified by the presence of the implant and its
characteristics, the stability of the fixation and the intraoperative heating injuries that include
death of osteocytes extending 100-500 micrometer into the host bone.
• Major stages of skeletal response to implantation-related injury after insertion and
mechanical fixation of cementless implants include hematoma formation and mesenchymal
tissue development, woven bone formation, and lamellar bone formation on the spicules of
woven bone.

24. BLOOD
• The first biological component to come into contact with an endosseous implant is blood.
• The blood cells entrapped at the implant interface are activated and release cytokines and other
soluble, growth and differentiation factors
• Blood cells including red cells, platelets, and inflammatory cells such as PMNLs and monocytes
emigrate from postcapillary venues and migrate into the tissue surrounding the implant.
• Initial interactions of blood cells with the implant influence clot formation.

25. CLOT FORMATION
• Osteogenic cells form osteoid tissue and new trabecular bone, eventually remodels into
lamellar bone in direct contact with most of the implant surface (OI).
• Osteoblasts and mesenchymal cells migrate and attach to the implant surface from day one
after implantation, depositing bone-related proteins and creating a noncollagenous matrix
layer on the implant surface that regulates cell adhesion and binding of minerals..
• Platelets undergo morphological and biochemical changes as a response to the foreign surface
including adhesion, spreading, aggregation, and intracellular biochemical changes such as
induction of phosphotyrosine, intracellular calcium increase, and hydrolysis of phospholipids.

26. PERI-IMPLANT OSTEOGENESIS
• Peri-implant osteogenesis can be in distance and in contact from the host bone.
• The newly formed network of bone trabeculae ensures the biological fixation of the implant
and surrounds marrow spaces containing many mesenchymal cells and wide blood vessels.
• A thin layer of calcified and osteoid tissue is deposited by osteoblasts directly on the implant
surface. Blood vessels and mesenchymal cells fill the spaces where no calcified tissue is
present .

27. • Murai et al… the first to report a 20-50 mm thin layer of flat osteoblast-like cells,
calcified collagen fibrils and a slight mineralized area at a titanium implant-bone interface.
• The newly formed bone was laid down on the reabsorbed surface of the old bone after
osteoclastic activity.
• This suggested that the implant surface is positively recognizable from the osteogenic cells as
a biomimetic scaffold which may favour early peri-implant osteogenesis.

28. Early deposition of new calcified matrix on the implant surface.
Arrangement of the woven bone and bone trabeculae.
Appropriate for the periimplant bone healing process as it shows a very active wide surface area,
contiguous with marrow spaces rich in vascular and mesenchymal cells.
Woven and trabecular bone fill the initial gap at the implant-bone interface.
Woven bone is progressively remodeled and substituted by lamellar bone that may reach a high
degree of mineralization
At 3 months post-implantation, a mixed bone texture of woven and lamellar matrix can be found around
different types of titanium implants

30. IMPLANT-BONE INTERFACE
• The American Academy of Implant Dentistry (1986) defined fibrous integration as “tissue-to-implant
contact with healthy dense collagenous tissue between the implant and bone”
• This concept of Fibro-osseous integration was supported by Linkow (1970), James (1975), and Weiss
(1986)
• The role of osseointegration in bone healing was first described by Strock as early as 1939 and more
recently by Branemark et al in 1952

31. • Meffert et al (1987) redefined and subdivided osseointegration into:
- Adaptive osseointegration.
- Biointegration.

32. THEORIES REGARDING BONE TO IMPLANT
INTERFACE
1. Concept of soft tissue anchorage:
FIBRO-OSSEOUS INTEGRATION
Linkow (1970), James (1975), Weiss (1986).
Fibro-osseous ligament formed between the implant and the bone.
Hypothesis – collagen fibers function similar to Sharpey's fibers in the natural
dentition

33. The American Academy of Implant Dentistry (1986) Defined fibrous integration as “tissue-to-implant contact
with healthy dense collagenous tissue between the implant and bone”
Drawbacks:
- The fibers are arranged irregularly, parallel to the implant body.
- When forces are applied they are not transmitted through the fibers.
- No bone remodeling expected.

34. 2. Concept of bony anchorage:
OSSEOINTEGRATION, Branemark (1969)

35. OSSEOINTEGRATION (BRANEMARK):
• Direct connection between living bone and a load carrying endosseous implant at
the light microscopic level.
Unlike fibro-osseous integration, osseointegration was able to distribute vertical and slightly inclined
loads more equally in to surrounding bone.

36. TWO COMPONENTS OF OSSEOINTEGRATION:
Adaptive osseointegration:
- Depends on geometrical profile of implant (screws, threads, grooves)
Bio-active osseointegration:
- Active process depending on chemical nature of implant surface.
Meffert et al (1987)

37. Osseointegration occurs in 3 phases:
1. Osteophyllic phase
2. Osteoconductive phase
3. Osteoadaptive phase
PROCESS OF OSSEOINTEGRATION

38. OSTEOPHYLLIC PHASE
Osteoprogenitor cells
from the bone marrow
and the endocortical
and periosteal bone
envelopes migrate into
the site attracted by
chemotaxis.
Vascular ingrowths from
surrounding later
developing into more
matured vascular
network
Cellular differentiation,
proliferation and
activation begins
Migration of osteoblasts Ossification begins Lasts about 1 month

39. OSTEOCONDUCTIVE PHASE
Bone cells spread along the metal surface
Laying down of osteoid
This fibro cartilaginous callus eventually remodeled into
Bone callus
Maximum surface area of implant covered by bone

40. OSTEOADAPTIVE PHASE
After 3-4 months
Remodeling occurs
The woven bone thickens in response to load transmission
Reorientation of vascular pattern

41. STAGES OF OSSEOINTEGRATION
MISCH

42. • Osteogenic cells line the old bone surface which now provide a community of
osteogenic cells that lay down a new matrix that impinges on the implant.
• The blood supply to these cells is between the cells and the implant.
• Hence the bone is laid down on the old bone surface in peri-implant site.
1. DISTANCE OSTEOGENESIS:
BONE TISSUE RESPONSE
OSBORN AND NEWESLEY (1980)

43. 2. CONTACT OSTEOGENESIS:
• Osteogenic cells are first recruited to the implant surface and new bone (de novo ) forms first
on the implant surface.
• The blood supply is between the cells and old bone,

44. OSSEOINTEGRATION / OSSEO-COALESCENCE
Osseointegration: physical integration or mechanical fixation of an implant in bone.
Osseo-coalescence: chemical interaction between the bone and surface of an implant.
The term refers to calcium phosphate and bioactive glasses which undergo reactions that lead
to chemical bonding.

45. FACTORS AFFECTING OSSEO-INTEGRATION
Albrektsson et al. (1981)
Implant material biocompatibility
Implant design.
Implant surface characteristics
Surgical technique
Status of the host bed
Loading conditions

46. IMPLANT DESIGN CHARACTERISTICS
• 3-D structure of the implant.
• Form, shape, configuration, geometry, surface macro structure, macro irregularities.
Bone resorption has been associated with the use of press fit or cylindrical implants primarily due to
micromovements that occur during their use.

47. THREADED IMPLANTS
Alteration in the design, size and pitch of threads
Advantages:
- A threaded implant provides immediate fixation and dissipation of
stresses to resist functional forces long term when in cortical bone.
- Threads improve the primary implant stability.
- Avoids micro movement of the implants till osseointegration is
achieved.

48. SURFACE TOPOGRAPHY
Degree of roughness of the surface -
1. Isotropic surface
2. Anisotropic surface
Advantages of increased surface roughness:
 Increased surface area of the implant adjacent to bone.
 Improved cell attachment to the implant surface.
 Increased bone present at the implant surface.
 Increased biomechanical interactions of the implant with bone.

49. TYPES OF COMMERCIALLY AVAILABLE TI SURFACES:
1. Turned surface/ machined surface:
Flank with marks
II. Blasted surface – tio2 / al2o3 particles :
Isotropic surface with fine irregularities

50. Acid etch surface - HCl and H2SO4
 Fine irregularities with pronounced isotropy
Blasted + acid etched surface (Al2o3 particles & hcl and H2SO4))
 Pronounced pits
 High frequency irregularities
 Oxidized surface
 Lots of pores, increases surface area

51. Hydroxyapatite coated surface
 Increased average height deviation &short average
wavelength
Titanium plasma sprayed surface
 Some areas are smooth, others very rough.

52. Advantages of moderately rough surface:
• Faster osseointegration, retention of the fibrin clot, osteoconductive scaffold, osteoprogenitor
cell migration.
• Increase rate and extent of bone accumulation contact osteogenesis.
• Increased surface area renders greater osteoblastic proliferation, differentiation of surface
adherent cells.
Disadvantages:

53. Roughness parameter
0.04 –0.4 m - smooth
0.5 – 1.0 m – minimally rough
1.0 –2.0 m – moderately rough
>2.0 m – rough
• Surfaces smoother than 0.2µm will have no osteoblast adhesion thus also leading to
failure. (Wennerberg 1996)

54. TECHNIQUES USED TO COAT METALLIC IMPLANTS WITH HA
Plasma spraying:
Involves heating the HA by a plasma flame at a temperature of approximately 15,000° C to
20,000°C.
The HA is then propelled onto the implant body in an inert environment like argon, to a
thickness of 50 to 100 μm.
Ion-sputter coating:
Directing an ion beam at a solid-phase HA block, vaporizing it to create plasma - recondensing
this plasma on the implant .
 Bone formation and maturation - a faster rate in the initial phases on HA-coated implant

55. Disadvantages of additive surfaces:
Flaking, cracking, or scaling upon insertion.
Increased plaque retention when placed above the bone.
Increased bacteria adhesion and acts as a nidus for infection.
Complications of treating the failing implants.

56. ANCHORAGE MECHANISM / BONDING MECHANISM IN
OSSEOINTEGRATED IMPLANTS
Biomechanical bonding
In-growth of bone into small surface irregularities - three
dimensional stabilization.
Seen in machined/turned screw implant & blasted/acid etch surface.
Biochemical bonding
Bioactive implant surfaces -calcium phosphate coated implant
surfaces, HA coated implant surfaces
Oxidized/ anodized surfaces

57. Doped surfaces:
Contain various types of bone growth factors or
other bone-stimulating agents.
Studies have shown 2% Silver-doped HA surfaces have similar osteoconductive activity when
compared to HA and Ti surfaces. Also, doping of HA with Silver minimized the adhesion of bacteria
on its surface.

58. BONE FACTOR
• Bone quality: Bone with well formed cortex and densely trabaculated medullary
spaces.
• Bone quantity: Refers to the dimension of available bone in reference to length, width
and depth.

59. LEKHOM AND ZARB CLASSIFICATION 1985
Class I: Jaw consist almost exclusively of homogeneous compact bone.
Class II: Thick compact bone surrounds highly trabecular core.
Class III: Thin cortical bone surrounds highly trabecular core.
Class IV: Thin cortical bone surrounds loose, spongy core.

60. MISCH CLASSIFICATION 1988
D1 D2 D3 D4

61. 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.
Jaffin and Berman (1991)
– 44% failure in type IV bone.
• D1 and D2 – conventional threaded implants.
• D3 and D4 – ha coated or titanium plasma coated implants.

62. INFLUENCE OF SURGICAL PARAMETERS:
Minimum tissue violence which will favor optimum osseointegration.
• Controlled surgical technique
• Surgical skill / technical excellence
• Profuse irrigation for continuous / adequate cooling
• Use of well sharpened drills and use of graded series of drills
• Slow drill speeds
• Proper drill geometry
• Intermitent drilling

63. IMPLANT LOADING
Immediate loading: When implants are placed in good quality bone (anterior mandible).
If the implant moves during the early period of healing, a fibrous connective tissue capsule
develops around the body of implant.
Delayed loading: Healing period be respected both in duration and in avoidance of any
transmitted load.
The natural wound healing processes are harnessed and respected.

64. Implant placement on extraction socket:
Another primary advantage of immediate implant placement is reduced healing time.
When implant is placed at the time of extraction, the bone to implant healing begins
immediately.
In this type of bone forming activity - the bone to implant contact is compared with an
implant placed in a less ostegenically active site.

65. PATIENT
FACTORS
• Age.
• Previous irradiation - It has been seen that success rates are 10- 15%
lesser in irradiated patients as opposed to non-irradiated patients.
• History of smoking - Mean failure rates are twice as high in smokers as
in non-smokers.

66. SURGICAL CONSIDERATIONS
• Technique.
• Use of well-sharpened drills should be highlighted.
• Adequate cooling should be allowed.
• Slow drill speed (less than 2000 rpm and tapping at a speed of 15 rpm with irrigation).
• A moderate power used at implant insertion.
Loading conditions: Premature loading may cause soft tissue anchorage and poor long-term
function, while postponing the loading by using a two-stage surgery often results in better bone
healing and a positive long-term function.

67. SUCCESS CRITERIA OF IMPLANTS
• The mobility of the implant must be less than 1 mm when tested clinically.
• There must be no evidence of radiolucency.
• Bone loss should be less than 1/3rd of the height of the implant.
• Absence of infection, damage to structure or violation of body cavity.
Inflammation present must be amenable to treatment.
• The success rate must be 75% or more after 5 years of function.
Schnitman and Schulman criteria (1979)

68. • The individual unattached implant should be immobile when tested clinically.
• The radiographic evaluation should not show any peri-implant radiolucency.
• Vertical bone loss around the fixtures should be less than 0.2 mm annually after first year
of implant loading.
• The implant should not show any sign and symptom of pain, infection, neuropathies,
paresthesia, violation of mandibular canal and sinus drainage.
• Success rate of 85% at the end of 5 year observation period and 80% at the end of 10 year
service
(Albrektson and zarb 1980)

70. FAILURE OF OSSEOINTEGRATION
Local risk factors.
Systemic risk factors.

71. METHODS OF EVALUATION OF OSEOINTEGRATION
Non-invasive methods
• Percussion test: An osseointegrated implant makes a ringing sound on percussion whereas an
implant that has undergone fibrous integration produces a dull sound.
• Radiographs
• Reverse torque test: A reverse or unscrewing torque is applied to assess implant stability at the
time of abutment connection. Implants that rotate under the applied torque are considered
failures and are then removed.

72. RFA
Proposed by Meredith et al. (1996).
is a method used to determine stability (the level of osseointegration) in dental
implants.
The stability is presented as an implant stability quotient (ISQ) value.
The higher the ISQ value the higher the stability.
Utilizing RFA involves sending magnetic pulses to a transducer that is temporarily
attached to the implant. As the rod vibrates, the probe reads its resonance frequency
and translates it into an ISQ value.
This technique uses – hand held frequency response analyzer.
Transducer – screwed directly to implant body & shakes the implant –
starting at a low frequency & increasing in pitch until implant resonates.

73. PERIOTEST
• Noninvasive device used to monitor the implant stability.
• Quantifies the mobility of an implant – measuring the reaction of peri-implant tissues to a defined
impact load.
• Handpiece – electronically controlled translational hammer bearing an 8-gram rod with a sensor
at its tip.
• When activated – rod tapes implant abutment upto 16 times in 4 sec.
• Rod decelerate – touches the implant & accelerate – rebounds off the implant.

74. • Measures the elapsed time – from initial contact to the first rebound off the implant.
• Greater the implant stability – shorter the elapsed time.
• Software – convert these milliseconds into periotest values (ptv).
0 mobility - 0.4 – 0.5 sec
-8 to +4 - 0.65 sec (palpable movement)
+4 - +9 - high failure rate

75. FUTURE DIRECTION
• Direct bone anchorage of prosthetic teeth provides the patients with an increased sensory
perception capacity.
• Similar discriminatory capacity has also been observed in limb prosthesis.
• The interaction between the osseointegrated fixture bone tissue, receptor systems & nervous
system has to be studied.

76. CONCLUSION

77. REFERENCES
Jan lindhe “clinical periodontology and implant dentistry” 4th edition, blackwell publishing
Carranza’s clinical periodontology – 10th edition.
Carl e. Misch “implant dentistry” 2nd edition, mosby
Osseointegration- Key Factors Affecting Its Success-An Overview Dr. Naveen Reddy Vootla1,Dr. K.
Varun Reddy
Methods Used to Assess Implant Stability: Current Status Mihoko Atsumi et al int j oral maxillofac
implants Charles babbush “dental implants the art and science”
Per ingvar branemark “osseointegration and its experimental background” JPD 1983;50, 399-410
Hanson, albrektson “structural aspects of the interface between tissue and titanium implants” JPD 1983
vol. 50, 108-113.
Periodontology 2000; 1994: 58-73
Periodontology 2000; vol. 17, 1998, 22-35.
Periodontology 2000, val. 17, 1998, 7-21.
Jada 2002; 133:483-490.

78. THANK YOU