Osseointegration is the base of implant dentistry. Here I have included the basics, mechanism, factors affecting and evaluation of osseointegration.

1. OSSEOINTEGRATION - PART II
Dr Heenal Adhyaru
Seminar No: 15

2. CONTENT
 INTRODUCTION
 DEFINITIONS
 BONE PHYSIOLOGY
 TISSUE RESPONSE
 MECHANISM OF OSSEOINTEGRATION
 FACTORS AFFECTING OSSEOINTEGRAION
 DESIGN CHARACTERISTICS
 IMPLANT SURFACE
 BONE DENSITY
 SURGICAL TECHNIQUE
 EVALUTION OF OSSEOINTEGRATION
 CONCLUSION
2

3. CALCIUM METABOLISM
 Regulation of bone by systemic hormones
 Parathyroid hormone
 1, 25- dihyroxy vitamin D3
 Calcitonin
 Estrogens
3

4. 4

5. BONE PHYSIOLOGY
5
 The coupling theory is based on the observation that once
resorption occurs, osteoblast respond by making more bone
matrix.
 Resorbing bone produces factors that influence the rate and
extent of osteoblastic activity.

6. FACTORS REGULATING BONE FORMATION
FACTORS REGULATING BONE
RESORPTION
 Platelet Derived Growth
Factor
 Insulin-like Growth Factor
 Transforming Growth Factor
ß
 Bone Morphogenetic Protein
 Fibroblast Growth Factor
 Interleukin 1 & 6
 Tumor Necrosis Factor
 Colony-stimulating factor
 Prostaglandins
6

7. 7

8. FACTORS AFFECTING OSSEOINTEGRATION
 Design characteristics
 Implant surface
 Bone density
 Surgical technique
9

9. PRIMARY AND SECONDARY STABILITY
 Implant stability can occur at two different stages:
 Primary stability
 Secondary stability
 Primary stability is associated with the mechanical
engagement of an implant with the surrounding bone
 Secondary (biological) stability is associated with the bone
regeneration and remodeling phenomena.
10

10. 11
Factors affecting implant
stability
Factors influencing
primary stability
Bone quality
and quantity
Surgical
technique
Implant design
Factors influencing
secondary stability
Primary
stability
Bone
remodeling
Implant surface
condition

11.  Ilser T et al. in a study mentioned that the factors affecting
the primary implant stability can be divided into:
1. Patient-related (bone volume and quality)
2. Procedure-dependent parameters
 Type of implant
 Type of surgical procedure
12

12. BONE DENSITY
 Remodeling is a process of resorption and formation at the
same site that replaces previously existing bone and
primarily affects the internal turnover of bone, including that
region where teeth are lost or the bone next to an endosteal
implants.
 These adaptive phenomenon is associated with the
alteration of the mechanical stress and strain environment
within the host bone. (Currey et al. 1984)
 Stress is determined by the magnitude of force divided by
the functional area over which it is applied.
 Strain is defined as the change in length of a material
divided by the original length.
13

13.  The greater the magnitude of stress applied to the bone, the
greater the strain observed in the bone. (Bidez et al. 1992)
 Bone modeling and remodeling are primarily controlled by
the mechanical environment of strain.
14

14. 15

15.  The initial bone density
 Provide mechanical immobilization of the implant during
healing.
 After healing permits distribution and transmission of
stresses from the prosthesis to the implant bone
interface.
 The mechanical distribution of stress occurs primarily where
bone is in contact with the implant.
 The bone implant contact percent may influence the amount
of stress /strain at the interface.
 The bone-implant contact (BIC) percentage is significantly
greater in cortical bone than in trabecular bone.
16

16. Bo
ne
de
nsi
ty
Description Radiogr
aphic
(Hounsfi
eld units
-HU)
Tactile
analog
Typical
anatomical
location
Bone-implant
contact
D1 Dense
cortical
>1250 Oak or
maple
wood
Anterior
mandible
85%
D2 Porous
cortical
Coarse
trabecular
850-1250 White
pine or
spruce
wood
Anterior
mandible
Posterior
mandible
Anterior maxilla
65-75%
D3 Porous
cortical
Fine
trabecular
350-850 Balsa
wood
Anterior maxilla
Posterior maxilla
Posterior
mandible
40-50%
D4 Fine
trabecular
150-350 Styrofoa
m
Posterior maxilla <30%
18

17. SURGICAL TECHNIQUE
 Miyamoto et al. demonstrated that dental implant stability is
positively associated with the thickness of cortical bone
thickness.
 Surgical technique to improve the primary stability
 The use of a final drill diameter which is smaller than the
diameter of the implant. (Friberg B et al. 2001)
 Bone condensing: after using the pilot drill, the
cancellous bone is pushed aside with “condensers”
(osteotomes), thus, increasing the density of the
surrounding bone, increasing in that way the initial
implant stability. (Summer RB et al. 1994)
19

18.  The recommended protocol for immediate load is to insert
the implant with a torque of 45-60 Ncm. (Javed F 2010)
 Additional torque may result in pressure necrosis and
increase the strain magnitude at the interface and increase
amount of damage and remodeling which could decrease
strength of bone implant interface.
 Micromotions above 50–100 micrometers may negatively
influence osseointegration and bone remodeling by forming
fibrous tissues and inducing bone resorption at the bone-to-
implant interface. (Pilliar 1986)
20

19. IMPLANT DESIGN
 Stress is reduced by increasing the functional area over
which the force is applied.
 The surface area of the implant macrogeometry may be
increased to decrease stress to the implant bone interface.
 Macro design affects the magnitude of stresses and their
impact on the bone-implant interface.
 Micro design on implant body can increase the bone implant
contact percentage.
22

20. MACRODESIGN
23

21. 24
Thread pitch is the distance measured parallel between adjacent thread form
features of an implant.

22. MICRODESIGN
 The advantage of surface modified implants are that they:
1. Provided a better mechanical stability between bone and
implant immediately following installation — established by
a greater contact area
2. Provided a surface configuration that properly retained the
blood clot & stimulated the bone healing process
 Interaction of surface:
 Affects the attachment of fibroblasts and their
proliferation and differentiation
 Influence the production of local cell regulators e.g.
TGF-ß & PGE2
25

23.  Alteration of the
surface
 Subtractive process
 Electro-polishing
 Mechanical polishing
 Blasting
 Etching
 Oxidation
 Additive processes
 Hydroxylapatite (HA)
and other calcium
phosphate coatings
 Titanium plasma-
sprayed (TPS)
surfaces
 Ion deposition
26

24. TITANIUM PLASMA SPRAY
 Plasma sprayed implants are prepared by spraying molten metal
on the titanium base, which results in a surface with irregularly
sized and shaped valleys, pores and crevices.
 It increases the functional surface area by 25% to 30%.
 Advantage:
 Growth of the bone into the coating increases mechanical
interlocking
 Stimulate adhesion osteogensis
 Disadvantage:
 Detachment of titanium after implant insertion. (Franchi et al)
 BIC % was not significant compared turned surface (55.9%
compared to 56.2%) [Carr 2000]
27

25. SANDBLASTED SURFACES
 Sandblasting the metal core with gritting agents e.g.
aluminum oxide and TiO2 (25ɥm)
 Advantage:
 Allow adhesion, proliferation and differentiation of
osteoblasts
 Fibroblasts has limited adhesion and proliferation
 BIC % significantly greater than turned surface (31%-47%
compared to 18%-23%) [Wennerberg 1998]
28

26. ACID-ETCHED SURFACE
 Acid-etched surface is produced using baths of:
 Hydrochloric acid (HCl)
 Sulfuric acid (H2SO4)
 Nitric acid (HNO3)
 Hydrofluoric acid (HF)
 Dual acid etched technique produce a microtextured
surface.
 Advantage:
 Higher adhesion of platelet genes and higher expression
of extracellular genes (Park 2001)
 BIC % significantly higher in dual acid etched compared to
turned sites (62.5% compared to 39.5%) [Weng 2003]
29

27. SANDBLASTED AND ACID-ETCHED SURFACE
 Surface blasting produce macrotexture while acid etching
produce microtexture resulting in uniformly scattered gapes
and holes.
 BIC % significantly higher in sandblasted and acid etched
compared to turned sites (71.68% compared to 58.88%)
[Cochran 1998]
30

28. HYDROXYAPATITE
 A direct bone bond shown with HA coating and the
strength of the HA to bone interface is greater than
titanium to bone.
 Advantage:
 Increased surface area
 Faster healing bone interface
 Less corrosion of metal
 Disadvantage:
 Flaking, cracking on insertion
 Increased plaque and bacteria retention
 Increased cost
 Complication of treatment of failing implants
 BIC% significantly higher in HA compared to turned sites
(77.8% compared to 71.2% at 12 weeks) [Ong 2004]
31

29. BIOMATERIALS
32
 Biomaterials used for dental implants
1. Metals and alloys
 Titanium and Titanium-6 Aluminum-4 Vanadium (Ti-6Al-
4V)
 Cobalt-Chromium-Molybdenum based alloy
 Iron-chromium-Nickel based alloys
2. Ceramics and carbon
 Aluminum, Titanium and Zirconium oxide
3. Polymers and composites

30.  Osborn (1979) categorized this bio-response into the following
three groups:
 Biotolerant type:
 distance osteogenesis, surrounded by a fibrous connective
tissue.
 E.g. gold, cobalt-chromium alloys, stainless steel, polyethylene
and polymethylmethacrylate.
 Bioinert type:
 contact osteogenesis
 E.g. titanium and titanium alloys according to their surface
oxides.
 Bioreactive type:
 the implant allows new bone formation around itself,
 E.g. calcium phosphate layer.
33

31. 34
Metal oxidation

32. 36

33. TITANIUM ZIRCONIA
 Advantages:
 Biocompatibility
 High strength/weight ratio
 Corrosion resistance
 Easy shaping and finishing
 Alloy: Ti-6Al-4V
 Proteoglycan layer:
 200-400 A
 Advantages:
 Biocompatibility
 Corrosion resistance
 Esthetics
 Proteoglycan layer:
 300-500 A
37

34. 38

35. EVALUTION OF OSSEOINTEGRATION
39

36. PERIOTEST RESONANCE FREQUENCY ANALYSIS
 -8 to 0: good
osseointegration, can be
loaded
 +1 to +9: clinical
examination required,
implant cannot be loaded
 +10 to +50:
osseointegration is
insufficient.
 Implant Stability Quotient
(ISQ): 0-100
40

37. REFERENCES
41
 Najjar T. FONSECA: oral and maxillofacial surgery. Reconstructive and
Implant surgery
 Branemark PI. Tissue-integrated prosthesis: osseointegration in clinical
dentistry Chicago: Quintessence Publishing Co.; 1985.
 Ramazanoglu M. Osseointegration and Bioscience of Implant Surfaces -
Current Concepts at Bone-Implant Interface, Implant Dentistry- A
Rapidly Evolving Practice Turkyilmaz PI, editor.: Intech; 2001.
 Misch C. Contemporary Implant Dentistry, 3e. 3rd ed.; 2008.
 Friberg B. Branemark implants and osteoporosis: A clinical exploratory
study. Clin Implant Dent Relat Res 2001; 3: 50–56
 Summers RB. A new concept in maxillary implant surgery: The
osteotome technique. Compendium 1994; 15: 152
 Javed F. Role of primary stability for successful osseointegration of
dental implants: Factors of influence and evaluation. Interventional
Medicine & Applied Science 2013; 5 (4):162–167