Dental implants have a long history dating back thousands of years. Modern implantology began in the 1950s-60s when Branemark discovered titanium implants could bond irreversibly to bone, termed osseointegration. There are several types of implants but endosseous implants placed directly into the jawbone are most common. Osseointegration occurs in three stages - osteoconduction, de novo bone formation, and bone remodeling. Key factors for successful osseointegration include biocompatibility, implant design, surface, surgical technique, and loading conditions.

1. DENTAL IMPLANTS

2. HISTORY
• Dental implant history dates back thousands of years and
includes civilizations such as the ancient Chinese, who
4000 years ago inserted bamboo into the jaw bone for
fixed tooth replacements.
• The Egyptians and later physicians from Europe used
ferrous and precious metals for implants over 2000 years
ago, and the Incas used the pieces of sea shells to insert
in jaw bones to replace missing teeth.

3. • A dental implant is defined as shaping a foreign object
to a root and tooth crown form and placing it into an
empty socket or prepared osteotomy of the recipient..

4. The Birth of Modern Implantology
• The true birth of modern implantology, however, can be
found in the late 1950s and 1960s.
• Branemark discovered that the titanium had apparently
bonded irreversibly to the living bone tissue, an
observation which contradicted contemporary scientific
theory of the day..

5. • More importantly, he was able to demonstrate that this
could be achieved with a very high degree of
predictability and, without long-term soft tissue
inflammation, fibrous encapsulation or implant failure.
Branemark named the phenomenon osseointegration.

6. Types of Dental Implants
• Dental implants vary in several aspects, such as shape,
place of anchorage (within the bone or on top of the
bone), composition, coatings, etc.
• In general Oral Implants can be categorized into three
main groups:
– Endosseous Implants
– Subperiosteal Implants
– Transosseous Implants

7. • Endosseous Implants are implants that are surgically
inserted into the jawbone.
• Subperiosteal Implants are implants, which typically lie
on top of the jawbone, but underneath gum tissues. The
important distinction is that they usually do not penetrate
into the jawbone.

8. • Transosseous Implants are implants, which are similar
in definition to Endosseous implants in that they are
surgically inserted into the jawbone.

9. • Endosseous Implants are the most frequently used
implants today. They could be further categorized into
several sub-categories; based on their shape, function,
surgical placement and surface treatment.

10. Subperiosteal Implants
• You can see a typical
Subperiosteal implant for
the lower jaw. This
particular implant has a
whitish-gray
Hydroxyapatite coating
on its bone-contacting
portion.

11. Indications
• Usually a severely resorbed, toothless lower jaw bone,
which does not offer enough bone height to
accommodate Rootform Implants as anchoring devices.
• This implant is custom-made to each individual jaw.
Nowadays, a CT Scan is taken of the jaw and a
computerized modeling machine uses this data to
reproduce a three-dimensional plastic model of the jaw
to be treated.

12. x-ray of a fairly resorbed lower jaw image shows the same jaw with a
Subperiosteal implant in place

13. • After the implant has been
surgically inserted, only a bar
is visible extending from one
side of the lower jaw to the
other, onto which a denture can
be clipped via an internal
attachment mechanism.
• The denture can be made
approximately two weeks after
the surgery and is in general
smaller than a conventional
denture.

14. Endosseous Implants

15. • Bladelike
• Pins
• Cylindrical (hollow and full)
• Disklike
• Screw shaped

16. Blade implant
specifically
designed for the
back-most portion
of the lower jaw.
This implant offers
great anchorage in
that particular area
Custom-made
blade implant
specifically
designed for
the upper jaw
This implant was
specifically and custom-
designed for the lower jaw
of a patient. Notice the
difference in shape to the
upper-jaw implant. These
two implants also feature a
Hydroxyapatite coating

17. Indications
• where the residual bone ridge of the jaw is either too
thin (due to resorption) to place
• Nowadays, if a certain area of the jaw bone is too thin
and has undergone resorption due to tooth loss it is
recommended to undergo a Bonegrafting procedure,
which re-establishes the lost bone, so that conventional
Rootform Implants can be placed.

18. Here you can see an x-ray of a blade implant in place. An important
anatomical structure (mandibular nerve and vessel canal) is outlined in
black underneath. Notice how the implant was placed to avoid injury to
this structure

19. Transosseous Implants
The plate on the bottom is firmly
pressed against the bottom part of the
chin bone, whereas the long screw
posts go through the chin bone, all the
way to the top of the jaw ridge inside
the mouth.
The two attachments that will
eventually protrude through the gums
can be used to attach an overdenture-
type prosthesis.

20. Other Implants
Endodontic stabilizers
• They are placed into the bone through the apices of the
natural teeth.
Intramucosal inserts
• They are buttonlike, non-implanted retention devices that
can be used to stabilize full and partial maxillary and
mandibular removable partial denture prostheses.

21. Implant Systems

23. Osseointegration

24. According to Branemark, Zarb, and Alberktsson (1985)
Osseointegration is defined as structural and
functional connection between ordered living bone and
surface of load carrying implant.
According to American academy of implant dentistry
Osseointegration is the contact established
without interposition of non bone tissue between normal
remodeled bone and an implant entailing a sustained
transfer and distribution of load from implant to and
within the bone tissue.

26. THEORIES OF OSSEONTEGRATION
There are two basic theories regarding bone- implant
interface :
1)Fibro osseous integration supported by Linkow (1970),
2)Osseointegration (James and Weiss (1986) and
Branemark ( 1985)

27. Fibrous- osseous integration
• In 1986, the American academy of implant dentistry
defined it as “tissue to implant contact with healthy
dense collagenous tissue between implant and bone.
• Fibrous osseointegration refers to connective tissue made
of well organized collagen fibers present between bone
and implant. (Meffert 1987)

28. • In this theory collagen fibers functions similar to
Sharpey’s fibers in natural dentition. They are however
different from fibers in periodontal ligament natural
teeth. The fibers are arranged irregularly parallel to
implant surface. When forces are applied, they are not
transmitted through the fibers as seen in natural
dentition.

29. • No Sharpey ‘s fibers are present between bone and
implant so it is difficult to transmit the load. Therefore,
bone remodeling cannot be expected in fibro integration.
• More over the forces applied resulted in widening of
fibrous encapsulation, inflammatory reaction and gradual
bone resorption leading to implant failure.

30. Theory of Osseointegration
• According to Branemark , osseointegration is a
histological definition meaning “ a direct connection
between living bone and load carrying endosseous
implant at the light microscopic level. (Branemark 1969)
• Meffart et al., 1987 redefined and subdivided the term
osseointegration into "adaptive osseointegration and bio-
integratiion.“ Adaptive osseointegration " has the
osseous tissue approximating the implant without
apparent soft tissue interface at the light microscopic
level while Biointegration is a direct biochemical bone
surface attachment confirmed at electron microscopic
level.

31. • Other factors influencing successful osseointegration
include implant oxide layer contamination and poor
temperature control during drilling procedure.
• The oxide layer consist of Tio and Tio2 and Ti2O3,
Ti3O4 and can attract bio molecules. The contaminated
area changes the oxide layer contamination and
inflammatory reaction follows resulting in granulation
tissue formation similar to organization process.

32. • The osseointegration process observed after implant
insertion can be compared to bone fractured healing.
• There is coupling between bone apposition and bone
resorption.
• First woven bone is quickly formed in the gap between
the implant and the bone.
• Second after several months it is replaced by ,lamellar
bone under load stimulation.
• Third a steady stage is reached after about 11/2years

33. • The healing process in this implant system is similar to
primary bone healing. Initially ,blood is present between
fixture and bone, then the blood clot forms. The blood
clot is transformed by phagocytic cells, such as
polymorphonuclear leukocytes, lymphoid cells, and
macrophages.
• The phagocytic activity level peaks during first and third
day after surgery. During this, formation of procallus
occurs, containing fibroblasts, fibrous tissue and
phagocytes.
• The procallus becomes dense connective tissue and
mesenchymal tissue become osteoblasts and fibroblasts.

34. • Osteogenic fibers formed by osteoblasts has a potential
to calcify. The dense connective tissue then forms a
fibrocartilagenous pulley, usually forming between
fixture and bone.
• New bone penetrates and new bone matrix is called bone
callus. This new bone, matures and, increases in its
density and hardness.
• About this time, the prosthesis is attached to the fixture
and with stimulation, bone remodeling occurs. Haversion
bone calcifies becomes dense and homogeneous.
• Occlusal stresses stimulate the surrounding bone to
remodel and osseointegrated fixtures can withstand
masticatory forces.

35. • Junctional epithelium consists of basal cell layer with
basal cells attached by desmosomes . A
hemidesmosomal attachment is seen at the abutment
surface.
• It has both lamina lucida and lamina densa; lamina densa
is attached to the abutment surface.
• The precise attachment mechanism between lamina
densa and abutment is not known yet. However , the
surface oxide layer and hemidesmosomal glycoprotein
are thought to form chemical bond attachment.

36. Mechanism Of Osseointegration
• Osborn and Newsly in 1980 described two different
phenomenas (distance and contact osteogenesis) by
which bone gets integrated with the implant surface.
• Contact osteogenesis involves de novo bone formation
directly on the implant surface.
• Distance osteogenesis is formation of new bone on
surface of existing peri implant bone.

37. • The bone surfaces provide a population of osteogenic
cells that lay down matrix that encroaches the implant.
• An essential observation here is that new bone is not
forming on the implant, but the latter does become
surrounded by the bone. Thus in these circumstances ,
implant surfaces will be partially obscured from bone by
intervening cells.

38. • Distance osteogenesis can be expected in cortical bone
healing since vascular disruption of cortex caused during
the implant site preparation is known to lead to death of
the peri implant cortical bone and its subsequent
remodeling by osteoclasts invasion from the underlying
medullary compartment.
• Initiation of mineralisation of healing bone tissue did not
occur on the implant surface, but bone grew towards the
implant subsequent to the death of the intervening
tissues.

39. • In contrast ,in the process of contact osteogenesis ,new
bone is formed first on implant surface.

40. Stages Of Osseointegration
Osseointegration involves three stages
Stage 1. Osteoconduction
• Following the placement of an implant, wound healing is
initiated. Fibrin, produced as a result of transient blood
clotting at the wound site, adheres to the surface of the
implant, forming a scaffold into which osteogenic cells
derived from undifferentiated connective tissue cells can
migrate.

41. • As healing continues, the fibrin scaffold retracts, making
it critical that the implant surface be able to retain its
fibrin attachment and allow the differentiating
osteogenic cells to reach and remain at the implant
surface.

42. • The mechanical and chemical properties of the implant
surface have a profound influence on osteoconduction
because they)influence the anchorage of the fibrin
scaffold through which osteogenic cells reach the
implant surface.
• A rough implant surface, for example, promotes
osteoconduction by providing both a larger surface area
and sites into which the fibrin can become entangled.

43. Stage 2. De Novo Bone Formation
• De novo bone formation is initiated when the osteogenic
cells have fully differentiated. The four stage process
begins with the secretion of a collagen-free organic
matrix that provides nucleation sites for calcium
phosphate mineralization.
• Following nucleation, calcium phosphate crystal growth
begins at the developing interface, and collagen fiber
assembly is initiated.

44. • In the final stage, the collagen compartment calcifies.
New bone is thus separated from the implant surface by
a layer of non-collagenous bone proteins known as the
cement line.
• Bonding the new bone with the implant occurs by fusion
or micromechanical interlocking of the cement line
matrix with the implant surface.

45. Stage 3. Bone Remodeling
• During remodeling, bone tissue is sculpted by absorption
and deposition, and secondary osteons form. When these
osteons impinge on the implant surface, de novo bone
formation occurs on the transcortical implant.
• Bone remodeling is particularly important for the long-
term stability of the transcortical portion of the implant,
since cortical bone can necrose as a result of surgical
trauma.

46. • This stage leads to functional adaptation of the bony
structures load by changing dimensions and orientations
of supporting elements. (L.J Heitz Mayield,B. Schimd,
C. Weigel. Does excessive occlusal load affect
osseointegration? And experimental study in the dog .
Clin oral implant research 2004 :15 ;1285-89)

47. Key Factors Of Osseointegration
These include
• biocompatibility
• implant design
• implant surface
• implant bed
• surgical technique
• loading conditions