2. Osseointegration
A direct structural
and functional
connection
between ordered,
living bone and
the surface of a
load-carrying
implant
(Brånemark, 1985)
Cortical bone
Cancellous bone
Per-Ingvar Brånemark
4. Osseointegration
Osseous Healing:
•
•
•
•
•
•
•
•
Blood fills gap between implant and
damaged bone surface
Blood clots with fibrin network
formation (Platelets)
Inflammation (PMN s & Macrophages)
Resorption (Macrophages ingest
inflammatory debris & Osteoclasts
resorb damaged bone )
Neovascularization (Endothelial cells)
Migration/differentiation/
proliferation (MSC s, fibroblasts &
osteoblasts)
Osteoid & Woven bone (osteoblasts)
4-6 weeks after surgery
Replacement of woven bone by
lamellar bone (osteoclasts &
osteoblasts)
Basic multi-cellular unit
Osteoclast cutting cone: basic
remodeling process for bone renewal
7. Peri-Implant Soft Tissue
Healing & Biology
• Bone resorption occurs to
create a proper soft tissue
seal around implants
• The term biologic width is
used when describing the
soft tissue dimensions around
implants
• Epithelial cells are attached
by hemidesmosomes & basal
lamina
• Collagen fibers are oriented
parallel to the implant
surface
CTA
8. Osseointegration
Original Brånemark Protocol
•
•
Implants must be sterile
Made of highly biocompatible
material such as titanium
(covered by a biologically inert
TiO2 layer)
• Inserted with atraumatic surgical
technique that avoids
overheating of bone
• Implants must have good initial
stability at the time of placement
• Implants must not be subjected
to functional forces during initial
healing period
A non-loaded healing period:
1. Anterior MN: 3 m
2. Posterior MN: 4 m
3. Maxilla: 6 m
Submerged & Non-loaded
9. Traditional Loading
Maxilla: 6 months
Ant MN: 3 months
Post MN: 4 months
Two-Stage
Cover
Screw
Stage 1 Surgery
Healing
Abutment
Stage 2 Surgery
One-Stage
Final
Restoration
Healing
Abutment
Final
Restoration
11. Surgical Considerations
•
•
•
•
•
Excessive surgical trauma
and thermal injury result in
osseonecrosis and fibrous
encapsulation
Temperature over 47 °C for 1
min causes heat necrosis in
bone (Eriksson & Albrektsson
1983)
Heat generation is affected
by speed, load placed on
drill, drill sharpness and
design
Precise osteotomy
preparation by surgeon to
achieve good primary
stability
Good primary closure
47 °C
Precise osteotomy
preparation
Good Primary
Closure
From Larry Peterson,
Contemporary Oral
& Maxillofacial Surgery,
3rd Edition
12. Surgical Considerations
Implant Design
•
•
Primary mechanical
stability is provided by
implant design, bone
quality & precise
osteotomy preparation
The transition from
primary mechanical
stability to biologic
stability takes place
during early wound
healing & is provided by
newly formed bone
Threaded
Implant
Cylinder-Type
Implant
Press-fit
Precise Osteotomy
Preparation
13. Stage One Surgery
• When to tap?
• When to
countersink?
• Coolant (copious irrigation)
• Sharp drills
• Temp over 47 °C for 1 min
causes heat necrosis in bone
(Eriksson & Albrektsson 1983)
• Up & down motion for effective irrigation
• Avoid over-torque (Implant over-tightening
causes bone micro-fractures/bone necrosis)
14. Stage One Surgery
• Twist drills are longer than selected
implants
• Countersink only in presence of thick
cortical layer
• Excessive countersinking in poor quality
bone may compromise primary stability
• Tap only in dense bone (most implants
are self tapping i.e. self threading)
• Placement torque should not exceed 45
Ncm
19. How to Assess Implant Primary
Stability?
1.
•
•
•
•
Resonance Frequency
Analysis (RFA)/Implant
Stability Quotient (ISQ)
Transducer is excited
over a frequency range
Response is measured
RF is determined by
degree of stiffness at IBI &
level of bone surrounding
the implant
Implant stability quotient
(ISQ) is a numerical value
ranging from 0 – 100
reflecting the level of
stability
20. How to Assess Implant Primary
Stability?
2. Implant insertion torque
21. Stage Two Surgery
• Implant exposure
• Removal of cover screw
• Selection of healing abutment:
A periodontal probe determines ST
thickness
• Connection of healing
abutment using a screw driver
Abutments have to be fully seated
Cover screw exposure
Abutments emerge from
ST by about 1-2 mm
22. One-Stage Versus Two-Stage
Things to consider:
• Primary stability
• Interim prosthesis (can it
be modified without
weakening)
• Patient compliance
• Placement of implants &
simultaneous grafting e.g.
guided bone regeneration
(GBR)
Implant placed
as a two-stage
Implant placed
as a one-stage
23. One-Stage Versus Two-Stage
When to consider one-stage placement?
1. The implant has good primary stability
2. The interim prosthesis can be modified to
accommodate the healing abutment
3. Implant placement is associated with no
grafting or minimal grafting
24. Extraction & Immediate Implant Placement
Evaluation at the time of C/S
1.
Smile line (SL)
Ø
2.
Gingival Biotype (GB)
Ø
3.
4.
5.
Avoid in thin scalloped GB as it
is usually associated with thin
labial bone plate
Infection-free site
Inflammation-free site
Check radiographically for
proximity of apex of socket to
vital structures e.g. IAN,
Maxillary sinus &Nasal cavity
Ø
6.
Avoid in high SL
Avoid if there is proximity
Look for features that lead to
good primary stability e.g.
short and small roots, wide
inter-radicular bone, small
tooth size (molars vs. bicuspids
vs. incisors)
Thin Scalloped
Thick Blunted
25. Extraction & Immediate Implant Placement
Evaluation at the time of
extraction
1. Atraumatic extraction
2. Check height & thickness
of labial or buccal plate of
bone
3. Check morphology of
socket and gap between
implant & socket wall
(<2mm no grafting, >2mm
graft)
4. Primary stability
Ø
Avoid if you cannot get
good primary stability
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