Bone graft

CONTENTS
-Introduction
- History
- Definition
- Types of Bone Graft
- Forms of Bone Graft
- Autografts
- Allografts
- Synthetic Bone Grafts
-Sinus Bone Graft
- Bone Graft Handling
- Goals of Reconstruction
- Summary and Conclusion
- References
Dr. Firas Kassab

INTRODUCTION
Bone grafting is a dynamic phenomenon. A successful bone
graft is applied, heals, becomes incorporated, revascularizes and
eventually assumes the form desired. In their early application,
bone grafts were considered a mere strap lattice, and the results
were measured primarily by the graft’s ability to withstand the
mechanical stresses that surrounded them. Today, bone grafts are
viewed as biologic structures. Of course, mechanical stress, shear
stress (extrinsic and intrinsic), contouring, and remodeling are also
important in the long term and are the part of the healing process of
a bone graft.
Different forms of bone grafts vary on the basis of the
function that they must perform.
Dr. Firas Kassab

Grafts that must withstand the shear pressure of mechanical stress is
usually a large cortical bone graft. A bone graft intended for contouring, to expand
the biologic boundaries of the skeleton, and to change the three dimensional
configuration of the face is usually of the corticocancellous variety; these are soft
bone grafts that can be contoured and allowed to heal, vascularize, and augment
existing bone to produce the desired shape. Corticocancellous bone grafts are
applied to fill a discontinuity defect and require a carrier. There are many carriers
used for such applications.
Almost all bone grafts used currently by thousand of surgeons around the
globe are autogenous. Such autogenous bone grafts constitute the best biologic
bone grafting system for the human body. They vascularize bone grafts, they heal;
and they withstand mechanical stresses in due time. The more compact the bone
graft is, the less the chance of complete and rapid vascularization. The less
compact the bone graft is, the more rapid the revascularization and healing.
Dr. Firas Kassab

Whatever specialized group of surgeons uses bone grafting, whether on the
face, the mandible, or the extremities, the principles are the same. The techniques
and indications differ, but the contra indications may be the same (e.g. bone grafts
cannot be applied in areas that are heavily bacterially contaminated). Topical
application of antibiotics is gaining momentum, particularly the use of antibiotics in
small pellet form to obtain the maximal effect with the least disadvantage.
We cannot really finish the introductory remarks without noting two recent
advances. The first is the use of vascularized bone grafts, which have their own
vasculature. These can be implanted with microsurgical technique and allowed to
heal appropriately. In certain parts of the body, it may still be advantageous to allow
a bone graft to vascularize (e.g., in areas where mechanical stress and shear stress are
needed to ensure normal function).
Dr. Firas Kassab

The second aspect is the use and understanding of allografts. Allografts are
becoming a more accepted form of bone grafts. The majority of large allografts
assume a near normal function in individual who lack certain areas of the body that
have been resected for oncologic problems or for other reasons. It is frequently
possible for these areas to be replaced, and the patient can resume normal function.
However, these large bone grafts do not really completely vascularize as allografts.
Finally, bone grafts could not have become extensively popular, easy to implant,
and widely utilized around the globe, without the use of rigid fixation systems. The
rigid fixation systems brought a necessity for understanding biomaterials and
metallurgy. Whether the metal used is stainless steel, titanium, or vitallium, these
systems provide mechanical strength that is 200 times that of a natural bone. These
systems are getting smaller and smaller, to the extent that a system introduced in
1990 utilized screws measuring 0.8 mm.
Dr. Firas Kassab

Prospects for the future include the possibility that when
certain parts are needed, they can be fabricated within the same
biologic system as an autogenous bone graft and then reapplied,
particularly in discontinuity defects. This may benefit the patient with
skeletal problems undergoing oncologic treatment or the patient with
postoncologic deformities, as well as patients with post traumatic
defects.
Dr. Firas Kassab

HISTORY OF AUTOGENOUS BONE
GRAFTING
In 1682 VanMeekren transplanted canine skull bone to
calvarial defect.
Von Walter 1882 described use of corticocancellous bone graft.
Ollier 1867 reported transfer of periosteum and bone and
concluded that both must be alive to account for osteogenesis.
Barth in 1893 he revealed that several days after bone graft
transfer, the graft is dead. He felt that the graft worked via gradual
resorption and replacement of dead bone by creeping substitution of
dead graft by viable bone growing into it from living bone in contact
with it. This is currently called as Osteoconduction.
Dr. Firas Kassab

Axhausen in 1907 demonstrated in an experiment that
periosteally covered bone grafts exhibited osteogenesis from surface
cells surviving at the periosteum.
Phemister in 1914 concluded after a series of studies that some
osteogenic cells on surface of bone graft survive by diffusion of
oxygen and nutrients from the recipient bed.
It was later done by Ham and Gorden in 1952 and Hancock
1963.
Gallie & Robertson 1918, agreed that survival of cells on bone
graft is important, and that rate of survival was better with cancellous
bone than with cortical.
Mowlem in 1944 and later in 1963, used cancellous bone grafts
and demonstrated its superiority over cortical bone grafts.
Dr. Firas Kassab

Okland and associates in 1985 put forward that survival of
surface cells in autogenous bone grafts is much more superior to
freeze dried autogenous grafts, allografts, inorganic bone and its
substitutes.
ALLOGENIC BONE GRAFTING
History:
Bone induction principle was described by Urist for allogenic
bone in 1953. This induction was mediated through an acid-insolube
protein complex (BMP) derived from the grafted bone that directs
differentiation and activity of host osteocompetent cells towards bone
formation. Urist and Burwell in 1968 and later in 1969 that early use
of allogenic bone either fresh or frozen and dried.
Urist in 1968 also described that allogenic bone is replaced by
new host bone. Dr. Firas Kassab

Definition
A graft is a substance, foreign to the region of the body in
which it is placed, which is used to replace, augment or fill a defect
created by surgery, trauma, disease and developmental deficiency.
Graft is a living tissue, transplanted to a different site, that
continues to live and function in the new environment. If the tissues
does not survive the relocation, it is technically an implant rather than
a graft.
Graft (according to GPT) : Tissue or material used to repair a
defect or deficiency.
Dr. Firas Kassab

Indication for Bone Grafting
 Jaw resection following malignancy / other pathology
 Extensive trauma
 In orthognathic surgery
 As an onlay material in facial aesthetic surgery
 As a composite cartilage – bone graft in the reconstruction of the TMJ
(growth center)
 Large bony defects created by cysts and tumors
 In preprosthetic surgery as an onlay
 In preprosthetic surgery as a fill in material
 In cleft patients.
 In implantology e.g. : sinus lift procedure
 In periodontal surgery
Dr. Firas Kassab

Radiographic Assessment
Presurgically
- Radiographs to assess the bone density at recipient and
doner site.
- Radiographs to rule out aberrant anatomy and gross
pathology.
- Arteriograms for free grafts
Post surgically
- Increased or normal radio density at the grafted site.
- Irregular margins coinciding with osteoclastic activity
Dr. Firas Kassab

- At the end of healing phase : No radio density
- Scintography exhibits hot spots in areas of increased bone
activity – bone deposition.
- C.T. Scans show good resolution and clarity
- In M.R.I., shows up as high intensity images in both T1
and T2 scans.
- M.R.I. can detect marrow activity and is helpful in
predicting initial changes.
Dr. Firas Kassab

TYPES OF BONE GRAFTS
Auto graft : Bone graft transplanted from one site to
another from patients own body.
Xenograft / Heterograft : Bone taken from another
species. These can be both cancellous or cortical
Composite : Bone grafts are made partly allograft or
heterograft and partly autograft.
Allograft : Bone transplanted from one individual to
another genetically unrelated individual of same species.
Isograft : Bone graft transplanted from one person to
another genetically related individual of same species.
The donors are designated as Autologous, Heterologous,
Allologous, Isologous with respect to the recipient.
Dr. Firas Kassab

FORMS OF BONE GRAFT
1. Non-vascularised
2. Vascularised
3. Cancellous
4. Cortical
5. Corticocancellous, has properties of both types
Other types of grafts such as slurry bone, particulate bone,
bone pastes are small fragments of bones of different sizes
compacted together. The easier the penetration of blood vessel into
the graft to revascularise it, the less mechanical stress that graft can
take. More solid the bone graft is in its form to withstand mechanical
stress with appropriate stress shielding, the harder it is to
revascularise, incorporate and be viable bone.
Dr. Firas Kassab

CORTICAL BONE
Cortical bone can produce good mechanical filling of defect, and give
good functional result, although it takes longer time to revascularise .
Cancellous bone also fills defect but its healing is faster.
They have some clinical limitation. They are used primarily in areas
of great mechanical stress,and hence its proper fixation is important for
the stability of graft and for its proper function. It allows the graft to
survive with or without complete viability. This form of graft is useful
in long bones, not very effective when used in facial skeleton
membranous bone site. It used for discontinuity repair, to improve
existing contours, expand on the boundary to give patient a normal
aesthetic look.
Dr. Firas Kassab

CANCELLOUS BONE
This is used to get fusion and for correcting discontinuity
defects. They can be utilized in any type of wounds i.e.,
contaminated or clean. These usually do not have mechanical
strength desired for reconstruction of larger defects. Because of
large open areas in the grafts, revascularisation takes place very
well. Thus new cellular regeneration, remodeling and substitution,
of new bone occurs, as old bone is removed.
Dr. Firas Kassab

CORTICAL CANCELLOUS
Cortical bone grafts
revascularise slowly. They are
not permeated by the blood
vessels until 6-7days and graft is
not completely vascular till 1-
2months. This delay may be
due to the need to open, by the
osteoclastic activity, the existing
Volkmanns canals and
Haversian system. It may also
be due to smaller no of
endosteal cells available for the
end to end anestamosis.
There is end to end
anestomosis of host with grafted
vessels. This together with the
process of in-growth into the
marrow spaces takes place with
in 2 weeks. This
revascularization also allows the
grafted cells and host cells,
induced by osteogenic cells, to
differentiate into osteoblasts.
They surround isolate dead bone
and account for increased
radiodensity of graft initially.
Dr. Firas Kassab

The process of repair is
initiated by osteoclastic activity.
Here osteoclastic activity ceases
following the completion of the
task of walling off the remaining
necrotic bone. This mixture of
new necrotic bone remains until
the metabolic and the catabolic
phases of repair are complete.
Here we have viable and non
viable bone
In time decreased
radiodensity is seen, as a result
of removal of necrotic bone.
Also increased radio density is
due to increased no. of surviving
transplanted cells. The no. of
viable cells are more also because
of ability of more cells to be
nourished by diffusion from
surrounding host. The process of
repair is initiated by osteoblastic
activity.
Dr. Firas Kassab

This bone graft
decreases in mass and in
porosity, thus it is weakened
by 50% from 6 weeks to 6
months to 2 years following
grafting, the mechanical
strength is equal to normal
bone.
Here only new bone remains
and the necrotic bone is removed.
Here we have only viable bone.
Although in cancellous bone the
augmentation of new bone and its
homogenecity result in initial increase
in strength, in time mechanical
strength return to normal due to
osteoclastic activity and decreased
osteoblastic activity
Dr. Firas Kassab

Bone Graft
Cancellous
Cortical
Cortico – Cancellous
Autograft
Allograft Xenograft
Source
HIP, RIB, TIBIA
Cranium
Clinical application
varied
Clinical outcome
Accepted (special)
Not useful
Satisfactory
Standard Procedure
Dr. Firas Kassab

The bone used for grafts should have a structure and form so
that when it is placed in the recipient bed, it will proceed through
the natural process of healing.
Cortical bone contains pure cortex dense bone. It is usually
layered and the only open space for revascularisation is that of
nutrient blood vessels.Hence it is used for weight bearing areas.
Cancellous bone provides more open spaces for faster
revascularisation, but it lacks mechanical strength, particularly
when used for weight bearing areas. However corticocancellous
provides the advantage of both.
Bone grafts can be developed into blocks, chips, and paste.
Block of bone developed is used such that the defect is outlined on
the donor site, donor bone cut to the specification needed and graft
corresponds exactly to size and shape of the defect.
Dr. Firas Kassab

Bone chips are harvested as particulate bone. There is no
structure to such grafts. The defect must be well stented and
healing takes place as the pieces of bone become incorporated.
Rapid vascularization of grafted tissue is then ended by
solidification, then only can it withstand weight and forces. Only
disadvantage is that it takes about one year for its completion. Bone
paste is used as a carrier to bridge the defect to be closed. Thus
bone paste if made slurry can be packed in the defect.
. Some authors say addition of microfibrillar collagen
(avitene) gives form to paste, thus making it more easy to handle.
This also takes about, at least one year to become solid to withstand
mechanical forces. It should have sufficient rigidity to withstand
mechanical pressure during healing phase.
Dr. Firas Kassab

I Autograft
The most preferred bone graft, sites mainly being rib,
iliac crest as the primary source. This refers to bone tissue
transferred from one site to another in same individual.
Clinically these grafts can be further classified on the basis of
SITE OF ORIGIN
 Iliac
 Fibula
 Rib
GROSS ANATOMY
 Cortical
 Cancellous
 Corticocancellous Dr. Firas Kassab

 Bone marrow aspirate
 Vascular autografts
 Free tissue transplants
 Pedicle flaps
PHYSICAL FORM
 Paste
 Morsel
 Chip
 Strip
 Block
 Segment
 Match stick
Dr. Firas Kassab

1. Block Bone Grafts Devoid of Periosteium
The piece of bone contain both cortical and cancellous bone. It
is shaped to fit a defect either before or after the bone has been
removed from the donor site subperiostially. This type of graft is
useful for
a. Repairing a saddle nose.
b. Restoring continuity of the mandible
c. Filling skull defects
d. Restoring the zygomatic prominence.
Dr. Firas Kassab

2. Osteoperiosteal Grafts
These bone grafts have the periosteum attached. They are
obtained from the flat medial surface of the tibia and from the iliac
bone.
Dr. Firas Kassab

3. Cancellous Bone Grafts
The best source for these type of grafts is the ilium.
These grafts are useful for
a. Filling in surface bone defects
b. Interposing between separated bony fragments
c. Filling gaps beneath and between larger bone grafts
Dr. Firas Kassab

The chips are usually packed at the junction between larger
bone graft and the host bone. The advantages of chip cancellous
bone grafts include
a. They seem to be more resistant to infection
b. Regeneration occurs more rapidly than with other grafts
4. The Split – Rib Graft
This type of graft has been recommended by Hongacre and
Destefano (1975) for large cranial and facial defects in children as
regeneration of bone occurs in the donor site.
Dr. Firas Kassab

5. Fibular
The free vascularised fibular graft was the first free graft
used clinically. The advantage of it in long bone defects are
strength, length and growth plate. As it is purely cortical it can
withstand daily stresses. The disadvantages of this graft are that
vascular pedicle is as short as 1 cm. This means that there must be
appropriate vasculature close to the recipient site. It is used
basically for long bone defects.
Dr. Firas Kassab

In 1973, Taylor described its use as a reconstructive method. It is used
for reconstruction of mandibular deformities, craniofacial defect, long
bone defects etc. The advantage is its curvature, thickness of vascular
pedical length upto 8 cm. This can be raised as a composite flap,
myoosseous and osseocutaneous flap. Disadvantage: damage by
perforating the peritoneal cavity. The anatomy is such that either
superficial or deep circumflex iliac artery can be used as vascular
supply for flap closure.
Dr. Firas Kassab

II Allografts
This is the principle alternative to autogenous bone.
Allograft or alloimplant refers to bone which is harvested
from one individual and transplanted into another within same
species.
These bone tissue implants provide the form and matrix of
bone tissue, but no viable bone cells are transplanted. Some of
articular chondrocytes may remain viable if handled carefully.
Dr. Firas Kassab

1 Freeze dried bone allograft FDBA
This is not a synthetic bone,but it is a human bone,harvested from fresh
cadavers it is then sterilised,freezed and dried .It works primarily through
conduction, thus over a period,it will resorb and bone graft is replaced.These are
commonly used in sinus bone grafting procedures.
Barrier membrane (Gortex)Dr. Firas Kassab

This is probably the most frequently used alloimplant. It is
used mainly as a composite graft (i.e., in combination with marrow
from the recipient). In orthopaedic surgery, it is used to fill defects
resulting from the extirpation of bone tumors or cysts or as an
adjunct in spinal fusions. It is also used extensively by
periodontists to fill alveolar defects and by oral surgeons for
reconstruction in the maxillofacial region. However, lyophilized
bone has been shown to retain its antigenicity, and in applications
where larger segments of bone are required with ability to withstand
stress, the results have been very unfavorable, showing incomplete
incorporation and decreased ability to withstand torsional stress.
Longitudinal cracks have also been observed when freeze-dried
bone is rehydrated. It is suggested that freeze-dried bone be
supplemented with generous amounts of autogenous iliac bone
Dr. Firas Kassab

2 Demineralised bone matrix
It is a subset of alloimplant bone, which can be used as an
implant material. Preparation and dimineralisation of bone further
reduces antigenicity and makes bioactive proteins in bone matrix
more available for interaction with local cells. This demineralised
bone matrix has been used to induce bone formation and produce
healing. It was shown by Glowacki and coworkers that some of
its use is in craniofacial reconstruction; although its use is mostly
in orthopedic procedure.
In contrast to deproteinized bone, demineralized bone
retains its osteoinductive properties and has been used by Mulliken
et al for reconstruction in the craniofacial region. It is
acknowledged, however, that the use of radiation for sterilization
diminishes osteoinductivity, and other ways to sterilize the implant
are being investigated
Dr. Firas Kassab

DBX® Demineralized Bone Matrix Putty
Dr. Firas Kassab

Deproteinized Bone
Such bone preparations lack osteoinductivity. Despite one
report in which good results are claimed, experimental results
indicate the failure to incorporate deproteinized bone into the host
skeleton.
Chemosterilized Autolysed, Antigen-Extracted Allogeneic
(AAA) Bone
This particular alloimplant has been described and is being
used by Urist and Dawson. Cadaver bone is harvested as soon as
possible, after death, and processed so that the BMP is preserved
while nearly all the stainable intralacunar material is enzymatically
digested. It is then freeze-dried. The breaking strength is claimed
to be about one half that of whole, undemineralized wet bone. The
highest success rates come from operations on young children with
a high proliferative bone growing capacity.
Dr. Firas Kassab

III Xenografts
As noted earlier, the use of xenogeneic transplants has been
abandoned by most surgeons, although sporadic reports of their
use continues. The genetic transplantation differences between
human tissue and that of other species (e.g., bovine), are such that
the fate of such grafts is their eventual sequestration without any
new bone formation.
Dr. Firas Kassab

IV Synthetic bone grafts
Alloplast
These are expanding variety of synthetic or non tissue
bone graft. These includes biologic and synthetic polymers;
ceramics, matrix proteins and metals. Combinations of some of
these materials may replace autograft and allograft bone
materials.
The various alloplasts used for reconstruction or augmentation in the
craniofacial maxillary region include.
1. Solid or mesh metals such as titanium and its alloys, 316 L
stainless steel, and Cr. Co-Mb alloys.
2. Solid or porous polymicrons such as silicone rubber, proplast.
3. Hydroxylapatite
Dr. Firas Kassab

Selection of an alloplastic material for reconstruction involves two
considerations.
1. Physical properties dictate how such materials may be adapted to the deficit
and whether any functional load can be applied to it.
2. Biocompatibility of the material will determine whether the alloplast, in its
loaded or unloaded clinical adaptation, will be tolerated by the tissues.
Use of such implants has been investigated as substitutes for autogenous
grafts and allogenic implants. Attempts were directed toward creating a porous
material that would allow in-growth of bone.
For the fabrication of porous implant materials, several materials were
tested by implantation in the femurs and tibias of dogs, in the form of cylinders 1.0
cm long and 0.5 cm in diameter. Among the materials tested, hydroxyapatite and
calcium carbonate showed complete in-growth at 8 weeks with “normal appearing
and normally mineralizing osseous tissue.” Furthermore, it was observed that in 1
year the calcium carbonate skeleton had been resorbed.
Dr. Firas Kassab

CLASSIFICATION
POLYMERS
BIOLOGI C
collagen
fibrin
SYNTHETIC
Polylactic polyglycolic acid polymers
CERAMICS
Calcium phosphate
Hydroxyapatite
Tricalcium phosphate
Calcium Sulphate
METALS
Titanium alloy
Chrome cobalt alloy
Dr. Firas Kassab

BONE MATRIX PROTEINS
Osteonectin
Osteopontin
Fibronectin
Osteocalcin
GROWTH FACTORS
Bone morphogenic protein factor 1 to 7
Transforming growth factor
Insulin like growth factor I & II
Fibroblast growth factor
Platelet derived growth factor
Epidermal growth factor
Retinoic acid
Dr. Firas Kassab

Requirements
1. Non immunogenic
2. Strength and resilience to restore hard tissue form where
function is required.
3. Bend ability, mold ability or carvability to allow for intra
operative adaptation.
4. Stable and non-reactive surface whether loaded or not.
5. Modulus of elasticity similar to that of connective tissue at
the implant tissue interface.
Dr. Firas Kassab

HYDROXYAPATITE
It is an alloplastic material. This is a mineral substance,
basically a ceramic which is similar to cortical bone in its composition.
It is inorganic, stable, non absorbable and non biodegradable. They are
osteoconductive and not osteoinductive (ie) they will induce bone
formation when placed next to viable cells, but not when surrounded
by non bone forming tissue like skin.
Dr. Firas Kassab

Hydroxyapatite implants were tested by Holmes, who implanted them in
the mandibles of dogs in which 2-cm defects were treated with implants placed in
metal cast trays. At 4 months, bone extended into the implant for a distance of 3-
5mm. At 4 months, the entire length of the implant had been bridged in many of
the porous channels. At 6 months, all the channels had been filled with lamellar
bone with well formed osteons. At 12 months, the architecture of the implant was
notably diminished, and 88% of the implant area had been replaced by regenerated
bone. It is noteworthy, however, that similar defects created in the mandibles of
two dogs by the author and left without an implant were also completely bridged
with regenerated bone at 6 months. In a more recent paper, Holmes tested
experimentally the possibility of cranial reconstruction with porous
hydroxyapatite. The final composition of the implant was 39.3% hydroxyapatite
matrix, 17.2% bone in growth and 43.5% soft tissue in growth. He concluded that
a satisfactory contour can be obtained and the implant can function at least in part
as a bone substitute
Dr. Firas Kassab

CALCIUM PHOSPHATE
Calcium phosphate has also been
tested under the form of a ceramic
biodegradable implant called “Synthos”
(Miter Inc., Worthington, Ohio). This
material can be carved into the desired
shape and provides a uniform distribution
of large interconnecting pores from 100
to 300 microns in size. Testing in the
mandible, iliac crest, and inferior orbital
rims of dogs was undertaken.
Progressive invasion and replacement of
the implant with bone were observed.
Dr. Firas Kassab

ACRYLIC RESINS
Acrylic resin is available as a two component system; a
powder of small PMMA spheres and beads and a liquid monomer.
The polymerization is strongly exothermic (max. Temp. 120oC).
Disadvantages of solid, heat cured acrylics include
- Difficult handling
- Problems with thermal, electrical and X-ray conductivity.
Uses include dental implants, submucosal augmentation, contour
correction, cranial defect correction, orbital wall and floor defect
correction, intra ocular lenses
Dr. Firas Kassab

SILICONE RUBBER
Widespread use of this material is due to its biocompatibility
and excellent physical characteristics such as.
- Thermal stability
- Oxidative stability
- Retention of flexibility through wide temperature changes.
Basic building block is dimethylsiloxane with contributions
from other organic side chains i.e., Vinyl and Phenyl condensation
polymerization produces a high molecular weight molecule that has
a highly polar Si-O-Si backbone.
Dr. Firas Kassab

Disadvantages include low tear resistance and that it is
thrombogenic
Preformed silicone rubber implants with or without polymer fabric can
be used to augment chin, zygomatic and nasal deficiencies including
reconstruction of the dorsum, nasal tip and columella as a custom implant. The
disadvantage here being that it exhibits “Memory”. Therefore it must conform to
bone contour in the relaxed state.
Fluid silicone is clear, colourless odourless and has an oily lubricant feel to
it. It may be injected to lift depressed scars, unless they are bound down by
strong fibrous adhesions. Vertical and oblique brown lines in the glabella region
and nasolabial folds can be lifted. Sunken facial contours can be augmented.
Depressed defects of the dorsum of nose, defects of nasal tip etc. may be treated.
Augmentation in a flattened hemifacial contour is possible with this material too.
Dr. Firas Kassab

POLYETHENES
- Group of polymers made from ethane type monomers and
include polyethylene and polypropylene.
- Porous sponge form can be used in reconstruction in non load
bearing areas as in the middle ear. Also used to correct facial
and skull defects, reconstructing the external ear, the trachea
and rebasing the vocal folds.
Dr. Firas Kassab

POLYTETRAFLUROETHYLENE (TEFLON)
- Tetrafluoroethylene gas at high temperature and pressure.
- Non carcinogenic, resistant to corrosion, non adherent and can
be sterilized.
- Used for repair of orbital floor fractures. Available in sheet that
are 1.245 mm thick .
- Injectable form consisting of pure . particles of 50-100um.
suspended in 50% glycerin solution is used in paralyzed vocal
cords.
Dr. Firas Kassab

PROPLAST
- Porous low modulus implant material available in
3 forms basic material that forms the porous matrix
of proplast is prefluorocarbone polymer.
Advantages of proplast over solid polymers
1. Improved stabilization, on or in bone, in virtue of rapid
tissue in growth rather than only fibrous encapsulation.
2. A low modulus characteristic similar to that of soft tissue
which allows it to be bent or molded to appropriate contours.
3. Easy wettability
4. Light weight
Dr. Firas Kassab

5. Radiolucency
6. Ease of curving
7. Stable at very high temperatures, therefore can be sterilized by
autoclaving 3 times.
8. Proplast sheeting of 1-3mm permits repair of defects of
irregular depth.
Disadvantages
1. Macrophage response
2. Increased incidence of infection if contamination occurs during
emergency
3. Decreased pore size and therefore tissue in growth of the
materials if loaded or compressed
Dr. Firas Kassab

.
Contra indications
1. As an implant by itself in weight bearing or articulating bony
surface, where compressive loading is likely (TMJ).
2. Over sinus cavities
3. Where there is insufficient underlying bone or soft tissue to
prevent collapse in the event of external pressure.
Dr. Firas Kassab

4. In patients with systemic disorders that may compromise
tissue in growth or normal wound healing.
5. In recent areas of infection.
6. Available in block, preformed or customized implants for
chin, mandible, premaxilla, zygoma, orbit and nasal
augmentation.
Dr. Firas Kassab

POLYURETHANES
- Implanted in the form of rigid foams for bone replacement
and as bone adhesions.
- Consists primarily of varied arrangements of polymeric
molecules that share a common structure of urethane group
- Polyether polyurethanes are capable of long term
implantation with no significant physical changes.
Malar augmentation Mandibular repair Orbital Floor repair Surface
scan model Complex fracture analysis Fetal heart model
Dr. Firas Kassab

POLYAMIDE
- Is used successfully in facial augmentation..
- Can be used alone or in combination with autogenous
tissue in growth as an onlay material for the chin, maxilla,
nasal dorsum.
Disadvantages
Difficulty in contouring and handling and in placement of
the material during surgery.
Dr. Firas Kassab

CALCIUM PHOSPHATE CERAMICS
- These are polycrystalline ceramics, and either in porous or
dense forms, serve as permanent bone implants showing no
tendency to resorb in vivo.
- These are are hard tissue prosthetic materials that interact with
and may ultimately become an integral part of living bone.
Limitation :
- Brittle, low impact resistance and relatively low strength.
- Biocompatible
- Lack of local systemic toxicity. They bond directly to bone
without the need for porosity.
Dr. Firas Kassab

APPLICATIONS
Osteo Gen is clinically indicated for the contouring and improvement of alveolar
ridge deformities, support and filling of tooth sockets and cyst defects following
extraction or removal, and, for the filling and repair of marginal, periapical, and
periodontal alveolar bony defects. The granular material is mixed with sterile water
or the patient’s blood to form a putty like material. This material is then transferred
to the osteotomy.
When OsteoGen is implanted into a defect that has been demonstrated to
have healthy vascular circulation, it serves in part as a material that physically
occupies an empty bony void. Thus, a physical connection is achieved between all
sides of the bony void. As this occurs, the void fills with natural body fluids from
each side of the bony void. OsteoGen then serves as a material platform that allows
osteoblasts and other cellular material to invade the bony void.
Dr. Firas Kassab

OsteoGen granules serve as a osteoconductive material allowing new bone
to be slowly created over several months. An osteoconductive material such as
OsteoGen is defined as a material that does not inhibit the necessary cellular
material from invading the bony void to lay down new bone. In fact, on
osteoconductive material serves as a physical platform for the osteoblasts to move
into the bony void to lay down the new bone.
A second advantage of OsteoGen is that, as new bone is laid down, the
OsteoGen material resorbs. The resorption process of OsteoGen occurs
progressively over a six to eight month period; however, depending on the size of
the defect and the patient’s age, a large percentage will have resorbed some time
between three to five months. The net results is that the void is predominately
filled with bone, not a “Bone filling and Augmentation material”.
OsteoGen is avoidate in three sizes: 0.75 gm, 1.50 gm and 3.00gm.
Dr. Firas Kassab

TefGen-FD
Regenerative Membrane, designed for use in treating osseous and
periodontal defects with guided tissue regeneration.
It is available in a size of 25 mm x 30 mm x 0.2 mm.
It finds application in Periodontics, Implantology and Oral Surgery
where particulate bone graft is indicated.
It is available in quantities of 0.5cc and 1cc.
Dr. Firas Kassab

THE SINUS BONE GRAFT
The first use of bone grafting of the maxillary sinus, to
increase bony depth and bulk of osseous tissue for prosthodontic
reasons was in the 1960s by Boyne.
Grafting of maxillary sinus was used at that time to increase
the bulk of bone for later maxillary posterior ridge reduction to
obtain optimal prosthodontic inter arch distance.
However some patients presenting for conventional
complete maxillary and mandibular prosthesis had bulbous or
enlarged tuberosities that was impinging on the inter arch space, and
therefore it was impossible to construct a complete denture.The
removal of bone from mandible is not feasible, and therfore removal
of bone from the maxillary tuberosity was the option
Dr. Firas Kassab

To correct this condition, a Caldwell Luc opening was made
in maxillary antrum, the sinus membrane was elevated, and then an
autogenous particulate marrow cancellous bone (PMCB) graft was
placed in the sinus floor. Approximately 3 months later, the bone of
tuberosity could be reduced along with excess soft tissue.
Additional osseous structure had been obtained by the previous
grafting procedure.
Bone grafting of the maxillary sinus for metallic implants
- Blade implants
- Root form implants
Dr. Firas Kassab

Blade implants - During late 1970’s grafting was undertaken
for patients who had large, pneumatized antra and needed blade
implant for construction of fixed ,semi-fixed, or removal
prosthesis for edentulous areas of posterior maxilla.
Autogenous PMCB was usually used as a grafting material and
after a period of three months, blade implant was placed.
Dr. Firas Kassab

Root form implants
With the advent of titanium root form implants, it became
obvious that many possible, posterior maxillary reception sites for
implants were deficient in vertical bone height and width.
Various practitioners then undertook different surgical
techniques to enter the antrum to elevate the sinus membrane and to
place various types of bone graft
Dr. Firas Kassab

Three anatomic locations were utilized to enter the antrum.
1.The classic superior position of the Caldwell Luc opening,
located just anterior to the zygomatic buttress.
2. A mid maxillary entrance, between the level of the crest of the
alveolar ridge and the level of the zygomatic buttress area.
Dr. Firas Kassab

3. A low position along the anterior surface of the maxilla,
practically at the level of the existing alveolar ridge. Of the three
locations, the third area became quite popular because it gave a
quick access to the sinus floor and enabled the practitioner to make
an antral window to impact the buccal osseous plate into the
antrum, expediously implant the bone graft material, and close the
incision.
Dr. Firas Kassab

Indications for maxillary subantral augmentation
1. Implant placement in areas of insufficient bone volume
or decreased inter arch space.
2. Oro-antral fistula repair.
3. Alveolar cleft reconstruction
4. Le fort I down fracture with inter positional grafting
5. Cancer reconstruction for craniofacial prosthesis
Dr. Firas Kassab

Guidelines to follow for sinus grafting for dental implants may
also include.
1. Alveolar ridge bone height of less than 10 mm
2. Less than 4mm of residual bone width
3. No history of pathosis
4. No significant history of sinus disease
No anatomic limitations presented by anatomic structures or
scarring after previous surgery
Dr. Firas Kassab

Contraindications to maxillary subantral augmentation
General medical contra indications
1. Radiation treatment to the maxillary region
2. Sepsis
3. Severe medical fragility
4. Uncontrolled systemic disease
5. Excessive tobacco abuse
6. Excessive alcohol or substance abuse
Dr. Firas Kassab

Local factors that may contra indicate subantral augmentation
1. Maxillary sinus infections (empyema)
2. Chronic sinusitis
3. Alveolar scar ablation
4. Odontogenic infections
5. Inflammatory or pathologic lesions.
6. Severe allergic rhinitis.
Healing period for the graft
Because severe atrophy results in an unfavorable
vascularization of the maxillary alveolar process and the adjacent
maxillary sinus, the grafting material should be allowed to heal 1
to 2 months longer than normal.
Dr. Firas Kassab

Treatment Planning for Sinus Grafts
Treatment planning for dental implants must be based on
prosthetic considerations and, in all but the most simple cases,
should involve a complete dental restorative workup. In most
cases, this will minimally involve the following :
1. Facebow-mounted, articulated casts placed in centric
relation.
2. Diagnostic wax up.
3. Presurgical equilibration or restorative measures
4. Surgical stent manufactured by using a surveyor.
5. Radiographic or computerized tomographic verification
Dr. Firas Kassab

Use of Allografts for Sinus Grafting
The development of the sinus elevation procedure
originates from the clinical reports of Boyne, James and Tatum,
who recognized the need to supplement bone inferior to the
maxillary sinus to enable clinicians to perform alveolectomies and
subsequently place implants. Their efforts led to the development
of a technique whereby the external wall of bone, surrounding the
maxillary sinus was perforated with a careful osteotomy. In
Tatum’s technique, the osseous wall and underlying membrane
were infractured medially and pushed in a superior direction.. The
space created by this infracture was filled with an autogenous bone
graft. Boyne and James made no attempt to retain this external
wall of bone, when dissecting the sinus membrane away from the
underlying bone.
Dr. Firas Kassab

Allografts
Most of the cases are limited to the use of one specific type
of allograft. is demineralized freeze dried bone, without any other
supplements. The choice of the demineralized material over the
mineralized sources was merely to add an extra degree of safety to
the material.
The material has been used successfully for bone grafting
both in periodontal defects and around implants for reasonable
amount of time. It also gives a patient the option to avoid a
secondary site from which bone is harvested. (hip, chin, etc), which
may be more traumatic than placement of the implants.
Dr. Firas Kassab

As in all procedures, there are conditions that are not conducive to the use
of an allograft for sinus augmentation. The main situation would be in those
patients who lack adequate bone in the premaxillary area to support implants
under loading (patients who have fewer than 7 mm of bone from canine to canine).
While the antral augmentation might be successful, all the forces of occlusion will
be generated on the sinus placed implants, ultimately causing overload and failure.
The second contra indication would be inadequate buccopalatal width of
bone, in association with the deficiency in height, adjacent to the maxillary sinus.
Finally, patients who have fewer than 4 to 5 mm of bone and wish to have the
implants placed at the time of sinus augmentation would best be treated with a
large block inlay graft, which could receive the implant simultaneously. Major
vertical height advances, which are difficult, are also best treated with autogenous
block grafts.
Dr. Firas Kassab

The bone resorption process that occurs following tooth loss is four times
greater in the maxilla than in the mandible. The bone loss encountered in the
posterior regions of the edentulous maxillary arch is higher than in the posterior
mandible due to the pneumatization of the maxillary sinus. Furthermore, the
maxillary cortex is thinner and the trabecular structure is less dense than in the
mandible ; the posterior maxilla usually exhibits the poorest bone quality. Hence,
the quantity and quality of bone necessary for implant supported restorations are
less likely to be available in the maxilla. For these reasons, dental implants placed
in the posterior maxilla are likely to have higher failure rates than implants placed
in the anterior maxilla or mandible.
Different bone grafting materials have been used for this purpose,
including autogenous graft that the iliac crest and chin region, allo-grafts such as
freeze dried demineralized bone, and alloplasts such as porous hydroxyapatite and
non-porous hydroxyapatite.
Dr. Firas Kassab

Sinus bone grafting with hydroxyapatite
Dr. Firas Kassab

Sinus Grafting with Calvarial Bone
The cranial vault has always been an extremely valuable
source of bone grafts. Facility in harvesting, a simple post surgical
period, and solid construction make calvarial bone an ideal material
for reconstruction of the cranial or facial skeleton.
Although bone from the cranial vault had been used as early
as 1980 as part of an osteocutaneous flap by Konig and Muller, the
first autogenous cranial bone graft was apparently performed by
Dandy in 1929. Tessier, however, was the first to popularize the use
of the calvarium as a donor site of grafts for cranial and facial
reconstruction.
Dr. Firas Kassab

Harvesting of the cranial bone grafts
The harvesting is done in the parietal region, generally on the right side
(nondominant hemisphere) behind the coronal suture, and approximately 3cm
lateral to the sagittal suture or midline of the skull.
Dr. Firas Kassab

Grafting of the sinus floor
The construction is homogenous only if the sinus cavity is
partitioned in its inferior part by a large graft that rests on the sinus
walls and becomes the roof of the cavity to be filled. Thus, the
sinus graft starts with the positioning of a large rectangular strip of
cranial bone 10 to 15mm above the floor. Before its insertion, the
vertical side of the graft is thinned with a bur, and several holes are
made to facilitate its revascularization
Dr. Firas Kassab

Tibial Cancellous Autograft for Sinus Grafting
Various donor sites and bone harvesting technique are used
for the augmentation of the sinus floor prior to the placement of
osseointegrated implants, but seldom has the proximal lateral tibial
graft been utilized, despite its excellent accessibility and
availability. When the bone volume or bone quality is extremely
deficient, tibial graft is recommended.
Dr. Firas Kassab

Healing
The cancellous autogenous bone graft contains endosteal osteoblasts,
which can survive the transplantation process when handled appropriately. Also
transplanted are a host of growth factors, which provide the stimulus for
mesenchymal cell differentiation into osteoblasts, and growth promoters, which
accelerate bone production by these newly differentiated cells.
The cancellous graft heals by a combination of formation of new bone by
the transplanted osteoblasts, followed by the formation and remodeling of new bone
by the cells recruited from the periphery.
The cortioccancellous block graft provides transplanted osteoblasts and
growth factors as well as structural rigidity, which is frequently required when
implants are placed simultaneously. However, the cortical portion of the graft is
slow to revascularize and thus may be more prone to infection. The structural
rigidity of the graft allows accurate implant placement, independent of the thickness
of the sinus floor.
Dr. Firas Kassab

The healing of these bone grafts follows a course of events
that starts with basic wound healing and follows with bone
remodeling. Phase I bone healing includes osteoid production and
cellular proliferation. Phase 2 includes remodeling of the
disorganized phase 1 osteoid and replacement with lamellar bone.
In autogenous grafts, surviving osteoblasts and other cells are
responsible for primary bone production. These transplanted cells
survive through diffusion of nutrients during the first 4 days of
transplantation, during graft revascularization. The amount of bone
eventually produced by the transplanted cells is directly proportional
to the density of the surviving endosteal osteoblasts.
Dr. Firas Kassab

Autogenous Bone Combined with Demineralized Bone
Demineralized bone is bone that has had its mineral removed
through an acid treatment and then is washed and lyophilized until
reconstituted for use. When autogenous bone is demineralized, the
remaining organic substrate contains bone morphogenetic proteins.
Because the amount of autogenous bone available from the
jaws may be limited, demineralized bone can be combined with
autogenous bone to expand the graft’s volume. This combination of
autogenous bone expanded with allogeneic demineralized bone is a
useful method for obtaining phase I bone formation from the
autogenous bone graft as well as phase II bone formation from the
demineralized bone, and establishing the bulk of the graft.
Dr. Firas Kassab

Subnasal Elevation and Augmentation Procedure.
Surgical scrub is performed in the usual manner for the
placement of implants. After the surgical team scrubs, the patient is
draped. For intra oral preparation of the surgical site, a
Chlorhexidine antiseptic scrub and rinse can be used. Iodophor or
Chlorhexidine antiseptics can be used for preoperative extra oral
scrubbing of the skin.
Infiltration anesthesia has been successfully used, however a
more significant regional anesthesia occurs when the secondary
division of the maxillary nerve (V2) is blocked. With this technique,
anesthesia of the hemimaxilla, side of the nose, cheek, lip and sinus
area can be achieved.
Dr. Firas Kassab

Proper angulation of the needle prevents penetration into
the nasal cavity through the medial wall of the pterygopalatal
fossa.
A full thickness incision is made on the crest of the
maxillary ridge, from the distal end of the canine region to the
distal end of the contra lateral canine region.
A nasal undercut region is typically formed at the junction
of the lateral and inferior piriform rim that often corresponds to
the area of placement for implant (canine area). The nasal
mucosa in this region is elevated with a soft tissue curette in a
manner similar to that used for elevation of the mucoperiosteum
in subantral augmentation procedures. Depending on the depth of
the impression behind the piriform rim, the nasal mucosa is
elevated approximately 3 to 5 mm and then augmented with graft
material.
Dr. Firas Kassab

For subnasal augmentation, approximately 5 ml of cortical and
trabecular autogenous bone is harvested from the mandibular symphysis
and ground in a mill. This bone can then be mixed with freeze dried
bone allograft (if necessary to expand the volume) in 50 : 50 ratio and
compressed into a 1 - and 3 -ml tuberculin syringe. The mixture is
applied from the posterior regions of the nasal space to the most anterior
labial region of the nasal spine and piriform rim.
When subnasal augmentation is performed in conjunction with
iliac graft reconstruction of the maxilla, a 2- to 5- mm septal reduction is
performed in the anterior septum, taking care to avoid tears of the
mucosal lining of the nasal septum. A block graft that is 5 to 7 mm in
height is fixed with one or two miniscrews placed laterally; these can be
left permanently if facial augmentation is performed over them. This
provides enough stabilization for standard implants. If additional ridge
width is necessary, block grafts from the anterior mandible or ramus can
be used by fixation to the buccal aspect of the anterior maxilla. After
maturization of the graft, the appropriate sized implants can be placed.
Dr. Firas Kassab

Prior to suturing, the periosteum of the mucosal flap
covering the graft is horizontally scored with a scalpel to allow
tension free wound closure. The primary crestal incision and the
vertical relieving incisions are closed with 3-0 chromic or silk
sutures in either an interrupted or continuous mattress fashion. This
area should be permitted to heal for 4 to 6 months before implant
placement. In addition, the provisional partial denture or complete
denture should be adjusted to avoid contact with the grafted area.
Dr. Firas Kassab

Complications associated with maxillary sinus
augmentation
A) Intra operative complications
• Membrane perforation
• Fracture of the residual alveolar ridge
• Obstruction of the maxillary ostium
• Hemorrhage
• Damage to adjacent dentition
Dr. Firas Kassab

B) Early postoperative complications
• Wound dehiscence
• Acute infection
• Implant failure / loss
• Graft loss
• Exposure of barrier membrane
Dr. Firas Kassab

C) Late postoperative complications
• Graft loss
• Implant loss or failure
• Implant migration
• Oroantral fistula
• Chronic pain
• Chronic sinus disease
· Chronic infection
Dr. Firas Kassab

BONE GRAFT HANDLING
It is essential that the viability of the bone in the period
between its harvest and its placement be maintained. There are 4
important factors affecting graft cell viability .
1. Tonicity of storage medium
2. Temperature of storage medium
3. Sterility of bone cell handling
4. Trauma of bone handling.
Dr. Firas Kassab

1. STORAGE MEDIA
Distilled water and other hypotonic solutions are contraindicated as bone
cell storage media. These hypotonic solution diffuse through the cell membrane
resulting in swelling of cytoplasm, leading to cell death by physical rupture.
Hypertonic solution are also contra indicated as they draw the free water away
from cytoplasmic bone cells.
Blood and blood soaked sponges should not be used as clotted blood has
many membrane toxic intermediates of platelet aggregation and fibrin clot
formation including lysozyme, fibrin split products, osteoclastic, chemotactic,
factors etc. Also the blood soaked cells undergo a certain degree of drying,
causing cell death.
Saline is a good storage media, however the cellular activity is reduced
after saline immersion because bone cell growth factors are washed out of cells
stored in saline.
Dr. Firas Kassab

Tissue culture media, is an ideal storage medium. These are
isotonic balanced solution buffered at Ph. 7.42 and have organic and
inorganic cell nutrients. The advantage of tissue storage media is
that they maintain absolute cell viability, cell activity and do not
deplete intra cellular bone maintenance and growth factors.
2. TEMPERATURE
Chilling to point of physical freezing, maintains better cell
viability. Heating a storage medium is detrimental to survival as it
causes direct membrane and intra cellular protein coagulation with
enhanced toxicity from exogeneous agents. The media is kept
refrigerated at 4oC until its use. It is then allowed to warm towards
room temperature until placement.
Dr. Firas Kassab

3. STERILITY OF HANDLING
Incorporation of just a small inoculum of microorganism can
result in either clinical infection or subclinical graft cell death
yielding little bone. If overt contamination occur, graft should be
discarded, with another harvest taken. Graft can be irregular with
storage medium and finally antibiotic solution. Never autoclave
irradiate or treat it with any disinfectants or soaps.
4. ROUGH HANDLING
Bone cells are relatively resistant to rough handling by
compression or shearing forces. However excessive trauma by
crushing or when particulated into very small pieces, has caused
inflammation within tissue bud. Therefore trauma should be
minimal and tissue handling should be done with utmost care.
Dr. Firas Kassab

BIOLOGICAL MECHANISMS IN BONE GRAFTING
New bone formation occurs through three biologic
mechanisms
1. Osteogenesis
2. Osteo conduction
3. Osteo induction
Dr. Firas Kassab

1. Osteogenesis : Is the production of new bone by proliferation,
osteoid production and mineralization by transplanted osteo-
competent cells. It is the main mechanism exploited by surgeons to
graft large loss defects and it accounts for the greatest amount of bone
formed by the graft.
2. Osteoconductive : Is the production of new bone by the
proliferation and migration of local host osteocompetent cells along a
conduct. The conduct may be local vessels, epincurium allogeneic
bone or certain alloplasts the HA blocks. This accounts for a small
amount of the bone derived in bone reconstruction. This bone usually
originates from the endosteum of the host bone ends or residual
periosteum.
Dr. Firas Kassab

3. Osteoinduction: Is the formation of bone by connective tissue
cells trans formed into osteocompetent cells by inductive agents
usually proteins such as bone morphogenetic protein (BMP), skeletal
growth factor and osteogenin. This mechanism accounts for a small
amount of the bone produced by bone graft systems. This is an
important mechanism in inducing the recipient connective tissue
fibroblasts about the graft into a periosteum which accounts, partily
for its longevity.
Bone regeneration is responsible for healing of a bony graft
consisting of autogenous particulate bone and cancellous bone
marrow. The amount of bone produced in the graft is dependent on
the cellular density of the transplanted cancellous bone.
Dr. Firas Kassab

The critical bone transplant density as suggested by
simmons at the donor site is 2000 osteoblasts /mg of bone and
Frieden stein has reported that 1 106 osteocomponent cells/ cum are
needed within the recipient tissue bed for the formation of new
bone. The principle is basically to use cellular cancellous bone,
harvest a sufficient quantity of it and compact it into a high cell/unit
volume for maximal bone formation. It is for this reason the ilium is
the preferred donor site (4 times ostogenic cellularity of either
cortical bone sources and twice that of other cancellous bone
sources) 8-10cc of cancellous bone for each 1 cm of defect is a
simple yardstict one can fellow to ensure sufficient harvest of donor
bone. The bone can be compacted in by simple syringe compression
or hand instrument compression.
Dr. Firas Kassab

The transplanted cellular bone mainly the endosteal
osteoblasts on the cancellous surface, proliferate and produce new
osteoild. This bone produced is a cellular woven type of bone with
little structural organization. This is the first phase of bone and this
soon undergoes resorption and replacement to be replaced by a
second phase bone which is derived from the local cell population
of the host and is more structural. This phase is also responsible for
the longevity of the bone ossicle. Both the naturation of the bone
oesicle as well as its volume maintaining endosteal and periosteal
systems determine not only the longevity of the graft but as its
ability to remodel under applicances and even to osteointegrate
dental implants. It is also seen that the height and width of the graft
obtained at the time of its placement to the maximum it will ever be
as the osteocompetent cells proliferate and produce osteoid within
the limits of the cancellous bone volume.
Dr. Firas Kassab

GOALS OF RECONSTRUCTION / CRITERIA OF SUCCESS
There are certain goals toward which reconstruction should strive. These are :
1. Restoration of bone continuity
This, especially, in respect to the mandible helps in three ways namely.
a. Mandibular continuity restores much of the mechanical stability to the
function of mastication, speech and deglutition. Residual musculature,
adaptation of accessory muscles and the muscle of facial expression provide
adequate and sufficient function.
b. The patients self image improves. Thus he become more willing to return
to a normal life style.
c. Bony continuity of any part of the facial skeleton adds to more normal
contours and appearance, thereby providing foundation upon which more
enacting cosmetic procedure may be performed.
Dr. Firas Kassab

2. Restoration of osseous bulk : A thin and volume deficient
transplant is often associated with certain problems such as
a. They are prone to fractures
b. Usually do not supply sufficient contour.
c. Rarely support a prosthetic appliance
Osseous bulk is achieved by adhering to the biologic principles of graft
healing i.e.
i. Sufficient quantity of cellular cancellous graft materials
should be placed.
ii. Should be firmly fixated into a vascular and cellular tissue bed
free of contamination.
Dr. Firas Kassab

3. Restoration of alveolar bone height
Sufficient alveolar bone height is essential for the retention and stability
of conventional prosthesis and is necessary for implant systems to osteointegrate
effectively. Good alveolar bone height is accomplished in the dissection to
prepare the soft tissue for the graft. The dissection must free all scar within the
space of the mandible to a this overlying mucosa (1-3mm), without perforation
into the oral cavity. This is achieved by blunt dissection in this area with the
instruments spread parallel to the ridge or crestal scar, or by sharp dissection
palpating the maxillary dentition as a guide to tissue thickness, or by dissecting
under guidance from another member of the surgical team who has placed a
gloved hand within the oral cavity.
4. Bone maintenance
Maintenance of the bone ossicle throughout the left time of the patient is
one of the most important aspects of a successful reconstruction. Grafts that fail in
the first phase will show either.
Dr. Firas Kassab

Lack of bone formation or
b. Resorption of their non viable mineral matrix in the first 6
months.
Grafts that fail in the second phase will show resorption with
in 6-18 months. Grafts that maintain or increase their radiographic
mineral density beyond 18 months almost always maintain their
aside throughout the patients lifetime and can be considered
successful.
5. Elimination Soft tissue deficiencies
Residual soft tissue deficiencies often restrict tongue and lip
function and create unseating forces, and prevent a seal for
prosthesis. Such soft tissue deficiencies are eliminated either prior
to bone graft tissue flaps or after bone grafting with releasing
procedures using SSE or dermal grafts.
Dr. Firas Kassab

6. Restoration of facial contours
It is essential that facial form and function be restored and it is only after
this is done that cosmetic onlay grafts, contouring procedures and scar revisions
care staged.
ALLOPLASTIC CRIBS
All have features of biologic encapsulation non resorbability and biologic
inadaptability.
1. Dacron coated polyurethane crubs.
- Radiolucent therefore do not obscure post operative radiographic of graft
consolidation.
- Easily cut for contouring and shaping.
- Moderately flexible material but rigid enough to maintain its shape.
- Pore size is small but large enough to allow capillary in growth.
Dr. Firas Kassab

2. Titanium : more rigid
- Metal, obscures complete radiographic visualization of the
graft.
- Bio-lateral material
- Bendable and trimmable, more easily than other metals.
1. Stainless steel Very rigid difficult to cut or contour, and is
there customized for each patient.
Dr. Firas Kassab

Bone substitutes
1. Polymers : PMMA bone cement
PMMA / PHEMA
2. Bioinert alumina ceramics
3. Bioactive glass ceramics
4. Bioactive non glass ceramics
5. Corals – Biocorals
- Coralline HA
6. Hydronyapatite
Replam and interpore
Osprovit 200 – 600 mm pores
Cenos 80
Dr. Firas Kassab

7. Tricalcium phosphate
Cevos 82 TCP
Calciresorb
8. HA and TCP
Iriosite
Ostilit
9. CaCo3 (calcite)
10. Collagen
11. Collagen and particulate ceramic – collapat
12. Collagen and particulate ceramic – collagraft and ceraver osteal
produces
13. Carbon fiber implant
14. Ti mesh cylinder and fibremetal rods.
Dr. Firas Kassab

Summary and conclusion
The essence of a successful bone grafting is the variable transplantation
of osteocompetent cells. These cells must be sufficient in number and recipient
tissue bed must be sufficiently cellular and vascular to develop and maintain a
self remodeling bone.
Numerous grafts and its harvesting techniques have been proposed.
there is no real difference in the osteogenic potential of osteocompetent cells
from any of the popular donor sites.
The use of cortico-cancellous bone grafts for reconstruction was
proposed as it has a higher biomechanical rigitidy.
Autogenous bone grafts are used for various purposes like bridging gaps
in orthognathic surgeries and in preparing the implant sites. The advantage of
these graft is that large open areas will yield to revascularisation easily hence
bringing about new bone formation. Various techniques of harvesting bone
either black or particulate bone by the use of trephine has advantages over open
technique as morbidity and gait disturbance chance are low.
Dr. Firas Kassab

REFERENCES
1. Adll R, Eriksson B, Lekholm U, Branemark P.I. Jemt T.A. long- term
folow-up study of osseointegrated implants in the treatment of totally edentulous
jaws. Int J Oral Maxillofacial Implants 1990;5:347-35.
2. Albrektsson T, Zarb GA, Worthington P, Eriksson RA. The Long-term
efficcacy of currently used dental implants: a review and proposed criteria of
success. Int J oral Maxillofac Impalnts 1986;1:11-25.
3. Boyne PJ, James RA. Grafting of the maxillary sinus floor with
autogenous marrow and bone. J Oral Surg 1980; 38:63-616.
4. Branemark P-1, Adell R, Albrektsson T. An expermental and clinical
study of osseointegrated implants penetrating the nasal cavity and maxillary
sinus. J Oral Maxilofac Surg 1984;42:497-505.
Dr. Firas Kassab

5. Brunski JB. Biomaterials and biomechanics in dental implant
design. Int J Oral Maxilofac implants 1988;3:85-97.
6. Burchardt H. Biology of bone translantation Orthop Clin North
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