Bone grafts

Presented by:
Dr. Sapna K Vadera
(P.G. Student)
Guided by:
Dr. S.R.Shenoi
(Prof, Guide and H.O.D)
Dept Of Oral and Maxillofacial Surgery VSPM’S Dental College, Nagpur

Contents
• Definition
• Introduction
• What is a bone graft?
• History of bone graft
• Uses of bone graft
• Principles of bone grafting
• Risk factors for bone grafting
• Mechanism of bone regeneration and augmentation
• Types of bone grafts
• Sinus lift surgery
• Conclusion
• References

Definition...
Graft-
“is a piece of living tissue, organ etc transplanted
surgically”
-Oxford Dictionary.
“any tissue or organ for implantation or transplantation”
- Dorland’s Medical Dictionary 27th edition.

• Graft is a tissue that is detached from its own blood
supply and is placed in a new area (recipient site) with
a new blood supply i.e it does not maintain its original
blood supply.
• Flap is a tissue used for reconstruction or wound
closure that retains all or part of its original blood
supply after the tissue has been moved to the
recipient site i.e it maintains original blood supply.
Definition...
Craig M. Misch,autogenous bone grafting for dental implants, Raymond J Fonseca; Oral
and maxillofacial surgery;2nd edition:2009;saunders an imprint of elsevier inc.

Introduction
Bone grafts have been employed for repair for more
than a hundred years.It is a dynamic process and is
extensively used in reconstructive surgery.
Bone, which has been lost as a result of excision,
resorption or sequesterization, will not repair by
normal process of healing.
So they are to be replaced by means of alloplast, bone
grafts or its substitutes.
For a successful regeneration, bone graft when applied
should heal, become incorporated, revascularise and
eventually assume the desired form.
Kiokkevold R Perry , Localized bone augmentation and implant site development; Newman
Michael et al, Carranza’s Clinical Periodontology,12th edition: 2015; saunders an imprint of
elsevier inc.

To satisfy the ideal goals of implant dentistry, the hard and
soft tissues need to present ideal volumes and quality.
The alveolar process is affected so often after tooth loss,
augmentation is usually indicated to achieve optimum
results.
Because of an improved understanding of biomechanics,
requirements for long term prosthesis survival and the
increasing use of implants in esthetic restorations, ridge
reconstruction before implant placement has become a
necessary procedure for a number of edentulous patients.
Introduction
Kiokkevold R Perry , Localized bone augmentation and implant site development; Newman
Michael et al, Carranza’s Clinical Periodontology,12th edition: 2015; saunders an imprint of
elsevier inc.

History of bone graft
• The earliest known repair of cranial and facial defects is by
use of alloplast. Neolithic Peruvians used hammered gold
and silver plates over frontal bone defect.
• In 1889,Seydel was first surgeon to use autogenous bone
graft in facial region. He used autogenous bone from tibia.
• In 1978 & 1982 ,Bradley reported a two-stage procedure for
reimplantation of ‘autogenous freeze treated mandibular
bone.
Craig M. Misch,autogenous bone grafting for dental implants, Raymond Fonseca; Oral and
maxillofacial surgery;2nd edition:2009;saunders an imprint of elsevier inc.

• In 1989,McCarthy first applied the principle of distraction in
maxillofacial region.
• In 2008, R. Gutta and P.D. Waite described an extraoral
approach for cranial bone grafting with simultaneous implant
placement to the atrophic mandible.
• In 2010,Amrani et al. evaluated the utility of autogenous
extended mandibular ramus and coronoid process bone
grafts for maxillofacial reconstructive surgery.

• In 2013,Kolerman et al. conducted a study to evaluate the
regenerative potential of a fully synthesized homogenous
hydroxyapatite β-tricalcium phosphate alloplast material in
sinus lift procedures.

Uses of Bone graft
To encourage healing of non united fractures.To reconstruct posttraumatic deformity.To fill cavities following cyst enucleation.To restore continuity of bone following tumour excision.To improve facial contour for cosmetic purpose.To augment alveolar bone.To repair congenital defects.
Garg K Arun, Bone biology, Osseointegration, and Bone grafting, Implant Dentistry; 2nd
edition: 2010; an affiliate of elsevier inc.

Principles of Bone grafting
• Harvest bone from areas familiar.
• Contour bone graft to fit the defect.
• Fix the bone graft to the defect in a tension free manner.
• Ensure absolute immobilisation.

• Avoid contaminated sites.
• Do not have graft exposed.
• Ensure adequate blood supply to the graft.
• Assess “graft take” periodically.
Principles of Bone grafting

Risk factors for Bone grafting

Mechanisms of bone
regeneration and augmentation
• Osteogenesis
• Osteoinduction
• Osteoconduction

Osteogenesis
• Osteogenesis refers to the growth
of bone from viable cells
transferred within the graft.
• New bone is regenerated from
endosteal osteoblasts and
marrow stem cells transferred
with the graft.

Examples-
• Autografts
Osteogenesis

Osteoinduction
• Osteoinduction involves new bone
formation from osteoprogenitor
cells derived from primitive
mesenchymal cells under the
influence of one or more inducing
agents that arise from the bone
matrix.
• Capable of inducing bone
formation in a non-bony site by
recruiting and inducing(pluripotent)
cells to become osteoblasts

• The most commonly used
osteoinductive materials in
implant dentistry are bone
allografts and autografts.
• Frozen bone
• Freeze – Dried (FDBAs) and
• Demineralized freeze – Dried
(DFDBAs)
Osteoinduction

Osteoconduction
• Osteoconduction characterizes bone
growth by apposition from the surrounding
bone.
• Biocompatible material that provides a
physical structure into and along which
bone may grow

• The most common osteo-
conductive bone grafting
materials used in implant
dentistry are alloplasts and
xenografts.
Osteoconduction

Types of Bone grafts
Bone grafts can be classified:
1. Based on nature of bone (Graft anatomy).
2. Based on source of donor.
3. Based on form of grafts.
4. Based on grafting techniques.
5. Based on donor site.
Craig M. Misch Maxillary Autogenous Bone Grafting Oral and Maxillofacial Surgery Clinics of North
America - Volume 23, Issue 2 (May 2011) - Copyright © 2011 Saunders, An Imprint of Elsevier.

• Nature of the bone:
1. Cortical
3. Cortico-cancellous2. Cancellous

• Source of the donor:
1. Autogenous bone graft
2. Allograft
3. Isogenic bone graft
4. Xenografts
5. Composite grafts
6. Alloplastic materials (synthetic).

Characteristics:
• Historical standard of bone
grafting.
• ‘Gold Standard’
• Mechanisms:
- osteoconduction,
- osteoinduction, and
- osteogenesis

Considerations:
• Time of overall surgical procedure
• Second site surgery to procure
autograft
• Limited quantity of 50-55 cc

Complications:
• Blood loss
• Hematoma and arterial injury
• Nerve injury and numbness
• Hernia formation
• Infection
• Fracture and pelvic instability
• Cosmetic defects
• Chronic pain at donor site

Proposed Mechanism of Action:
Presence of osteoblasts provides direct osteogenesis,
presence of growth factors permits osteoinduction,
bone tissue allows osteoconduction.

2. Allograft
• Characteristics
• Cortical allografts may provide
structural support and may be
immediately load bearing.
• Various geometric and shapeable
forms.

ADVANTAGES:
• It reduces additional surgery and the
resultant morbidity.
• Operating time is reduced.
• All the bone required is readily
available
2. Allograft

DISADVANTAGES:
• Chances for disease transmission.
• Difficult storage of graft.
• Loss of viable osteo-progenitor
cells.
2. Allograft
• Graft rejection due to immune
reaction.
• Reputed tissue bank required.

Primarily acts through osteoconduction. Cancellous
allograft may have some osteoinductive potential but it will
vary depending on the source and how it was processed and
sterilized.
2. Allograft

A. Allograft Sub-set
Cortical bone with mineral removed (via
acid extraction) leaving collagenous and
non-collagenous proteins with a low
concentration of growth factors.

Characteristics:
• Contains type I collagen,non-collagenous proteins,and a
low concentration of growth factors (BMP) which may
impart osteoinductivity.

Primarily acts through osteoconduction.
Studies reports that the presence of growth factors
(e.g. BMP) imparts osteoinductivity.

B. Growth Factor Based
Growth factors bind to receptors
on cell surfaces stimulating the
formation of proteins to be used
inside the cell or externally (e.g.
formation of extracellular
matrices like bone tissue)

Bone MorphogeneticProteins (BMPs)
(aka recombinant human bone
morphogenetic protein or rhBMP)
Insulin-Like
Growth Factor 1 & 2
(IGF-1), (IGF 2)
Platelet Derived Growth
Factor (PDGF)
Transforming Growth
Factor Beta
(TGF-β)
Fibroblast Growth
Factor (FGF)
Growth
Factors

Considerations:
• Most common complications include osteolysis,
swelling/ edema, heterotopic bone formation, and
antibody reaction.

Acts via osteoinduction.
BMP binds to mesenchymal stem cell receptors resulting
in proliferation and differentiation into osteoblasts.

Platelet Rich Plasma (PRP) is obtained by fractioning
whole autologous blood by centrifugation
C. Cellular Based:
PRP

Characteristics:
• PRP contains PDGF, EGF,
and FGF-2 which stimulate
proliferation of osteoblast
progenitors.
• Also contains TGF-β which
increases type I collagen
synthesis.
C. Cellular Based:
PRP

Considerations:
• Outcome is donor dependent and varies with preparation
technique.
• Proteases present in the platelet fraction may degrade
some of the growth factors.
C. Cellular Based:
PRP

Platelet gels provide a rich source of growth factors
that direct mechanisms involved in bone healing and
subsequent osteogenesis.
C. Cellular Based:
PRP

3. Alloplastic materials
Alloplastic material:
A. Ceramic based
B. collagen based

• Calcium Sulfate
• Calcium Phosphate
• Synthetic Hydroxyapatite
• Tricalcium Phosphate (TCP)
COLLAGEN BASED MATERIAL
• Typically composites
with ceramic materials.
CERAMICS
3. Alloplastic materials

A.Ceramic Based
Characteristics:
• Osteoconductive
• Can be used in the presence of infection
• Resorption (5-7 week period)

Considerations:
• Mechanical properties variable, due to high dissolution
rate.
• Implantation should be limited to confined defects.
• Calcium sulfate – complications associated with
inflammatory reactions.
A.Ceramic Based

Calcium sulfate serves as an osteoconductive matrix for
the ingrowth of osteogenic cells.
A.Ceramic Based

B.Collagen Based
Characteristics:
• Collagen is the most abundant
protein found in bone tissue
• Osteoconductive matrix with a
favourable physical and
chemical matrix for bone
regeneration

Considerations:
• Weak structural and mechanical properties
• Collagen is usually coupled with other bone
substitutes (HA, β-TCP, bone marrow, etc.)
B.Collagen Based

• Primarily acts through osteoconduction and/ or via
mechanisms from the component that is added to
it.
B.Collagen Based

• Form of graft:
1. Bone blocks
2. Particulate bone
3. Bone slurry
4. Bone paste

1.Bone Blocks

2. Particulate Bone
-

3.Bone Slurry

4.Bone Paste

• The Grafting technique:
Onlay graftsClothes pin (H grafts)
Inlay graftsDowel graftsStrut grafts

• Donor site:
• Intra oral sites
• Extra oral sites.

Intra oral
Patrick J. Louis, Bone Grafting the MandibleOral and Maxillofacial Surgery Clinics of North
America;Volume 23,Issue 2 (May 2011).Copyright © 2011 Saunders, An Imprint of Elsevier.

Extra oral

DONOR SITE MAXIMUM VOLUME
Posterior iliac crest 140 ml
Anterior iliac crest 70 ml
Tibia 20-40 ml
Cranium 40 ml
Ascending ramus 5-10 ml
Mandibular symphysis 5 ml
Maxillary tuberosity 2 ml

The main donor sites are:
1. Mandibular Symphysis
2. Mandibular Ramus
3. Maxillary Tuberosity

The miscellaneous sites are:
1. Residual ridge crest area
2. Canine eminence areas
3. Lateral to the nasal spine
4. Maxillary and mandibular tori and exostosis
5. Particulate bone from implant drills and screw taps.

Mandibular Symphysis
Patrick J. Louis, Bone Grafting the Mandible Oral and Maxillofacial Surgery Clinics of North

Advantages-
• Easy access
• Corticocancellous block
morphology
• More cancellous bone than any other intra oral sites.

Contraindication-
• Mandible with longer anterior teeth
• Inadequate mandibular height or width
• Gross vertical bone loss
• Width augmentation spanning more than four teeth.

Complications-
• Damaged submental and sublingual arteries
• Damage to mandibular tooth roots
• Mental nerve paresthesia
• Temporary altered sensation of lower lip
• Chin ptosis

Mandibular Ramus

Complications-
• Potential damage to inferior
alveolar nerve
• Limitation of size and shape of graft
• Postoperative trismus
• Potential damage to lingual nerve during flap incision
Mandibular Ramus

Coronoid Process

Advantages
• No facial scarring or damage
to teeth.
• Harvesting the bone is relatively
easy.
Complications
• Trismus
• Damage to the buccal branch of the trigeminal nerve.
Coronoid Process

Maxillary Tuberosity
Kahnberg Karl-Erik, Bone Grafting Techniques for Maxillary Implants, 1st edition:
2005;Blackwell Munksgaard, a Blackwell Publishing company.

Complications –
• Oroantral fistula
• Hematoma formation
from disruption pterygoid
venous plexus.
Maxillary Tuberosity
Kahnberg Karl-Erik, Bone Grafting Techniques for Maxillary Implants, 1st edition:
2005;Blackwell Munksgaard, a Blackwell Publishing company.

Extra Oral Donor Bone Grafts
The Preferred extra-oral donor sites of
autogenous bone include:
1. Tibia
2. Cranium and
3. The iliac crest
4. At a lesser degree rib and fibula

Cranial Bone

Advantages –
• Slow resorption
• High stability for osteo
integration
• Low morbidity at donor site
• Easy screw fixation
• Harvesting of large grafts
Cranial Bone

Complications-
• Surgical wound infection
• Dural injuries
• Transitory neurological defects
• Epidural hematoma
• Alopecia
Cranial Bone

Tibia

Advantages-
• 20 to 40 cu.cm of noncompressed cancellous bone can
be harvested from the marrow space.
• Procedure straightforward
• Less surgical time 20-40mins
• Minimal postoperative pain and dysfunction.
• Immediate postoperative weight
• Blood loss is minimal
• Drainage is not required.
Tibia

Contraindication-
• Patients younger than 18 years
• Patients with knee injury or knee surgery
• Patients with advanced rheumatoid or degenerative
arthritis
• Patients with metabolic bone disease
Tibia

Complications-
• Potential entrance into joint space
• Post operative edema
• Large/unsightly scar
• Gait disturbance
• Fracture
Tibia

Iliac Crest

Advantages
• excellent source of large segments of cortico-cancellous
grafts or pure cortical or cancellous grafts.
• Sculptured segments can be used for onlay,
interposition or construction in craniomaxillofacial
surgery.
• Iliac cortico cancellous grafts are easily incorporated
into rigid fixation plates and provide immediate
mechanical strength.
Iliac Crest

Complications
• Perforation of the bowel
• Hernia
• Gait disturbance-damage to gluteus medius or
gluteus maximus muscle
Iliac Crest
• Cosmetic deformity
• Injury to sensory nerves-iliohypogastric nerve,
lateral femoral cutaneous nerve
• Fractures

Rib

Advantages-
• Can be harvested in length of 10 to 15cm and then split to
double the surface area of the graft.
• Cortico-cancellous ribs are quite malleable and are easily
fashioned for use in the curved contours of cranio-facial
skeleton.
• Rib regenerate from the ends if the periosteal sheath is
preserved.
Rib

Disadvantages-
• The regenerated bone from the rib is never the same
quality as the original rib.
• Potential for pneumothorax, chest wall depression,
persistent pleuritic pain with exercise.
• The cortices are thinner. So incorporation of implants
are not successful.
• It has minimal cancellous bone
Rib

Sinus Lift Procedure Using
Bone Graft

Conclusion
Choice of graft should be according to osteogenic
potential of the site and the type of defect.
Intra oral autogenous bone grafts and allografts (FDBA)
are used in small defects with low to moderate
osteogenic potential.
Moderate to large reconstructions in defects of low to
moderate osteogenic potential are treated with extra oral
autogenous bone grafts-iliac crest grafts and tibial graft.
Small reconstruction with high osteogenic potential is
usually done with alloplasts like anorganic bovine bone
& microporous hydroxyapetite
Patients should be informed about possible
complications associated with bone harvest as well as
complications that may develop at the grafted site.
The predictable outcome of these procedures
depends on several biologic principles that must be
followed.
Diagnosis, treatment planning, careful execution of the
surgical treatment, postoperative follow-up, and
appropriate implant loading are all important factors in
achieving success.
Craig M. Misch Maxillary Autogenous Bone GraftingOral and Maxillofacial Surgery Clinics of North
America - Volume 23, Issue 2(May 2011) - Copyright © 2011 Saunders, An Imprint of Elsevier.

References
• Craig M. Misch,autogenous bone grafting for dental implants,
Raymond J Fonseca; Oral and maxillofacial surgery;2nd
edition:2009;saunders an imprint of elsevier inc.
• Kiokkevold R Perry , Localized bone augmentation and implant
site development;Newman Michael et al, Carranza’s Clinical
Periodontology,12th edition:2015;saunders an imprint of
elsevier inc.
• Garg K Arun, Bone biology, Osseointegration, and Bone
grafting, Implant Dentistry;2nd edition:2010; an affiliate of
elsevier inc.

• Kahnberg Karl-Erik, Bone Grafting Techniques for Maxillary
Implants, 1st edition:2005;Blackwell Munksgaard, a Blackwell
Publishing company.
• Patrick J. Louis, Bone Grafting the Mandible Oral and Maxillofacial
Surgery Clinics of North America - Volume 23, Issue 2 (May 2011) -
Copyright © 2011 Saunders, An Imprint of Elsevier.
• Craig M. Misch Maxillary Autogenous Bone Grafting Oral and
Maxillofacial Surgery Clinics of North America - Volume 23, Issue
2(May 2011) - Copyright © 2011 Saunders, An Imprint of Elsevier.
References

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