Tissue grafting /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


TISSUE GRAFTINGBIOLOGICAL CONSIDERATIONS
OF AUTOGENOUS &
HETEROGENOUS GRAFTS


INTRODUCTION
Surgeons do not heal tissue; they merely
place it where nature can heal it.
 DEFINITION
 TYPES OF TISSUE

GRAFTS


WHAT IS BONE GRAFT ?


Classification of bone
grafts
 Four types of bone grafts :
• Autograft or autogenous graft
• Allograft or homograft
• Xeno graft or hetrograft
• Alloplast


AUTOGENOUS BONE GRAFTS
 Advantages

 Disadvantages


Clinically, grafts can be classified :

•

Site of origin :
 Extra oral

 Intra oral

•

Graft anatomy :
 Cortical
 Cancellous
 Corticocancellous

•

Vascular autografts :
 Free tissue transplants
 Pedicle flaps

SITE OF ORIGIN
EXTRA ORAL SITES
INTRA ORAL SITES


GRAFT ANATOMY
 Cortical
 Cancellous

 Corticocancellous
 Bone slurry


CORTICAL BONE GRAFT
 Cortical bone grafts have strictly limited clinical

applications.
 Primarily used in area where there is great
mechanical stress


Cancellous bone graft


Corticocancellous bone
graft


POTENTIAL FUNCTIONS OF BONE
GRAFT :
 Osteogenic activity

 Osteoconductive activity
 Osteoinductive activity
 Vascularity


OSTEOGENESIS


DIFFERENT FORMS OF BONE
GRAFTS
 VASCULARISED GRAFT
 NON –VASCULARISED GRAFT


OSTEOINDUCTION
 Chemotaxis

 Mesenchymal cell proliferation
 Mesenchymal cell differentiation
 Cartilage into the bone


Growth factors
 Platelet derived growth factor
 Transforming growth factor

 Insulin like growth factor
 Endothelial growth factor
 Fibroblast growth factor


BONE MORPHOGENETIC PROTEIN
 MARSHALL R. URIST

 Functions of BMPs
 Types of BMPs


OSTEOCONDUCTION
 Creeping substitution


Healing of autograft:
• Inflammation
• Revascularization
– 2x time for Cancellous grafts due to
porosity
• Osteoinduction
• Osteoconduction
• Remodeling


Healing of allograft:
 OSTEOINDUCTION

 OSTEOCONDUCTION-

“Creeping substitution”


FACTORS IMPORTANT FOR
SUCCESSFUL INCORPORATION OF
AUTOGENOUS BONE GRAFT
Revascularisation
Structure & biomechanical features
Rigid fixation of the graft
Local growth factors
Embryological aspect


Factors affecting
revascularisation





Recipient bed environment
Graft microarchitecture
Rigid fixation
periosteum


GRAFT MICROARCHITECTURE


Rigid fixation of the graft


periosteum

 Fibrous layer
 Cambium layer


Embryological aspects
 Membranous bone

 Endochondral bone.


SKIN GRAFTING
Involves the removal of skin from one site and
reattachment at another site.


CLASSIFICATION OF SKIN
GRAFTS

Andreasi; Clinics of Dermatology 2005 : 332-337

G

R
A
F
T

T
H
I
C
K
N
E
S
S

A-THIN SPLIT THICKNESS(THIERSCH) GRAFT.
B-SPLIT THICKNESS SKIN GRAFTS.(0.012-0.018 inch)
C-THREE QUARTER SKIN GRAFTS.
D-FULL THICKNESS SKIN GRAFTS.

SPLIT THICKNESS SKIN GARFTS
INDICATIONS

Temporary coverage for a wound
 Large defect coverage too large for FTSGs


Disadvantages Relatively poor cosmetic result
 Contraction
 Abnormal pigmentation


FULL THICKNESS SKIN GRAFT
INDICATIONS To avoid functional deformity
 To achieve good cosmesis
 When there is insufficient skin to create a

local flap
 When distant flaps are inappropriate


ADVANTAGES Resists contraction
 Good colour match
 Good texture

 Use in children


WOUND PREPARATION


BOLUS DRESSING

1. Ensure that there are no blood clots underneath the graft.
2. Inner layer of petrolatum gauze is applied and the sutures are kept long.

3. Layer of fluffed gauze is applied and the sutures are tied. Assistant holds first loop
to prevent slippage.
4. Avoid removal before 7 th day.

VARIATION OF THE BOLSTER TIE DOWN DRESSING


PHASES OF SKIN GRAFT
SURVIVAL
 Plasmatic imbibition-

Hubscher & Goldman
Clemmesen
Smahel


GRAFT REVASCULARIZATION
Autografts and allografts.

Bert -

“abouchement”

Thiersch - “inosculation”
Garre - made the following observations…
1. 5 ½ hours- endothelial mitosis in host bed.

2. 9 hours - presence of inflammatory cells in the grafts.
3. 11 hours - invasion of white cells into the donor vessels
4. Third or fourth day- actual revascularization as an invasion of the graft
by host capillary buds.


Factors influencing graft
viability:
 Blood supply to recipient bed

 Microcirculation on the surface of the
recipient bed
 Vascularity of the donor graft tissue

 Contact between graft and recipient bed
 Patient’s overall health


Skin Graft “Take.”

Cellular Hyperplasia

MATURATION

Graft contraction

Pigment changes

Dermal Collagen Turnover

Epithelial appendages

Innervation of skin Grafts

Durability and Growth

DONOR SITE HEALING
 SPLIT THICKNESS GRAFT

 FULL THICKNESS GRAFT


1. INADEQUATE GRAFT BED – non viable tissue,
crushed material, foreign bodies, excessive
fibrosis, irradiation.
2. HEMATOMA
3. MOVEMENT
4. INFECTION
5. TECHNICAL ERRORS SUCH AS
•

PLACEMENT OVER EPITHELIZING WOUNDS,

•

GRAFTS CUT TOO THICK OR THIN OR UPSIDE DOWN.

6. POOR STAGE OF GRAFTS.

CONCLUSION


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Tissue grafting /certified fixed orthodontic courses by Indian dental academy

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Tissue grafting /certified fixed orthodontic courses by Indian dental academy