Topic 11 (Wound Healing) Flashcards
It is a process by which the tissues are restored to an anatomic and physiologic arrangement after they have been injured, to prevent irritants from entering into the underlying tissues which may cause infection.
Healing
is the process of repair that follows injury to the skin and other soft tissues.
Wound healing
It is the interaction of a complex cascade of cellular events that generates resurfacing, reconstitution, and restoration of the tensile strength of injured tissue.
Healing
Under the most ideal circumstances, healing is a systematic process, traditionally explained in terms of 3 classic phases:
- Inflammation
- Proliferation
- Maturation
Damaged cells release histamine
Inflammatory Exudative 1-3 Days Approx
Histamine causes vasodilatation of the surrounding capillaries
Inflammatory Exudative 1-3 Days Approx
Increased blood supply brings about oedema & engorgement resulting in the inflammatory
appearance.
Inflammatory Exudative 1-3 Days Approx
The exudate assists in dilution and flushing out of microbes and toxins.
Inflammatory Exudative 1-3 Days Approx
This a natural response to injury and does not indicate infection.
Inflammatory Exudative 1-3 Days Approx
Signs & symptoms: heat, redness, pain, swelling, loss of function.
Inflammatory Exudative 1-3 Days Approx
What does the damage cells release?
Histamine
What causes vasodilation of the surrounding capillaries?
Histamine
Histamine causes ____ of the surrounding capillaries.
Vasodilation
What are the signs and symptoms during inflammatory exudative?
- Heat
- Redness
- Pain
- Swelling
- Loss of function
Stage 2-3 days after injury (can last for weeks)
Proliferative Regeneration Stage
A process includes:
- Granulation
- Contraction
- Epithealisation
Proliferative Regeneration Stage
In this phase of normal healing, the wound remains red and raised
Proliferative Regeneration Stage
In this stage, new blood vessels are formed.
Proliferative Regeneration Stage
In this stage, wound contraction begins.
Proliferative Regeneration Stage
Later stages proliferation occurs.
Proliferative Regeneration Stage
In this stage, Epithealisation occurs.
Proliferative Regeneration Stage
What is the other term for Maturation?
Reparative
In this phase tensile strength increases.
Maturation/Reparative
This can take considerable time - 12 months or longer.
Maturation/Reparative
The maximum tensile strength (following wound breakdown and repair) that can be obtained is 80% of previous skin strength.
Maturation/Reparative
At first the wound is pink, but gradually contracts to become a pale scar.
Maturation/Reparative
Hair follicles and sweat glands that are lost in open wounds are usually not replaced.
Maturation/Reparative
These wounds cannot be thought of as completely healed and can breakdown again.
Maturation/Reparative
The maximum tensile strength that can be obtained is ____ of previous skin strength.
80%
During this stage, what are lost in open wounds and are usually not replaced?
Hair follicles and sweat glands
What are the 2 Major Ways of Healing:
Regeneration and Repair
It is the restoration of destroyed tissue by the same kind of cells.
Regeneration
It is the restoration of function and tissue continuity but distortion of the normal architecture.
Repair
Repair by dense connective tissue is a formation of ____.
Scar Tissue
It is a formation of scar tissue.
Repair by dense CT
What are the 2 types of Wound Healing:
- Primary Union
- Secondary Union
Healing by first intention
Primary Union
Healing by secondary intention
Secondary Union
Narrow space between 2 cut surfaces of a wound undergo bleeding.
Primary Union/First Intention
Margins of the wound undergo mild acute inflammation releasing plasma and PMNL into the space.
Primary Union/First Intention
After 24 hours, caplliaries begin to grow into the wound space, followed by macrophages and fibroblasts.
Primary Union/First Intention
Macrophages phagocytose wound debris and hemosiderin from hemoglobin breakdown
Primary Union/First Intention
Fibroblasts begin to form ground substance
Primary Union/First Intention
Cells from the wound margin undergo mitosis and
move toward the center of the wound forming a
complete but thin epithelial covering
Primary Union/First Intention
The epithelium undergo maturation to regain full thickness.
Primary Union/First Intention
The underlying C.T. scar becomes fibrous and
avascular.
Primary Union/First Intention
Healing is complete in 2-3 weeks.
Primary Union/First Intention
After 24 hours, ____ begin to grow into the wound space, followed by macrophages and fibroblasts.
After 24 hours, caplliaries begin to grow into the wound space, followed by macrophages and fibroblasts
After 24 hours, caplliaries begin to grow into the wound space, followed by ____ and ____.
After 24 hours, caplliaries begin to grow into the wound space, followed by macrophages and fibroblasts
____ begin to form ground substance.
Fibroblasts
Cells from the wound margin undergo ____ and
move toward the center of the wound forming a
complete but thin epithelial covering
mitosis
The epithelium undergo ____ to regain full
thickness
maturation
The underlying C.T. scar becomes ____ and ____.
fibrous and avascular
In Primary Union, healing is complete in ____.
2-3 weeks
The 2 cut surfaces cannot be approximated so there is a large gap.
Secondary Union/Secondary Intention
There is bleeding, followed by blood clot formation Mild short-lived acute inflammatory reaction occur in the wound margins.
Secondary Union/Secondary Intention
Granulation tissue begins to move into the wound base and sides.
Secondary Union/Secondary Intention
Granulation tissue is made of:
- Capillary buds
- Fibroblasts
- Macrophages
- Plasma cells
- Lymphocytes
The macrophages fibroblasts, PMNL remove tissue debris.
Secondary Union/Secondary Intention
As the fibrous tissue is laid down in the deeper layers of the wound, this granulation tissue heals the wound from the base then going up to the layers above.
Secondary Union/Secondary Intention
As more collagen layers are formed in the granulation tissue, the wound undergoes contraction, showing fibroblastic activity.
Secondary Union/Secondary Intention
The space between the 2 edges of the wound is closed by granulation tissue and wound contraction thus closing the wound by epithelial migration and mitosis
Secondary Union/Secondary Intention
What are the Stages of Wound Healing:
- Coagulation/Inflammation
- Tissue Formation
- Remodeling
Wound Healing:
- Mins
- Hrs
- Days
Coagulation/Inflamation
Wound Healing:
Weeks
Tissue Formation
Wound Healing:
Months
Remodeling
- Hemostasis
- Neutrophils
- Monocyte
Coagulation/Inflammation
- Keratinocytes
- (Myo)Fibroblasts
- Endothelial cells
Tissue Formation
- Collagen
- Scar Appearance
Remodeling
Re-epithelialization
Keratinocytes
MMP Production
Keratinocytes
ECM Formation
(Myo)Fibroblasts
MMP Production
(Myo)Fibroblasts & Endothelial Cells
Angiogenesis
Endothelial Cells
Small, parallel bundles
Collagen
Thin Fibers
Collagen
Thin Fiber
Collagen
Increased Synthesis and Crosslinks
Thin Fibers and Thick Fibers
Flat and Discolored
Normal Scars
Scar raised
Hypertrophic Scars
Scar raised and Spread beyond wound boundaries
Keloid Scars
- Blood clot
- Blood Vessel
Bleeding/Hemostasis
- Scab
- Fibroblast
- Macrophage
- Blood Vessel
Inflammation
- Fibroblast proliferating
- Subcutaneous fat
Proliferation/Proliferative
- Freshly healed epidermis
- Freshly healed dermis
Remodeling
Give the 4 stages of Wound Healing:
- Hemostasis
- Inflammatory
- Proliferative
- Remodeling
Cut blood vessels bleed into the wound.
Hemostasis Phase
Blood clot forms, and leukocytes clean wound.
Inflammatory Phase
Blood vessels regrow, and granulation tissue forms.
Proliferation Phase
Epithelium regenerates, and connective tissue fibrosis occurs.
Maturation/Remodeling Phase
cells stick together to form a blood clot to stop the bleeding, and inflammatory molecules move into the wound to start the process of healing.
Blood Clotting
Initial response to wound healing
Hemostasis
network of fibrin thread in which varying amounts of platelets and blood cells are enmeshed; formed within 5 to 10 minutes after injury.
Clot
Clot formed within ____ after injury.
5 to 10 minutes
formed by a meshwork of fibers, red blood cells and platelets.
Clot
beginning of inflammatory process.
Next 24 to 48 hrs
Infiltration of ____ and ____.
Neutrophils and Macrophages
Other name for Neutrophils
polymorphonuclear leukocytes
It is the first inflammatory cell to invade the wound.
Neutrophils (polymorphonuclear leukocytes)
to remove bacteria
Nautrophil/PMNL
What is the main function of PMNL
to remove bacteria
Cells reach a maximum concentration at about ____ before they die.
24 hrs
Convert to macrophages which initiate tissue repair.
Monocytes
Their accumulation at the wound site is considered to be histologic sign of acute inflammation.
Neutrophils (polymorphonuclear leukocytes)
Wound fluid that contains dead neutrophils, wound debris and other factors.
Pus
predominant cell type in damaged tissue at 5 days.
Macrophage and Mononuclear Leukocytes
Participate in connective tissue formation by providing nutrients & oxygen.
Blood Vessels
Secrete bioactive substances (endothelial cells) and allowing inflammatory cell migration to the site of injury.
Blood Vessels
Blood vessels participate in connective tissue formation by providing ____ and ____.
Nutrients and Oxygen
Blood vessels secrete ____ and allowing inflammatory cell migration to the site of injury.
Bioactive Substances (Endothelial Cells)
is a mark left in the tissue after the wound heals
Scar
Represents an area that has a slightly higher than normal ratio of collagen fibers
Scar Tissue
Gingival tissues will heal with practically no scar formation.
Scar Tissue
What tissue will heal with practically no scar formation?
Gingival Tissues
- Matrix formation
- Remodelling
Final Stage of Wound Healing
The wound finishes closing over and becomes strong enough to allow for complete healing
Stage 4 (Remodeling)
Superficial wounds that only affect the top layer of skin do not scar.
Stage 4 (Remodeling)
Deeper wounds may cause some degree of scarring.
Stage 4 (Remodeling)
Wounds that only affect the top layer of skin do not scar.
Superficial wounds
Wounds may cause some degree of scarring.
Deeper wounds
Give the factors which influence wound healing in the mouth:
- Blood Supply
- Size of the wound
- Foreign Material
- Early Movement
- Infection
- Alveolar Osteitis
The most important factor in proper wound healing.
Blood Supply
The larger the wound, the more time needed for repair.
Size of the wound
The most common causes of Complication in post extraction healing
Foreign Material
Give the examples of Foreign Material:
- Suture
- Enamel
- Amalgam
- Bone
- Fragments
- Calculus
- Food debris
This is a particular cause of delay in bone fracture healing.
Early Movement
The most important post extraction complication.
Infection
The most common cause of delayed post operative pain
Alveolar Osteitis
The loss of blood clot from the socket, foul odor, severe radiating pain
Alveolar Osteitis
Symptoms: start on the 3% to 5th day after extraction
Alveolar Osteitis
Treatment: relief of pain and irrigation of the socket
Alveolar Osteitis
Alveolar Osteitis symptoms start on the ____ after extraction
3% to 5th day
Alveolar Osteitis treatment ____ and ____.
relief of pain and irrigation of the socket