د حاتم البيطار استشاري وجراح الفم والاسنان 01005684344 اتصل للحجز بالعيادة Dr.Hatem EL-Bitar

2. Low Level LASER(LLLT)
Therapy(Biostimulation).

3. Laser classification according
power
 Lasers were classified according to power
into
 1-Hard or hot surgical
lasers(CO2,Nd:YAG……..)These types of
lasers are usually used with high power I.e
power is measured in watt.
 2-Cold or soft lasers (Diode,HeNe in red and
IR region) The power is usually measured in
mw.

4. Advantages of LLLT
 Accelerate wound healing
 Enhance repair and remolding of bone
 Accelerate restoration of normal neural
function after injuries
 Pain attenuation
 Stimulate endorphin release

5. Biological effects of LLLT
 The major absorption
structures(chromospheres) for red and near
IR used in LLLT are proteins
 The exact receptor is still not known but it is
believed that it may be present in
mitochondrial cytochrome system or
endogenous prophyrins in the cell
 Penetration depth of laser energy ranges 5-
10mm(may be coherent or non coherent eg
NASA)

6. Effect on fibroblasts
 The low doses e.g. 2J /cm² stimulates
proliferation ,while higher doses e.g. 16J/ cm²
suppress proliferation
 Fibroblast maturation and locomotion
through matrix so increase the tensile
strength
 In low doses stimulate production of basic
fibroblast growth factor (bFGF) so increase
proliferation.

7. Transformation of fibroblasts to
myofibroblasts responsible for wound
contraction which occurs early as 24 h
after laser irradiation
LLLT stimulate immune cells to secrete
cytokines and other growth regulatory
factors for fibrobalsts
Macrophages release unknown factor
which promote fibroblast proliferation

8. Effect Of LLLT on immune cells
 Increase both phagocytosis and
chemotactic activities so enhances
debridment and establish conditions
necessary for proliferative phase

9. Effect OF LLLT on epithelial
cells
 LLLT increases the mobility of human
keratinocytes

10. Effect OF LLLT on bone cells
 Increases cell proliferation and DNA
synthesis (when the cells in active
phase)
 Invitro it increases accumulation of
calcium in bone and accelerate
calcification

11. Effect on blood vascular system
 Vascular spasm can result in tissue
ischemia , and has been linked to a
many painful conditions .LLLT can
induce relaxation in vascular smooth
muscles so decrease ischemia and so
lower pain

12. Soft tissue applications of LLLT
 1-Rheumatoid arthritis , chronic pain
and muscle strain
 2-Accelerate wound healing
 3- Accelerate healing of dentoalveolar
abscess
 4Analgesia either direct or indirect as in
case of acupuncture
 5-Nerve regeneration

13. 6-Post surgical pain
7-Sinusitis (improves
microcirculation and reduce edema
8-Post herpetic neuralgia
9-Gingivitis

14. LLLT in hard tissue
 Treatment of TMJ pain
 Decrease dental hypersensitivity by inducing
changes in neural transmission network
within the pulp
 Decrease periodontal ligament pain during
tooth movement in orthodontic treatment by
decreasing secretion of prostaglandins and
interleukin-1
 Effect on microorganisms (PDT)
 Never use LLLT in cancer patient

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16. Laser in phototherapy
Presented by :
• Ahmed
• Adham
• Kawther
• Ghada seif mohammed
Photochemistry and photobiology group.
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17. Laser used in medical applications
laser alone
• Photo ablation
• Lasik
• Enhance healing
• Photocoagulaton
• tatoo
With photosensitizer
• In photo dynamic
therapy (PDT)
• treat superficial cancers
• destroy tumors
• relieve certain symptoms
of cancer
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18. Laser alone
• is often given through a flexible endoscope
• It is inserted through an opening in the body
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19. Laser in PDT
• PDT
What is PDT
Mechanism
• What is photosensitization and photosensitizer
Two possible mechanisms
Good photosensitizer
• Singlet oxygen
• Treatment using laser
Types of laser used incancer therapy
Advantage
Limitations
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20. What is PDT
Is a ternary treatment for cancer in which
• PDT uses laser, or other light sources, combined with
a light-sensitive drug to destroy cancer cells
• It is also being investigated for treatment of psoriasis
and acne, and is an approved treatment for wet
macular degeneration.
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21. Mecanism of PDT
In PDT, visible light, a light sensitive drug
(photosensitizer) and oxygen are combined,
leading to the production of reactive oxygen
species to inactivate ( or destroy) tumor
cells, viruses, bacteria….
It involves two main processes
1) Photosensitization of the patient
2) Exposure of the photosensitized patient to
light preferably laser light
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22. • Mechanism:
a) Sensitizer + hv  Sensitizer*
b) Sensitizer* + 3O2 Sensitizer + 1O2
c) 1O2 + Substrate  Oxidative damage
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23. Photosensitization and photosensitizer
• Photosensitization is a reaction to light that is mediated by a
light-absorbing molecule that is not the ultimate target
observed or assessed.
• . photosensitizer is a chemical compound that readily
undergoes photoexcitation and then transfers its energy to
other molecules, thus making the reaction mixture more
sensitive to light.
• NOT all light-absorbing molecules are photosensitizers
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25. Two possible Mechanisms
• Type I photosensitization the excited
photosensitizer (3Sen*) abstracts an
electron/hydrogen atom from another
component
• Type 2 reactions the photosensitizer transfers
its excitation energy to ground state dioxygen
resulting in singlet oxygen (1O2) and ground
state photosensitizer.
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27. Good photosensitizer
• Absorb photons efficiently (have high molar extinction coefficient)
• Have a high quantum yield of triplet formation
• The triplet must be long-lived
• Able to donate and /or accept electron easily (type I)
• Generate 1O2 with high yields
• Cell penetration
• Extent relation to quenchers
• Best if amphiphilic
• transparency of biological tissues
• minimum toxicity in the dark
• rapidly excreted from the body
• (Basic or acidic ( according to the type of target substrate
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28. Singlet oxygen
• When O2 has excess energy, the two unpaired electrons in the
outer orbital can pair up. Giving singlet oxygen.
• There are two forms of singlet oxygen
1) Short lived , highly reactive 1O2
2) 1 O2 is involved in photosensitization.
Singlet oxygen is not a free radical because all electrons are spin-
paired. It is electrophilic and thus reacts readily with electron-rich
molecules
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29. Photosensitizer and oxygen
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30. Treatment using laser
• photosensitizer or photosensitizing agent, is
injected into a patient and absorbed by cells
all over the patient’s body
• After a couple of days, the agent is found
mostly in cancer cells.
• Laser light is then used to activate the agent
and destroy cancer cells.
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32. · What types of lasers are used in
cancer treatment?
• CO2 and argon lasers can cut the skin’s surface
without going into deeper layers
• Argon lasers are often used to activate the
drugs used in PDT.
• Nd:YAG laser is more commonly applied
through an endoscope to treat internal organs
• . Each of these can shrink or destroy tumors
and can be used with endoscopes
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33. Advantages of Lasers in PDT.
 Monochromaticity provides maximum effectiveness
 Lasers can produce high irradiance to minimize the
therapeutic exposure time
 Lasers can be readily coupled to fiberoptics, enabling light
delivery to any organ
Output needs to be 1-4W
 Drug free, pain free, side effect free
 Reduction or elimination of withdrawal symptoms and the
pain
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34. several limitations of laser therapy
• expensive and requires bulky equipment
• may not last long, so may have to repeat
• Surgeons must have specialized training
before they can do laser therapy
• strict safety precautions must be followed.
• There are many environmental considerations
(smoking)
• Sensitivity to light , Swelling
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