This document provides an overview of lasers used in oral and maxillofacial surgery. It discusses the history of lasers, laser physics including population inversion and stimulated emission, laser design components, methods of laser light delivery including articulated arms and optical fibers, laser focusing modes, and different types of lasers including CO2, Nd:YAG, and argon lasers. The key properties and applications of each laser type are described.

1. GITAM DENTAL COLLEGE & HOSPITAL
DEPARTMENT OF
ORAL & MAXILLOFACIAL SURGERY
SEMINAR ON
LASERS IN ORAL &
MAXILLOFACIAL SURGERY
Presented By:
Dr. Sambhav K Vora
II. MDS
1

2. CONTENTS-
1. Introduction
2. History of lasers
3. Laser physics
4. Laser design
5. Focusing
6. Laser types-
 Carbon-di-oxide laser
 Nd:YAG laser
 Argon laser
 Er:YAG laser
 Ho:YAG laser
7. Interactions with biologic tissues
8. Laser effect on dental tissues
9. Lasers in Preneoplasia of oral cavity
10. Lasers for soft tissue excision
11. Skin resurfacing in the aesthetic zone
12. Resection of the cancer
13. Laser assisted uvulopalatoplasty
14. Lasers in laryngeal surgery
15. Laser hazards & safety
16. Conclusion
17. References
2

3. Introduction
Laser is an acronym, which stands for light amplification by stimulated
emission of radiation. Several decades ago, the laser was a death ray, the
ultimate weapon of destruction, something you would only find in a science
fiction story. Then lasers were developed and actually used, among other
places, in light shows. The beam sparkled, it showed pure, vibrant and intense
colors. Today the laser is used in the scanners at the grocery store, in compact
disc players, and as a pointer for lecturer and above all in medical and dental
field. The image of the laser has changed significantly over the past several
years.
With dentistry in the high tech era, we are fortunate to have many
technological innovations to enhance treatment, including intraoral video
cameras, CAD-CAM units, RVGs and air-abrasive units. However, no
instrument is more representative of the term high-tech than, the laser. Dental
procedures performed today with the laser are so effective that they should set
a new standard of care.
This presentation intends to discuss the role of lasers in dentistry.
History of Lasers
• Approximately, the history of lasers begins similarly to much of modern
physics, with Einstein. In 1917, his paper in Physikialische Zeil, “Zur
Quantern Theorie der Strahlung”, was the first discussion of stimulated
emission.
• In 1954 Townes and Gordon built the first microwave laser or better
known as ‘MASER’ which is the acronym for ‘Microwave Amplification
by stimulated Emission of Radiation’
• In 1958, Townes, working with Schawlow at Bell Laboratories, published
the first theoretic calculations for a visible light maser – or what was then
called a LASER.
• In May 1960, Theodore Maimen at Hughes Aircraft company made the
first laser. He used a ruby as the laser medium.
3

4. • One of the first reports of laser light interacting with tissue was from
Zaret; he measured the damage caused by lasers incident upon rabbit
retina and iris.
• The first gas laser was developed by Javan et al in 1961. This was the first
continuous laser and used helium – neon.
• The Nobel Prize for the development of the laser was awarded to Townes,
Basor and Prokhovov in 1964.
• The neodymium – doped (Nd): glass laser was developed in 1961 by
Snitzer.
• In 1964 Nd: YAG was developed by Geusic.
• The CO2 laser was invented by Patel et al in 1965.
• In 1968 Polanyi developed articulating arms to deliver CO2 laser to remote
areas.
• Polanyi in 1970 applied CO2 laser clinically.
• In 1990 Ball suggested opthalmologic application of ruby laser.
Laser Physics2
Laser is a device that converts electrical or chemical energy into light
energy.
In contrast to ordinary light that is emitted spontaneously by excited
atoms or molecules, the light emitted by laser occurs when an atom or
molecule retains excess energy until it is stimulated to emit it. The radiation
emitted by lasers including both visible and invisible light is more generally
termed as electromagnetic radiation. The concept of stimulated emission of
light was first proposed in 1917 by Albert Einstein.
4

5. He described three processes:
1. Absorption
2. Spontaneous emission
3. Stimulated emission.
Einstein considered the model of a basic atom to describe the
production of laser. An atom consists of centrally placed nucleus which
contains +vely charged particles known as protons, around which the
negatively charged particles. i.e. electrons are revolving.
When an atom is struck by a photon, there is an energy transfer causing
increase in energy of the atom. This process is termed as absorption. The
photon then ceases to exist, and an electron within the atom pumps to a higher
energy level. This atom is thus pumped up to an excited state from the ground
state.
In the excited state, the atom is unstable and will soon spontaneously
decay back to the ground state, releasing the stored energy in the form of an
emitted photon. This process is called spontaneous emission.
If an atom in the excited state is struck by a photon of identical energy
as the photon to be emitted, the emission could be stimulated to occur earlier
than would occur spontaneously. This stimulated interaction causes two
photons that are identical in frequency and wavelength to leave the atom. This
is a process of stimulated emission.
If a collection of atoms includes, more that are pumped into the excited state
that remain in the resting state, a population inversion exists. This is necessary
condition for lasing. Now, the spontaneous emission of a photon by one atom
will stimulate the release of a second photon in a second atom, and these two
photon will trigger the release of two more photons. These four than yield
eight, eight yield sixteen and so on. In a small space at the speed of light, this
photon chain reaction produces a brief intense flash of monochromatic and
coherent light which is termed as ‘laser’.
5

6. Properties of Laser11
1. Coherent: Coherence of light means that all waves are in certain phase
relationship to each other both in space and time
2. Mono- chromatic: Characterized by radiation in which all waves are of
same frequency and wavelength.
3. Collimated: That means all the emitted waves are parallel and the beam
divergence is very low. This property is important for good transmission
through delivery systems.
4. Excellent concentration of energy: When a calcified tissue for eg. dentin
is exposed to the laser of high energy density, the beam is concentrated at
a particular point without damaging the adjacent tissues even though a lot
of temperature is produced ie 800-900o
C.
5. Zero entropy.
Laser Design
The laser consists of following components.
1. A laser medium or active medium: This can be a solid, liquid or gas.
This lasing medium determines the wavelength of the light emitted from
the laser and the laser is named after the medium.
2. Housing tube or optical cavity:
• Made up of metal, ceramic or both.
• This structure encapsulates the laser medium.
• Consists of two mirrors, one fully reflective and the
other partially transmittive, which are located at
either end of the optical cavity.
6

7. 3. Some form of an external power source: This external power source
excites or “pumps” the atom in the laser medium to their higher energy
levels. A population inversion happens when there are more atoms in the
excited state rather than a non-excited state. Atoms in the excited state
spontaneously emit photons of light which bounce back and forth between
the two mirrors in the laser tube, they strike other atoms, stimulating more
spontaneous emission. Photons of energy of the same wavelength and
frequency escape through the transmittive mirror as the laser beam. An
extremely small intense beam of energy that has the ability to vaporize,
coagulate, and cut can be obtained if a lens is placed in front of the beam.
This lens concentrates the emitted energy and allows for focussing to a
small spot size.
Laser Light Delivery
Light can be delivered by a numbered of different mechanisms.
Several years ago a hand held laser meant holding a larger, several hundred
pound laser usually the size of desk above a patient. Although the idea was
comical at the time, it is becoming more feasible as laser technology is
producing smaller and lighter weight lasers. In the more future it is probable
that hand held lasers will be used routinely in dentistry.
1. Articulated arms
Laser light can be delivered by articulated arms, which are very simple
but elegant. Mirrors are placed at 45o
angles to tubes carrying the laser light.
The tubes can rotate about the normal axis of the mirrors. This results in a
tremendous amount of flexibility in the arm and in delivery of the laser light.
This is typically used with CO2 laser. The arm does have some disadvantages
that include the arm counter weight and the limited ability to move in straight
line.
2. Optical Fiber
Laser light can be delivered by an optical fiber, which is frequently
used with near infrared and visible lasers. The light is trapped in the glass and
propagates down through the fiber in a process called total internal reflection.
7

8. Optical fibers can be very small. They can be either tenths of micros or
greater than hundreds of microns in diameter. Advantages of optical fiber is
that they provide easy access and transmit high intensities of light with almost
no loss but have two disadvantages, one the beam is no longer collimated and
coherent when emitted from the fiber which limits the focal spot size and
second disadvantage is that the light is no longer coherent.
Patient to laser
Another method of delivering laser light to the patient is actually to
bring the patient up to the laser. Eg: Slit lamp used in the ophthalmologist gist
has been doing this for quite some time. The ophthalmic laser microscope is
simply a slit lamp with a laser built into it. The doctor simply images what he
wants on the cornea or retina and then pushes the foot pedal to deliver laser
beam to the target.
Once the laser is produced, its output power may be delivered in the
following modes.
1. Continuous wave: When laser machine is set in a continuous wave mode
the amplitude of the output beam is expressed in terms of watts. In this
mode the laser emits radiation continuously at a constant power levels of
10 to 100 w. Eg: CO2 laser
2. Gated: The output of a continuous wave can be interrupted by a shutter
that “chops” the beam into trains of short pulses. The speed of the shutter
is 100 to 500ms.
3. Pulsed: Lasers can be gated or pulsed electronically. This type of gating
permits the duration of the pulses to be compressed producing a
corresponding increase in peak power, that is much higher than in
commonly available continuous wave mode.
4. Super pulsed: The duration of pulse is one hundredth of microseconds.
5. Ultra pulsed: This mode produces an output pulse of high peak power that
is maintained for a longer time and delivers more energy.
8

9. 6. Q-scotched: Even shorter and more intense pulse can be obtained with
this mode.
Focussing
Lasers can be used in either a focussed mode or in a defocused mode.
A focussed mode is when the laser beam hits the tissue at its focal
points or smallest diameter. This diameter is dependent on the size of lens
used. This mode can also be referred as cut mode. Eg. While performing
biopsies.
The other method is the defocused mode. By defocusing the laser beam
or moving the focal spot away from the tissue plane, this beam size that hits
the tissue has a greater diameter, thus causing a wider area of tissue to be
vaporized. However, laser intensity / power density is reduced. This method is
also known as ablation mode. Eg. In Frenectomies. In removal of
inflammatory papillary hyperplasias.
Contact and Non contact modes
In contact mode, the fiber tip is placed in contact with the tissue. The
charred tissue formed on the fiber tip or on the tissue outline increases the
absorption of laser energy and resultant tissue effects. Char can be eliminated
with a water spray and then slightly more energy will be required to provide
time efficient results. Advantage is that there is control feed back for the
operator.
Non contact mode: Fiber tip is placed away from the target tissue. The
clinician operates with visual control with the aid of an aiming beam or by
observing the tissue effect being created.
So generally laser can be classified as
9

10. Dental Lasers
Those work in
both
Solely in the non Contact & focussed Non
contact contact
mode &
defocused
Eg: CO2 Eg: Agon, HO : YAG,
Nd:YAG
Laser Types
I. Based on wavelength.
1. Soft lasers
2. Hard lasers
II. Based on the type of active / lasing medium used
1. ArF excimer
2. KrF excimer
3. XeCl excimer
4. Argon ion
5. KTP
6. Ruby
7. Nd: YAG
8. HO: YAG
9. YSGG
10. Er: YAG
11. CO2
10

11. I.
1. Soft Lasers: With a wave length around 632mm Soft lasers are lower
power lasers.
Eg: He Ne, Gallium arsenide laser.
These are employed to relieve pain and promote healing eg. In
Apthous ulcers.
2. Hard lasers: Lasers with well known laser systems for possible surgical
application are called as hard lasers.
Eg: CO2, Nd: YAG, Argon, Er:YAG etc.
CO2 Lasers5
The CO2 laser first developed by Patel et al in 1964 is a gas laser and
has a wavelength of 10,600 nanometers or 10.6  deep in the infrared range of
the electromagnetic spectrum.
• CO2 lasers have an affinity for wet tissues regardless of tissue color.
• The laser energy weakens rapidly in most tissues because it is absorbed by
water. Because of the water absorption, the CO2 laser generates a lot of
heat, which readily carbonizes tissues. Since this carbonized or charred
layer acts as a biological dressing, it should not be removed.
• They are highly absorbed in oral mucosa, which is more than 90% water,
although their penetration depth is only about 0.2 to 1mm. There is no
scattering, reflection, or transmission in oral mucosa. Hence, what you see
is what you get.
• CO2 lasers reflect off mirrors, allowing access to difficult areas.
Unfortunately, they also reflect off dental instruments, making accidental
reflection to non-target tissue a concern.
11

12. • CO2 lasers cannot be delivered fiber optically Advances in articulated arms
and hollow wave guide technologies, now provide easy access to all areas
of the mouth.
• Regardless of the delivery method used, all CO2 lasers work in a non-
contact mode.
• Of all the lasers for oral use, CO2
13
is the fastest in removing tissue.
• As CO2 lasers are invisible, an aiming helium – neon (He Ne) beam must
be used in conjunction with this laser.
Nd: YAG Laser: Here a crystal of Yttrium – aluminum – garnet is doped with
neodymium. Nd: YAG laser, has wavelength of 1,064 nm (0.106 ) placing it
in the near infrared range of the magnetic spectrum.
• It is not well absorbed by water but are attracted to pigmented tissue. Eg:
hemoglobin and melanin. Therefore various degrees of optical scattering
and penetration to the tissue, minimal absorption and no reflection.
• Nd: YAG lasers work either by a contact or non-contact mode. When
working on tissue, however, the contact mode in highly recommended.
• The Nd: YAG wavelength is delivered fiber optically and many sizes of
contact fibers are available. Carbonized tissue remains often build of on
the tip of the contact fiber, creating a ‘hot tip’. This increased temperature
enhances the effect of the Nd:YAG laser, and it is not necessary to rinse
the build up away. Special tips, the coated sapphire tip, can be used to
limit lateral thermal damage. A helium-neon-aiming beam is generally
used with Nd: YAG wavelength.
• Penetration depth is ~ 2 to 4m, and can be varied by upto 0.5-4mm in oral
tissues by various methods.
• A black enhancer can be used to speed the action.
12

13. • Most dental Nd: YAG lasers work in a pulsed mode. At higher powers and
pulsing, a super heated gas called a plasma can form on the tissue surface.
It is the plasma that can be responsible for the effects of either
coagulation, vaporization or cutting. If not cooled (e.g. by running a water
stream down the fiber) the plasma can cause damage to the surrounding
tissues.
• Suffer from dragability
• The Nd:YAG beam is readily absorbed by amalgam, titanium and non-
precious metals, requiring careful operation in the presence of these dental
materials.
Argon Lasers
• Argon lasers are those lasers in the blue-green visible spectrum.
• They operate at 488nm or 514.5nm, are gas like CO2 lasers and are easily
delivered fiber optically like Nd:YAG.
• Argon lasers have an affinity for darker colored tissues and also a high
affinity for hemoglobin, making them excellent coagulators. It is not
absorbed well by hard tissue, and no particular care is needed to protect the
teeth during surgery.
• In oral tissues there is no reflection, some absorption and some scattering
and transmission.
Argon laser: end point is
"whitening" of lesion.
13

14. • Argon lasers work both in the contact and non contact mode
• Like, Nd: YAG lasers, at low powers argon lasers suffer from ‘dragability’
and need sweeping motion to avoid tissue from accumulating on the tip.
• Enhances are not needed with Argon lasers.
• Argon lasers also have the ability to cure composite resin, a feature shared
by none of the other lasers.
• The blue wavelength of 488 nm is used mainly for composite curing, while
the green wavelength of 510nm is mainly for soft tissue procedures and
coagulation.
Er: YAG laser
• Have a wavelength of 2.94 m.
• A number of researchers have demonstrated the Er: YAG lasers ability to
cut, or ablate, dental hard tissue effectively and efficiently. The Er: YAG
laser is absorbed by water and hydroxyapatite, which particularly
accounts for its efficiency in cutting enamel and dentin.
• Pulpal response to cavity preparation with an Er: YAG laser was minimal,
reversible and comparable with pulpal response created by a high-speed
drill.
Ho: YAG laser [Holmium YAG lasers]
• Has a wavelength of 2,100 nm and is a crystal
• Delivered through a fiber optic carrier.
14

15. • A He-Ne laser is used as an aiming light
• Dragability is less compared to Nd: YAG and argon lasers
• Like Nd: YAG, can be used in both the contact and non-contact modes and
are pulsed lasers.
• Ho: YAG laser has an affinity for white tissue and has ability to pass
through water and acts as a good coagulator.
Laser interaction with biologic tissues
Light can interact with tissues in four different mechanisms
1. Reflected
2. Scattered
3. Absorbed
4. Transmitted
Reflection: Reflected light bounces off the tissue surface and is directed
outward. Energy dissipates after reflection, so that there is little danger of
damage to other parts of mouth and it limits the amount of energy that enters
the tissue.
Scattering: occurs when the light energy bounces from molecule to molecule
within the tissue. It distributes the energy over a larger volume of tissue,
dissipating the thermal effects.
Absorption: occurs after a characteristic amount of scattering and is
responsible for the thermal effects within the tissue. It converts light energy to
heat energy The absorption properties of tissue and cells depends on the type
and amount of absorbing pigments or chromophores. Eg. Hemoglobin, water,
Melanin, Cytochromes etc.
Transmission: Light can also travel beyond a given tissue boundary. This is
called transmission. Transmission irradiates the surrounding tissue and must
be quantified. Its effects should be considered before laser treatment can be
justified.
15

16. Tissue effects on laser irradiation
When radiant energy is absorbed by tissue 4 basic types of interactions
occurs.
Laser effects on Dental Hard Tissues
The absorption and transmission of laser light in human teeth is mainly
dependent on the wavelength of the laser light.
For eg. – Ultraviolet laser light is well absorbed by teeth.
In water and in hydroxyapatite, there is a very low absorption at a
wavelength of 2m in comparison to high absorption of laser energy at 3m
and 10m.
The laser effects can be grouped as:
16

17. 1. Thermal effects:
The best known laser effect in dentistry is the thermal vaporization of
tissue by absorbing laser light i.e. the laser energy is converted into thermal
energy or heat that destroys the tissues.
From 45o
– 60o
 denaturation occurs
>60o
 coagulation and necrosis
At 100 o
C  water inside tissue vaporizes
>300o
C  carbonization and later hydrolysis with
vaporization of bulky tissues.
2. Mechanical effects:
High energetic and short pulsed laser light can lead to a fast heating of
the dental tissues in a very small area. The energy dissipates explosively in a
volume expansion that may be accompanied by fast shock waves. These shock
waves lead to mechanical damage of the irradiated tissue.
3. Chemical effects:
Here molecules can be associated directly with laser light of high
photon energies.
Histologic Results:
With continuous wave and pulsed CO2 lasers.
When continuous wave and pulsed CO2 lasers were used, structural
changes and damage in dental hard tissue were reported. Microcracks and
zones of necrosis and carbonization are unavoidable. Because of drying
effects, the microhardnes of dentin increases. The crystalline structure of
hydroxyapatite changes and a transformation of apatite to tricalcium
phosphate takes place.
Nd: YAG Lasers:
17

18. The Nd: YAG laser shows low absorption in water as well as in
hydroxyapatite. Therefore the laser power diffuses deeply through the enamel
and dentin and finally heats the pulp. In dentin, at the laser impact, zones of
debris and carbonization are surrounded by an area of necrosis can be seen.
Microcracks appear when energies above a threshold of 100mj / pulse are
used. But the appearance and the extent of the side effects are not predictable.
Er: YAG Laser:
In dentin, shallow cavities were surrounded by a zone of necrosis of 1-
3m thickness when water-cooling systems were used. In deeper cavities
areas of carbonization and microcracks were observed. Ablating enamel
always cracked and deep zones of debris appeared.
Excimer Lasers:
No pathologic changes in the tissue layers adjacent to the dissected
areas were found after the ablation.
The ablation effects of dental hard tissues are predictable. Compared to
conventional diamond and burs, however, the effectiveness is low. Thermal
side effects increase as photon energies of excimer lasers decrease.
Laser Effects on Dental Pulp:
Recent histologic evidence suggests that a normal odontoblasts layer,
stroma and viable epithelial root sheath can be retained following laser
radiation provided damage threshold energy densities are not exceeded. If pulp
temperatures are raised beyond the 5°C level, research has shown that the
odontoblasts layer may not be present. Characteristics of the dentinogenesis
process related to root development, predentin and reparative dentin
formation, dentinal bridge presence, typically reflect the overall trauma that
has been induced in the odontoblasts.
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19. Application of Lasers in Dentistry:
Application Possible Laser Types
Basic research
Laser tissue interaction
Technical development of applications
of lasers in dentistry
All types
All types
Measurement and diagnosis
Holography
Laser Doppler fowmetry
Spectroscopy (caries diagnosis)
He Ne, diodes
He Ne, diodes
Various types
Oral and Maxillofacial Surgery
Cutting and Coagulation
Photodynamic therapy
CO2, Nd: YAG, Ar, dye
Dye, Au-Cu vapour
Conservative dentistry
Preventive dentistry (fissure sealing)
Caries treatment
Composite resin light Curing
Tooth surface conditioning
CO2, Nd:YAG, ruby
CO2, Nd:YAG, Er: YAG, Excimer
Ar, dye, HeCd
Excimer, CO2, Nd:YAG, Er:YAG
Endodontics
Root canal treatment
Apicoectomy
Nd: YAG, CO2, Excimer
CO2, Nd:YAG
Periodontics
19

20. Laser sealing of affected root surfaces
Excision of gingival soft tissues
CO2, excimer
CO2
Analgesic effect and bio-stimulation
Stimulation of wound healing
Low power laser radiation with analgesic
Effects
He Ne, diodes
Nd: YAG
Other applications:
Laser processing of dental materials
• Welding of dental alloys
Cobalt – chrome – molybdinum
Nickel – chrome – aluminum
Silver Palladium
Titanium alloys
• Welding of ceramic materials
Still under investigation
Advantages of laser welding:
1. High bond strength and corrosion resistance since laser welding is a form
of sweating that does not use solders of different materials.
2. Reduced oxidation when argon gas is used for welding.
3. Decreased thermal influence and greater precision in processing than with
soldering or other techniques.
.
Lasers in Surgical Systems:
20

21. Lasers are an alternative to conventional surgical systems. Stated best
by Apfelberg in 1987, lasers are a “new and different scalpel” (optical knife,
light scalpel).
Advantages:
• Easy access to the anatomic site
• Possess inherent hemostatic properties.
• Capable of ablation of lesions in proximity to normal
structures, with minimal damage to normal structures.
• Reduced pain during surgical procedures and less post
operative pain.
• Enhanced healing
• Bactericidal and virucidal effects of laser result in decreased
rates of wound infection.
Certain proven uses for dental soft tissue procedures using lasers are:
1. Frenectomy
Maxillary midline
Lingual (Tongue tie)
2. Incisional and exasional biopsies.
3. Removal of benign lesions
Fibrous
Papillous
Pyogenic granuloma
Lichen Planus
Erosive lichen planus
Nicotinic stomatites
Verruca vulgaris
Inflammatory papillary hyperplasia
21

22. Epuli
4. Gingivoplasty
5. Soft tissue tuberosity reduction.
6. Soft tissue distal wedge procedure.
7. Gingivectomy
A. Removal of hyperplasias
1. Dilantin etc
2. Idopathic
B. Crown trough.
8. Aphthous ulcer
9. Operculectomy
10. Removal of hyperkeratotic lesions
11. Removal of malignant lesions
12. Soft tissue crown lengthening
13. Coagulation.
A. Graft donor sites.
B. Seepage around crown preparation.
14. Vestibuloplasty
15. Removal of granulation tissue – periodontal clean out
16. Removal of vascular lesions
A. Hemangioms
B. Pyogenic granuloma
22

23. 17. Removal of lesion in patients with hemorrhagic disorders.
A. Hemophelia etc.
18. Implants – Stage II – at the time of recovery.
A. Soft tissue removal
Lasers in Preneoplasia of the oral cavity-
Successful treatment of superficial mucosal disease of the oral cavity
mandates selective ablation of the abnormal epithelium including the
parabasal layer attached to the basement membrane. The carbon dioxide laser
does not impart magical properties to the tissues, but it does provide a
selective therapeutic advantage for the treatment of intramucosal Preneoplasia
by avoiding damage to subjacent tissue, thereby eliminating scar formation
and the creation of oral deformities. Preneoplastic lesions of the oral mucosa
include leukoplakia6
, erythroplakia, and oral submucous fibrosis, with 85% of
the preneoplasias being accounted for by leukoplakia.
SURGICAL TREATMENT: C 0 2 LASER12
Conventional surgical treatment, which consists of excision with a scalpel, is
successful and adequate for limited local disease. The literature reports control
rates of around 90 % .Failure becomes likely when this local treatment is
applied to extensive disease. Because the multicentric nature of precancer (the
condemned mucosa concept) manifests itself as multifocal disease by
occurring at multiple sites in the oral cavity and oropharynx, a more global
treatment concept than local excision is required. Failure rates following local
surgical excision are as high as 33%.4 Muliicentricity demands excision of
topographically large areas of mucosa. However, the denudation of large areas
of oral mucosa results in scarring and wound contraction as well as
postoperative pain, edema, and nutritional depletion. Despite the greatest care,
the minimum thickness of tissue removed with a scalpel results in exposure
and removal of the submucosa. Both scarring and incomplete epithelial
regeneration occur. The traditional solution to this problem is to replace the
mucosa with a split-thickness skin graft. This, however, is an unsatisfactory
solution because skin dews not function as well as mucosa. The graft
ultimately contracts as time passes, and the grafted skin covers remaining
elements of regenerated mucosa that may be unstable. Lastly, even for local
23

24. treatment, site-specific consequences may dictate against locally invasive
surgery that induces scarring. For example, removal of the thinnest layer of
mucosa over the opening of Wharton's or Stensen's duct may cause scarring,
glandular obstruction, and infection. Excision of large lesions at the oral
commissure causes deformity of the oral stoma. The advantage of replacing
traditional excisional techniques with C 0 2 laser photoablation is that the laser
permits removal of the damaged epithelium with as little as 0.1 to 0.2 mm of
reversible thermal injury to the submucosa. Precise control of thermal damage
makes it possible to remove even the epithelium directly over the salivary duct
orifices without inducing sialodochitis and glandular obstruction. Extensive
areas of mucosa may be ablated without skin grafting because epithelium is
regenerated from normal tissue at the wound periphery in no more than 5
weeks for lesions as large as 40 cm2 . After healing, the mucosa al risk is still
observable by direct visual inspection during recall examination. Of equal
importance, there is little postoperative swelling and patients may take oral
fluids immediately after surgery. These patients may be operated upon as
outpatients, and there is usually no bleeding or swelling. Pain, which is highly
variable, is easily managed with oral analgesics, rarely lasts more than a few
days, and only occasionally shows a secondary increase in intensity on days 3
to 5, which then abruptly terminates.
SURGICAL
TECHNIQUE-
The oral mucosa is assessed
and the requisite biopsies are
obtained in the manner
previously described. At the
time of laser surgery, the
vital staining is repeated.
Local anesthesia is used
unless the patient receives a
general anesthetic. No pre-
or perioperative antibiotics
are given and no antiseptic
preparation solution is used for the mouth. The face is protected with wet
surgical drapes and the eyes are covered. If endotracheal intubation is utilized,
the hypopharynx is packed with a wet gauze. After identifying the extent of
the pathology, the laser is set at an average power of 20 to 30 W for pulsed
modes, and 15 to 20 W for CW mode. The spot size will vary between 2 and 3
24

25. mm in diameter. The clinical end point for ablation of the mucosa is to cause a
"rapid bubbling of the epithelium which is opalescent in color and is
accompanied by a crackling noise."2 1 The lesion is outlined with a suitable
margin of several millimeters and then parallel lines of application of the laser
are placed within the marginal outline This is called rastering. After
completion of this first layer of lasing, there should be almost no
carbonization. If the wound appears blackened, there has been excessive heat
conduction because of prolonged contact between the laser beam and the
tissue as a result of excessively slow hand speed in moving the handpiece or
microscope joystick-directed laser beam across the lesion. The more heat
conducted, the greater the desiccation occurring at surgery. A moist gauze is
now used to wipe away the treated area of mucosa. This allows one to assess
the depth of penetration of the laser. A pale pink base that does not bleed
indicatesremoval of the epithelium at the level of the basement membrane . If
there are scattered droplets of blood, then the superficial aspect of the
submucosal plane has been breached. If the depth of penetration is too
superficial, a second raster is applied to reach the required depth, which results
in removal of the entire thickness of the epithelium. In areas of thick
hyperplasia as for nicotine stomatitis or fibroepithelial hyperplasia ofthe palate
,several layers of rastering may be required. The submucosal layer is identified
both by the appearance of blood vessels and by the appearance of tissue of
granular appearance and yellow color. At the conclusion of surgery the
abnormal (issue has been removed and there should be no bleeding except
where it was necessary to extend tissue removal into the submucosa. as may
be required in this case of papillary hyperplasia of the palate where four
rasters are needed for complete tissue removal. The fibrin coagulum that
formed within the first 24 hours is still present at one week. Complete mucosal
reepithelialization and healing has occurred within 5 weeks
Lasers for soft tissue excision-
FIBROEPITHELIAL POLYP-
The polyp arising from the
dorsal midline of the
anterior tongue was both
interfering with suckling
and causing consternation
for the parents and the
25

26. pediatrician. At approximately 7 weeks of age the patient was brought to the
operating room where, using general anesthesia delivered by an oral
endotracheal tube and without supplemental local anesthesia, the polyp
was bloodlessly removed in one minute of operating time. Laser parameters
were handheld CO: rapid superpulsed laser at 50 pps. evaporative spot si/.e of
0.3 mm, average power output of 10 W
EAR TAG-
Skin tags occasionally
occur in newborns as well
as adults. In this illustrative
case a consultation was
received from the newborn
nursery to remove an ear
tag. Otologic and auditory
examinations were normal.
The baby was brought to
the laser lab where he was
first fed. Then, after falling
asleep the base of the
lesion was inliltrated with 0.25 mL of 2% lidocaine. The lesion was then
removed with the superpulsed CO, laser at 6 W average output power, 0.3-mm
spot size using a handpiece at 118 pps. The operation required less than a
minute and there was no blood loss
EXPOSURE OF IMPACTED TEETH-
Although exposure of impacted teeth (soft tissue impaction) is easily
accomplished in the dental operatory using local anesthesia and a loop cautery,
there is less swelling, less postoperative pain, and less chance of thermal
injury to the exposed tooth if the free beam C 0 2 or the contact
heodymium:yttrium-aluminum-garnet (Nd:YAG) laser is used.
The C 0 2 laser may be used at PD of approximately 10,000 W/cm2 at 50 PPS,
10 W average output power and 0.3 mm spot size to incise around the
impacted crown of the tooth. As dissection proceeds, the mucosal flap is
elevated. Mucosa well healed at 3 weeks. Bonded bracket ready to be used to
start tooth movement. with tissue forceps until the underlying crown is
identified. At this point, the handpiece is moved away from the tissue to
26

27. diminish PD, thereby permitting dissection of the mucosa away from the
crown without marring.Ihe enamel surface from inadvertent laser strikes
at high PD. Alternatively, the Nd.YAG laser in contact mode using a short
scalpel tip at 5 to 10 W average output power is used to excise the gingival
cuff. Rapid identification of the crown permits the operator to avoid
inadvertently damaging it by excessive heating from the scalpel tip.
There is no bleeding.
HEMANGIOMAS AND VASCULAR
MALFORMATIONS-
Hemangiomas in the oral cavity are most effectively treated with the argon
laser by direct application after compressing the lesion with a glass slide or for
larger lesions by
intralesional introduction of
the liber. Large,higher-flow
lesions are occasionally
treated with the Nd:YAG
laser. However, small,
localized, low-flow lesions
may be excised with the C 0
2 laser. A small vascular
malformation of the labial
27

28. sulcus was excised
with the C 0 2 laser.
GINGIVAL HYPERTROPHY-
Key elements of laser
technique for gingivoplasty
include the use of a
superpulsed CO: laser with the
handpiece at a PD of 500 to
625 W/cm2 by varying the
spot size between 2.0 and 2.5
mm at 58 pps 600 mJ/pulse at
an average power output of 25
W. A matrix band is secured
around the cervical margin of
the tooth below the free
margin of the gingiva to
protect the enamel and cementum from injury by the laser beam. Gingiva
removed by each raster is wiped away to remove the carbonization prior to
applying additional rasters with the laser.
FACIAL NEVI-
Vaporization technique with rapid super pulsed (RSP) C 0 2 laser was chosen
to reduce scarring. Laser parameters: RSP C 0 2 laser (110 mJ/pulse) at 108
pps using the microscopic and microslad system. The laser spot size was 2.0
mm at an output power of 15 W and a PD of approximately 450 W/cm2 . The
target site was anesthetized by infiltration of 1% lidocaine local anesthetic. No
skin preparation was performed . Two raster’s were administered under 10X
magnification and the surface of the target tissue was debrided with a wet
28

29. gauze sponge after the first and second raster. One year later there was only a
faint depression at the treatment site and there was no change in skin color.
SKIN RESURFACING IN AESTHETIC SURGERY-
Skin wrinkles, or rhylidcs from excessive sun exposure, particularly those
occurring on and around the lips and eyes, may be reduced by treatment with
the COs laser using an automated scanner such as the SilkTouch flash-scanner.
The wrinkle is treated by ablating the area adjacent to the deepest point of the
wrinkle fold with the laser set at 7 W average output power in the pulsed mode
at 0.2-s cycles. This permits assessment of the laser effect after completion of
a single cycle (one complete revolution
of the flash scanner within its target
circle). As always, the target tissue is
removed with a saline moistened gauze
sponge. Pending the area to be treated,a
second and third pass may be necessary
to penetrate into or through the
papillary dermis. Alternatively, a
Computer Pattern Generator (Coherent
Lasers) can be used with an ultrapulse
C 0 2 laser at 175 to 300 mJ/pulse and an average power of between 60 and
100 W. Benign cutaneous growths and atrophic scars and pits can be treated
similarly. Postoperative results are consistently good. C02 lasers resurfacing
with Coherent Ultrapulse 5000C CPG scanner at 225 ml, 60W. with one pass
at moderate density over lower lid and 2-3 passes over lateral and infraorbital/
malar areas.
29

30. EPULIS FISSURATUM-
Epulis fissuratum, which consists of hyperplastic mucogingival folds from
fibroepithelial
proliferation
secondary to ill-fitting
dentures, prevents
proper denture seating
on a stable base. It
responds well to laser
excision with minimal
postoperative
discomfort and
swelling. In this case,
a defo cused beam at
5 to 10 W CW is used
to aid hemostasis and
promote a dry field.
Alternatively, a pulsed waveform at 20 W, PRR = 50-200 pps at 2.0 to 3.0-
mm spot size may be used. The existing denture is relined with soft denture
liner. The wound re-epithelializes in about 3 weeks with little loss or no loss
of sulcus depth
Lasers in resection of the cancers-
Transoral resection of
stages I and II oral cancer
is a well-accepted
treatment method in
oncologic surgery. The
specific surgical technique
is less important than is
the sound application of
oncologic principles to
achieve adequate resection
of the tumor. The gold
standard for outcome is
the result achieved by scalpel resection. Any other technique such as
30

31. electrosurgery, cryosurgery, or laser surgery must produce comparable or
improved cure rates. Cure rates achievable with the surgical laser match those
attributed to scalpel or electrosurgery, and also provide the significant
advantages of better hemostasis, less postoperative edema, shorter hospital
stay, diminished infection rates, and elimination of the need for split-thickness
skin grafting. In
addition, in theory, because of the laser's ability to seal small blood vessels
and lymphatics, there is a reduced likelihood of inducing tumor microemboli
during surgical extirpation of the tumor, which in turn reduces the chances of
"seeding" the surgical site or the vascular or the lymphatic system.
Compared with patients having stages I and II oral cavity tumors that were
treated by conventional surgery using transoral resection technique, the laser-
treated cases did not show increased local recurrence or regional metastases.
The most important negative aspect to consider in evaluating laser surgery is
whether the laser beam itself might have any tumor-promoting effects that
might enhance recurrence or spread to loco-regional or distant sites. Because
the beam is applied only to clinically normal tissue at the resection margin and
not on the tumor itself, any enhancement of spread would be expected to be a
consequence of direct handling of the neoplastic tissue by retraction
instruments. This being the case, one would not expect to find a diminished
control rate with laser use and, in fact, the literature does not support such a
negative outcome in surgical laser treatment of human oral malignancies
Laser assisted uvulopalatoplasty-
The laser-assisted uvulopalatoplasty (LAUP) is a surgical technique designed
to correct breathing abnormalities during sleep that result in snoring or mild to
moderate obstructive sleep apnea syndrome. This is a short operation
performed in the office using local anesthesia and a surgical laser. The
objective is to reduce pharyngeal airway obstruction by reducing tissue
volume in the uvula, the velum, and the superior part of the posterior
pharyngeal pillars.
contraindications to LAUP are severe maeroglossia and morbid obesity with
hypopharyngeal obstruction at the tongue base. In the rare condition of floppy
epiglottis, LAUP is also not of benefit.
The C 0 2 laser or contact neodymium:yttrium- aluminum-garnet (Nd:YAG)
laser is preferred to the use of the Nd:YAG fiber-delivered laser in this
procedure because of the low volume of absorption of the C 0 2 laser beam or
contact Nd:YAG in tissue. This property prevents excessive thermal necrosis
of the target tissue. The YAG laser also does not have a backstop, although
31

32. this problem is eliminated for contact YAG lasers. An additional advantage of
the C 0 2 laser is its use as a "no-touch" technique, thereby eliminating contact
with the palate and pharyngeal walls. This property reduces gagging,
especially for the hypersensitive individual whose gagging occurs on a
psychological basis despite having adequate anesthesia at the surgical site.
LAUP is performed with a free-beam CO, laser with a backstop. Beam
guidance is provided by a coaxial helium neon (HeNe) laser. Standard C O :
laser safety precautions have to be followed. The output power is set at 20 to
30 W average power in a pulsed mode, depending on the thickness of tissue
that is to be incised. A specific snoring handpiece is used with a variable spot
size of 0.6 to 3.51 mm at a focal length of 300 mm. This handpiece has a
focus-defocus ring: focus to cut. and defocus to coagulate
This procedure can be done in
• Single stage procedure
• Multiple stage procedure
Lasers in laryngeal surgery-
Laryngeal papillomas are cauliflower-like lesions caused by infection with the
human papilloma virus (HPV). This lesion is the most common benign
neoplasmof the larynx. During infancy or adulthood its presenting symptoms
are hoarseness or airway obstruction. The natural history of this disease is one
32

33. of multiple recurrences, especially with the juvenile onset type co laser
vaporization of these lesions, although the accepted procedure
of choice today, is thought to be only palliative in most cases. Multiple
recurrences are thought to be caused by persistent growth of HPV in
subclinically infected normal-appearing tissue bordering the area of treatment.
The goal of laser vaporization is to eradicate this lesion and establish an
adequate airway and functional voice without causing submucosal damage
that may result in vocal fold scarring and fibrosis. Simultaneous removal of
papillomas from both sides of the anterior or posterior commissure should be
avoided, as this maneuver always results in commissure web formation.
Typical co laser settings for such a procedure includes using a 025mm spot
size at a working distance of 400 mm, 2- to 3-W power & 0.5 to 1.0 second
pulse duration.
LARYNGEAL AND SUBGLOTTIC HEMANGIOMAS
Hemangiomas are uncommon neoplasms that may occur anywhere in the
larynx and histologically are capillary, cavernous, or mixed
capillary/cavernous lesions. They may present in a pediatric or adult form; the
pediatric form is predominantly capillary in nature and the adult form more
often mixed or cavernous. The pediatric hemangioma characteristically
presents shortly after birth, has a proliferative phase that may last up to 1 year
followed by an involutional phase occurring from 1 to 7 years of age. These
lesions often occur subglottically and may progress in size, resulting in airway
obstruction.co laser treatment may be used safely to remove these lesions
while simultaneously maintaining a patent airway and thereby avoiding need
for a tracheotomy.'' With the use of a subglottoscope and a laser with
increased pulse duration settings to allow for more thermal diffusion and
better coagulation of small vessels, capillary hemangiomas may be effectively
treated. These lesions can be managed using a laser with a 0.25-mm spot
size at a 400-mm focal distance, 2- to 3-W power, and 0.5- to 1.0-second pulse
durations. Cavernous lesions often present bleeding problems during removal
that are not effectively controlled using the co laser, thereby requiring the use
of other forms of therapy.
Reinke's Edema And Vocal Fold Polyps, Granuloma, & Malignant Neoplasms
are the conditions which also can be treated by laser therapy.
Laser-Assisted Temporomandibular Joint Surgery-
Advances in arthroscopic instrumentation and technique for small joint
surgery have recently found application in surgery for the temporomandibular
joint (TMJ). Coupled with the advent of high-resolution magnetic resonance
imaging (MRI) the accuracy of diagnosis of TMJ disorders has been greatly
enhanced. Arthroscopy of the TMJ has consequently progressed from an
instrument of diagnosis to one of treatment. As its usefulness for the treatment
33

34. of internal derangements, particularly nonreducing disk displacement (closed
lock), has become generally accepted, the search for improved instrumentation
has resulted in the development of various laser systems for TMJ surgery
The Ho:YAG laser4
configured for arthroscopic surgery consists of a free-
beam laser with a sterile fiber-optic delivery system and the appropriately
adapted arthroscope and video system. Because the Ho:YAG emission is
highly absorbed by water with an average depth of absorption of 0.3 mm. It
removes tissue precisely. Because the target tissueitself has a high water
content and the laser operates within SSSSa fluid medium, there is very little
unwanted thermal damage lateral to the vaporization crater. Nevertheless,
even with minimal unwanted heat effects the actual thermal injury may vary
from 0.1 to 1.0 mm depending on tissue type and the exposure parameters of
the individual laser. Tarro" measured tissue necrosis with Ho:YAG and found
it to be 0.4 to 0.6 mm, whereas electrocautery produced necrosis of 0.7 to 1.8
mm. In addition to the thermal effects the short pulse width of 350 ps
associated with high fluence rates may also induce photomechanical and
photoacoustic effects that also contribute to tissue ablation.
Commercially available low output Ho:YAG lasers8
are quite adaptable for
TMJ arthroscopic surgery. Several fiber delivery methods are available. The
specific styles and specifications vary among manufacturers. It is rare to
require an output power in excess of 10 W or a post-repetition rate (PRR)
exceeding 10 Hz to resect fibrocartilage or recontour bone. Lower settings are
suggested for making releasing incisions.
Biostimulation and Photodynamic Therapy:
Photodynamic therapy is an experimental cancer treatment that is
based on a cytotoxic photochemical reaction. This reaction requires molecular
oxygen, the photoactive drug dihematoporphyrin ether, a hematophorphyrin
derivative and intense light, which is typically delivered by a laser.
Dihematoporphyrin which is relatively retained in malignant tissue after
several days, is given intravenously to a patient. Laser light at a wavelength
corresponding to the absorption peak of the drug is used to activate the drug to
an excited state. The drug then reacts with molecular oxygen to produce
singlet oxygen, a highly reactive free radical which ultimately leads to tissue
necrosis.
Laser Hazards and Laser Safety:
The subject of dental laser safety is broad in scope, including not only
an awareness of the potential risks and hazards related to how lasers are used,
34

35. but also a recognition of existing standards of care and a thorough
understanding of safety control measures.
Laser Hazard Class for according to ANSI and OSHA Standards:
Class I - Low powered lasers that are safe to view
Class IIa - Low powered visible lasers that are hazards only when
viewed directly for longer than 1000 sec.
Class II - Low powered visible lasers that are hazardous when viewed
for longer than 0.25 sec.
Class IIIa - Medium powered lasers or systems that are normally not
hazardous if viewed for less than 0.25 sec without magnifying
optics.
Class IIIb - Medium powered lasers (0.5w max) that can be hazardous if
viewed directly.
Class IV - High powered lasers (>0.5W) that produce ocular, skin and
fire hazards.
35

36. The types of hazards can be grouped as follows:
1. Ocular injury
2. Tissue damage
3. Respiratory hazards
4. Fire and explosion
5. Electrical shock
1. Ocular Injury:
Potential injury to the eye can occur either by direct emission from the
laser or by reflection from a specular (mirror like) surface or high polished,
convex curvatured instruments. Damage can manifested as injury to sclera,
cornea, retina and aqueous humor and also as cataract formation. The use of
carbonized and non-reflective instruments has been recommended.
2. Tissue Hazards:
Laser induced damage to skin and others non target tissues can result
from the thermal interaction of radiant energy with tissue proteins.
Temperature elevation of 21°C above normal body temp (37°C) can produce
cell destruction by denaturation of cellular enzymes and structural proteins.
Tissue damage can also occur due to cumulative effects of radiant exposure.
Although there have been no reports of laser induced caroinogenesis to date,
the potential for mutagenic changes, possibly by the direct alteration of
cellular DNA through breathing of molecular bonds, has been questioned.
The terms photodisruption and photoplasmolysis have been applied to
describe these type of tissue damage.
3. Respiratory:
Another class of hazards involves the potential inhalation of airborne
biohazardous materials that may be released as a result of the surgical
application of lasers. Toxic gases and chemical used in lasers are also
responsible to some extent.
During ablation or incision of oral soft tissue, cellular products are
vaporized due to the rapid heating of the liquid component in the tissue. In the
36

37. process, extremely small fragments of carbonized, partially carbonized, and
relatively intact tissue elements are violently projected into the area, creating
airborne contaminants that are observed clinically as smoke or what is
commonly called the ‘laser plume’. Standard surgical masks are able to filter
out particles down to 5m in size. Particle from laser plume however may be
as small as 0.3m in diameters. Therefore, evacuation of laser plume is
always indicated.
4. Fire and Explosion
Flammable solids, liquids and gases used within the clinical setting can
be easily ignited if exposed to the laser beam. The use of flame-resistant
materials and other precautions therefore is recommended.
Flammable materials found in dental treatment areas.
Solids Liquids Gases
Clothing
Paper products
Plastics
Waxes and resins
Ethanol
Acetone
Methylmethacrylate
Solvents
Oxygen
Nitrous oxide
General anesthetics
Aromatic vapors
5. Electrical Hazards:
These can be:
- Electrical shock hazards
- Electrical fire or explosion hazards
Summary of laser safely control measures recommended by ANSI
Engineering controls:
- Protective housing
- Interlocks
- Beam enclosures
- Shutters
- Service panels
37

38. - Equipment tables
- Warning systems
- Key switch
Administrative controls:
- Laser safety officer
- Standard operating procedures
- Output limitations
- Training and education
- Medical surveillance
Personal protective equipment:
- Eye wear
- Clothing
- Screens and curtains
Special controls:
- Fire and explosion
- Repair and maintenance
Conclusion:
Laser has become a ray of hope in dentistry. When used efficaciously
and ethically, lasers are an exceptional modality of treatment for many clinical
conditions that dentists treat on daily basis. But laser has never been the
“magic wand” that many people have hoped for. It has got its own limitations.
However, the futures of maxillofacial surgery with the laser is bright with
some of the newest ongoing researches.
38

39. REFERENCES-
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2. Dent Clin North Am 2000 oct; 44(4): 851-73
3.Desiate A, Cantore S, Tullo D, Profeta G, Grassi Fr, Ballini A. 980 nm diode
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4. Hendler BH. Ciatcno J. Mooar P. et al. Holmiuin:YAG laser arthroscopy of
the temporomandibular joint. J Oral Maxillofac Surg 1992:50:931-934.
5. J.Canzona, Carbon-di-oxide laser in oral & maxillofacial surgery JOMS.vol
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8. Koslin MG. Martin JC. The use of the holmium laser for
temporomandibular
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9. Laser artifacts & diagnostic biopsy . Oral Surg Oral med Oral path Oral
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12. Roodenburg JL. Panders AK. Vermey A. Carbon dioxide laser surgery of
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40. 13. Shinichi Takeuchi, Effect of the carbon-di-oxide laser vapourisation on
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