PRESENTED BY:

DR.VENU SAMEERA PANTHAGADA

MDS POSTGRADUATE IN ORAL AND

MAXILLOFACIAL SURGERY

Lasers are widely used in dentistry for various clinical procedures

like cavity preparation, surgical procedures, scaling and root

planning etc. Since its first use in 1960, lasers are now evolved to

be used in all aspects of dentistry.

Lasers are effective in ablation of various potentially malignant

disorders, obtaining biopsy, periodontal plastic surgeries and

providing incisions in surgical conditions.

Technological advances have led to increased use of lasers in

surgery and the laser has become a useful tool in the surgeon’s

armamentarium.

THEODORE H.MAIMAN built the first laser (synthetic red ruby) at

HUGHES AIRCRAFT RESEARCH LABORATORY.

One year later MILTON ZARET of NEWYORK UNIVERSITY

SCHOOL OF MEDICINE used a laser to produce ocular lesion in

animals.

Laser is an acronym for light amplification by the stimulated

emission of radiation.

Every laser has a laser medium such as ruby ,argon, carbon

dioxide each laser has a source of energy to excite atoms.

Source can be electrical, chemical, or another light source.

Photon is the basic of light.

A laser emits photons of only one wavelength (monochromatic) and

are emitted in parallel (collimation).

As photons are produced ,they continue to travel with in the laser

chamber, exciting more atoms.

The intensity of energy increases with in the laser chamber as this

chain reaction continues. This is called amplification.

The ability to direct the monochromatic, collimated photons is

called coherence.

The light is delivered from the laser chamber to the tissue in variety

ways.

fibre optic cable

articulated arm system

hollow wave guide

lasers must be delivered to the tissue by a contact or noncontact

mechanism .

Most lasers have a handpiece with a lens attchment.

In noncontact laser systems, lens allows the beam of light to be

focused.

Some noncontact or free beam laser systems have angled mirrors

to direct the beam either at 90 or 120 degrees.

Contact laser systems offer the advantage of tactile sense during

operating.

Some Nd:YAG lasers have interchangeble sapphire or ceramic tip.

Tip is heated when laser is activated enabling tissue to be cut and

coagulated with a precise light powered scalpel

When laser light is directed at tissue,compounds with in the tissue

called CHROMOPHORES absorb the wavelength of light.

Generally four reactions can happen when laser light interacts with

tissue.

1.REFLECTION off the tissue

2.SCATTERING to surrounding tissue

3.TRANSMISSION through the tissue

4.ABSORPTION by tissue chromophores

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The balance of these reactions is determined by wavelength of light

and type of tissue.

Amount of absorption determines the amount of selective tissue

destruction.

Amount of scatter determines the amount of peripheral tissue

damage.

There are five important types of biological effects that can occur

once the laser photons enter the tissue: fluorescence,

photothermal, photodisruptive, photochemical, and

photobiomodulation.

Fluorescence happens when actively carious tooth structure is

exposed to the 655nm visible wavelength of the Diagnodent

diagnostic device.

The amount of fluorescence is related to the size of the lesion, and

this information is useful in diagnosing and managing early carious

lesions.

Photothermal effects occur when the chromophores absorb the

laser energy and heat is generated.

This heat is used to perform work such as incising tissue or

coagulating blood.

Photothermal interactions predominate when most soft tissue

procedures are performed with dental lasers.

Photothermal ablation is also at work when CO2 lasers are used on

teeth as hard tissue is vaporized during removal.

Heat is generated during these procedures and great care must be

taken to avoid thermal damage to the tissues.

Photodisruptive effects (or photoacoustic) can be a bit more

difficult to understand.

Hard tissues are removed through a process known as

photodisruptive ablation.

Short-pulsed bursts of laser light with extremely high power

interact with water in the tissue and from the handpiece causing

rapid thermal expansion of the water molecules.

This causes a thermo-mechanical acoustic shock wave that is

capable of disrupting enamel and bony matrices quite efficiently.

Erbium lasers’ high ablation efficiency results from these micro-

explosions of superheated tissue water in which their laser energy

is predominantly absorbed.

Thus tooth and bone are not vaporized but pulverized instead

through the photomechanical ablation process. This shock wave

creates the distinct popping sound heard during erbium laser use.

Thermal damage is very unlikely as almost no residual heat is

created when used properly, particularly when the concept of

thermal relaxation is considered.

Photochemical reactions occur when photon energy causes a

chemical reaction. These reactions are implicated in some of the

beneficial effects found in biostimulation

Photobiomodulation or Biostimulation refers to lasers ability to

speed healing, increase circulation, reduce edema, and minimize

pain.

Many studies have exhibited effects such as increased collagen

synthesis, fibroblast proliferation, increased osteogenesis,

enhanced leukocyte phagocytosis, and the like with various

wavelengths.

The exact mechanism of these effects is not clear but it is

theorized they occur mostly through photochemical and

photobiological interactions within the cellular matrix and

mitochondria.

Biostimulation is used dentally to reduce postoperative discomfort

and to treat maladies such as recurrent herpes and aphthous

stomatitis. Low Level Laser Therapy (LLLT) is another term used to

describe this phenomenon.

37-60*F = tissue retraction, protein conformational changes

>60*F = proteins denature and coagulation

90-100*F =carbonization and char formation

>100*F =ablation of tissue

STAGES IN LASER PRODUCTION

1 Optical pumping or state of excitation

electric discharge

chemical reaction

xenon or krypton flash lamp

2 Population inversion

3 Stimulated emission

4 Cascade process----collimated beam

5 Amplification –light is coherently amplified after reflection from mirrors

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This is the process in which energy is driven into resonant

chamber or cavity from an external or internal source that is

specific for a laser system .

For example electric discharge ,chemical reaction or an external

high powered radiant source ,such as xenon or krypton flash lamp.

This energy is used to change the energy level or quantum state of

lasant species .

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OPTICAL PUMPING & POPULATION INVERSION

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This is the phenomenon when there is a transition of electrons in

whole active medium from low energy to high energy levels after

the absorbtion from external source or optical imaging .

STIMULATED EMISSION

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After the population inversion of the laser ,there is stimulated emission.

The atoms existing in higher energy state, gradually drop to a lower

energy level and emit photons in the process.

After stimulated emission ,photons move longitudinally along the

long axis of the laser chamber and stimulate other proximal excited

atoms to emit additional identical photons that will travel with the

same directionality as the stimulated photons with the laser

chamber .

The cascade of light that is parallel with the long axis of the laser

cavity from a collimated beam of intense radiant energy .

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CASCADE PRODUCTION

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Amplification or oscillation is what is critical in the process

called optical feedback.

This optical feedback is produced by causing the photons to

bounce between mirrors placed on either side of the optical

cavity.

As light continues to reflect back and forth making round trips

with in the laser cavity ,the light is coherently amplified by

this process.

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Developed by PATEL in 1964

Wavelength of 10600 nm

Medium: mixture of co2 ,nitrogen and helium.

Uses an articulated arm to deliver the beam

Uses: for excision and ablation of superficial lesions

for skin resurfacing

co2 laser is the most commonly used laser in oral cavity reason

being 1.the

chromophore that absorbs the co2 wavelength is water 2.shallow

depth of penetration 0.2mm

3.little scatter ,reflection, transmission

Developed by BRIDGES in 1964 at HUGHES AIRCRAFT

RESEARCH LABORATORIES

Delivers green blue light beam with wavelength of 488-514nm

Deliveerd with fibre optic cable and hand piece

Argon beam is highly absorbed by hemoglobin, and is an excellent

hemostatic laser.

Used to excise gingival soft tissue lesions.

In the treatment of vascular hemangiomas.

Developed by GUESIC in 1964

Wavelength of 1064 nm

Neodymium yattrium aluminium garnet

Delivered by fibre optic cable

Used with specially designed sapphire or ceramic tips and used as

contact laser scalpel or ablation tool, with excellent hemostasis and

cutting abilities.

Uses: treatment of vascular lesions

intraoral and extraoral pimented lesions

open TMJ arthroplasty

malignant lesion excision

Modified version of Nd:YAG laser

Wavelength : 532nm

Its absorption is similar to that of the argon laser

Used in treatment of vascular and pigmented lesions, tattoo

removal, blepharoplasty,some endoscopic procedures.

Holmium yttrium aluminum garnet

Emits wavelength of 2140 nm.

An aiming beam with fibre optic cable is used for delivery

Used in both contct and noncontact mode.

Well absorbed by synovium and joint surface.

Extensively used in endoscopic orthopedic surgery

Used in TMJ for lysis of adhesions and sculpting of

fibrocartilaginous disk tissue.

Erbium : YAG laser for facial resurfacing and incision and ablation

of soft tissues.

Wavelength :2940 nm

Advantage is its ability to remove superficial skin layers even more

precisely than co2 laser.

It allows reorganization of collagen with less total energy.

Safety in the surgical theatre is of greater importance when lasers

are used.

NOMINAL HAZARD ZONE is defined as surgical area in which the

laser is used and could potentially cause injury or damage , usually

related to eye exposure.

NHZ is determined by wavelength of light, maximum power, type of

delivery system, diameter if the beam.

Greater the calculated NHZ zone, greater the probability that injury

can occur.

Laser protective eyewear must be worn by all people in the NHZ.

Patients should also be provided with scleral shields, when laser is

being used on the face.

Scleral shields are used when blepharoplasties and facial

resurfacing techniques are used.

Special surgical laser masks with protective filters are worn to

prevent inhalation of infectious or toxic plume smoke.

Evacuation systems with high speed suction are used to remove

plume from the field.

Exposure to skin can be limited by use of noninflammable gowns

that offer maximal body coverage.

When preparing the patient for surgery, no alcohol based

preparation solutions should be used in order to prevent ignition

and severe burns.

Wet towels are used to drape the patient, and they should be

moistened throughout the procedure to prevent ignition of drapes.

An open basin of sterile water with an irrigating syringe should be

available in case fire developes.

Most inhalational anesthetics are not flammable ,but gases like

oxygen support combustion. Therfore oxygen concentration should

generally be less than 40%.

PVC endotracheal tubes are highly flammable and not

recommended for use during laser surgery.

With scalpel there is 200% decrease in elasticity compared with

normal mucous membrane. While with lasers there is only 50%

decrease in elasticity.

The extraordinary rapid cell vaporization, with loss of intracellular

chemical mediators (cytokines) is posited to result in a markedly

less intense local inflammatory response and consequently, less

local pain, edema and cicatrix formation.

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Photocoagulation technique

Incisional and excisional technique

Ablation or vaporization technique

Contact laser technique

C02 LASER can be used to coagulate or photoablate vessels

smaller than 500 um in diameter.

Laser is used in defocused mode to a spot size of approx 2mm with

a power density lessthan 5W.

CO2 LASER is absorbed readily by water, the area must be

relatively dry for effective coagulation of the vessels.

Increasing the exposure time heats the tissue to critical

temperature needed for hemostasis.

As hemoglobin is a major chromophore, blood components are

directly lased, surrounding vessel is damaged by collateral heat

after being coagulated.

Crisscross or circumferential pattern can be used in a defocused

mode.

Carbon dioxide laser is a superb light scalpel.

Near bloodless field allows for excellent visualization of the

specimen during surgical removal.

Point to be considered during biopsy is LATERAL ZONE OF

THERMAL NECROSIS.

Zone of necrosis is generally less than 500um when using the

carbondioxide or contact ND:YAG Laser.

First ,topical, local, general anesthesia is administered as the

procedure indicates.

Area should be dried to increase the accuracy of absorption of

energy.

To outline the specimen, choose single or slow repeating pulse

mode and mark the area of incision.

A row of dots can be used to outline the specimen with desired margin.

Power density is adjusted and incision made to the desired depth.

Gentle tension on the specimen with a forceps is used to deliver the lesion as it is surgically removed.

Advancing the handpiece in to the incision keeps the spot size and distace constant.

Hemostasis is achieved.

Lesions can be left open.

Specimen should be handled in usual manner and the pathologist informed the use of laser.

One of the greatest advantages of laser is its ability to ablate or

vaporize lesions layer by layer.

It is useful in removing discrete benign lesions, useful in eradicating

multiple , diffuse lesions of the oral cavity.

An anesthetic plan is implemented as type of procedure indicated.

5 to 10 w of power on the carbon dioxide laser is adequate for

efficient and controlled ablation of a lesion layer by layer.

Lesion is outlined .

Crisscrossing patterns of horizontal, vertical, and oblique lines can

be used when clearing the wound of char between passes.

Contact laser has several advantages over traditional beam.

ND:YAG & HO:YAG LASERS are commonly used contact lasers.

The specially designed tips of contact lasers allow for transmission

of laser energy to the tissue directly from the tip surface.

Effect of laser is concentrated to just around the tip surface.

There is less tissue penetration and less collateral tissue damage.

Helpful in the lysis of adhesions with in TMJ.

Benefit of contact laser surgery is WAVELENGTH CONVERSION

EFFECT.

Laser tissue interaction actually involves many cellular and

subcellular events.

There is vaporization of intra cellular fluid that helps disintegrate

cell structure almost instantaneously, and the subcellular structures

often vaporized.

This likely occurs without normal cascade of cytokines seen in

acute inflammation.

Slower healing due to delayed epithelial migration and decreased

scar formation.

Nerve endings are histologically sealed which claims of decreased

post op pain.

Finding of fewer myofibroblasts at wound edges after laser surgery

has been postulated as the reason for lessened scarring.

INCISIONAL AND EXCISIONAL PROCEDURES

Gingivectomy , Operculectomy, Frenectomy, Tuberosity reductions

Co2 laser is well suited for removal of gingival tissue.

Gingivectomy procedure involves the use of laser beam focused

using smallest spot size.

Specimen is excised and hemostasis is obtained using

photocoagulation technique.

Palliation of pericoronitis by excising operculam can be done.

Frenectomy can be accomplished by grasping the tissue with a

hemostat at its supero inferior attachment .

Tissue is then excised by directing the laser along the hemostat.

EPULIS FISSURATUM AND PYOGENIC GRANULOMA AND

GRANULATION TISSUE EXCISION:

Excision of epulis fissuratum may be performed rapidly without the

loss of vestibuar depth by using carbondioxide laser.

Traction is applied to the lesion using forceps and it is excised

along its base.

Granulomatous soft tissue masses are vascular lesions are excised

using co2 laser.

MUCOCELE AND MUCOUS RETENTION CYST:

Here minor salivary glands should be bluntly dissected with

scissors and a hemostat and then excised with laser.

Photocoagulation can be used to obtain hemostasis.

This minimizes the chance of recuurence of mucocele

IMPLANT OR TOOTH EXPOSURE:

Role of lasers in perisurgical implant care has expanded.

Nd:YAG LASER was shown to have adverse thermal effect on

fixture which then destroyed the surface layer of plasma titanium.

Lasers are relatively contraindicated for use with hydroxyapatite

coated implants as both ND:YAG AND CO2 lasers remove the

outer coating and expose the metal core.

RANULA AND SIALOLITH REMOVAL:

They can be easily marsupialised with the co2 laser and sialoliths

can be easily located and removed with co2 laser.

VESTUBULOPLASTY:

CO2 Laser is useful in performing a submucosal and secondary

epithilialization vestibbuloplasty.

Only the initial incsion for vestibuloplasty with split thickness graft

should be made with laser.

Deeper extent of incision should not be mad with laser because

laser inhibits epithelial migration.

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LASER ASSISTED ASSISTED UVULOPLASTY:

Done for surgical treatment of chronic snoring, upper airway

resistance syndrome, obstructive sleep apnoea.

Uvulopalatopharyngoplasty for the treatment of snoring was

intoduced by Ikematsu in 1964.

Later LAUPP is developed by KAMAMI

Procedure is described in one stage & multi stage technique

To perform the procedure , patient is placed in a comfortable ,

upright position.

Topical anesthetic spray is applied to the nostrils and posterior

oropharynx, including the palate.

1.5 ml of 2% lidocaine with 1:100000 epinephrine is injected in to

uvula at its base and the junctions of the soft palate.

In multistage technique, inferior half of the uvula is ablated or

excised.

Verticle incisions of 10mm are given just lateral to the uvula through

the soft palate.

In one stage procedure , lateral vertical cuts are initially made in

longer fashions.

Vertical incisions terminate just prior to the insertion of levator

palatini muscle. Then the uvula is reduced to a normal presurgical

length.

MAXILLO FACIAL COSMETIC AND DERMATOLOGIC LASER

SURGICAL PROCEDURES:

Cosmetic laser surgery has recently recieved much attention in the

literature and media.

Laser makes facial resurfacing more accurate and predictable than

dermaabrasion and chemical peel.

FACIAL RESURFACING:

CO2 and ER:YAG Lasers offer excellent results with a more

accurate and reproducing technique.

Selective photothermolysis is possible with the laser delivery

systems there by decreasing collateral tissue damage.

Ablation is accurately and repeatedly taken to level of the

midreticular dermis.

As the tissue heals, new elastic fibres reorganize and realignment

of collagen fibres occur in more parallel fashion

Laser technique works well for fine wrinkles at areas like perioraland periorbital areas.

Deeper wrinkles associated with more muscular actions like forehead lines respond less favourably.

Visible contraction of skin is evident as treatment continues.

Patients with history of radiation therapy in expected treatment area, and prior use of isotretinoin should usually be excluded from laser therapy because their healing is completely different.

Make up can be worn after epithelialization is complete,usuallyabout 12 to 14 days.

Complications include scarring, hyopigmentation, erythema , induartion , herpes simplex activation, and infection.

BLEPHAROPLASTY:

Technique for blepharoplasty can be aided by using a

carbondioxide, KTP, or Nd:YAG laser for the dissection to help

create a blood less field.

If blepharoplasty alone is planned , IV sedation with LA

INFILTARTION AND topical opthalmic anesthetics are sufficient.

Corneal shields are placed .

Initial incision can be made with scalpel and further dissection can

be advanced with laser .

The fat pads are then removed with co2 laser using a wet cotton tip

applicator.

Incisions are then closed in standard fashion.

Instructions to keep the head elavated and to use cold compresses

are important.

SKIN PIGMENTED LESION REMOVAL:

Laser treatment ,resurfacing , or ablation can lighten or completely

remove these lesions.

Melanosomes are the target cells and they absorb variety of

wavelength.

Lesions that extent in to the dermis require deeper penetration by

the laser and are best treated by longer wavelengths.

The pulsed tunable dye laser at 510 nm is commonly used to treat

superficial pigmentation such as cafe au lait macules .

Noncontact ND:YAG laser at 1064nm are used to treat deeper

lesions.

The area should be evalauted 6 weeks after treatment for signs of

lightening or hyperpigmentation.

Hyperpigmentation can be resolved by topical applcation of

hydroquinone , glycolic acid.

Alster and other groups used the pulsed dye laser at 585 nm to

treat various types of scarring, with significant clinical improvement.

Topical or local anesthetic is usually adequate for patient

comfort,but care must be taken not to inject LA directly in to tissues

as this may change the absorption of laser energy.

Entire scar is treated and the patiet is instructed to keep the area

clean and bandaged lightly.

Perioperative acyclovir may be prescribed if the scar is in a region

of previous herpes simplex activation.

Unger has published extensively on hair transplantation using micrografts and the added benefits of using ultrapulse co2 laser as an adjunct.

Hair transplantation with excised grafts leaves rows of hair that are easily visible and a hairline that is unnatural.

The advent of micrografting helped decrease the unsightyappearance of rows of plugged hair .

Smaller slits are made to place the microcut hair grafts in place.

The co2 laser is used to make the recipient sites slighter wider , creating even more natural hairline.

Laser assisted hair removal is currently being evaluated .

Alexandrite , Nd:YAG and ruby lasers have been selected for their

specificity for the red and near infrared sensitive dermal tissues .

Carbon based solution applied to the hair bearing area to engulf the

hair papilla , making it susceptible to the heat effects of the laser.

The heat then destroys the follicle and causes a reduction in hair

producing elements in that area.

Difficulty of treating some TMJ disorders has been evident since ANNADALES first surgical attempts in 1887.

Mccain’s contributions to arthroscopy have advanced the field significantly.

Hendler and Koslin described as sculpting fibrocartialginous and retrodiscal tissue safely and easily with Hol:YAG laser.

TRAUNER showed that the Hol:YAG laser was less damaging to the surrounding tissues when sculpting fibrocartilage.

Hol:YAG laser works well in a saline environment and can be used with a fibre optic quartz fibre.

This allows for easy manipulation with in the joint using standard traiangulation techniques described by McCain.

In endoscopic brow lift surgery , small incisions are made in the

scalp area to dissect with in a subgaleal or subperiosteal plan or

both to alter the muscular action of the procerus and corrugator

musculature as well as reposition of the brow tissue.

ENDOSCOPIC LASER LITHOTRIPSY OF SALIVARY GLAND

STONES:

the endoscope is advanced with in a salivary gland duct to view the

stone , and the laser fibre is advanced to ablate the stone .

This technique may restore the salivary flow with the advantage of

minimally invasive surgery.

Photodynamic therapy is currently being evaluated for the

treatment of head and neck ,skin, intraabdominal cancers.

Lasers have also been used in the microanastomosis of nerve and

vascular tissue with some success.

Summary

Surgical laser is a powerful tool that adds great dimension to the

oral and maxillofacial surgeon’s practice but one must command

the knowledge and temperament to use it for the proper indications

References:

Textbook of oral and maxillofacial surgery. RAYMOND

J.FONSECA VOL 1

Textbook of oral and maxillofacial surgery: NEELIMA

MALIK

Thank you