LASERLASERS AND IT’Z APPLICATIONS IN DENTISTRY

By: Lokender Yadav

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• Introduction

• History

• Fundamentals Of Laser Operation

• Classification Of Lasers

• Current Uses

• Technique For Use Of Laser In OMFS

• Laser Safety

• Conclusion

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Introduction

Advances in technology are increasing and

changing the ways that patient experience dental

treatment. Technology helps to reduce treatment

time and treatment more comfortable.

One of the milestones in technological

advancements in dentistry is the use of LASERS.

The term Laser is the acronym for “Light

Amplification by Stimulated Emission of Radiation”.

They provide more efficient , more comfortable and

more predictable outcomes for the patient.

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HISTORY

1917- Einsteen Theory of stimulated

emission

1958 – Townes & Schawlow Laser principle

1960 - Maiman Ruby laser

1961 - Johnson Neodymium ion doped

yttrium aluminium garnet rod

1964 - Patel CO2 Laser

1977 - Shafir First documented case in

OMFS using lasers

1989 – Terr Myers First Dental Laser – Nd:YAG

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3 Mechanisms of Light

Emission

For atomic systems in thermal equilibrium with their

surrounding, the emission of light is the result of:

Absorption

And subsequently, spontaneous emission of energy

There is another process whereby the atom in an upper

energy level can be triggered or stimulated in phase with

the an incoming photon. This process is:

Stimulated emission

It is an important process for laser action

1. Absorption

2. Spontaneous Emission

3. Stimulated Emission

Therefore 3 process

of light emission:

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Absorption

E1

E2

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Spontaneous Emission 8

Stimulated Emission 9

Background Physics

In 1917 Einstein predicted that:

under certain circumstances a photon incident upon a

material can generate a second photon of

Exactly the same energy (frequency)

Phase

Polarisation

Direction of propagation

In other word, a coherent beam resulted.

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Fundamentals Of Laser Operation

Components -

Active medium [ Lasing Medium ]

Pumping mechanism

Optical Resonators

Laser Delivery System

Cooling system

Control Panel

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12

E1

E2

h

(a) Absorption

h

(b) Spontaneous emission

h

(c) Stimulated emission

Inh

Out

h

E2

E2

E1 E

1

Absorption, spontaneous (random photon) emission and stimulatedemission.

© 1999 S.O. Kasap, Optoelectronics (Prentice Hall)

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Stimulated Emission 14

Properties Of LASER

Monochromaticity

Directionality

Coherence

Brightness

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Photobiology Of Lasers

Photochemical

Biostimulation - Stimulatory effects of laser on biochemical and molecular processes that normally occur in tissues such as healing and

repair.

Photodynamic Therapy – induce reactions in

tissues for the treatment of pathologic condition.

Tissue fluorescence - used as a diagnostic

method to detect light reactive substance in

tissue.

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Photo thermal interactions-

Photo ablation – removal of tissue by vaporization andsuper heating of tissue fluids , coagulation, and

hemostasis.

Photopyrolysis

Photomechanical

Photo disruption - breaking apart of structures by laser light.

Photoaccoustic interaction- involve removal of tissue with shock wavegeneration.

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Photoelectrical Interaction- include photoplasmolysis

which describes how tissue is removed through the

formation of electrically charged ions and particles

that exist in a semi gaseous high energy state.

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LASER INTERACTION WITH

ORAL BIOLOGIC TISSUE

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Photocoagulation : Laser heats the tissues

to 60 deg C for a limited time

leading to coagulation of the

tissues with minimal alteration in the

appearance of tissue structure. As

a result of these proteins enzymes

cytokines and other bio active

molecules get denatured.

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Classification Of Lasers

General Classification

Class 1 Non Hazardous Producing

Laser

Class 2 Hazard producing when

passed through magnifying

optics

Class 2 M Safe, if not viewed through

optical instruments

Class 3 R Safe with restricted beam

viewing

Class 3 B Direct viewing hazardous to

eye

Class 4 Serious injury potential to

eye and skin

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Laser Classification as per medium

Used

Solid State Laser Eg-Neodymium-yttrium aluminium

garnet laser

Gas Laser Eg- Helium & Helium Neon

Excimer Laser Uses reactive gases like chlorine and

fluorine eg : argon laser

Dye Laser Complex dyes like Rhodamine 6G

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Medical Classification Of

Lasers

High Power Lasers-Used for surgical

purpose

Low power Lasers-Used to promote

tissue regeneration

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General Medical Uses Of Laser

Angioplasty

Cancer diagnosis

Cancer treatment

Laser hair removal , tattoo removal

Dermatology

Medical imaging

Microscopy

Ophthalmology

Optical coherence tomography

Prostatectomy

Surgery

Laser Dentistry

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Photodynamic Therapy 25

Uses In Dentistry

Excimer Lasers

Hard tissue ablation/ Dental Caries removal.

Argon Fluoride / Xenon fluoride lasers are used.

They have a wave length from193nm to 308nm.

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Gas Laser

Carbon dioxide lasers are used for intra oral and implant

soft tissue surgery , aphthous ulcer , melanin pigmentation.

Has a wavelength of 10600nm. Color- Infrared

Helium Neon Lasers has a wavelength of 637nm and is used

for dentin hypersensitivity , analgesia etc. Color-Red

Argon lasers having a wavelength of 488nm & are used fortooth whitening , curing of composites , curettage etc

Color-Blue

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Diode Lasers

Indium Gallium Arsenide Phosphorous are used for

caries and calculus detection and has wavelength of

655nm. The color of the laser is Red.

Gallium Aluminum Laser – Intra oral Surgery , Implant

soft tissue surgery , sulcular debridement , Pulpotomy ,

root canal disinfection removal of enamel caries etc,

Wavelength- 840nm Color-Infrared

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Solid state Laser

Neodymium:YAG Laser – Intra oral soft tissue surgery ,

sulcular debridement , analgesia , Pulpotomy , root

canal treatment, removal of gingival melanin

pigmentation . Has a wave length of 1064nm and is

infrared.

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Erbium Group

Erbium:YAG is used for modification

of enamel and dentin surface ,

implant soft tissue surgery , sulcular

debridement , osseous surgery ,

treatment of dentin hypersensitivity

, apthous ulcer treatment etc

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Techniques For Incisional Biopsy

Provide local or general anesthesia.

Outline the intended superficial incision

line without deep penetration.

Connect the outline marks.

Excise the specimen.

Obtain Homeostasis.

Consider the need for suturing.

Consider tagging the biopsy margins.

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Lesions treated

Fibroma

Mucocele

Papilloma

Gingival lesion

Salivary stones

Malignancy removal

Vestibuloplasty

Incisional and excisional biopsy

Tongue lesion treatment

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Technique for ablation and vaporization

Laser vaporization is an effective , non-morbid , inexpensive , quick , and relativelypainless method of managing pre malignantlesions.

A spot size of 1.5 to 3mm is typical for mostintra oral vaporization procedures. The beamis transverse in vertical strokes.

A constant speed must be maintained tocreate a uniform depth. Increasing depth canbe accomplished by increasing power.

Allows for removal of a surface lesion inlayers.

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Uses Of Laser Ablation

Solar chelitis

Leukoplakia

Dysplasia

Lichen Planus

Oral melanosis

Nicotine stomatitis

Tissue hyperplasia

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Lasers are also used in arthroscopic surgery of TMJ

Scar revision is also made possible these days with the help of pulsed dye

lasers[PDL]. PDL have hb as their chromophores and penetrate the epidermis

without de-epithelisation. They reduce scar tissue erythema and induce

collagen remodeling to flatten and soften scars. Indicated in cases with

erythematous and hypertrophic scars of maxillofacial region.

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Low level Laser therapy

Also known as therapeutic laser

treatment.

Promotes tissue healing , reduces

edema , inflammation and pain.

Used in cases of – dermatological

conditions , neural ailments ,

mucoskeletal ailments etc

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Easy and safe to handle

Improved surgical versality- ability to vaporize

coagulate and incise tissue.

Reduces / Eliminate bleeding.

Spot coagulation and vaporization gives

excellent hemostasis.

Reduces Operating Time.

Anesthesia free soft and hard tissue cutting

No need for suturing

Instant sterilization of surgical site

No sensory disturbances

No functional /mobility disorder

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Demerits

Cannot be used in teeth with restoration and prosthesis.

Hazard to patient , operating and assisting team.

Maintenance requirements

Electrical hazards of laser equipments

Expense of laser equipments

Specialized arrangements

Fire hazards

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Laser Hazards

Primary Hazards: Caused directly by laser beam.

Endangers mainly two organs-

Eyes and Skin

In case of eyes it damages retina , cornea , & the

lens and slight carelessness can destroy vision

permanently.

Secondary Hazards : Its related to operation of the

laser and are independent of radiation

characteristics.

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Operating Room Safety

Use of non inflammable materials

Use of eye shields for the patient

Use of laser resistant shielding materials for surgical

field and for protecting anesthesia equipments

Certain anesthesia techniques may also decrease

potential hazard

Patient Safety

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Personnel Safety

Post signs that lasers are being used

Eye shields to be worn by all personnel in operating room

Safety shields must be used

A laser safety officer should be stationed at the laser unit

Use only wet cloth in operative field

Use only non-combustible anesthetic agent

Avoid alcohol based topical anesthetic and gauze

Protect tissues adjacent to surgical site

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Sterilization And Infection Control Of Laser Unit

Steam sterilization is the standard of care

Protective housing around the laser and

articulating arm should receive spray disinfectant

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Treatment Process 45

Conclusion

The past decade has seen a variable explosion of research

into clinical application of lasers in dental practice. Laser

treatment not only is helpful in treating general problems of

the teeth but also helps to reduce the fear and anxiety of the

patient towards the treatment.

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