Indian Dental Academy Guide to Laser Dentistry

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

FLOW CHART
- INTRODUCTION
- HISTORY
- EXPLANATION OF TERM – LASER
- BASIC COMPONENT OF LASER
- CLASSIFICATION OF LASER
- LASER DELIVERY SYSTEM & EMISSION MODE
- LASER EFFECT ON TISSUE
- MEDICAL USES OF LASER
- DENTAL USES OF LASER
- ROLE OF LASER IN ENDODONTICS
- LASER HAZARDS & CONTROL MEASURES

INTRODUCTION
• Most patients still associate the sound and vibration of
the drill with pain. However, with the new advancements
in this field, several options have become available to
progressive dentists to allay fears and offer patients
state of the art treatment. One such advancement is the
advent of the laser technology presenting new vistas for
dentists in fields of dentistry .
• The unique characteristics of the laser are that it is
monochromatic, coherent and collimated. This allows
concentration of tremendous amount of energy to a
small area.

HISTORY
The dental lasers of today have benefited from decades of laser
research and have their basis in certain theories from the field of
quantum mechanics formulated by Danish physicist Bhor.(1900)
 Einstein’s atomic theories on controlled radiation (1917) can be
credited as the foundation for laser technology.
40 years later, American Physicist, Townes first amplified microwave
frequencies by the stimulated emission process and the acronym
MASER. (Microwave amplification by stimulated emission of radiation).
In 1958 they discussed extending the maser principle to the optical
portion of the electromagnetic field hence. LASER (Light amplification
by the stimulated emission of radiation).
Albert
Einstein

L – Light

LASER LIGHT IS
MONOCHROMATIC
REGULAR LIGHT IS POLYCHROMATICwww.indiandentalacademy.com

COLLIMATION:
BEAM HAVING SPECIFIC SPATIAL
BOUNDARIES
Constant beam size
Constant shape.

COHERENCY

A- Amplification means that a very bright intense beam of
light can be created. The laser may be activated by a few
photons which then act to produce many more, and the initial
light generated is computed to make a very bright compact
beam.

S – Stimulated : Means that the photons are
amplified by stimulating an atom to releases
more photons.
E-Emission refers to the giving off photons.
The exited atom emits a photon by absorbing
energy.

The term stimulated emission of radiation is based on the
quantum theory of physics first postulated by Bohr

R-Radiation mean giving or omitting photons.

THE BASIC
COMPONENTS OF
LASER

 The wave energy of laser ranges
between gamma rays to radio waves.
 All the available dental laser devices have
emission wave lengths of approximately
0.5µ or 500 nm to 10.6µ in 10,600 nm.

All dental lasers
emit either a visible
light beam or an
invisible infra red
light beam in the
portions of non-
ionizing spectrum
called thermal
radiation.

CLASSSIFICATION OF LASERS

GAS LASERS
Eg: CO2 laser
Argon laser

Solid state lasers
Eg: Nd:YAG Laser
Ho:YAG Laser
Er:YAG Laser
DIODE Laser

LASER DELIVERY SYSTEMS AND EMISSION MODES
Delivery systems
Flexible hollow wave guide or tube that has an interior
mirror finish.
The laser energy as reflected along this tube and exits
through a hand piece at the surgical end, with the beam
striking the tissue in a non contact fashion.

The second delivery system is a glass fiberoptic cable.
• It comes in various diameters and sizes ranging from 200-
1000µm
• The glass fiber is encased in a resilient sheath, it can be
somewhat fragile and cannot be bent into a sharp angle.
• It can be used in a contact or a non contact mode.

EMISSION MODES
☼ Continuous wave:- beam emitted at one power
level continuously as long devise is active.
☼ Gated pulse mode:- periodic alteration of
laser energy being on or off, similar
to blinking of eye. Mode achieved by opening
closing of shutter in front of beam path
☼ Free running pulsed mode:- large peak energy of
laser light are emitted for short time(microsecond)
followed by long time when laser is off.

Laser effects on tissue
The light energy from a laser can have four different
interactions with the target tissue, and these interactions
depend on the optical properties of that tissue and wave
length used.
Reflection :
♦ laser beam become more divergent
as distance from handpiece increases.
♦ Can be dangerous

Absorption
This effect is the usual desirable effect, and the amount of
energy that is absorbed by the tissue depends on the tissue
characteristics such as pigmentation and water content, and
on the laser wavelength and emission mode.
Short wave lengths, from about 500-1000nm are absorbed
readily in pigmented tissue.
Argon has high affinity for melanin and hemoglobin. .
Diode and Nd : YAG have a high affinity for melanin and less
interaction with hemoglobin.
Longer wavelength are more interactive with water &
hydroxyapatite – Erbium , carbon di-oxide.

3. Transmission:
 Transmission of laser energy directly through the tissue,
with no effect on target tissue.
 Water is relatively transparent to Nd:YAG whereas tissue
fluids readily absorb carbon di-oxide.
4. Scattering
 Scattering of the laser light causes weakening the energy
and possibly producing no useful biologic effect.
 May cause heat transfer to tissue adjacent to the surgical
site and unwanted thermal damage can occur.

Besides photothermal effects there are other effects that
lasers have on selected tissue.
Photochemical effects that lasers create to stimulate
chemical reactions, such as curing of composite resin.
They can also cause break in chemical bonds, such as in
the process of photodyanamic therapy.

IN 1961 Goldman established the first laser medical laboratory
at the university Of Cincinati, he is recognized as the first
physician to use laser technology.
L’Esparance was the first to report clinical use of an argon laser
in1968 in opthalmology .
In 1972 Strong and Jako reported the first clinical use of Co2
laser in otolaryngyology.
Keifhaber etal documented the first clinical use of Nd:YAG laser
in1977 in Gastroenterology.
History

Cardiovascular surgery
Dermatology and plastic surgery
Gastroenterology
General and oncologic surgery
Gynecology
Neurosurgery
Ophthalmology
Orthopedic surgery
Ornitholaryngology
Podiatry
Pulmonary medicine
Thoracic surgery
Urology
Vascular surgery

History
 In 1960, first working laser , PULSED RUBY LASER , built by
Maiman of huges research lab.
 During the 1970’s and 1980’s intraoral use of Co2 laser was
confined primarily to Specialists such as oral surgeons and some
periodontists.
 In 1990 Myer and Myer’s developed a pulsed Nd:YAG laser
which was recognized as the first laser specifically fo general
dentistry called the deLase 300

Intra oral soft tissue application
• Ablating, incising, excising, and coagulating
Co2, Nd:YAG, Ho:YAG
• Co2 laser has been favorite instrument for oral
surgeons b’cos of its wave lengths ready absorption
into water (soft tissue).
• Nd:YAG is also used because of its excellent
coagulation ability, flexible fibroptic delivery system,
ease of use and precision.

LASER – ASSISTED UVULOPLASTY
♠ Is a clinical application for the treatment of obstructive sleep
apnea and snoring.
♠ Kamami is credited as originator of tech.
♠ CO2 laser is used for this purpose.

Treatment of pathologic conditions
Tuffin and Carruth were the first report on use of Co2 laser
in pathologic lesions.
Co2 It is predominantly used.
Nd:YAG laser was also used to treat similar conditions.
Photodynamic therapy

Other conditions
 Drug induced hyperplasia
 Orthodontically induced hyperplasia
 Apthous ulcers
 Lichen planus
 Sialoliths
 Epulis
 Mucoceles
 Ranula
 Granuloma
 Haemangioma
 Papillomatosis
 Lymphangioma
 ANUG.

Hard tissue applications
 Caries removal, inhibition and detection
 Cavity preparation
 Surface modification
 Calculus removal
 Bone ablation and cartilage reshaping
 Dentin desensitization
-occlusion of dentinal tubules
- nerve analgesia thru depression of nerve tranmission

Analgesia :
- interfere with sodium pump mechanism
- change cell membrane permeability
- block depolarization of c and Aß fibers
- Other Dental Applications
Laser diagnostics.
- laser doppler flowmetry.
- flow cytometry.
Instrument sterilization
Bio stimulation
♣ He- Ne , diode lasers
♣ Analgesia, pain relief, accelerated wound healing , fibroblast
proliferation, enhanced neuron regeneration, bone formation
and dentinal hypersensitive.www.indiandentalacademy.com

Lasers used for endodontics
Laser type Wave length
(nm)
Argon 488 – 515
CO2
10,600
Nd:YAG 1064
Diode 800-980
Er:YAG 2.94
Er :YSGG 2.79

Argon Laser :-
Active medium of argon gas &delivered fiber optically in continuous-
wave &gated pulse modes.
Laser has two emission wavelengths– 488nm (blue) & 514nm
(blue-green)
488nm wavelength needed to activate camphoroquinone.
Used with other dental materials- light activated impression paste & light
activated bleaching gel.
514nm wavelength peak absorption– red pigment
tissue containing hemoglobin, hemosiderin, melanin –intract with laser
Surgical laser with excellent hemostatic capabilities
Poor absorption into enamel, dentine – advantage when used for cutting
& sculpting gingival tissues thus no damage to tooth structure
Both wavelength used for caries detection – orange-red color.
Argon Laser :-

CO2 Laser
• Uses hollow wave guide delivery system
• Has gas active medium, delivered in continuous &gated pulse
mode . Wavelength - 10,600nm
• Effective in pain reduction & dentin hypersensitivity
• It is used as an adjunct to mechanical root instrumentation The
CO2 laser’s ability to act as bactericidal
• It is found effective in removing masses of tissue

Nd:YAG laser
 has solid active medium, crystal of Y-A-G doped with Nd
 delivered fiber optically in free running pulsed mode, wavelength -
1064nm
 Can be used in contact and non – contact modes for cutting and
ablating tissue.
 It can be used on effective adjunct to mechanical root
instrumentation.
 It is used for curettage.
 Has been used in frenectomies, gingivoplasty,crown
lengthening,gigivectomy
 Excision or destruction of lesions, such as leukoplakia or fibromas.
Used in direct pulp capping , vital pulp amputation,disinfection of
infected root canals, apicoectomy, retrograde apical cavity prepration

DIODE LASER
Diode laser have solid active medium
 Is solid state semiconductor laser uses combination –aluminum,galium
,&arsenide, to change electric energy to light energy.
 delivered fiber optically in continuous-wave &gated pulse mode in contact
with tissues. Wavelength - 800nm to 980nm.
Excellent soft tissues surgical laser indicated – cutting, coagulating
gingiva,soft tissue curettage
useful adjunct in reducing gingival inflammation and providing analgesic
effects. www.indiandentalacademy.com

Different laser systems used in dentistry

ROLE OF LASERS IN
ENDODONTICS

VITAL AND NON VITAL DIAGNOSIS OF
DENTAL PULP BY LASER
Use of Laser Doppler Flowmetry
• EPT uses electric current to stimulate A δ nerve fibre within pulp.
• Intact nerve fibre does not mean pulp is vital.
• Teeth that have experienced recent trauma or are in position of the
jaw that has undergone orthognathic surgery.
• Laser doppler flowmetry uses specific wave length.
• HeNe and Diode laser at a lower power of 1 or 2 mW are used in
laser doppler flowmetry.
• Wave length of HeNe laser – 632.8mm
Diode laser – 780 to 820mm

• Prevent reflecting from surrounding gingiva – used under
rubber dam.
• Advantages – Allow painless diagnosis
- Vital and non vital diagnosis of immature or
traumatized teeth.
- Patient sensitive to tooth pain.

Dentinal Hypersensitivity
• It is a short, sharp pain from exposed
dentin.
• Erosion, abrasion, attrition, gingival
recession are risk factors.
• Management of Dentinal hypersensitivity
involves therapies that reduces flow of
dentinal fluid.

• Blocking dentinal fluid flow – decreases
DH.
• This is obtained by application of Oxalate
salt, isobutyl cynoacrylate, fluoride
releasing resin, varnish, potassium
containing dentifrices, fluoride containing
medicaments and agent with 10%
strontium chloride.

• Laser induced reduction in dentinal
hypersensitivity – 2 mechanism.
1. Direct effect of laser on electric activity of
nerve fibre within pulp.
2. Modification of tibular structure of dentin by
sealing dentinal tubule.
• The laser is used for treatment in 2 groups
- Low output power laser (HeNe, diode)
- Middle output for laser (Nd:YAG, Co2)

DIFFERENTIAL DIAGNOSIS OF PULPITIS BY
LASER STIMULATION
Normal pulp and Acute Pulpitis
• Normal pulp stimulated by Nd: YAG laser at 2W and
20pps at distance 10mm - pain produced within 20-30
sec and disappear a couple of seconds after stimulation
is stopped.
• However, in case of acute pulpitis pain is induced
immediately after application and continues for 30sec
after stopping the stimulation.

Acute Serous Pulpitis and Acute
Suppurative Pulpitis
• Obtained by combining the electric current
resistance of caries and pain induced by laser
stimulation.
• If electric current resistance is greater than
15.1mΩ and patient experience continuous pain
for more than 30 sec – acute serous pulpitis.
• If electric current resistance is less than 15 mΩ
and pain continuous for more than 30 sec –
Acute suppurative pulpitis.

• Because of advantage of control of
haemorrhage and sterilisation - DPC
• Diameter of pulpal exposure must be
2mm or less and there must be no
infection in pulp.
• CO2 laser can be used for this purpose
TREATMENT BY LASER FOR
DIRECT PULP CAPPING

• Laser irradiation performed at 1 or 2W after
irrigating alternatively with 8% sodium
hypoclhorite & 3% H2O2 for 5 min.
• Ca (OH)2 paste must be used to dress the
exposure site.
• After which the cavity is tightly sealed with
cement e.g carboxylate cement.
• High success rate because – ability to control
haemorrhage, disinfection, sterilization,
carbonization and stimulation on dentinal pulp
cells.
• Others – Nd:YAG, argon, diode, Er : YAG.

• Closure of dentinal tubule and sedative
effect on pulpitis.
• Indication – Deep cavities, hypersensitive
cavities & cavities requiring sedative
treatment
• Pulsed Nd:YAG laser + air spray used at
2W and 20 pps for 1 sec.
• CO2 can be used for IPC at low energy for
1sec.
Treatment by Laser for Indirect
Pulp Capping

ACCESS CAVITY PREPARATION AND
ENLARGEMENT OF ROOT CANAL
ORIFICE BY LASER
• Access cavity preparation has
been performed - Air turbine
• And Enlargement of canal orifice
– Gates Glidden drill.
• Er:YAG and Er, Cr : YSGG laser,
which ablate enamel and dentin
can replace air turbine.

• Indications – Vital extripation of infected
root canal
- Gates glidden cannot be inserted
because of difficulty in opening
mouth.
- Difficulty to find root canal orifices.
• Access cavity and orifice enlargement is carried out
at 5W and 6Hz under water spray.

CLEANING & SHAPING OF
ROOT CANAL BY LASER
• Optical fiber of laser can cut enamel &dentin making
possible to remove pulp tissue & prepare root canal
wall
• Er:YAG laser at 8hz & 2w can be used
• Laser tip must slide gently from apical portion to
coronal portion
• laser irradiation performed in combination with usual
root canal preparation – shown that smear layer
removed completely & dentinal tubules opened.

• One limitation with use of laser – laser is emitted
.straight ahead,making it almost impossible to
irradiate the lateral canal walls
• Stabholz, et al – reported development of a new tip that
can be used with Er:YAG laser system
• This is called as RC Lase side firing tip
• The beam of laser delivered through hollow tube, tip
of tube sealed at its far end thus preventing the
transmission of irradiation through apical foramen.
• Thus laser is delivered laterally to the walls of canal
through spiral slit located along the tip.

LASERS FOR REMOVING PULP REMNANTS
& DEBRIS AT APICAL FORAMEN
♦pulsed Nd:YAG , Er:YAG – recommended
♦ A power of 2 – 5 w for 1 sec is recommed
♦ Carried out in combination with 5.25% sodium hypochlorite
or 14% EDTA
♦ Laser produces cavitation effect similar to ultrasonic
♦ Indication - straight , slightly curved canal ,wide root canal

STERLIZATION OR DISINFECTION
OF INFECTED ROOT CANAL
laser is effect tool in killing micro organism
 Nd:YAG in combination with 38% silver ammonium sol.
At 2W & 20 pps for 5 sec are recommed.
 Silver ammonium sol has been used as iontrophoresis of
infected root canal
 To prevent leakage of 38% silver ammonium sol into
periapical tissue , a cotton pellet is placed in apical 1/3rd
of root canal
 If no symptom – obturate root canal
otherwise – calcium hydroxide intracanal dressing given

• LASER CAN ALSO BE USED FOR
APICOECTOMY , RETROGRADE ENDODONTIC
APICAL CAVITY PREPARATION, & PERIAPICAL
CURETAGE

Laser hazards are basically categorized into a categories
according to ANSI or OSHA standards
Class Description
I Low powered lasers that are safe to oral
II Low powered visible lasers that are
hazardous when viewed for larger than
0.25sec
III Low powered visible lasers that are
hazardous when viewed for larger than
1000sec
IIIa Medium powered lasers that are normally
not hazardous if craves for less than
0.25sec without magnifying optics
IIIb Medium powered lasers (0.5w) that can be
hazardous viewed directly
IV High powered lasers (>0.5w) that produce
ocular, skin, and fire hazards.www.indiandentalacademy.com

∀•        The lasers generally used for surgical procedures in
dentistry fall under class IV.
∀•        The types of hazards that may be encountered
within clinical practice of dentistry may be grouped as
follows.
•1.     Occular injury
•2.     Tissue damage
•3.     Respiratory hazards
•4.     Fire and explosion
•5.     Electrical shock

LASER HAZARD CONTROL
MEASURES
• USE OF PROTECTIVE WEAR
• THE SMALL FLEXIBLE FIBEROPTIC , HANDPIECES OR
Tip MUST BE STEAM STERLIZED IN STERLIZING POUCHES.
• USE OF SCREEN & CURTAINS SHOULD BE PROMOTED
• USE OF PROPER CLOTHING
• USE OF ANTI-FIRE EXPLOSIVE
• THEIR SHOULD BE PROPER TRANING EDUCATION FOR
USE OF LASER

C0NCLUSION
The last 20 years have witnessed many new
developments in dental technologies, and
the next 20 years promise to be even
richer in technologic advancements.
Lasers will be in the forefront of that
growth.

REFRENCES
- THE DENTAL CLINICS OF NORTH AMERICA –
VOL-44; NO-4;OCT 2000
- TEXT BOOK OF ENDODONTIC – JOHN I INGLE –
5TH
Edi.
- www.HOW STUFF WORKS – LASERS
- CLEANING AND SHAPING OF ROOT CANALWITH
Nd:YAG LASER:A COMPARATIVE STUDY. J.O.E
18;123-127;1992.
- EFFECT OF LASER TREAT ON ROOT CANAL OF
HUMAN TEETH. DENTAL TRAUMATOLOGY 13;139-
145;1997.
- THE DENTAL CLINIC OF NORTH AMERICA -
VOL-48;NO-8;2004www.indiandentalacademy.com


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