2. CONTENTS
ďą INTRODUCTION
ďą HISTORY
ďą FUNDAMENTALS OF LASER
ďą LASER DELIVERY SYSTEMS
ďą EMISSION MODES
ďą LASER EFFECTS ON TISSUES
ďą CLASSIFICATION OF LASERS
ďą LASERS IN OPERATIVE DENTISTRY
ďą LASERS IN ENDODONTICS
ďą CONCLUSION
ďą REFERENCE
3. INTRODUCTION
ďą LASERâ ď light amplification by stimulated emission of radiation.
ďą Lasers were first developed in the 1960s.
ďą Dental researchers ď investigated ď numerous applications of laser instruments
ďą intraoral soft tissue surgery, hard tissue applications, dental materials and
endodontics.
5. âMASERS AND LASERSâ
⢠In 1954ď Townes and Gordon ď first microwave laser or âMASERâ ď
âMicrowave Amplification by stimulated Emission of Radiationâ
⢠In 1958, Townesď first theoretic calculations for a visible light maser ď
LASER.
⢠The Nobel Prize for the development of the laser was awarded to Townes,
Basor and Prokhovov in 1964.
6. Milestones
1971- Weichman & Johnson:
lasers in endodontics
6
1979 Adrian & Gross:Argon
laser sterilisation of dental
instruments.
1964 â Stern, Sognnaes &
Goldman: lasers in dentistry.
Nd: YAG was developed by
Geusic.
⢠1960 Theodore Maiman introduced the
acronym âlaser,â ruby laser
1985 Shoji et al
Laser aided
pulpotomy
1965ď CO2 laser ď Patel et
al
7. Milestones
1994-Morita: Nd:YAG lasers for root resection &
retrograde cavity preparation
7
⢠1986-Zakariasen et al: sterilization
of root canals
1998 Mazeki et al : Root
canal shaping with Er:YAG
laser.
1993âPaghdiwala : Er:YAG
lasers for root resection &
retrograde cavity
preparation.
⢠1990 Potts & Petrou - laser aided
photopolymerization of camphoroquinone
activated resins.
1988 Miserendino: Apicectomy
with CO2 laser
9. Laser is a device that converts electrical or
chemical energy into light energy.
ďą LIGHT
ďą AMPLITUDE
ďą STIMULATED EMISSION
ďą RADIATION
10. LIGHT
⢠Form of electromagnetic energy
⢠Behaves ď wave and a particle.
⢠Basic unit of this energy is calledď
photon.
11. ⢠Ordinary light ď white ď sum of many colors of visible spectrum â
violet, blue, green, yellow, orange, and red
⢠Laser energy ď one specific color ď monochromaticityď dental
applications that color may be visible or invisible.
12. COHERANCY
⢠Waves produced in laser instrument
are all in phase with one another
⢠Have identical shapes when plotted
on a graph
13. COLLIMATION
⢠Beamď collimated ď rays or beams
are all parallel within laser
instrument.
⢠Once laser beam enters certain
delivery systemsď optical fibers or
tips ď diverges at fiber tip
14. AMPLITUDE
⢠Total height of wave oscillation from top of peak to the zero line on a
vertical axis.
⢠Indication ď amount of intensity in the wave:
⢠Larger amplitudeď greater amount of useful work that can be performed.
16. Components of a laser instrument
⢠An optical cavity ď at center of the
device.
⢠Three components make up the laser
cavity:
â Active medium
â Pumping mechanism
â Optical resonator
18. ACTIVE MEDIUM
⢠Composed of chemical elements, molecules, or compounds.
⢠Lasers ď generically named ď material of active medium
19. ď A container of gas : canister of carbon dioxide gas ď CO 2 laser
ď A solid crystal ď erbium-doped YAG (Er:YAG) laser
ď A solid-state semiconductorď Diode lasers
ď A liquid - medical laser devices.
20. Pumping mechanism
⢠Surrounding this active medium ď excitation sourceď flash lamp strobe
device, electrical circuit, electrical coil, or similar source of energy that
pumps energy into active medium.
21. When this pumping mechanism drives energy into active medium
Electrons in outermost shell of active mediumâs atoms absorb the
energy.
These electrons have absorbed a specific amount of energy to reach
the next shell farther from the nucleus, which is at a higher energy
level.
A âpopulation inversionâ occurs when more of the electrons from the
active medium are in the higher energy level shell farther from the
nucleus than are in the ground state
The electrons in this excited state then return to their resting state
Emit that energy in a form known as a photon
Spontaneous (not stimulated) emission
22. OPTICAL RESONATORS
⢠Two mirrorsď one at each end of optical cavityď
placed parallel to each other/ semiconductor diode
laserď two polished surfaces at each end.
⢠Act as optical resonatorsď reflecting waves back
and forth, ď help to collimate and amplify the
developing beam.
⢠A cooling system, focusing lenses, and other
controlling mechanisms complete the mechanical
components.
23. SIMULATED EMISSION
⢠Process by which laser beams are produced
inside laser cavity.
⢠Theory of stimulated emission ď postulated
by Albert Einstein in 1916.
24. Quantum ď smallest unit of energy emitted from an
atom.
Einstein ď an additional quantum of energy may be
absorbed by the already-energized atom, resulting in a
release of two quanta.
This energy is emitted, or radiated, as identical photons,
traveling as a coherent wave.
These photons in turn are then able to energize more
atoms in a geometric progression
Further causes emission of additional identical photons,
resulting in an amplification of the light energyâthereby
producing a laser beam
27. LASER DELIVERY SYSTEM
2 delivery system
ďś hollow guide or tube
ďś flexible glass fibreoptic cable
fragile and cannot be bent sharp
Various size of diameter
Encased in resilient sheath
Fit into handpiece with bare end or attached glass like tip
28. ⢠Shorter-wavelength instruments
â KTP, diode, and Nd:Y-AG lasers
â Small, flexible fiberoptic systems with bare glass fibers that deliver
the laser energy to the target tissue
29. ⢠Erbium and CO 2 laser
â wavelengths are absorbed by waterď
which is a major component of
conventional glass fibersď these
wavelengths cannot pass through these
fibers.
â Special fibers capable of transmitting
the wavelengths, with semiflexible
hollow waveguides, or with articulated
arms
30. ⢠Small quartz or sapphire tips that
attach to the laser device for contact
with target tissue; others employ
noncontact tips
⢠Erbium lasers incorporate a water
spray for cooling hard tissues.
31. ⢠Lasersď different fiber diameters,
handpieces, and tips
⢠Each of these elements plays a
significant role in the delivery of energy
32. ⢠Dental lasers ď either in contact or out of contact.
⢠Fiber tip can easily be inserted into a periodontal pocket to remove small
amounts of granulomatous tissue or treat an aphthous ulcer
34. ⢠Dental laser devices can emit light energy in two modalities as a function
of time:
â Constant on
â Pulsed on and off.
35. ⢠Pulsed lasers can be further divided into gated and free-running modes for
delivering energy to the target tissue.
⢠Thus three different emission modes are described.
36. 1. Continuous-wave mode
⢠Beam ď emitted at only one power
level for as long as the operator
depresses the foot switch.
37. 2.Gated-pulse mode
⢠Periodic alternations of the laser energy, similar to a blinking light.
⢠Opening and closing of a mechanical shutter in front of the beam path of
a continuous-wave emission.
⢠All surgical devices that operate in continuous-wave mode have this
gated-pulse feature.
38. 3. Free-running pulsed mode
⢠True pulsed mode.
⢠This emission is unique in that large peak energies of laser light are
emitted usually for microsecondsď followed by a relatively long time in
which the laser is off.
39. 4. Super pulsed: duration of pulse is one hundredth of microseconds.
5. Ultra pulsed: produces output pulse of high peak power that is maintained
for a longer time and delivers more energy.
6. Q-scotched: Even shorter and more intense pulse ď obtained with this
mode
40. FOCUSSING
1. A focussed mode :
⢠Laser beam hits the tissue at its focal points or smallest diameter.
⢠This diameter ď dependent on size of lens used.
⢠Cut mode.
⢠Eg. While performing biopsies.
41. 2. Defocused mode
⢠By defocusing laser beam or moving focal spot away from tissue planeď
beam size that hits tissue has a greater diameterď thus causing a wider
area of tissue to be vaporized.
⢠Laser intensity / power density is reduced.
⢠Ablation mode.
⢠Eg. In Frenectomies. In removal of inflammatory papillary hyperplasias
42. 1.CONTACT MODE
⢠Fiber tip is placed in contact with tissue.
⢠Charred tissue formed on fiber tip or on the tissue outline -increases
absorption of laser energy and resultant tissue effects.
⢠Char -eliminated with a water spray and then slightly more energy will be
required to provide time efficient results.
⢠Advantage-- control feed back for the operator.
43.
44. 2.NON-CONTACT MODE
⢠Fiber tip placed away from target tissue.
⢠Clinician operates with visual control with aid of an aiming beam or by
observing tissue effect being created.
45. ⢠In noncontact use, the beam is aimed at the target some distance away
47. ⢠Depending ď Optical properties of tissueď light energy from a laser may
have four different interactions with target tissue:
â Reflection
â Absorption
â Transmission
â Scattering
48. 1.Reflection
⢠Beam ď redirected off the surface ď with no effect on target tissue.
⢠Reflected light ď maintain its collimation in a narrow beamď or it may
become more diffuse.
⢠Dangerous ď energy could be redirected to an unintentional target, such
as eyes.
⢠Potential mistargeting ď major safety concern in laser operation and the
reason that every person in the dental treatment room must wear
wavelength-specific safety glasses with appropriate side shields.
49. Titanium implant in patient
⢠Interaction between a CO 2 laser and a patientâs titanium implants.
⢠CO 2 laser energy reflected off the implants could be redirected to the dentistâs
eyes
50. 2.Absorption
⢠Absorption of laser energyď intended target tissue ď most
desirable effect.
⢠Amount of energy absorbed by tissue depends on that
tissueâs characteristics
â pigmentation
â water content,
â laser wavelength.
⢠Primary and beneficial goal of laser energy ď absorption of
laser lightď intended biologic tissue.
51. 3.Transmission
⢠Transmission of laser energy directly through
tissueď no effect on target tissue.
⢠Dependent on wavelength of laser light.
52. ⢠Water ď Relatively âtransparentâ to (does not absorb)ď diode and Nd:YAG
wavelengths,
⢠Water component of tissue fluids readily absorbs erbium and CO 2 wavelengths
at the surface, so minimal energy is transmitted to adjacent tissues.
⢠The diode and Nd:YAG wavelengths are transmitted through the sclera, lens, iris,
cornea, vitreous humor, and aqueous humor of the eye before being absorbed on
the retina.
53. 4.Scattering
⢠Scattering of laser lightď weakens intended energy.
⢠Predominant ď use of near-infrared lasers in
healthy soft tissue.
⢠Causes photons to change directionsď increased
absorptionď correspondingly increased chances of
interacting with predominant chromophore of those
wavelengths.
54. ⢠Cause heat transferď tissue adjacent to surgical siteď potential for injury from
unwanted laser effects.
⢠However, a beam that is scattered, or deflected in different directionsď useful in
facilitating laser curing of composite resin.
56. DCNA ,2000
I. According to the wavelength (nanometers)
ďą UV (ultraviolet) range â 140 to 400 nm
ďą VS (visible spectrum) â 400 to 700 nm
ďą IR (infrared) range â more than 700 nm
57. 1. Hard laser (for surgical work)
ď CO2 lasers (CO2 gas)
ď Nd:YAG lasers (Yttrium-aluminium-garnet crystals dotted with
neodymium)
ď Argon laser (Argon ions)
2. Soft laser (for biostimulation and analgesia)
ď He-Ne lasers
ď Diode lasers
58. III. According to the delivery system
â Articulated arm (mirror type)
â Hollow waveguide
â Fiber optic cable
59. IV. According to the type of active medium used
â Gas, solid, semi-conductor or dye lasers
⢠V. According to type of lasing medium
â E.g. Erbium: Yttrium Aluminium Garnet
60. VI. According to pumping scheme
â Optically pumped laser
â Electrically pumped laser
VII. According to operation mode
â Continuous wave lasers
â Pulsed lasers
61. VIII. According to degree of hazard to skin or eyes following
inadvertent exposure
This laser classification system is based on the probability of damage occurring.
ďą Class I- (< 39mw) Exempt; pose no threat of biological damage
ďą Class II- (< 1 mw) The output could harm a person if he were to stare into the beam
for a long period of time. The normal aversion response or blinking should prevent
you from staring into the beam. No damage can be done within the time it takes to
blink.
62. ďą Class IIIA - ( 5OOmw) : Can cause injury when the beam is collected
by optical instruments and directed into the eye
ďą Class IIIB - Causes injury if viewed briefly, even before blinking can
occur.
ďą Class IV - (> 5OOmw) Direct viewing and specular and diffuse
reflections can cause permanent damage including blindness.
64. Nd:YAG Laser
64
Neodymium: Yttrium Aluminium-Garnet Laser
⢠Developed by Geusic in 1964
⢠Wavelength-1.06 micron
⢠Penetration depth-0.5-4 mm
⢠Affinity for pigmented tissues
⢠Penetrates wet tissues more rapidly.
65. DIODE LASER
65
â˘Diode -Have a solid active medium;
it is a solid-state semi conductor laser
⢠Uses some combination of Al, gallium and arsenide to change
electric energy into light energy.
-Wave length range from 800-980nm
66. ⢠Laser energy is delivered fiber optically in continuous or pulse
mode & used in contact with the tissue.
⢠Poorly absorbed by tooth structure
⢠An excellent soft tissue surgical laser indicated for cutting and
coagulating gingiva and mucosa.
⢠Affinity for pigmented tissues
66
67. CO2 LASER
⢠Developed by Patel et al in 1964
⢠Wavelength-10.6 microns
⢠Limited penetration depth (0.2-0.3 mm)
⢠Focused beam-fine dissection
⢠Defocused beam-ablates the tissue.
67
68. ⢠Delivered through a hollow tube system via handpiece & cant be
delivered in a fiberoptic
⢠Especially useful for cutting dense fibrous tissue.
⢠Focused onto the surgical site in a non-contact fashion.
⢠Highly absorbed by both hard & soft tissues.
68
69. ARGON LASER
⢠Active gas medium of argon gas that is fiberoptically delivered in continuous ,pulsed
modes.
⢠Two emission wavelengths, 488nm (blue in color) and 514 nm (blue â green)
69
70. 70
â˘488nm- used to cure light activated composites,impression
materials, bleaching gels.
â˘514nm- highest absorption in Hb, used for its good hemostatic
capabilities.
71. Er:YAG & Er,Cr:YSGG
⢠Solid active medium crystal containing yittrium aluminium garnet that is doped with
erbium.
⢠Wavelength Er:YAG -2940 nm Er,Cr:YSGG â 2790 nm
⢠Delivered throuh a fiberoptic system in a pulsed mode.
71
72. 72
Have highest absorption in water & have high affinity to hydroxy apatite.
Ideal for hard tissue cutting& drilling.
POTASSIUM-TITANYL-PHOSPHATE (KTP)
laser emits green light that is avidly absorbed by both melanin and
oxyhemoglobin.
75. 1.DIAGNOSTIC LASER
⢠DIAGNOdent ď used for early detection of
smooth cuface and occlusal caries and calculus
detection
⢠By emitting nonionizing laser beam ď
wavelength 655nm (at a 90degree angle)ď
specific darkened groove on the occlusal surface
of a patientâs tooth where bacterial decay is
suspected
⢠Or along long axis of a root surface ď detect
presence of a bacteria-laden calculus.
76. ⢠Photons of this laser wavelengthď absorbed into any existing bacteria in these
areas of the patientâs toothď laser-induced fluorescence.
⢠Digital display ď indicates number of bacteria in this area of tooth
⢠Correspond to extent of decay or existence of calculus
Krause F et al , Eur J Oral Sci 2007
77. Diode laserď irradiates red light within the visible spectrum
with 638â655 nm wavelength
Absorbed by organic and mineral tooth content.
Light is absorbed by teeth and creates infrared fluorescence
(light photon with longer wavelength)
The results are shown by numbers between 0â99.
Values âĽ20 and 25 indicate ď presence of carious lesion.
Higher values indicate greater penetration depth of caries.
Increased fluorescence indicates caries.
Nouhzadeh et al , Photodiagnosis Photodyn Ther. 2019
78. Dye enhanced laser fluorescence (DELF)
technique.
⢠Use of dyes with wavelengths close to absorbance spectrum of DIAGNOdent laser
⢠Based on penetration of fluorescent dye into initial carious lesion ď enhance its detection by DIAGNOdent
laser.
⢠In absence of dental plaque ď DELF is a better diagnostic method than quantitative laser fluorescence for
caries detection.
⢠Visual assessment of amount of absorbed dye ď can effectively help in detection of inter proximal
subsurface lesions
Nouhzadeh et al , Photodiagnosis Photodyn Ther. 2019
79. 2. Cavity preparation:
⢠Several laser types with similar wavelengths in the middle infrared
region of the electromagnetic spectrum are being used commonly for
cavity preparation and caries removal.
⢠The Er: YAG laser was tested for preparing dental hard tissues for
the first time in 1988.
⢠Er:Cr:YSGG: Erbium-chromium-doped yttrium scandium gallium
garnet Er:YAG: Erbium: yttrium- aluminium âgarnet
⢠Nd:YAG: Neodinium-doped yttrium aluminium garnet
80. ⢠Even without water-coolingď prepared cavities showed no cracks and low or no
charring.
⢠Iincrease in the mean temperature of the pulp cavity was about 4.3 degrees
Burkes EJ et al, 1992
81. 81
There should be at least 1mm of clearance between the end of the laser tip and the tooth
structure.
frequency range: 2 to 20 hz
pulse energies : 50 to 1000 mj
power: 1-8 w (depending on the type of tissue.)
82. â Dental treatments could be more comfortable by using a preliminary phase of
low-power lasers, limiting or eliminating pharmacological agents for pain
controlâ
Femiano F et al , Effectiveness of low-level diode laser therapy on
pain during cavity preparation on permanent teeth.
Am D journal ,2018
83. â˘
Laser assisted cavity
preparation
Conventional cavity
preparation
â˘Lasers cut at a point of their
tip
â˘To be used with up and
down motion
â˘Rough edges that need
hand instruments such as
excavators to carry away the
ablation products
â˘Removes smear layer
â˘Considered safe in cases of
unexpected patient
movement
â˘Burs produce abrasive
cutting from their sides and
are also cut at the end
â˘Side brushing action is also
used along with end cutting
â˘Produces smooth edges
â˘Produces a smear layer
â˘Considered unsafe in cases
of unexpected patient
movement
84. Er,Cr:YSGG ablation allows selective
ablation of the caries; the outline form
follows the extension of the decay without
enlarging in healthy tissue
84
Lower second molar with class 1
cavities on
the occlusal fissures
85. 85
Wear and fracture of the
incisal margin of the upper
central incisor
Minimal tissue removal after Er,Cr:YSGG
irradiation just to clean, decontaminate and
condition the enamel and dentin surfaces
86. 86
Lower premolar shows a cervical
decay (class 5)
Er:YAG laser class 5 cavity preparation
allows minimal, selective and precise
carious removal at 150 > 120 mJ; note the
absence of any overpreparation both on
the enamel and in dentin
87. 87
Cavity preparation using Er:YAG laser and conical 600 Îźm tip approaching the cavity
with buccal & palatal angulation
88. 3. Restoration removal
⢠Er: YAG laser ď capable of removing cement, composite resin and the glass
ionomer.
⢠Ablation is comparable ď enamel and dentine.
⢠Lasers should not be used to ablate the amalgam restorationsď because of the
potential release of mercury vapour.
89. ⢠Er: YAG laser is incapable of removing gold crowns, cast restorations and
ceramic materials ď low absorption of these materials and the reflection
of the laser light.
90. 4.ETCHING
⢠Laser etching ď alternative to the acid etching of enamel and
dentine.
⢠Er: YAG laser produces micro-explosions during hard tissue
ablation ď result in microscopic and macroscopic
irregularities.
⢠These micro-irregularities make the enamel surface
microretentive and they may offer a mechanism of adhesion
without acid-etching.
91. Er wave ď well-absorbed by water and dental hard tissue.
Strong absorption of water reduces the level of heat during
tooth preparation.
Water reaches boiling point and causes micro-explosion of
the tooth.
Breaks up surrounding tissue into small pieces and
dissipates them at the same time.
Preparation induced by water.
92. ⢠However, it has been shown that adhesion to the dental hard tissues
after Er: YAG laser etching is inferior to that which is obtained after
conventional acid etching
Martinez-Insua A et alJ Prosthet Dent, 2000
93. 5.Lasers Effects on Enamel for
Caries Prevention
⢠Lasers ď considered to have a potential effect for caries prevention since ď studies
conducted by Stern and Sognnaesď ruby
93
Stern RH, Sognnaes RF, Goodman F (1966). J Am Dent Assoc.
94. ⢠Two possible mechanisms for the laserâinduced increase of fluoride uptake.
94
Journal of Clinical and Diagnostic Research. 2012 MaJournal of Clinical and Diagnostic Research.
2012 Ma.
FIRST MECHANISM
Laserâfluoride treatment
produces numerous spherical
precipitates that morphologically
resemble calcium fluorideâlike
deposits on the dental surfaces
Serve as a reservoir to replenish
fluoride.
SECOND MECHANISM
Emphasizes role of lasers in enhancing
fluoride uptake into crystalline structure
of tooth in the form of firmly bound
fluoride.
Alteration of characteristics of the
enamel surface by creating microspaces
that trap calcium, phosphate, and
fluoride ions during an acid challenge.
95. ⢠Lasers can induce crystallographic changes on enamel, effectively
increasing its acid resistance and significantly inhibiting caries
development and progression.
⢠CO2
⢠Argon
⢠Nd:YAG
⢠Erbium: YAG
95
P. A. Ana et al ,2006.
96. ⢠Heating of enamel surface leads to a caries inhibition effect.
⢠Heating of enamel surface leads to changes in its organic and/or inorganic
constituent.
96
97. Temp < 100 °C is insufficient to cause crystal changes in hydroxyapatite .
60 and 200 °Cď enamel dehydration and protein denaturation ď reduced
permeability
350 and 400 °Cď protein decomposition occurs ď increases enamel
permeability.
Carbonate decomposition starts at 420 °Cď decreased
Promotes ď thermal decomposition of more soluble carbonate
hydroxyapatite into the less soluble hydroxyapatite.
97
98. Disadvantages
⢠Cost
⢠Bulky
Naizy MA Et al ,C.D.J.2009: 25(3); 415-424
98
â˘Laser irradiation alone can significantly enhance acid resistance of sound
enamel surfaces and prevent caries progression.
â˘Combined use of topical fluoride + laser irradiation on sound enamel surfaces
- best protection against caries initiation and progression
99. - Al-Maliky MA, Lasers Med Sci. 2019
99
â˘If enamel surface is heated to 1200 °Cď melting, crystal size
growth and recrystallization will take place ď lased enamel favors
fluoride uptake thereby increasing its caries-preventive effect.
100. 6.Laser In Treatment Of Root-Caries
⢠Lee, C.Q., Lemire, D.H., Cobb, C.M. advocate the use of CO2 laser irradiation on tooth-
root cementum.
100
101. 7.Curing of Composites
⢠The Laser used is Argon with a wavelength of 488 nm(blue).
⢠This is near the wavelength of initiator used (camphoroquinone) in composite resins.
101
Argon wavelength activates camphorquinone(photoinitiator)
polymerisation of the resin composites.
103. 8.Dentin Bonding
⢠It is established that dentinal bonding is substantially increased (upto 300%) if the
dentin is pretreated with a pulsed CO2 laser prior to bonding.
⢠Improved dentin bonding with Argon or Nd:YAG Lasers
103
104. Koumpia et
al,2012
⢠Laser irradiation ď formation of a microscopically
rough dentin surface with a micro-retentive pattern
that reveals tubule openings without a smear layer.
⢠Favor bond strength of resin-based materials with
dentin
104
105. 9.Indirect Restorations
⢠Erbium laser preparation must be limited to the removal of carious tissue
⢠Final finishing with specific burs,smoothening of the margins is performed with
fine grit chamfer bur or with ultrasonic tips or hand scalpels.
105
106. 10.Indirect Restorations Using
CAD/CAM Lasers
⢠Lasers are used to scan intraoral tissues to create 3D digital impressions
⢠Occlusal contacts can be scanned 3-dimensionally using lasers
⢠To create restorations by selective laser melting or laser sintering
106
107. 11.BLEACHING
⢠Laser whitening Gel has a unique mix of Thermal Absorption Crystals integrated into gel of highly
processed fumed silica and 35% H2O2.
⢠Bleaching gel is applied and is activated by high intensity light source or plasma arc light.
⢠Crystals in gel absorb thermal energy from light, allowing better dissociation of oxygen and easy
penetration into the enamel matrix thus increasing the lighting effect on teeth.
107
108. BLEACHING
⢠KTP laser which emits a green visible light(532 nm)
⢠Diode lasers (from 803 up to 1064 nm),
⢠Nd:YAG laser (1064 nm),
⢠Er:YAG laser (2940 nm),
⢠Argon Laser â 488 nm
⢠CO2 â 10,600 nm
⢠Photochemical laser whitening â smart bleach
108
all emitting
invisible infrared
light.
109. BLEACHING- Argon laser
⢠Blue light with the wavelength of 480 nm in the visible part of the spectrum.
⢠Dark stains absorb these light.
The Argon laser rapidly excites the already unstable and reactive H2O2
moleculeď The H2O2 molecules - combine with the chromoprhilic structure
of the organic molecules, altering them and producing simpler chemical chains
ď The result is a visually whitened tooth surface.
109
110. BLEACHING- CO2 lasers
⢠wavelength of 10,600 nm
⢠basically used for enhancing the effect of Argon lasers.
⢠It is unrelated to the color of the tooth
110
111. BLEACHING- CO2 lasers
The energy is emitted in the form of the heat.
⢠The laser penetrates only 0.1 mm into water and H2O2, where it gets absorbed. This
energy can enhance the effect of the whitening agent after the initial Argon laser
process
111
112. BLEACHING- Diode lasers
Different forms
⢠Infrared diode -wavelength of 790 nm.
⢠Laser with blue light emission diode - wavelength of 467 nm.
The bleaching agent used is 38% hydrogen peroxide.
⢠GaAIAs diode: The diode works at different watts.
The bleaching agent utilizes 38% H2O2.
112
114. Photochemical Laser Whitening-(KTP
Smartbleach)
⢠The pH of the bleaching gel is alkaline (approximately 9.5). etching of the tooth
surface does not occur.
⢠The primary action of Smart bleaching is photochemical & not photothermal.
⢠The perhydroxyl radical is produced compared to superoxide, which is more reactive
than the superoxide and other radicals.
⢠Particularly useful in bleaching tetracycline stained teeth.
114
116. 116
Bleaching handpiece for KTP laser KTP laser
green light bleaching, using specific
rhodamine base pink-purple gel
Bleaching handpiece for KTP laser
117. The use of laser light as a bleaching
product activator â advantages
⢠It reduces the operation time, risk of over-bleaching and postoperatiive sensitivity.
⢠A minimum increase of intra-pulp temperature,
⢠It lets the nascent oxygen penetrate deeper into the enamel and dentin, exercising an
efficient action.
⢠The treatment can be complete and be efficient in just one session.
117
118. 12.Dentin Hypersensitivity
The various types of Lasers used are
⢠CO2 Laser
⢠Nd:YAG Laser middle output power lasers
⢠Er:YAG Laser
⢠He:Ne Laser- low output power lasers
118
119. ⢠The direct effect of laser irradiation on the electric activity of nerve fibers within
the dental pulp,
⢠Modification of the tubular structure of the dentin by melting and fusing of the hard
tissue or smear layer and subsequent sealing of the dentinal tubules.
119
120. ⢠Helium-neon laser irradiation affects electric activity (action potential) rather than Ad- or
C-fiber nociceptors
(Rochkind et al . 1987, Jarvis et al.1990)
⢠GaAlAs laser radiation at 830 nm has a pain suppressive effect by blocking the
depolarization of C-fiber afferents (Wakabayashi et al .1993)
120
121. ⢠The Nd:YAG lasers can be combined with fluoride varnish to produce an effective
protocol for treating dentin hypersensitivity.
⢠Er:YAG laser has been used in combination with a dentin-sensitizing agent to reduce
discomfort.
121
Ladalardo TC, Pinheiro A, Campos RA, et al.Braz Dent J 2014
122. 13.Lasers in traumatic injuries
⢠Complicated crown fracture - pulp capping,partial pulpotomy, pulpectomy and root
canal therapy
⢠Pulp capping -Erbium and CO2 laser are the first choice for the decontamination and
coagulation of the exposed pulp, performed.
⢠Pulpotomy -by using diode, Nd:YAG, Erbium (with water) or CO2 lasers
⢠RCT- Traditional protocols followed by -Erbium laser provides effective
122
124. 1. Detection Of Pulp Vitality by Laser
Use of laser doppler flowmetry
Hene and gaal ď semiconductor diode lasers at a low power of 1 or 2 mw are used.
Principle:
ď§ Laser light enters the tooth & gets absorbed by the red blood cells which leads to shift in the
frequency of scattered light â doppler effect.
This shift does not occur in light that is absorbed by stationary objects.
ď§ Proportion of doppler shifted light is detected with photodetector. 124
125. ⢠Presence of blood movement within the pulp space can be determined.
⢠Differentiate a healthy traumatized tooth with reduced blood supply from a non vital
tooth.
125
126. Heat stimulation to check pulp
vitality
⢠The pulsed stimulation by Nd:YAG laser produces mild and tolerable pain.
126
Samraj RV, Indira R, Srinivasan MR. Recent advances in pulp vitality testing. 2003;15(1):14â19.
127. Differential diagnosis of pulpitis by laser
stimulation
⢠In normal pulp on stimulation of Nd: YAG laser pain is produced within 20-30seconds and
disappears after interruption.
⢠Acute pulpitis, instantly after laser application, pain is induced and continues for more than
30 seconds after interruption of stimulation.
127
128. 2. Direct Pulp Capping
lasers used - Nd: YAG, Er: YAG, Argon
laser, diode laser, co2 laser
⢠Bloodless field
⢠Sterilization of the treated wound
⢠Direct stimulation of dentin formation (Paschoud and Holz, 1988)
128
130. 3.Indirect Pulp capping
⢠In cases of deep and hypersensitive cavities a reduction in the permeability of the
dentin- achieved by sealing the dentinal tubules
⢠LASERS USED Nd: YAG â 2W & 20 PPS for less than one sec with black ink
⢠CO2 laser â with silver ammonium fluoride solution
⢠NO POST OPERATIVE PAIN
130
131. 4.Pulpotomy
⢠Reduce pulpal inflammation and improve its healing. Laser can also improve formation of
fibrous matrix and hard tissue barrier
⢠LLLT, Diode laser, Nd:YAG laser
⢠Clinical trial with Nd:YAG-pulpotomy on human primary molars 97% success clinically,
94% success radiographically.
Liu JF, Journal of Endodontics 2006
131
132. 5.Preparation of the access cavity
⢠Erbium lasers, which can ablate enamel and dentine.
⢠Use of a short tip is recommended (from 4 to 6mm), with diameters
between 600 and 800Âľm made of quartz to allow the
⢠use of higher energy and power.
⢠Laser allows for a minimally invasive access into the pulp chamber , decontamination
and removal of bacterial debris and pulp tissue.
132
133. ⢠Erbium lasers -removal of pulp stones and in the search for calcified canals.
133
134. 5.Disinfection of root canals.
⢠CO2, Nd:YAG, Er:YSGG, XeCl, Er:YAG, Diode, Nd:YAP, argon.
⢠Nd :YAG, Er:YSGG, argon, Diode lasers delivered to root canal using thin fiberoptics
(200Îź)
⢠Er:YAG, CO2 lasers â hollow tube
134
136. ⢠The Nd:YAG penetrates for 1000 ¾ into the dentinal walls, and the 810 nm Diode
laser decontaminate the dentin walls up to a depth of 750 microns
[Schoop et al., 2004)
136
137. LIMITATIONS
⢠Impossible to obtain uniform coverage of the canal surface using a laser
⢠Thermal damage to the periapical tissues potentially is possible, may affect the supporting
tissues of the tooth adversely -teeth with close proximity to the mental foramen or to the
mandibular nerve
137
138. ⢠Er:YAG laser with sidefiring tip rather than direct
emission through a single opening at its far end.
⢠Spiral tip was designed to fit the shape and the volume
of root canals .
⢠The tip is sealed at its far end, preventing the
transmission of irradiation to and through the apical
foramen of the tooth.
138
Stabholz A, Zeltzser R, Sela M, et al. The use of lasers in dentistry: principles of operation and clinical applications. Compend
2013;24:811â24.
140. ⢠17% EDTA and irradiated with Er:YAG laser,using 500 mJ per pulse at a frequency of 12
Hz for four cycles of 15 seconds each.
⢠The lased roots were removed, split longitudinally, & submitted for SEM evaluation
⢠Revealed clean surfaces, free of smear layer and debris. Open dentinal tubules were
clearly distinguishable
⢠Stabholz A, Zeltzser R, Sela M, Peretz B, Moshonov J, Ziskind D. The use of lasers in
dentistry: principles of operation and clinical applications. Compendium 2003;24:811â24.
140
141. Photo-activated disinfection
⢠Small diode laser connected to a delivery fiber.
⢠Based on Photodynamic Antimicrobial Chemotherapy in which the photosensitizer molecules
attach to the bacterial membrane.
⢠1. introduction of a photosensitizer, 2. irradiation of the photosensitized tissue
141
142. 6.Obturation
⢠Obturation with AH âplus and composite resin activated by Argon lasers
⢠Laser initiates photo polymerization by activation of composite resin
⢠Argon laser, CO2 laser, Nd:YAG, Er:YAG. - soften the guttapercha â vertical
compaction
⢠Argon lasers â good apical seal
142
It is useful to use lasers as adjuncts to conventional treatment, but it is not
possible to use lasers alone for treatment.
143. 7.ENDODONTIC RETREATMENT
⢠The rationale - to remove foreign material from the root canal system that may otherwise be
difficult to remove by conventional methods.
⢠Farge et al. examined the efficacy of the Nd-YAP laser (1340 nm) in root canal retreatment
(200 mJ and a frequency of 10 Hz).
concluded that using laser radiation alone would not completely remove debris and obturating
materials from the root canal.
143
144. ⢠Time required for removal of any root canal-filling materials is shorter.
⢠Nd:YAG laser irradiation is an effective technique for removal of root canal-filling materials
and may offer advantages over conventional methods.
Anjo T, Ebihara A, Takeda A, et al. Removal of two types of root canal filling material using pulsed Nd-YAG laser irradiation. Photomed Laser
Surg 2004;22:470â6.
144
145. 8.Apical Surgery
ďą Ability of laser to coagulate & seal small blood vessels,- bloodless surgical
field.
ďą Sterilisation of surgical site.
ďą Potential of lasers to cut hard dental tissues without causing elaborate thermal
damage to adjoining tissues.
145
146. ⢠The first attempt to use a laser in endodontic surgery
- Dr. Weichman at the University of Southern California.
⢠Attempted to seal the apical foramina of extracted teeth from which the pulps had been
extirpated -using a high power CO2 laser.
⢠Melting of the cementum and dentin was observed with a ââcapââ formation that could,
however, be easily removed.
146
147. ⢠Treatment of apical abscess with CO2 laser.- Miserendino 1988
⢠Ability of Er:YAG laser to prepare apical retrograde cavities. â Ebihara
⢠Excellent results with smooth, clean resected surfaces,devoid of charring with an
Er:YAG laser.- paghdiwala.
147
148. ⢠The preparation of apical cavities by Er:YAG laser and ultrasonics was also studied by
Karlovic et al.
⢠lower values of microleakage when the root end cavities were prepared with the
Er:YAG laser irrespective of the material used to seal those cavities.
148
Karlovic Z, Pezelj-Ribaric S, Miletic I, et al. Er-YAG laser versus ultrasonic in preparation of root-end
cavities. J Endod 2005; 31:821â3.
149. ⢠Laser activation of irrigants -photomechanical and photothermal mechanisms.
⢠The agitation of fluids in the root canal permits enhanced penetration of fluids into the
corners of the root canal anatomy. The simultaneous increase in temperature accelerates
chemical reactions, namely etching and protein dissolution.
149
150. 9.Advanced laser endodontic therapy
⢠Laser activated irrigation using PIPS⢠technique:
⢠low energy (20 mJ), a pulse repetition rate of 15 Hz, and a very short pulse duration (50 Οs).
150
Photon-induced photoacoustic streaming (PIPS)
151. ⢠The Er:YAG laser wavelength (2940 nm) has the highest absorption in water and a high
affinity to hydroxyapatite,
⢠The PIPS tip does not need to reach the canal terminus, and it is placed into coronal access
opening of the pulp chamber only & kept stationary without advancing into the orifice of the
canal.
⢠Minimally invasive preparation of the root canal.
151
154. 2.Gingival troughing
⢠Bloodless gingival troughing done before taking impressions.
⢠The tissue is âledgedâ to expose the preparation margin by placing the laser tip below the
gingival crevice height.
⢠Diode laser used
154
155. Dental Laser Welding
⢠Connecting or repairing metal prosthetic frameworks
⢠Fewer effects of heating on area which surrounds the spot which has to be
welded
⢠No further procedures, such as those which are used for conventional
solderingď necessary.
â Fabricating metal frameworks of prostheses
â Recovering metal ridge and cusp
â Blocking holes on the occlusal surfaces after excess occlusal adjustment
â Thickening the metal framework
â Adding contact points after excess grinding
â Adjusting of the crown margins.
155
156. Attenuation of gag reflex
⢠Nausea ď p6 acupunctural point.
⢠At a separation of 1 inch from the wrist, wrinkle underside of the wrist is
actual location for a p6 point.
⢠In attenuation of gag reflexď the application of 4J energy has proven to be
very successful.
â In patient facing a problem during radiograph film placement
â Rubber dam placement or during impression making
156
157. PBM (photobiomodulation)
⢠Treatment of temporomandibular joint (TMJ) disorders or in
facial pain.
⢠Neuropathic pain
⢠â Impact of laser therapy on c-filaments, osteoblasts,
endorphins levels, and odontoblasts make PBM a great
instrument in restorative dentistry.â
â˘
157
(Srivastava et al,ijds 2020)
158. CONCLUSION
⢠Lasers provide the clinicians ,the ability to better care for patients with advanced
diagnostic methods and improved treatment techniques.
⢠Further scientific and medical research in the development of advanced laser systems
will revolutionise its clinical use much more significantly in the field of conservative
dentistry.
158
159. REFERENCES
⢠Cohenâs pathways of dental pulp â10th edition
⢠Ingleâs Endodontics-6th edition
⢠Art And Science Of Operative Dentistry, Sturdevent. 7th Edition
⢠Phillipsâ science of dental materials, 12th ed,Anusavice
⢠Grossmans endodontic practice 13th edition.
⢠Kimura Y, Wilder-Smith P, Matsumoto K. Lasers in endodontics: a review.
International Endodontic Journal, 33,173â185, 2000.
⢠Jhajharia K (2018) Laser Update in Endodontics. J Orthod Endod Vol.4 No.1:2 159
160. REFERENCES
⢠Laser in Endodontics ( Part 2 )Rolando crippa,Stefano Benedicenti,Giuseppe
Iaria,Enrico Divito,Vassilios,Kaitsas,Giovanni Olivi
⢠A. Stabholz et al / Dent Clin N Am 48 (2004) 809â832
⢠Hegde MN, Garg P, Hegde ND. Lasers in dentistry: an unceasing evolution. J
Otolaryngol ENT Res. 2018;10(6):422-426.
⢠Pandey V. lasers in Operative Dentistry and Endodontics.
⢠Lasers in Restorative Dentistry A Practical Guide Giovanni Olivi,Matteo Olivi
160
Editor's Notes
All currently available dental laser devices - emission wavelengths of approximately 500 to 10,600 nmď visible / invisible (infrared) nonionizing portion of the electromagnetic spectrum,
3. Poorly absorbed by tooth structure so that soft tissue surgery can be performed safely in close proximity to enamel, dentine and cementum.
LastâŚâŚâŚand for soft tissue curettage, or sulcular debridement.
Beam can be focused to create a precised coagulation of small blood vessels
, but the tissue ablation can be precise with careful technique.
2. and both are visible to the human eye
3.488 emission is the exact wavelength needed to activate camphoroquinone.
If the task is to remove hard tissues as in caries removal and cavityIf the dentist needs to alter the tissue composition and solubility by heating, the laser must be well absorbed in the surface region and converted to heat without damage to the dental pulp(1 preparations, the laser must be absorbed by these tissues.
Erbium, chromium-doped yttrium, scandium, gallium and garnetÂ
tLaser Interaction with Dental Hard Tissues-he pulse duration becomes an important parameter for determining laser tissue interaction. If the pulse duration of the laser used is the same or less than the thermal relaxation time for the tissue, the energy will remain in the volume where it was absorbed leading to large temperature increases near the surface using low energy input. If the pulse duration is much longer than the tissueâs thermal relaxation time, the thermal energy will flow towards the center of the tooth and heat a large volume of the tissue. A large fraction of the absorbed laser energy will be conducted away from the enamel surface resulting in insufficient surface heating and possible pulpal damage. On the other hand, if the pulse duration is much shorter than the tissueâs thermal relaxation time, the deposited energy density will be too high, causing ablation and removal of the tissue instead of desired heating and fusion
mid infrared ranges include the erbium and CO2 types.
mid infrared ranges include the erbium and CO2 types.
mid infrared ranges include the erbium and CO2 types.
mid infrared ranges include the erbium and CO2 types.
mid infrared ranges include the erbium and CO2 types.
Neodymium-Doped Yttrium Aluminium Garnet)
Neodymium-Doped Yttrium Aluminium Garnet)
Although topical fluoride gels, toothpastes, and rinses have been used to prevent or to inhibit the development of root caries, there is a problem of access to the proximal surfaces. Consequently, the development of better methods to facilitate the prevention of root caries has become an important issue in dentistry.
Lasers have been used to cure composites.
Lasers have been used to cure composites.
has also been reported.
has also been reported.
In case of indirect restoration, erbium laser preparation must be limited to the removal of carious tissue
fi nally high-speed drilling was performed for shaping the outline form before the impression
Micro-hybrid composite inlay has been bonded on the prepared surface, u
impression materials and casting model/die. However, these materials are linked to a number of
adverse effects such as dimensional changes, infection, and intolerance or gagging in certain patients
2. Molten powder granules present in each layer fuse together to form a layer of a solid. New layers are added on top of each other to create different prostheses.
The procedure utilizes 30â35% H2O2 which is usually applicable in routine bleaching.
Different sources of laser light used today are
2 ensures that the yellow brown color can be easily removed.
TEMPERATURE changes during bleaching- Argon laser: It increased the temperature by 9.4°C
irrespective of the use of colorant. 5. Diode laser: The increase in temperature recorded was 37°C at 1W and 28.6°C at 3W. The presence of
bleaching gel, however, reduces the increased temperature.
The surface temperature can be raised from 36°C at 1W to 86°C with 3W.
Pulpal temperature increased from 4.3°C to 16°C.
The commercial hydrogen peroxide system has the
potential to affect dental enamel because of the acidic pH of the solution in its native form, which ranges from 5.0 to 6.0. ⢠The concentrated solutions of hydrogen peroxide (30%) can transiently reduce the microhardness of enamel and dentin. The lasers also result in post-treatment sensitivity. these problems do not occur as ..1..
Last .. and the results obtained with KTP and argon lasers are equal to photobleaching.
The chelate formed between tetracyclines and hydroxyapatite is a red quinone product dimethylamino tetracycline - resistant to oxidation from peroxide, but can be broken down (photo-oxidised) by green light in a particular narrow spectral range (512 to 540 nm).
Because this energy aligns particularly well with the wavelength of KTP laser (532 nm), energy from this laser can cause terminal
photo-oxidation of the quinone molecule, which renders it colorless. The use of the KTP laser in combination with a hydrogen peroxide based gel ensures that complete and irreversible bleaching of red quinone occurs.
compared to other professional techniques, home bleaching,or in-offi ce bleaching.
2nd point.. If used correctly, it determines
3. even in the deepest dyschromia,such as the tetracycline.
He ne - the mechanism causing the reduction in
hypersensitivity is not apparent, it was claimed that helium-neon laser
irradiation affects electric activity (action potential) [30] rather than Ad- or
C-fiber nociceptors
2 mechanisms proposed..
If the exposure is very small and the treatment is provided within 24-48h, a pulp capping can be performed-limited rise in temperature in the pulp chamber during laser tooth preparation when the Erbium
is the treatment of choice for larger exposures (1>2mm2 ):
If the intervention is delayed for days or even weeks, the most indicated treatment is pulpectomy.
can provide important improvements to the therapy
Noninvasive method of assessing & accurately measuring the rate of blood flow in a tissue.
1âŚâŚâŚâŚ.. of 1 or 2 mW are used. in laser Doppler flowmetry.
Expensive- Not used as routine special investigation in dentistry.
Technique sensitive, requires splints to hold the sensors in place.
The hot gutta percha method to assess vitality cannot always be performed due to thick enamel and dentin or the great perception of pain of dental pulp tissue.
Kimura Y, WilderâSmith P, Matsumoto K. Lasers in endodontics: a review. Int Endod J. 2000;33(3):173â185.
Grossman, indirect pulp capping- sealing the dentinal tubules.
Laser may be considered as an adjuvant alternative for vital pulp therapy on human primary teeth, but due to the limited number of high-quality clinical research articles on laserassisted pulpotomy, various types
The preparation of the access cavity can be per-formed directly with
laser allows for a minimally invasive access into the pulp chamber , and, at the same time, allows for the
 decontamination and removal of bacterial debris and
are useful in the 2. (because it is selective)
These lasers used for disinfection of root canal.
3. Hollow tube is employed for this purpose in co2 &er⌠grossman
ability to remove debris and the smear layer from the root canal walls following biomechanical instrumentation.
ND:Y AL PEROVSKITE
laser is delivered through a hollow tube, with an endodontic tip that allows lateral emission of the irradiation It emits the Er:YAG laser irradiation laterally to the walls of the root canal through a spiral slit located all along the tip.
the principle of
generate a toxic photochemistry on the target cell, leading to cell lysis. synergism effect
for thermoplasticized gp obturation system.
INGLE
for using laser irradiation
in non-surgical
retreatmentmay be ascribed to the need
YAL perovskite
1 by laser isâŚâŚâŚâŚâŚthan that required using conventional methods.
Potential for using lasers is due to following observations,âŚâŚâŚâŚâŚgrossman
INGLE
The apices of those specimens were irradiated
2. They found
1- takes place mainly by
2. the tip must be placed in the coronal chamber with open access to the canals âŚâŚâŚâŚâŚThe subablative parameters in the PIPS technique result in a photochemical effect, which occurs when light energy is pulsed in a fluid, rather than thermal effect
PIPS with a radial and stripped tip of novel design with a radial and stripped tip of novel design
which makes it suitable for use in root canal treatment
The traditional laser applications necessitate conventional preparation for atleast up to size 30 and the laser tip need to reach apical third of the root. However,
2Therefore, this technique allows for
lasers have the ability to sterilize metal and alloy instruments including hand pieces and endodontic files without any adverse effects
help eradicate the need for vasoconstrictors and retraction cords.