#laser #dental #painless #effective

1. LASERS IN CONSERVATIVE
DENTISTRY AND
ENDODONTICS

2. CONTENTS
 INTRODUCTION
 HISTORY
 FUNDAMENTALS OF LASER
 LASER DELIVERY SYSTEMS
 EMISSION MODES
 LASER EFFECTS ON TISSUES
 CLASSIFICATION OF LASERS
 LASERS IN OPERATIVE DENTISTRY
 LASERS IN ENDODONTICS
 CONCLUSION
 REFERENCE

3. INTRODUCTION
 LASER’  light amplification by stimulated emission of radiation.
 Lasers were first developed in the 1960s.
 Dental researchers  investigated  numerous applications of laser instruments
 intraoral soft tissue surgery, hard tissue applications, dental materials and
endodontics.

4. HISTORY

5. “MASERS AND LASERS”
• In 1954 Townes and Gordon  first microwave laser or ‘MASER’ 
‘Microwave Amplification by stimulated Emission of Radiation’
• In 1958, Townes first theoretic calculations for a visible light maser 
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 – Stern, Sognnaes &
Goldman: lasers in dentistry.
Nd: YAG was developed by
Geusic.
• 1960 Theodore Maiman introduced the
acronym “laser,” ruby laser
1985 Shoji et al
Laser aided
pulpotomy
1965 CO2 laser 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.
1993–Paghdiwala : 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

8. FUNDAMENTALS OF LASER

9. Laser is a device that converts electrical or
chemical energy into light energy.
 LIGHT
 AMPLITUDE
 STIMULATED EMISSION
 RADIATION

10. LIGHT
• Form of electromagnetic energy
• Behaves  wave and a particle.
• Basic unit of this energy is called
photon.

11. • Ordinary light  white  sum of many colors of visible spectrum –
violet, blue, green, yellow, orange, and red
• Laser energy one specific color monochromaticity 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
• Beamcollimated rays or beams
are all parallel within laser
instrument.
• Once laser beam enters certain
delivery systems optical fibers or
tips diverges at fiber tip

14. AMPLITUDE
• Total height of wave oscillation from top of peak to the zero line on a
vertical axis.
• Indication  amount of intensity in the wave:
• Larger amplitude greater amount of useful work that can be performed.

15. AMPLIFICATION
Amplification is part of a process that occurs inside the laser.

16. Components of a laser instrument
• An optical cavity  at center of the
device.
• Three components make up the laser
cavity:
– Active medium
– Pumping mechanism
– Optical resonator

17. 17

18. ACTIVE MEDIUM
• Composed of chemical elements, molecules, or compounds.
• Lasers  generically named  material of active medium

19.  A container of gas : canister of carbon dioxide gas  CO 2 laser
 A solid crystal  erbium-doped YAG (Er:YAG) laser
 A solid-state semiconductorDiode lasers
 A liquid - medical laser devices.

20. Pumping mechanism
• Surrounding this active medium  excitation source 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 medium’s 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 “population inversion” 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 mirrors one at each end of optical cavity
placed parallel to each other/ semiconductor diode
laser two polished surfaces at each end.
• Act as optical resonators reflecting waves back
and forth,  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  postulated
by Albert Einstein in 1916.

24. Quantum  smallest unit of energy emitted from an
atom.
Einstein  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 energy—thereby
producing a laser beam

25. 4. Radiation
Radiation refers to photons
being emitted.

27. LASER DELIVERY SYSTEM
2 delivery system
 hollow guide or tube
 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
– KTP, diode, and Nd:Y-AG lasers
– Small, flexible fiberoptic systems with bare glass fibers that deliver
the laser energy to the target tissue

29. • Erbium and CO 2 laser
– wavelengths are absorbed by water
which is a major component of
conventional glass fibers these
wavelengths cannot pass through these
fibers.
– 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. • Lasers different fiber diameters,
handpieces, and tips
• Each of these elements plays a
significant role in the delivery of energy

32. • Dental lasers  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

33. EMISSION MODES

34. • Dental laser devices can emit light energy in two modalities as a function
of time:
– Constant on
– 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  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 microseconds 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  obtained with this
mode

40. FOCUSSING
1. A focussed mode :
• Laser beam hits the tissue at its focal points or smallest diameter.
• This diameter  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 plane
beam size that hits tissue has a greater diameter 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.

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

46. Laser Effects on Tissue

47. • Depending Optical properties of tissue light energy from a laser may
have four different interactions with target tissue:
– Reflection
– Absorption
– Transmission
– Scattering

48. 1.Reflection
• Beam  redirected off the surface  with no effect on target tissue.
• Reflected light  maintain its collimation in a narrow beam or it may
become more diffuse.
• Dangerous  energy could be redirected to an unintentional target, such
as eyes.
• Potential mistargeting  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 patient’s titanium implants.
• CO 2 laser energy reflected off the implants could be redirected to the dentist’s
eyes

50. 2.Absorption
• Absorption of laser energy intended target tissue  most
desirable effect.
• Amount of energy absorbed by tissue depends on that
tissue’s characteristics
– pigmentation
– water content,
– laser wavelength.
• Primary and beneficial goal of laser energy  absorption of
laser light intended biologic tissue.

51. 3.Transmission
• Transmission of laser energy directly through
tissue no effect on target tissue.
• Dependent on wavelength of laser light.

52. • Water  Relatively “transparent” to (does not absorb) 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 light weakens intended energy.
• Predominant  use of near-infrared lasers in
healthy soft tissue.
• Causes photons to change directions increased
absorption correspondingly increased chances of
interacting with predominant chromophore of those
wavelengths.

54. • Cause heat transfer tissue adjacent to surgical site potential for injury from
unwanted laser effects.
• However, a beam that is scattered, or deflected in different directions useful in
facilitating laser curing of composite resin.

55. CLASSIFICATION OF LASER

56. DCNA ,2000
I. According to the wavelength (nanometers)
 UV (ultraviolet) range – 140 to 400 nm
 VS (visible spectrum) – 400 to 700 nm
 IR (infrared) range – more than 700 nm

57. 1. Hard laser (for surgical work)
 CO2 lasers (CO2 gas)
 Nd:YAG lasers (Yttrium-aluminium-garnet crystals dotted with
neodymium)
 Argon laser (Argon ions)
2. Soft laser (for biostimulation and analgesia)
 He-Ne lasers
 Diode lasers

58. III. According to the delivery system
– Articulated arm (mirror type)
– Hollow waveguide
– Fiber optic cable

59. IV. According to the type of active medium used
– Gas, solid, semi-conductor or dye lasers
• V. According to type of lasing medium
– E.g. Erbium: Yttrium Aluminium Garnet

60. VI. According to pumping scheme
– Optically pumped laser
– Electrically pumped laser
VII. According to operation mode
– Continuous wave lasers
– 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.
 Class I- (< 39mw) Exempt; pose no threat of biological damage
 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.  Class IIIA - ( 5OOmw) : Can cause injury when the beam is collected
by optical instruments and directed into the eye
 Class IIIB - Causes injury if viewed briefly, even before blinking can
occur.
 Class IV - (> 5OOmw) Direct viewing and specular and diffuse
reflections can cause permanent damage including blindness.

63. Lasers used in dentistry

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
•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 – green)
69

70. 70
•488nm- used to cure light activated composites,impression
materials, bleaching gels.
•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 – 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.

73. LASERS IN OPERATIVE DENTISTRY

74.  Diagnostic/curing lasers
 Cavity preparation
 Etching
 Photopolymerisation
 CAD/CAM technology
 Caries prevention
 Laser desensitization
Gaurangi Kakodkar et al , JCDR 2017

75. 1.DIAGNOSTIC LASER
• DIAGNOdent  used for early detection of
smooth cuface and occlusal caries and calculus
detection
• By emitting nonionizing laser beam 
wavelength 655nm (at a 90degree angle)
specific darkened groove on the occlusal surface
of a patient’s tooth where bacterial decay is
suspected
• Or along long axis of a root surface  detect
presence of a bacteria-laden calculus.

76. • Photons of this laser wavelength absorbed into any existing bacteria in these
areas of the patient’s tooth laser-induced fluorescence.
• Digital display  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 laser irradiates red light within the visible spectrum
with 638–655 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 0–99.
Values ≥20 and 25 indicate  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  enhance its detection by DIAGNOdent
laser.
• In absence of dental plaque DELF is a better diagnostic method than quantitative laser fluorescence for
caries detection.
• Visual assessment of amount of absorbed dye 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 –garnet
• Nd:YAG: Neodinium-doped yttrium aluminium garnet

80. • Even without water-cooling 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. “ Dental treatments could be more comfortable by using a preliminary phase of
low-power lasers, limiting or eliminating pharmacological agents for pain
control”
Femiano F et al , Effectiveness of low-level diode laser therapy on
pain during cavity preparation on permanent teeth.
Am D journal ,2018

83. •
Laser assisted cavity
preparation
Conventional cavity
preparation
•Lasers cut at a point of their
tip
•To be used with up and
down motion
•Rough edges that need
hand instruments such as
excavators to carry away the
ablation products
•Removes smear layer
•Considered safe in cases of
unexpected patient
movement
•Burs produce abrasive
cutting from their sides and
are also cut at the end
•Side brushing action is also
used along with end cutting
•Produces smooth edges
•Produces a smear layer
•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 μm tip approaching the cavity
with buccal & palatal angulation

88. 3. Restoration removal
• Er: YAG laser  capable of removing cement, composite resin and the glass
ionomer.
• Ablation is comparable  enamel and dentine.
• Lasers should not be used to ablate the amalgam restorations because of the
potential release of mercury vapour.

89. • Er: YAG laser is incapable of removing gold crowns, cast restorations and
ceramic materials  low absorption of these materials and the reflection
of the laser light.

90. 4.ETCHING
• Laser etching  alternative to the acid etching of enamel and
dentine.
• Er: YAG laser produces micro-explosions during hard tissue
ablation  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  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  considered to have a potential effect for caries prevention since  studies
conducted by Stern and Sognnaes ruby
93
Stern RH, Sognnaes RF, Goodman F (1966). J Am Dent Assoc.

94. • Two possible mechanisms for the laser‐induced increase of fluoride uptake.
94
Journal of Clinical and Diagnostic Research. 2012 MaJournal of Clinical and Diagnostic Research.
2012 Ma.
FIRST MECHANISM
Laser–fluoride treatment
produces numerous spherical
precipitates that morphologically
resemble calcium fluoride‐like
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 °C enamel dehydration and protein denaturation  reduced
permeability
350 and 400 °C protein decomposition occurs  increases enamel
permeability.
Carbonate decomposition starts at 420 °C decreased
Promotes  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
•Laser irradiation alone can significantly enhance acid resistance of sound
enamel surfaces and prevent caries progression.
•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
•If enamel surface is heated to 1200 °C melting, crystal size
growth and recrystallization will take place  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.

102. Advantages
• Shorter curing time
• Better physical properties
• Increased depth of cure
• Better polymerization
• Reduced polymerization shrinkage
102

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  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 – 488 nm
• CO2 – 10,600 nm
• Photochemical laser whitening – 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
molecule The H2O2 molecules - combine with the chromoprhilic structure
of the organic molecules, altering them and producing simpler chemical chains
 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

113. BLEACHING
113
Specific multi-tip handpiece for 940 nm diode
laser (Epic, Biolase; USA)
Irradiation of lower arch using
the multi-tip
handpiece for 940 nm diode
laser

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

115. 115

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 – 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

123. 123
LASERS IN ENDODONTICS

124. 1. Detection Of Pulp Vitality by Laser
Use of laser doppler flowmetry
Hene and gaal  semiconductor diode lasers at a low power of 1 or 2 mw are used.
Principle:
 Laser light enters the tooth & gets absorbed by the red blood cells which leads to shift in the
frequency of scattered light – doppler effect.
This shift does not occur in light that is absorbed by stationary objects.
 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):14–19.

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

129. 129

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 – 2W & 20 PPS for less than one sec with black ink
• CO2 laser – 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 800µm 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
(200μ)
• Er:YAG, CO2 lasers – hollow tube
134

135. Diode laser disinfection of root canal
135
Root canal disinfection with an Nd: YAG
laser.

136. • The Nd:YAG penetrates for 1000 µ 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;24:811–24.

139. • The RCLase Side-Firing Spiral Tip.
139

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;24:811–24.
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 –plus 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 – vertical
compaction
• Argon lasers – 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;22:470–6.
144

145. 8.Apical Surgery
 Ability of laser to coagulate & seal small blood vessels,- bloodless surgical
field.
 Sterilisation of surgical site.
 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 ‘‘cap’’ 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. – 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; 31:821–3.

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 μs).
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

152. OTHER APPLICATIONS
152

153. 1.Sterilization of endodontic instruments
• Argon lasers
• CO2 lasers
• Nd:YAG lasers
153

154. 2.Gingival troughing
• Bloodless gingival troughing done before taking impressions.
• The tissue is ‘ledged’ 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
soldering necessary.
– Fabricating metal frameworks of prostheses
– Recovering metal ridge and cusp
– Blocking holes on the occlusal surfaces after excess occlusal adjustment
– Thickening the metal framework
– Adding contact points after excess grinding
– Adjusting of the crown margins.
155

156. Attenuation of gag reflex
• Nausea  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 reflex the application of 4J energy has proven to be
very successful.
– In patient facing a problem during radiograph film placement
– Rubber dam placement or during impression making
156

157. PBM (photobiomodulation)
• Treatment of temporomandibular joint (TMJ) disorders or in
facial pain.
• Neuropathic pain
• “ Impact of laser therapy on c-filaments, osteoblasts,
endorphins levels, and odontoblasts make PBM a great
instrument in restorative dentistry.”
•
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
• Cohen’s pathways of dental pulp –10th edition
• Ingle’s Endodontics-6th edition
• Art And Science Of Operative Dentistry, Sturdevent. 7th Edition
• Phillips’ 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, 33,173–185, 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) 809–832
• 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