1. LASERS IN ENDODONTICS
PRESENTER:
DR.RITIKA MUNDHRA
(MDS III YEAR)

2. HISTORY OF LASERS
“Laser” is an acronym of light amplification by stimulated
emission of radiation.
1.1958 Charles Townes and Arthur Schawlow coined the word
“maser”
2. Word laser was first coined in 1957 by Gordon Gould
3. Theodore Maiman , who introduced the acronym “laser,”
4. 1965, the physicist Leon Goldman was the first to use a ruby
laser

3. What is a wavelength ?
What is electromagnetic spectrum?
What is Visible spectrum of radiation ?
What is invisible spectrum of radiation?

4. CLASSIFICATION OF DENTAL LASERS
1.BASED UPON THEIR WAVELENGTH
1. ULTRAVOILET 130-400 nm
2. VISIBLE 400-700 nm
3. NEAR INFRARED 700-1500 nm
4. MEDIUM INFRARED 1500-3000 nm
5. FAR INFRARED >3000 nm

5. CLASSIFICATION OF DENTAL LASERS
ULTRAVOILET VISIBLE NEAR INFRARED MEDIUM
INFRARED
FAR INFRARED
EXCIMER BLUE ARGON
LASER
DIODE 810 nm Er.Cr.YSGG CO2 LASER
9300 nm
308 nm 470-488 nm DIODE 940 nm 2780 nm CO2 LASER
9600 nm
GREEN ARGON
LASER
DIODE 970 nm CO2 LASER
10,600 nm
514 nm DIODE 1064 nm Er: YAG
GREEN
KTP LASER
Nd:YAG 1064 nm 2940 nm
532 nm Nd:YAP 1340nm

6. 2. BASED ON THEIR PENETRATING POWER:
1.SOFT TISSUE LASER DIODE LASER 445-1064 nm
(ATHERMIC LASER) Nd: YAG LASER 1064 nm
Nd: YAP LASER 1340 nm
CO2 LASER 10,600 nm
2.HARD TISSUE LASER Er.Cr.YSGG LASER 2780 nm
(THERMIC LASER ) Er.YAG LASER 2940 nm
(SURGICAL LASER) Excimer 308 nm

7. 2. BASED ON THE TYPE OF ACTIVE MEDIUM USED:
1.GAS LASER He:Ne LASER
CO2 LASER
2.LIQUID LASER DYLASE
3.SOLID LASER RUBY LASER
Nd:YAG LASER
Er.YAG LASER
Ho:YAG LASER
4.SEMICONDUCTOR LASER DIODE LASERS
[GALLIUM ARSENIDE LASER]

8. According to ANSI and OHSA standards :
CLASS POWER NATURE
Class I LOW SAFE
Class IIa LOW HAZARDOUS>100s
Class IIb LOW Hazardous >0.25 s
Class IIIa MEDIUM Hazardous <0.25 s
Class IIIb MEDIUM Hazardous {viewed directly}
Class IV HIGH Ocular Skin and fire Hazards
>0.5 W

9. CLASSIFICATION OF LASERS USED IN
ENDODONTICS

10. DIFFERENT LASERS USED IN
ENDODONTICS
1. ARGON LASER:
• It produces different kinds of wavelengths, among them two in the
blue spectrum (470–488 nm) and one in the green spectrum (514
nm).
• The possibility of using the Blue argon laser (470 nm)
(Showa University School of Dentistry, Tokyo, Department of
Endodontics, in 1998 and 1999)
Ability of argon laser for smear layer and debris removal from the root
canals, prepared in a conventional way and irradiated at 1 W, with
0.05 s pulse duration and 5 Hz pulse frequency

11. 2.KTP LASER
Potassium Titanium Phosphate Laser :
1.In the spectrum of visible light, in the green band, the
wavelength 532 nm was chosen for the construction of the KTP
laser (a duplicate neodymium of 532 nm), with high affinity with
hemoglobin
2.It has the capacity for soft tissue cutting and coagulation
3.It’s root canal decontamination ability after conventional
endodontic instrumentation was studied, at different power
output (at 1 and 1.5 W), in dry mode or wet model

12. 3.DIODE LASER
Introduced in 1980’s initially for treatment of dentin
hypersensitivity and to bio-modulate the inflammatory response
during vital pulp therapy (pulp capping or pulpectomy)
Today, diode lasers represent a valid alternative to Nd:YAG
lasers root canal decontamination.
The active medium is a semiconductor, which is, nowadays,
miniaturized, made up of various layers (wafer-like
construction).
The gallium arsenide (GaA1As), doped with aluminum atom or
indium as doping atom (IGaAsP).

13. 3.DIODE LASER
It uses an optic fiber (diameter 200–300–400 μm) which ends in
a terminal handpiece, going through it and coming out in a
terminal curve tip.

14. 3.DIODE LASER
The fiber/tip activation is performed at 1 W on dark-blue
articulating paper, repeating the procedure 4–5 times up to seeing
the tip becomes darker
The use of thin fiber (200 μm) inside a root canal permits
decontamination in the endodontic system at up to 500–750 μm of
distance from the main canal

15. 4. ERBIUM YAG AND ERBIUM CHROMIUM
LASERS
The erbium YAG laser (2,940 nm) [first and then the erbium,
chromium YSGG laser (2,780 nm) were introduced in dentistry
with the idea of substituting the drill for caries removal.
The Er:YAG laser has a solid active medium, a crystal of yttrium, aluminum, or
garnet, doped with erbium atoms. Erbium is a silver metal of the group of rare
heart elements (Er, atomic number of 68)
The Er,Cr:YSGG laser also has a solid active medium, a crystal of yttrium,
scandium, gallium, and garnet (YSGG), doped with atoms of erbium and
chromium

16. 4. ERBIUM YAG AND ERBIUM CHROMIUM
LASERS
The photothermal effect of erbium lasers produces vaporization of
the smear layer and a certain grade of ablation and
decontaminating effect that are however limited to the dentin
canal surface (up to 250–300 μm in depth), where laser energy is
mainly absorbed and where it produces a direct photothermal
effect.

17. 4. ERBIUM YAG AND ERBIUM CHROMIUM
LASERS
• The affinity of erbium lasers with water explains the activation
and agitation of the irrigant solution (NaOCl ed EDTA).
• Tridimensional streaming of irrigants through the endodontic
system (LAI and PIPS techniques), and their effect on
bacteria decontamination, on debris and smear layer
removal, via an indirect laser action.
• The great presence of water in the oral soft tissues; in the
hard dental tissue, such as the enamel and the dentin; and
much more in the carious tissue explains the extensive use of
erbium lasers in dentistry.

18. 5. CO2 LASER
1. CO2 far-infrared lasers (9,300–10,600 nm) were the first to
be studied and used in endodontics for the
decontamination and fusion of the apex in endodontic
surgery
1. Advantages of the CO2 laser
• less or no bleeding, resulting in a dry surgical field •
reduction of surgical time due to better visibility • reduced
swelling
• reduced pain due to the fact that superficial nerve
endings are coagulated
• less or no sutures, resulting in shorter treatment time
• less scaring.
It was reported the use of the CO2 laser was unfavourable
because of the loss of the odontoblastic layer

19. Properties of Laser Light
LASER
LIGHT
Wave
Characteristics
Photonic
Corpuscular
Characteristics
Collimated
Coherent
Monochromatic
Visible or
invisible
spectrum

20. Components of Laser
HAND PIECE
AND TIPS
Optical
Resonator
Active
Medium
Energy Source
Controller
Cooling Unit
Delivery
System

21. • Photons, emitted by the excitement of the active medium
(stimulation), are reflected inside the optical cavity and pass
through the active medium many times, amplifying their energy
• The active medium can be solid, liquid, gas, or a semiconductor
(diode) and determines the specific wavelength of different
lasers; its name identifies different lasers

22. • Source of energy is usually represented by an electric coil or a diode
laser or a flash lamp.
• Controller is a microprocessor that verifies the characteristics of the
production of laser energy, the laser emission mode (continuous
wave, mechanically interrupted or pulsed)
• The cooling system is necessary to dissipate the heat produced during
the pumping process
• There are various systems of delivery, depending on the difference of
the wavelength carried: optic fiber, hollow fiber, and the articulated
arm

23. • The ideal handpiece should be small, lightweight, and handy. Some
handpiece does not have any terminal tip, but a reflecting mirror
which works at a distance from the tissue (tipless or noncontact or
far-contact handpiece)

25. LASER PARAMETERS
LASER EMISSON MODE
1.Continuous Wave and Gated Mode
2. Free-Running Pulsed Mode
3. Pulse Duration and Pulse Repetition Rate

26. LASER POWER
LASER EMISSON MODE
1.Continuous Wave and Gated Mode
2. Free-Running Pulsed Mode
3. Pulse Duration and Pulse Repetition Rate

27. OPERATOR MODALITY
Operator modality of the clinician includes distance from the
target, angulation of the irradiation, speed of the movement, and
time of irradiation.
Distance from the target influences energy density and power:
when the distance between fiber and tip of the laser increases, the
density of emitted energy decreases, enlarging the size of the spot

28. Laser-Tissue Interaction in Endodontics
• Reflected • Absorbed • Diffused • Transmitted
Reflection is an optical phenomenon due to the lack of affinity
and absorption of light from the target, which, once hit, rejects
the light completely
Absorption: It is the expression of high affinity between light and
the target which retains light in the point of irradiation.
Diffusion depends on the capacity of the light to spread
irregularly deeper into the target. The portion of laser energy
which diffuses into the tissues is responsible for the therapeutic
effects of some wavelengths

29. • Transmission is the passage of light through a body or tissue, in
the absence of interaction with it and, in consequence, without
producing physical or biological effects

30. Laser Effects in Endodontics
PHOTOTHERMAL
EFFECT
Results from the
direct laser
irradiation on the
dentinal walls,
when the lasers
are used with the
conventional
technique for the
decontamination
and removal of the
smear layer,
positioning the fi
ber inside the
Canal
PHOTOCHEMICAL
EFFECT
Causes the activation
of photosensitive
substances
(photosensitizers)
inoculated in the canal
and responsible for
the antibacterial
effects of the
photoactivated
disinfection (PAD),
without direct
irradiation (and
interaction) on the
dentin
PHOTOTHERMAL
EFFECT PRIMARILY
AND
PHOTOMECHANICAL-
ACOUSTIC EFFECT
This activate the
commonly used
irrigants in
endodontics during
the laser-activated
irrigation and PIPS,
without any direct
irradiation (and
interaction) on the
radicular dentin,
when the irrigant
liquids are present
and remain in the
canal

32. PARAMETERS INFLUENCING LASER
ENDODONTICS
1. Continuous Wave Mode
Diode lasers emit the energy in continuous wave (cw).
The power higher than 1.5 W, the continuous emission in the root
canal is inadvisable because of the excessive thermal damage
released on the canal’s walls
Therefore Chopping or Gating of emission is important as it
produces more or less thermal effect.
Short duration of t on , of 10–20 ms, is correctly and effectively used
in endodontics with diode lasers at a power ranging from 2 to 3 W

33. 2.Pulse Repetition Rate
The more frequent the repetition is, the shorter the time for thermal
release is and the greater the thermal effect on the tissue is
Repetitions of pulse (5–10 Hz/ pps) allow a longer time for thermal
relaxation and more control of tissue irradiation
3. Fluence and Power Density
It depends on the diameter of the tip used and of the irradiated
square surface;
For the same amount of energy and power emitted, larger is the
diameter of the fiber or the irradiated surface, and lower is the
density of power and energy.

34. 4. Pulsed Mode and Pulse Duration
Short duration of pulse permits to control the side effects of thermal
emission; when the energy is concentrated in a short time
5. Distance Between Target and Fiber
When the distance between the target and fiber/tip of the laser
increases, the density of emitted energy decreases, enlarging the size
of the spot due to the effect of a certain grade of emission divergence
and increasing the necessary amount of energy for the interaction

35. LASER TECHNIQUES USED IN
ENDODONTICS
• Conventional Laser Endodontics or
• Direct Laser Irradiation
• PAD-Photoactivated Disinfection Or
• aPDT-antibacterial Photodynamic Therapy
• Laser Activated Irrigation Or
• PIPS-Photon Induced Photoacoustic streaming

36. 1.CONVENTIONAL LASER
ENDODONTICS
The fiber is positioned in a dry canal 1 mm shorter from the apex and
is retracted with helical motion in an established time (2 mm/s)
Olivi
(2013)

37. • It requires the use of fibers or tips with a thin (narrow) diameter
(generally 200–300 microns) that are flexible and resistant to
negotiate the anatomical curvatures of dental roots with minimal
risk of breakage.
• It requires helical (circular) movement of the fiber, in order to
increase the irradiation angle between laser fiber and dentin
surface
• It is suitable for most wavelengths used in dentistry, in the visible
(532 nm) , in the near-infrared (from 810 to 1340 nm), and
medium-infrared (2780 and 2940 nm)

38. MECHANISM OF ACTION
The near-infrared wavelengths, which are not well absorbed by the dentin
chromophore, are more penetrating in depth.
determination of absorption, diffusion, or transmission of laser light.
Depending on the wavelength, there are different effects and
different depths of penetration
The medium infrared wavelengths, which are well absorbed by the
dentin water (chromophore), spread their energy superficially over
the canal surface
leaving the dentinal tubules open
laser fiber/tip is inserted into the canal
The presence and concentration of specific chromophores on the
canal surface and inside the Dentinal Tubule

39. IN ACCESS CAVITY PREPARATION
1. The access to the pulp chamber can be performed with
erbium lasers
2. It is able to remove all the hard and soft dental tissues:
enamel, dentin, carious tissue, and pulp without contact
3. The following are the suggested energy setting to
progressively use on enamel, dentin, carious tissue, and
pulp
4. A study by Hibst et al. (1996) demonstrated that bacteria
are killed during cavity preparation up to a depth of 300–
400 microns, under the irradiated surface

40. FOR ROOT CANAL PREPARATION
EXCIMER
LASER
• Value of
excimer
laser
technolo
gy in
endodont
ics was
limited
Nd:YAG
LASER
• Levy (1992), in
a SEM study,
concluded that
Nd:YAG laser
preparation was
possible and
that it allowed
better cleaning
of canal surface
than
conventional
instrumentation
ND:
YAP
LASER
• Different
conventional
manual
preparations,
associated
with both
laser
irradiation
and subsonic
irrigation,
showed no
statistically
significant
differences

41. FOR ROOT CANAL PREPARATION
ERBIUM
LASERS
•A study by Minas et al.
(2010) showed positive
results using
Er,Cr:YSGG laser at 20
Hz and different power
settings of 1.5, 1.75,
and 2,0 W and higher
water spray
DIODE
LASER
810nm
DIODE
LASER
980nm
•Alfredo et al. (2009)
evaluated the
alteration of the canal
dentin irradiated with
the 980 nm diode laser
at different
parameters, i.e., 1.5
and 3 W in CW and
gated mode at 100 Hz
after irrigation with
NaOCl and EDTA. It
was concluded that
the laser produced
morphological
alterations depending
on the chemical pre-
treatment.
Parirokh et al.
(2007), in their in
vitro study,
concluded that 808
nm diode laser
produced closure of
the dentinal tubules
of the irradiated
surface in every
condition of use and
especially at the
level of the apical
third

42. SEM Images of Dentinal tubules irradiated with 810 nm diode laser at 2.5 W in gated
mode (20 ms on and 20 ms off) with 200 micron tip, in root canal irrigated with 5 %
NaOCl (2 mm/s speed

43. ROOT CANAL IRRIGATION
• The first lasers to be used in wet canals with water or
irrigants were the Er:YAG laser and the Er,Cr:YSGG
laser and later the near-infrared laser
LAI PIPS

44. 2. LASER ACTIVATED IRRIGATION
2.1 Wavelengths and Target Chromophore
Matsumoto et al. (2011) and Gregorcic et al. (2012) described,
through in vitro visualisation studies
(Er:YAG and Er,Cr:YSGG), these two wavelengths are currently the
only two capable of being extensively absorbed by different irrigant
solution
The experience of the authors, the 810 and 940 nm diode laser or
neodymium:YAG laser (1064 nm) does not induce cavitation effect

45. Water absorption coefficient and penetration depth of
different wavelengths

46. 1.Photothermal Interaction: Heating of the Irrigant
2.Hydrodynamic Cavitation
Bubble Formation and Collapse: Expansion and Implosion of
Vapour Bubbles in Water
The first effect of the absorption of erbium laser in water is a thermal
effect
an instantaneous superheating of the irrigant to the boiling point of
water (100 °C)
an initial vapour bubble which expands at the tip of the fibre and ends
with consecutive implosion
This mechanism had been previously referred to as “the Moses effect
in the microsecond region” by van Leeuwen et al

47. Collapse of the laser-induced bubble follows immediately after
the expansion.
The shrinkage creates a cavitation-generated pressure wave that
travels at supersonic speed (shock wave) in the beginning and at
sonic speed (acoustic waves) later
a highspeed liquid jet is formed
fluid surrounding the bubble quickly flows inside the
decompressed vapour gap, inducing fluid velocities of several
metres per second

48. 2. HYDRODYNAMIC CAVITATION
Cavitation is defined as “the formation of an empty space (bubble) and
fast collapse of a bubble in a liquid”
The process is very fast and evolves mainly in the range of
100 μs–1 ms.
When a bubble collapses, primary cavitation is formed, followed by
secondary cavitation bubbles that create highspeed fluid motions in the
canal
The primary and secondary cavitation bubbles create microjets in the
fluid that generate high forces and shear stress along the dentin walls
sufficient to remove smear layer and biofilm

49. Effect of Tip Design
• 1. Conventional laser tips and fibres are flat-end fi ring so that no
energy is directed laterally.
• 2. Today tips are available with different designs such as conical
shaped, tapered and tapered and stripped (PIPS™), thereby allowing
more energy to be delivered laterally and less frontally
• 3. Tips allow for lateral diffusion of the energy in the irrigant fl uid,
decreasing the frontal pressure and improving the safety of the
procedure

50. The flat laser generated an oval bubble, long and almost
elliptically shaped due to the frontal emission of energy.
The use of a conically shaped tip resulted in the formation of a
round bubble due to the three- dimensional (frontal and lateral)
emission of the energy

51. TIP POSITION
In order to prevent extrusion, the laser fibre/tip should be kept away from
the apex.
At present there are two approaches: the one moving or keeping the fibre
tip stationary in the root canal and the other using the fi bre tip stationary
in the pulp chamber.

52. • LAI advocates positioning the tip inside the canal filled with
irrigant.
• The different techniques proposed for laser- activated irrigation:
( a ). 200–300 μm flat and conical tips are positioned stationary 5 mm
from the apex
( b ). 280 μm flat tip at 1 mm short of the working length and moved it
slowly up and down in the fi nal 4 mm of the apical third
( c ). conical tip inside the coronal one- third only (for 4 mm) slowly
withdrawing it back to the pulp chamber
( d ). 300 μm flat tip inside the canal
( e ). 200 μm conical tip at the entrance of the orifice
( f ). 600 μm fl at tip in the chamber hovering over
the orifice of the canal

53. Advanced Laser-Activated Irrigation: PIPS
Technique and Clinical Protocol
1. PIPS is an acronym fi rst described by Enrico DiVito (2006) and
stands for photon-induced photoacoustic streaming
2. Process by which photons of light are emitted at very low energy
levels and with short microsecond pulse duration
3. PIPS TM utilizes a unique tapered and stripped tip design that
allows for lateral dispersion and propagation of the generated
shock wave in liquids

54. • PIPS TM protocol has been confirmed by thousands of clinical trials
and differs from the other investigated LAI techniques in the
following way:
1. It uses a specific and unique tip design
2. It uses sub ablative or minimally ablative energy.
3. It is delivered via a very short pulse duration thus producing a
very high peak power.
4. It requires an easy positioning of the tip in the pulp chamber only
and not into the canal.
5. It advocates minimal root canal and apical preparation.

55. 6.It is based on new “minimally invasive” or “biomimetic” concept
7.It minimizes the use of intracanal instrumentation without
compromising the ability for irrigation to effectively reach all aspects
of the root canal system
8. Photon-induced photoacoustic streaming (PIPS TM ) uses a cutting-
edge erbium:YAG laser technology (2940 nm) at high peak power to
pulse extremely low energy levels of laser light to generate
photoacoustic shock waves into liquid filled root canals

56. Clean delta at the apical one-third of root
canal seen after PIPS. Thermal damage is
avoided because PIPS does not require
that its tip be placed into the canal
preparation at all but rather stationary in
the coronal pulp chamber only
Ledging and thermal damage on root
canal surface as a result of Er,Cr:YSGG
laser radial tip placed into the canal as
advocated with conventional protocol

57. Sequential still frame shots showing the bubble cycle with increase ( a
PIPS tip before activation, expansion from b – g ) and subsequent
decrease (collapse from h – n ) of the bubble resulting in primary and
secondary cavitation, seen from the PIPS tip during fluid activation at
20 mJ and 50 μs pulse duration

59. Effects of PIPS
• 1.On Vapour Lock:
• Chemical reaction of sodium hypochlorite produces free chlorine
ions, specifically the hypochlorous acid (HO Cl) and the
hypochlorite ion (OCl − )
• PIPS pressure waves to eliminate vapor lock from inside the artificial
canal model
• 2. On Intracanal Tissue, Debris and Smear layer:
A recent study from Arslan et al. (2014) compared the efficacy of PIPS
technique and 1 % NaOCl with conventional, sonic, and ultrasonic
irrigation on the removal of apically placed dentinal debris from an
artificial groove created in a root canal.
PIPS resulted in signifi cantly more effective removal of dentinal
debris than conventional irrigation ( p < 0.001), sonic irrigation ( p <
0.001), or ultrasonic irrigation ( p = 0.005) [

60. 4 The final step before obturation requires patency to be
confi rmed using .06 or .08 fi le after NaOCl irrigation
activates by PIPS
The final step before obturation requires patency to be confirmed using .06 or .08 file after
NaOCl irrigation activates by PIPS

61. PIPS final irrigation protocol utilizes 17% EDTA activated by PIPS TM for 30s; after 60s
resting time, sterile distilled water agitated by PIPS is used for 30s to inactivate the
EDTA;
Fnally three cycles of 5–6 % NaOCl are activated by PIPS for 30s; each cycle has 30s
rest phase to allow the hypochlorite to react.
Again sterile distilled water agitated by PIPS is used for 30s to inactivate the oxygen
before obturation using resin-based sealer

62. PHOTO ACTIVATED DISINFECTION
(PAD)
1.It is also known as aPDT. When microorganisms are the targeted cells,
PDT is referred to as photodynamic antimicrobial chemotherapy (PACT)
2.It involves the use of a dye (photosensitizer) in combination with (laser)
light to selectively kill cells. These cells can either be diseased cells,
malignant or pathogenic cells or microorganisms
3.PAD application requires three fundamental elements
• A photosensitizer
• A light source
• Tissue oxygen

63. MECHANISM OF ACTION OF PAD
• ,
No direct effect on tissues or
bacteria but photoactivates a
specific compound that releases
toxic elements to the target
light transforms the drug from its
ground state into an excited singlet
state
excited state may then undergo intersystem
crossing (the spontaneous change of a system
from one spin quantum number to another)
to the slightly lower energy
triplet state, which may then react
further by one or both of the two
pathways known as the Type I and Type
II photo processes, both of which
require oxygen

64. The reactive oxygen species (ROS) resulting from both pathways
mediate cellular damage. Amongst the ROS, singlet oxygen plays a
central role for cytotoxicity in PAD,The greater the amount of singlet
oxygen the target is exposed to, the more effectively bacteria are killed
In order to reach the photosensitizer in situ, the penetration depth of the
light is also important. Therefore, the wavelengths have to fall within the
so called “ therapeutic window ” of the electromagnetic spectrum
between 635 and 1000 nm, the area with the maximum penetration of
light into the tissues.

65. • Type I and II reactions require sufficient oxygenation of the
target area. This might not be the case in the anaerobic
environment found in primary root canal infections

66. 1. LASER IN ANALGESIA
• The pulsed Nd:YAG laser is widely used as a analgesia in endodontics.Its
wavelengths interfere with the sodium pump mechanism, change cell
membrane permeability, temporarily alter the nerve endings of sensory
neurons and block depolarization of C and A nerve fibers.
• Laser analgesia is a non-invasive, non-destructive, and non-thermal bio-modulating
technique with the ability to reduce or suppress painful sensations; it is obtainable in a
low-energy-level irradiation form.

67. 2. PULPAL DIAGNOSIS
A) LASER DOPPLER FLOWMETRY
• Non-invasive method used to assess blood flow in micro
vascular systems.
• This method uses Helium Neon and diode lasers at a
lower power of 1 or 2 Mw, based on Doppler principle to
measure the blood flow in the pulp.
MECHANISM OF WORKING

68. • A beam of laser light is directed to the tooth surface through a fibre
optic source
• Light enters the tooth and gets absorbed by red blood cells in pulpal
capillaries leading to shift in frequency of scattered light.
• In moving blood cells their frequency shift according to Dopplers
principle.
• This shift in frequency does not occur in light that is absorbed by
stationary objects
• A proportion of doppler shifted light is detected with the help of a
photodetector .
• Signal is then calculated with preset algorithm in LDF machine

69. B). THERMAL TESTING
1. Pulsed Nd:YAG laser has been used and it shows better pulpal
response than hot gutta percha.
2. As a differential diagnosis between normal pulp, acute pulpitis and
chronic pulpitis.
3.Laser used - Nd:YAG at 2W, 20 pulses per sec (pps) at a distance of
10mm from the tooth surface.
4.Normal pulp- mild transient pain with in 20 to 30 sec and disappears
in a couple of seconds after laser stimulation is stopped.
6. Acute pulpitis – pain induced immediately and continuous more
than 30sec.
7.Chronic pulpitis – no pain or pain
started after one min application and
continuous more than 30sec.

70. 3.PULPCAPPING AND
PULPOTOMY
• Since laser has the ability to coagulate and seal small blood vessels
and leads to potentially bloodless field.
• The wound will be sterile after interacting with laser and will have
an improved prognosis.
• No damage in the underlying laser ablated tissues has been found in
studies using Nd:YAG and CO2 lasers.
• There was presence of secondary dentin and the odontoblasts layer
was regular and not disturbed.

72. 4. IN
OBTURATION
• Argon, CO2 and Nd: YAG lasers have been used to soften gutta-
percha and results indicate that Argon laser produces a very good
apical seal.
• Thermo plasticised gutta percha system are one of the efficient
methods in achieving a fluid- impervious seal.
• Softening of gutta percha has been attempted with CO2, Nd:YAG
and Er:YAG lasers.

73. 5.ENDODONTIC
RETREATMENT
• Rationale of using laser in non surgical endodontic retreatment may
be ascribed to need to remove foreign material from root canal
system which is difficult to achieve by conventional methods
• Nd:YAP (1340 nm) laser Neodymium doped yttrium aluminium
perovskite laser used in root canal retreatment cases.
• Nd:YAG laser used to remove gutta percha and broken files from
root canal.

74. LASER IN BLEACHING
Whitening process achieved by chemical oxidation
process.
Lasers used for bleaching :-
Carbon dioxide (10600 nm)
Nd:YAG
Argon (515 nm)
Diode (980 nm)
KTP (532 nm) KTP is Potassium titanyl Phosphate laser.
Reducing agent + Oxidising agent Tooth Bleaching material Free
reactive radicals react with unsaturated bonds Larger stain molecules
converted into smaller ones Simple molecules are formed Reflect less
light or become colorless
Application of laser light generates heat Activates bleaching
agent(fused silica+35%H2O2) H2O2 H2O+ O2 (nascent oxygen)

75. TREATMENT OF INCOMPLETE TOOTH
FRACTURE
1. Lasers are used in repairing incomplete vertical fractures by
causing fusion of the fracture.
2. CO2 and Nd:YAG lasers have been unsuccessfully used to
approximate fractured roots.
INDICATIONS:
a. Teeth with lateral canal leading to periodontal involvement.
b. Teeth with pulp necrosis and purulent pulpitis.
c. Teeth with periapical lesions upto 5mm or more.
d. Teeth that has been treated at least 3 months with no success.
CONTRAINDICATIONS :
In advanced periodontitis cases.
A deep crown and root fracture.
Obliterated root canals in endodontic treated teeth.

76. REFERENCES
• 1) Nisha Garg, Textbook of Endodontics, 2nd edition.
• 2) Grossman, Endodontic Practice,13th edition.
• 3) Cohen, Pathways of Pulp, 10th edition.
• 4) Stabholz A et al. Lasers in endodontics. Dent Clin N Am 48 (2004)
809-832.
• 5) Nishad SG et al. Laser in Endodontics J Adv Med Dent Sci Res
2016;3(2):137-141.
• 6) Bansode PV et al. Lasers in Endodontics-A Literature Review. IOSR J
Dent Medi Sci 2016; 15( 12 ) :87-91 .
• 7)Ratnakar P et al. Lasers in Endodontics- A beginning of new era.
Indian J Stomatol 2010 :1(2);84-87

77. THANKYOU