A clear simple compilation about lasers used in dentistry.

1. Dr Ambreen Azam
MSc, Dental Materials, UK.

2. Over view
• Drill and fill dentistry
• Need for change
• Fundamentals of laser
operation
• Tissue interactions
• Types of lasers
• Commonly used lasers in
dentistry
• Application of lasers
• Laser safety
• Conclusion

3. Drill & Fill
• Anesthesia, tooth prep and filling.

4. Need for a change
• Need for a comfortable treatment within short
time.
• One of the milestones in technological
advancements in dentistry is the use of
LASERS.
• They provide more efficient , more
comfortable and more predictable outcomes
for the patient.

5. Laser Technology
Laser stands for
Light
Amplification
by the
Stimulated
Emission
Of
Radiation

6. How it differs from ordinary light?
• Form of electromagnetic
energy
• Compared to an ordinary bulb
laser light is very focused and
intense.
• High intensity like a 50 Watt
laser is very harmful as
compared to a 50 Watt bulb.

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

8. S – Stimulated, E- Emission
• If an atom in the excited state is struck by a photon
of identical energy as the photon to be emitted, the
emission could be stimulated. This stimulated
interaction causes two photons that are identical in
frequency and wavelength to leave the atom.

9. Properties of lasers
• Monochromatic-Characterized by radiation in
which all waves are of same frequency and
wavelength.
• Collimated: all the emitted waves are parallel
and the beam divergence is very low. This
property is important for good transmission
through delivery systems.

10. Properties of lasers
• Coherent: Single or just a few frequencies
going in one precise direction
• Intense: Focused photons.

11. Laser System Components
• Optical Resonators/ Tube containing the active
medium
• Active medium [ Lasing Medium ] solid, liquid or gas
• Pumping mechanism
• Controller
• Laser Delivery System

12. Process of supplying energy for amplification-
pumping
Laser Components

13. Laser Light Delivery
1-Fiber optic delivery system
• Lasers in the visible (445 and 532
nm) and near infrared (from 810 to
1,064 nm) spectrum utilize optic
fibers, generally made of quartz, to
deliver the laser energy to the tissue,
directly or via terminal hand piece,
with straight and angular tips
• Disadvantage is wear with time

14. Why Fiber optic is important?
• 1. Light weight
• 2. Easy to approach
• 3. Easy sterilization
• 4. Tactile sensation

15. Laser Light Delivery
2- Hollow Fiber Some type of laser (Er: YAG and
CO 2 lasers) utilizes a hollow tube with reflective
internal walls which transmit laser energy along
its internal axis.
• Disadvantage loss of energy over time with
lack of control over variability of energy due to
internal reflection.

16. Laser Light Delivery
3- Articulated arm delivery system
• This delivery system uses a series
of articulated mirrors (usually 7)
connected one to each other,
leading to transmission of energy
with
• Disadvantage requires a precise
system for alignment of mirrors

17. Hand Pieces
• Close Contact Handpiece
• works using tips of
different size, shape,
length, and angle.
• designed for specific
interaction with different
kinds of tissues.
• The emission of the laser
beam close to or in direct
contact with the target
tissue.
• Improves precision of
work.
• Noncontact Handpiece
• also called tipless, uses
a sapphire lens, located
in the final part of the
handpiece.
• specific distance from
the target (usually from
5 to 10 mm depending
on the type).

18. Hand Pieces
Close Contact Hand Piece
No Contact Hand Piece

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

20. Laser & Tissue interactions
• The light energy from a laser can have four
different interactions with the target tissue,
and these interactions depend on the optical
properties of that tissue and wave length
used.

21. 1-Reflection
• Laser beam become more divergent as
distance from handpiece increases.
• Can be dangerous

22. 2- Absorption
• This effect is the usual
desirable effect, and the
amount of energy that is
absorbed by the tissue
depends on the tissue
characteristics such as
pigmentation and water
content, and on the laser
wavelength and emission
mode.

23. Absorption
• Diode and Nd : YAG have a high affinity for
melanin and less interaction with hemoglobin.
• Longer wavelength are more interactive with
water & hydroxyapatite – Erbium , carbon
dioxide laser.
• Short wave lengths, from about 500-1000nm
are absorbed readily in pigmented tissue.

24. 3- Transmission
 Transmission of laser energy
directly through the tissue,
with no effect on target tissue.
 Water is relatively transparent
to Nd:YAG whereas tissue
fluids readily absorb carbon
di-oxide.

25. 4- Scattering
 Scattering of the laser light
causes weakening the energy
and possibly producing no
useful biologic effect.
 May cause heat transfer to
tissue adjacent to the surgical
site and unwanted thermal
damage can occur.

26. Types Of Tissue Interactions
• Photochemical effects that lasers create to
stimulate chemical reactions, such as curing of
composite resin.
• They can also cause break in chemical bonds,
such as in the process of photodynamic
therapy.

27. Photodynamic Laser Therapy

28. Types Of Tissue Interactions
• Photo ablation – removal of tissue by
vaporization and super heating of tissue fluids
, coagulation, and hemostasis.
• Tissue fluorescence - used as a diagnostic
method to detect light reactive substance in
tissue. Diagnodent for caries detection

29. Laser ablation
• When a laser is absorbed, it elevates the
temperature and produces photochemical
effects depending on the water content of the
tissues. When a temperature of 100°C is
reached, vaporization of the water within the
tissue occurs, a process called ablation.

31. Vaporization & Carbonization
• At temperatures below 100°C, but above
approximately 60°C, proteins begin to
denature, without vaporization of the
underlying tissue.
• Conversely, at temperatures above 200°C, the
tissue is dehydrated and then burned,
resulting in an undesirable effect
called carbonization

32. Laser Absorption
• Requires absorbers in the tissues called
chromophores which have a certain affinity for
specific wavelengths of light.
• The primary chromophores in the intraoral soft
tissue are Melanin, Hemoglobin, and Water.
• In dental hard tissues, Water and Hydroxyapatite.
• Different laser wavelengths have different
absorption coefficients with respect to these
primary tissue components, making the laser
selection procedure-dependent.

33. Effects of lasers
• Analgesia: decrease release of pain mediators
from injured tissues.
• Decrease sensitivity of pain receptors as well
as transmission of impulses.
• Reduce tissue edema by improving lymphatic
drainage.
• Reduces pressure on the nerve endings
reducing pain.

34. Effects of lasers
• Antisepsis: Kills bacteria in the operating field
giving asepsis
• Clear operating field: cauterize the blood
vessels leading to less blood flow and clear
working field.

35. Classification Of Lasers
• Based on active medium
• Solid, Liquid, Gas
• Based on wavelength
• Based on Application
– Soft tissue lasers
– Hard Tissue lasers

36. Commonly Used Lasers In Dentistry
1- Carbon dioxide Lasers ( Gas Lasers)
• Advantages
• Possess high
affinity for water,
rapid soft tissue
removal
• Quick hemostasis
with shallow
penetration
• Disadvantages
• Possess highest
absorbance of any
laser
• Large size, high
cost
• Greater hard
tissue destruction

37. 2- Neodymium- Yttrium Aluminum Garnet
Laser (Nd- YAG Solid state Lasers)
• Advantages
• Highly absorbed by
pigmented tissues.
• Effective for cutting
and coagulating
dental soft tissues
• Good hemostasis
• Used in non
surgical sulcular
debridement
• Disadvantages
• High cost and size.

38. 3- Erbium Laser (Solid state Lasers)
• Advantages
• Erbium
wavelengths have a
high affinity for
hydroxyapatite and
the highest
absorption of
water.
• Used for both soft
and hard tissues
• Disadvantages
• High cost.
• Slightly prolonged
treatment time
but better results.

39. 4- Diode Lasers(Solid state Lasers)
• Advantages
• Absorbed
primarily by tissue
pigment (melanin)
and hemoglobin.
• Used for soft
tissue applications
• Disadvantages
• Poorly absorbed
by the
hydroxyapatite
and water present
in the enamel

40. Laser soft tissue Applications
1- wound Healing
• At low doses laser application stimulates
proliferation, while at high doses it is
suppressive
• It affects fibroblast maturation and
locomotion
• Contribute to the higher tensile strengths
reported for healed wounds

41. 2- Post herpetic neuralgia and
Apthous ulcer
• Photo stimulation of aphthous ulcers and
recurrent herpetic lesions, with low levels of laser
energy (HeNe) can provide pain relief and
accelerate healing.
• In the case of recurrent herpes simplex labialis
lesions, photo stimulation during the prodromal
(tingling) stage seems to arrest the lesions before
painful vesicles form, accelerate the overall
healing time, and decrease the frequency of
recurrence

42. 3- Photo activated dye disinfection
using lasers
• The photo activated dye (PAD) technique can be
undertaken with a system using low power (100
mill watts) visible red semiconductor diode lasers.
• Effective in killing bacteria in complex biofilms,
such as, sub gingival plaque, which are typically
resistant to the action of antimicrobial agents
• Disinfection of root canals, periodontal pockets,
deep carious lesions, and sites of peri-implantitis

43. 4-Aesthetic gingival re-contouring and
crown lengthening
• With the advent of the diode laser, many
clinicians are choosing to include optimization
of gingival aesthetics as part of the
comprehensive orthodontic treatment when
compared with conventional Gingivectomy.

44. Laser Gingivectomy

45. 5-Exposure of unerupted and partially
erupted teeth
• An impacted or partially erupted tooth can be
exposed for bonding by conservative tissue
removal, allowing for reasonable positioning
of a bracket.

46. Crown Exposure

47. 6- Removal of inflamed, hypertrophic
tissue
• Isolated areas of transient tissue hypertrophy
can easily be excised with the diode laser
without specialist referral.

48. 7- Frenectomies
• Frenectomies performed with a laser permit
excision of the frena painlessly, without
bleeding, sutures, or surgical packing, and
with no need for special postoperative care.

49. Laser Hard Tissue Applications
1- Photochemical effects
• The argon laser produces high intensity visible
blue light (488 nm), which is able to initiate
photo polymerization of light-cured dental
restorative materials, which use
Camphorquinon as the photo initiator.
• It also alter the surface chemistry of both
enamel and root surface dentine, which
reduces the probability of recurrent caries

50. 2- Cavity preparation, caries, and
restorative removal
• Er: YAG, since 1988, for removing caries in the
enamel and dentine by ablation, without the
detrimental effect of rise in temperature on
the pulp.
• Capable of removing cement, composite resin,
and glass Ionomer.

51. 3- Etching
• Alternative to acid etching of enamel and
dentine.
• Enamel and dentine surfaces etched with (Er,
Cr: YSGG) lasers show micro-irregularities and
no smear layer.

52. 4- Treatment of dentinal
hypersensitivity
• Desensitizing of hypersensitive dentine with
an Er: YAG laser is effective, and maintenance
of a positive result is more prolonged than
with other conventional agents.

53. 5- 3-D Laser scanner for e-model
preparation
• The laser scanner can be used as a soft tissue
scanner and is a valuable tool for its ease of
application and creation of 3D images of oral
dental structures. There is no need of cast
preparation as e-models are prepared from
scanned impressions.
• assess the clinical outcomes in surgical and
non-surgical treatments in the head and neck
regions

54. Laser Bleaching
• removes extrinsic and intrinsic stains vital in
esthetic dentistry.
• The reactive oxygen species released by
bleaching materials is responsible for oxidizing
dentin chromogens and causing whitening
effect.
• Diode lasers (Low light laser therapy LLLT),
Argon lasers are also used.

55. BLEACHING
SMILE

56. Nd: YAG laser

57. DIAODE LASER
SEMICONDUCTOR LASER
Gallium Arsenide chip
No mirror to clean and align
No gas tube, flashlamps,
laser rod, water cooling
Portable
No special power
No cooling connection
No heat
Quiet
Affordable
More powerful, less traumatic
250microsecond-10sec
0.05 Hz - 200 Hz
Expand Practice* Sulcular debridement
* Root canal treatment

58. Advantages Of Lasers
• No anesthesia, no drill
• Less blood loss, Less pain hemostatic, analgesic
effect.
• Reduce post –operative edema
• Less postop scarring.
• Early healing, rapid regeneration, reduce post
sensitivity in restorations
• Dressing & suturing is not required for wound closer.

59. Advantages Of Lasers
• Less chances of metastasis
• Sterilization of treatment site-no infection
• Laser exposure to tooth enamel causes
reduction in caries activity.
• Patient becomes free of fear & anxiety.
• Advantageous for medically compromised
patients, since no medication is required like
antibiotics or pain-killers
• Patient becomes free of fear & anxiety.

60. Disadvantages Of Lasers
• Laser beam could injure the patient or operator
By direct beam or reflected light, causing retinal
burns
• Laser - more expensive
• Need trained personal
• Lasers can't be used
- fill cavities located between teeth
- remove defective crowns or silver fillings
- prepare teeth for bridges

61. LASER HAZARD CONTROL MEASURES
 The small flexible fiber optic , hand pieces or
tip must be steam sterilized in sterilizing
pouches
 Use of protective wear
 Use of screen & curtains should be promoted
 Use of proper clothing
 Use of anti-fire explosive
 Proper training and courses

62. LASER HAZARD CONTROL MEASURES
• Use of laser filtration masks prevents air borne
contamination
• Foot pedal control switch with protective hood prevents
accidental depression by surgical staff.

63. • Lasers - alternative to conventional surgical
systems
• Lasers are a “new and different scalpel”
(optical knife, light scalpel)

64. References
• Laser Application in Dentistry: Irradiation Effects of
Nd:YAG 1064nm and Diode 810nm and 980nm in
Infected Root Canals—A Literature Overview. Yves
Saydjari,1,2 Thorsten Kuypers,2 and Norbert
Gutknecht1,Volume 2016,
• The use of Erbium: Yttrium-aluminum-garnet laser in
cavity preparation and surface treatment: 3-year
follow-up Isil Buyukhatipoglu1 and Asli Secilmis1 2015
Apr-Jun; 9(2): 284–287.
• Buyukhatipoglu, I., & Secilmis, A. (2015). The use of
Erbium: Yttrium-aluminum-garnet laser in cavity
preparation and surface treatment: 3-year follow-
up. European Journal of Dentistry, 9(2), 284–287.
http://doi.org/10.4103/1305-7456.156843