Lasers in periodontology

1. LASERS AND ITS APPLICATIONS
IN PERIODONTOLOGY

3.  In 1953, Charles Townes, experimenting with
microwaves, produced a device whereby this
radiation could be amplified by passing it
through ammonia gas.
 This was the first MASER (microwave amplifi
cation by the stimulated emission of radiation)
and was developed as an aid to communication
systems and time-keeping (the ‘atomic clock’).

4.  A laser is a device that emits light
(electromagnetic radiation) through a process
of optical amplification based on
the stimulated emission of photons.
 The term "laser" originated as
an acronym for Light Amplification by
Stimulated Emission of Radiation.

5. Fundamentals of dental lasers:
science and instruments
 In 1960, Theodore Maiman, a scientist with
the Hughes Aircraft Corporation, developed
the first working laser device, which emitted a
deep red-colored beam from a ruby crystal
based on the theory originally postulated by
Albert Einstein.

6.  Frame, Pecaro, and Pick cited the benefits of CO2
laser treatment of oral soft-tissue lesions and
periodontal procedures.
 A portable tabletop model was made available in
1987, and 2 years later Myers and Myers received the
US Food and Drug administration’s permission to sell
a dedicated dental laser, a Nd:YAG device
 The clinician must be familiar with the fundamentals
of laser physics and tissue interaction so that the
proper laser device is used to obtain the treatment
objective safely and effectively.

7.  God heals and the doctor takes the fee.
--------------------Benjamin Franklin

8. Basic science and concept
Photonic emission, showing spontaneous (Bohr’s model, upper) and
stimulated emission (Einstein’s model, lower)

9.  Components of a typical laser:
1. Gain medium
2. Laser pumping energy
3. High reflector
4. Output coupler
5. Laser beam

11.  An optical cavity is at the center of the device.
The core of the cavity is comprised of chemical
elements, molecules, or compounds and is called
the active medium.
 Lasers are generically named for the material of
the active medium, which can be a container of
gas, a crystal, or a solid-state semiconductor.
 There are two gaseous active medium lasers used
in dentistry: argon and CO2.
Amplification

12. Laser delivery systems
 Two delivery systems.
 One is a flexible hollow waveguide or tube
 The second delivery system is a glass fiber optic
cable.

13.  a laser used in contact can provide easy access
to otherwise difficult-to-reach areas of tissue.
 For example, a fiber tip can be used around the
lining of a periodontal pocket to remove small
amounts of granulation tissue.
 When used out of contact, the beam is aimed a
few millimeters away from the target.

14.  Focal point should be used for incisional and
excisional surgery.
 For the optic fiber and accessories, the focal
point is at or near the tip, which has the
greatest energy.
 In either case, the beam becomes divergent and
defocused as the handpiece is moved away
from the focal point.

15. Laser emission modes
 Continous mode
 Pulsed mode
 Gated-pulse mode
 superpulsed mode
 free-running pulsed mode

16.  Thin or fragile soft tissue, for example, should be
treated in a pulsed mode
 the amount and rate of tissue removal is slower
 the chance of irreversible thermal damage to the target
tissue and the adjacent non-target tissue is minimal.
 Longer intervals between pulses can also help to
avoid the transfer of heat to the surrounding
tissue.
 In addition, a gentle air stream or an air current
from the high volume suction aids in keeping the
area cooler.

17. Target tissue effects in relation to temperature
37–50 Hyperthermia
60–70 Coagulation, protein denaturation
70–80 Welding
100–150 Vaporization, ablation
>200 Carbonization

18.  The first event, hyperthermia, occurs when the tissue is
elevated above normal temperature but is not destroyed.
 without any vaporization of the underlying tissue.
 The tissue whitens or blanches
 Useful in surgically removing diseased granulomatous
tissue -------the biologically healthy portion can remain
intact.

19.  Coagulation refers to the irreversible damage
to tissue, congealing liquid into a soft semi-
solid mass.
 produces the desirable effect of hemostasis
 Soft tissue edges can be ‘‘welded’’ together
with a uniform heating to 70 0 C to 800 C.

20.  At 1000C, vaporization of the water occurs, a process
also called ablation.
 There is a physical change of state; the solid and
liquid components turn into vapor in the form of
smoke or steam.
 Because soft tissue is composed of a high percentage
of water, excision of soft tissue commences at this
temperature.
 This micro-explosion of the apatite crystal is termed
‘‘spallation.’’

21.  At 200 0C------dehydrated and then burned in
the presence of air.

22. Laser–tissue interaction
 Absorption
 Transmission
 Reflection
 Scattering

23. Absorption
 Depends on the tissue characteristics, such as
pigmentation and water content, and on the laser
wavelength and emission mode.
 Hemoglobin is strongly absorbed by blue and
green wavelengths. (500–1000 nm)
 The pigment melanin, which imparts color to
skin, is strongly absorbed by short wavelengths.
(Diode and Nd:YAG)

24.  The longer wavelengths are more interactive with water
and hydroxyapatite. The largest absorption peak for
water is just below 3000 nm, which is at the Er:YAG
wavelength.
 Hydroxyapatite is the chief crystalline component of
dental hard tissues and has a wide range of absorption
depending on the wavelength. (Erbium)
 CO2 at 10,600 nm is well absorbed by water and has
the greatest affinity for tooth structure

26. Transmission
 Water, for example, is relatively transparent to
the shorter wavelengths like argon, diode, and
Nd:YAG, whereas tissue fluids readily absorb
the erbium family and CO2 at the outer
surface, so there is little energy transmitted to
adjacent tissues.

28. Reflection
 A caries-detecting laser device uses the
reflected light to measure the degree of sound
tooth structure.
 This reflection can be dangerous because the
energy is directed to an unintentional target,
such as the eyes; this is a major safety concern
for laser operation.

29. Scattering
 Weakening the intended energy and possibly
producing no useful biologic effect.
 Cause heat transfer to the tissue adjacent to the
surgical site, and unwanted damage could
occur.
 However a beam deflected in different
directions is useful in facilitating the curing of
composite resin or in covering a broad area.

30. Laser wavelengths used in dentistry
The lasers are named according to their active
medium, wavelength, delivery system,
emission mode(s), tissue absorption, and
clinical applications. The shortest wavelength
is listed first.

31.  All available dental laser devices have
emission wavelengths of approximately 500
nm to 10,600 nm.

34. Argon
 The 514-nm wavelength has its peak
absorption in tissues containing
hemoglobin, hemosiderin, and melanin;
thus, it has excellent hemostatic
capabilities.
 Acute inflammatory periodontal disease
and highly vascularized lesions, such as
a hemangioma, are ideally suited for
treatment by the argon laser
 The poor absorption into enamel and
dentin is advantageous when using this
laser for cutting and sculpting gingival
tissues because there is minimal
interaction and thus no damage to the
tooth surface during those procedures.

35. Diode Laser
 Diode is a solid active medium laser, manufactured
from semiconductor crystals using some combination
of aluminum or indium, gallium, and arsenic.
 Wavelengths for dental use range from about 800 nm
for the active medium containing aluminium to 980 nm
for the active medium composed of indium
 Each machine delivers laser energy fiberoptically in
continuous wave and gated pulsed modes and is used in
contact with soft tissue for surgery or out of contact for
deeper coagulation.

36.  These lasers are relatively poorly absorbed by
tooth structure so that soft tissue surgery can
be safely performed in close proximity to
enamel dentin and cementum.
 cause a rapid temperature rise in the target
tissue.
 The clinician should use air and sometimes
water to cool the surgical site and to continue
to move the fiber around the treatment area.

37.  The diode is an excellent soft tissue surgical
laser and is indicated for cutting and
coagulating gingiva and mucosa and for
sulcular debridement
 The chief advantage of the diode lasers is one
of a smaller size, portable instrument.

38. Neodymium:YAG
 Nd:YAG has a solid active medium, which is a
garnet crystal combined with rare earth elements
yttrium and aluminum, doped with neodymium
ions.
 Common clinical applications are for cutting and
coagulating of dental soft tissues and sulcular
debridement

39.  Pigmented surface, carious lesions can be
vaporized without removing the healthy
surrounding enamel
 When used in a noncontact, defocused mode,
this wavelength can penetrate several
millimeters, which can be used for procedures
such as hemostasis, treatment of aphthous
ulcers, or pulpal analgesia.

40. The erbium family
 Erbium, chromium: YSGG
(2780 nm) has an active medium
of a solid crystal of yttrium
scandium gallium garnet that is
doped with erbium and
chromium.
 Erbium:YAG (2940 nm) has an
active medium of a solid crystal
of yttrium aluminum garnet that
is doped with erbium.

41.  These two wavelengths have the highest absorption in
water of any dental wavelength and have a high affinity
for hydroxyapatite
 The increased water content in dental caries allows the
laser to preferentially interact with that diseased tissue
 Osseous removal proceeds easily due to this
wavelength’s affinity for the composition of osseous
tissue
 The advantage of erbium lasers for restorative dentistry
is that a carious lesion in close proximity to the gingiva
can be treated and the soft tissue recontoured with the
same instrumentation.

42. CO2
 This wavelength has the highest absorption in
hydroxyapatite
 Therefore, tooth structure adjacent to a soft-tissue
surgical site must be shielded from the incident laser
beam
 The continuous wave emission and delivery system
technology of CO2 devices limit hard-tissue
applications because carbonization and crazing of tooth
structure can occur due to the long pulse duration and
low peak powers

43.  The scientific basis and tissue effects of dental lasers
have been discussed.
 It is most important for the dental practitioner to
become familiar with those principles and then choose
the proper laser(s) for the intended clinical application.
 Each wavelength and each device has specific
advantages and disadvantages. The clinician who
understands these principles can take full advantage of
the features of lasers and can provide safe and effective
treatment.

45. Advantages and Limitations of Lasers
 Wigdor et al described the advantages of lasers
over cold steel surgical procedures as follows:
 Dry and bloodless surgery
 Instant sterilization of the surgical site
 Reduced bacteremia
 Reduced mechanical trauma
 Minimal postoperative swelling and scarring
 Minimal postoperative pain

46.  The ability to precisely interact and, in some cases, remove
almost a few cell layers at a time.
 Erbium lasers can have some selectivity in removing
diseased tooth structure, since carious lesions have much
higher water content than healthy tissue.
 Advantages over conventional high speed handpiece
interaction on the tooth surface, such as the elimination of
micro-fractures and a reported lowering of pulpal
temperature as the preparation proceeds.
 Osseous tissue removal and contouring can also proceed
easily with reported faster healing.
 Moreover, it has been demonstrated that the lased enamel
has a good potential for bonded restorations as long as they
are subsequently etched with acid.

47.  Lasers also allow the clinician to reduce the
amount of bacteria and other pathogens in the
surgical field and in the cavity preparation
 In the case of soft tissue procedures, achieve very
good hemostasis with the reduced need for sutures
and surgical packing.
 Several manuscripts point out that post operative
scar formation is minimized; since the laser
incision is more broad and irregular than that of a
scalpel, the healing tissue better blends with the
surrounding structures.

48.  Periodontally diseased tissue can be
disinfected and detoxified.
 Lasers can successfully and safely be used on
a wide range of the population such as children
and pregnant women unlike some prescribed
and/or sulcularly delivered drugs.
 Unlike those medications, the patient will not
experience allergic reactions, bacterial
resistance, or untoward side effects when the
laser is used.

49.  With good control of bleeding, there is greatly
improved visualization of the surgical field, and
many laser procedures can be performed with less
injectable anesthesia.
 In those situations, additional treatment might be
able to be performed on the same appointment.
 Furthermore, initial postoperative discomfort and
swelling are reduced because of the sealing of
nerves and lymphatics

50.  Compared to the traditional dental drill, lasers
may cause less pain in some instances,
reducing the need for anesthesia.
 May reduce anxiety in patients uncomfortable
with the use of the dental drill.
 Minimize bleeding and swelling during soft
tissue treatments.

51. Disadvantages of Laser
 My doctor gave me six months to live but
when I couldn't pay the bill, he gave me six
months more.
- Matthau, Walter

53. Disadvantages
 Presently available dental lasers only emit
energy from the tip of the delivery system----
end cutting
 Although they are useful for caries removal
and tooth preparation, the Erbium family of
lasers is unable to remove gold and vitreous
porcelain, and has only a small interaction with
amalgam.

54.  In some cases, the delivery system can be more
cumbersome than an air rotor or electric
handpiece, and accessibility to the treatment area
could be limited.
 The clinician must carefully observe and monitor
the rate of tissue removal to prevent overheating
and lateral thermal damage.
 For enamel removal, the laser is not as fast as a
rotary bur, although it can be more conservative
by not removing as much healthy tooth structure.

55.  The initial investment for some devices must
be considered, as well as required supplies and
maintenance.
 The instruments range in size from a
paperback novel to a large dental cart, so
logistics or space can become a factor.
 All units operate at line voltage and the
Erbium lasers require an additional air supply.

56.  Lasers do not eliminate the need for
anesthesia.
 Laser treatment tends to be more expensive
than traditional treatment, since lasers are
much more expensive than conventional dental
drills.

57. Possible Intraoperative Complications
 Burns – There is a risk of accidental injury by the
laser energy which could cause permanent
scarring; however, this is very unlikely because
the laser energy is carefully metered and
contained.
 Eye Damage – Injury of the eyes is possible if
you look into the laser beam. eye protection that
will prevent this must be in place at all times
when the laser is in operation.

58. Possible Short-Term Effects of Laser
Dental Treatment:
 Pain or a burning/itching sensation may occur for a few days
after treatment.
 Redness/Inflammation/Swelling of the tissue will likely be
noticed for the first few days.
 Wound Healing – Oozing of the tissue in the treated area will
usually persist for a short time.
 Tissue Hyperpigmentation – transient darkening of the tissue
in the area especially in dark skinned people.
 Tissue Hypopigmentation can be permanent.

59. Possible Long-Term Complications of Laser
Dental Treatment:
 Scarring – The risk of scarring exists. It is variable and
often related to genetic makeup. It can be minimized by
carefully following appropriate aftercare instructions.
 Tissue Pigment Changes – Soft tissue color and texture
changes may occur. At the junction of treated and
untreated areas, a difference in color, texture, and/or
thickness may appear.
 Infection – There is a risk of infection common to all
surgical procedures. It can be minimized by proper
post-operative care.

62. Bacterial reduction
 Doxycycline and metronidazole are used
systemically to fight periodontal infections.
 One essential criterion for selection of an
appropriate wavelength for nonsurgical
periodontal therapy is definitive proof of a
bactericidal effect on periodontal tissues.

63.  Allergic reactions and compliance with taking
prescribed medications can be a concern. Soft tissue
lasers reduce bacterial populations photothermally
and eliminate those problems related to antimicrobial
therapy.
 These lasers successfully and safely can be used on a
wide range of the population, including children and
pregnant women, unlike some prescribed or
sulcularly delivered drugs.
 Unlike those medications, the patient will not
experience allergic reactions, bacterial resistance, or
untoward side effects when the laser is used.

64.  HCMV and EBV were estimated in GCF of
chronic periodontitis patients
 Laser treated group showed significant
reduction of EBV in chronic periodontitis
patients
Herpes viruses and Lasers

65.  Another essential criterion is the delivery system. The
practitioner must be able to deliver a bactericidal
wavelength to the tissue efficiently.
 If a bactericidal wavelength is available, but the
delivery system does not lend itself easily to
applications within the periodontal pocket, that
wavelength is therapeutically useless
 A third criterion is the effect of the wavelength on the
surrounding tissue. In the case of nonsurgical
periodontal therapy, the surrounding tissue is the hard
tissue of the root surface.

66.  The only two soft tissue wavelengths that currently
meet the criterion of having a delivery system able to
deliver laser energy efficiently and effectively to the
periodontal pockets for nonsurgical periodontal
therapy are Nd:YAG and diode.
 Well absorbed by melanin and hemoglobin and other
chormophores present in periodontally diseased
tissues. The laser energy is transmitted through water
and poorly absorbed in hydroxyapitite.

67.  Both of these wavelengths have been shown to be
extremely effective against periodontal pathogens in
vivo and in vitro ( Moritz 1998, Pinhero J 1997).
 These investigators concluded that the diode laser
revealed a bactericidal effect, helped reduce
inflammation, and supported healing of the
periodontal pockets through the elimination of
bacteria.

68.  Neill and Mellonig in a double-blind, split-mouth study,
assigned patients to one of three treatment regimens:
scaling and root planing alone, Nd:YAG laser treatment
with root planning, and control group with no laser
treatment or scaling.
 Their results showed that the laser-treated patients
exhibited significantly greater improvement in
measurement of their gingival index and gingival
bleeding index. At 6 months postoperative, the laser
treated group showed significant improvement in
attachment gain.

69.  At 3 months, the laser-treated group
maintained significant reduction in P
gingivalis and P intermedia, whereas the
scaling and root-planing group showed a
measurable repopulation of these bacteria from
initial treatment.

70.  The laser energy of the erbium family of lasers is well
absorbed by hydroxyapatite and highly absorbed by
water.
 Ando and Aoki showed that an erbium:yttrium-
aluminum-garnet laser in vitro has a significant
bactericidal effect on both P gingivalis and A
actinomycetemcomitans, which are primary
components of periodontal infection.
 The clinician must be careful to keep the fiber in
contact with the target tissue during soft tissue
procedures with this wavelength to achieve a good
result.

71.  Bader described the advantage of laser curettage as
enhanced bacterial reduction with good hemostasis in a
procedure that is less invasive than open flap surgery.
 The laser energy is directed solely onto the soft tissue
lining of the periodontal pocket.
 When the laser energy is directed parallel to the root
surface, the laser removes from the soft tissue the bacteria
and their exotoxins (eg, hyaluronidase, collagenase) that
are responsible for breakdown of the periodontium.
 When the laser energy is directed onto the root surface
rather than the soft tissue lining of the periodontal pocket,
the root surface can be damaged.

72. Quotes
 “Put your hand on a hot stove for a minute,
and it seems like an hour. Sit with a pretty girl
for an hour, and it seems like a minute.
THAT'S relativity.”

74. Therapy is started with the laser fiber at the top of the sulcus. Start at the
top of the sulcus and aim the fiber at the diseased tissue, not toward the
tooth structure.

75.  The fiber is moved with a sweeping motion on the soft tissue side of the
pocket. Move the fiber both horizontally and vertically, maintaining contact
with the soft tissue at all times. Inspect the fiber frequently and wipe off
accumulated tissue.

76.  Laser treatment continues until the calibrated depth is
reached

77. Bacterial reduction is complete when signs of fresh bleeding
occur. The laser energy is then changed to a coagulation setting
and the fiber is held in contact with the tissue with the same
motion—from the top of the sulcus to the bottom—until the
bleeding stops. Laser therapy is now complete at the site.

78. What happens if laser contacts the root surface?
 Severe damage, including crater-like defects and grooves,
occurred on the root surface (Schwartz et al)
 Morlock et al found similar results with Nd:YAG lasers.
 These studies and others led the American Academy of
Periodontology to conclude that neither the diode laser nor the
Nd:YAG laser is an alternative to root planing.
 The key word in the American Academy of Periodontology
report is alternative. With diode and Nd:YAG intrasulcular
treatment protocols, as with most dental laser treatment
protocols, the laser is used as an adjunct to standard treatments
rather than as a replacement for standard treatments.

79.  Laser curettage of periodontal pockets is unsuccessful unless it
is combined with standard scaling and root planing to remove
bacteria and accretions from the root surface.
 Neill and Mellonig and Moritz et al emphasized in their in
vivo clinical studies that the most significant improvement was
found in the group of patients who had conventional scaling
combined with laser treatment.
 Conventional instruments are used for standard scaling and
root planing procedures, and laser energy is used solely on the
soft tissue lining the pocket.

80.  Laser-assisted new attachment procedure (the LANAP
protocol) is a surgical therapy designed for the treatment
ofperiodontitis through regeneration rather than resection.
 This therapy and the laser used to perform it have been in use
since 1994. Developed and refined by Robert H. Gregg
II, and Delwin McCarthy, to achieve consistently effective
and predictable outcomes.
 The U.S. Food and Drug Administration cleared the LANAP
protocol for the treatment of periodontitis, or gum disease, in
2004.

81.  In LANAP surgery, a variable free-running
pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG at
1064 nm wavelength) dental laser is used by a trained and
certified dentist or periodontist to treat the periodontal pocket.
 The laser energy selectively removes diseased or infected
pocket epithelium from the underlying connective tissue.
 The necrotic epithelium is stripped from the connective tissue
at the histologic level of the rete ridges. Since the laser energy
is quite selective for diseased tissue, the
underlying pleuropotential connective tissue is spared, thereby
permitting healing and regeneration rather than formation of a
pocket seal by long junctional epithelium.

82.  In periodontics, the LANAP protocol is a process through
which cementum-mediated periodontal ligament new
attachment to the root surface in the absence of long junctional
epithelium is achieved for the treatment of moderate to
severe gingivitis and periodontitis.
 Stimulation of existing stem cells permits the formation of
new root surface coating (cementum) and new connective
tissue (periodontal ligament) formation (collagen) on tooth
roots.
 The procedure’s success has challenged the old paradigm of
periodontal healing in the absence of guided tissue
regeneration barriers (GTR) or bone grafting materials
(allografts).

83. Regenerative periodontal surgery
 The most difficult step in a typical periodontal
surgical procedure, and the step that ultimately
determines the success or failure of the surgical
procedure, is the removal of the diseased tissue from
the surgical site.
 If the diseased soft tissue and calcified accretions on
the root surface are not removed, the surgical
procedure is doomed to failure.

84.  Trylovich et al evaluated the effects of the Nd:YAG
laser on fibroblast attachment to endotoxin-treated
root surfaces. These investigators concluded that the
laser alters the cementum surface in such a way that it
makes it unfavorable for fibroblast attachment.
 Spencer et al, Thomas et al, and others also found that
when the Nd:YAG laser is used directly on the root
surface, the surface is altered unfavorably.
 Schwartz et al compared a diode laser, an
erbium:YAG (Er:YAG) laser, and scaling and root
planing. The in vivo study selected teeth scheduled
for extraction.

85.  The teeth were assigned into one of three
groups: scaling, Er:YAG treatment, or diode
treatment.
 The diode group had the highest mean number of
craters on the root surface (14.6 craters),
 The scaling and root planing group had a mean of
3 craters per sample, and
 The Er:YAG group had no craters.

86.  The diode produced craters also were significantly deeper than
the craters produced by hand instrumentation. Schwartz et al
concluded that the diode laser was unsuitable for calculus
removal because it altered the root surface in an undesirable
way.
 This study reached the same conclusions as Kreisler et al , in
his evaluation of the effects of diode laser irradiation on root
surfaces.
 These results lead to the conclusion that diode and Nd:YAG
lasers may be used for initial periodontal therapy and soft
tissue excision/ablation procedures, but extreme caution must
be taken to ensure that neither of these wavelengths has a
significant interaction with the root surface during regenerative
periodontal surgery.

87.  The conclusion regarding the use of Er:YAG laser on
root surface was that Er:YAG provided selective
subgingival calculus removal on a level equivalent to
that provided by scaling and root planing.
 In vivo, Er:YAG laser instrumentation produced
nearly smooth root surfaces, with no cracks or
thermal effects.
 The results of this study are similar to two previous
studies done by Schwartz’s et al using the Er:YAG
wavelength on root surfaces. Both studies showed
that Er:YAG lasers are excellent tools that can be
used on root surfaces safely and effectively

88.  One of the most significant studies detailing the
potential for the use of Er:YAG for periodontal
regeneration was performed by Schwartz et al. They
studied the in vivo effects of the Er:YAG laser on the
biocompatibility of periodontally diseased root
surfaces and periodontal ligament fibroblasts.
 Their results showed that the Er:YAG laser promotes
the attachment of periodontal ligament fibroblasts on
previously diseased root surfaces and that the surface
structure of Er:YAG laser instrumented roots offers
better conditions for the adherence of periodontal
fibroblasts than scaling and root planing.

89.  Ando 1996, Aoki A 1994, Folwaczny M 2000, Schwarz F
2001, have examined erbium lasers in the treatment of
periodontal disease
 The published literature has shown that erbium lasers can be
an alternative therapy for root surface debridement because the
laser can ablate calculus without producing major thermal side
effects to adjacent tissue. Other studies have shown that
nonsurgical periodontal therapy with the Er:YAG laser leads
to significant gain of clinical attachment [Watanabe H 1996,
Schwarz F, ,2003]
 These same studies looked at the instrumentation of pockets
with the Er:YAG laser and found that there was minimal
removal of tooth substance and no increase in gingival
recession.

90.  The Er:YAG laser will ablate not only calculus but also the
underlying dentin, cementum, bone, and tissue. This
wavelength is not selective for calculus. Numerous studies
have shown that the erbium family of lasers will ablate the
underlying cementum’s superficial surface. (Schwarz F,
Watanabe H, Aoki A).
 During the debridement of a diseased root surface, a certain
amount of cementum ablation is acceptable whether an erbium
laser or ultrasonic scaler is used.
 The issue is whether there is a significant increase in the
amount of cementum removed when the erbium laser is used
compared with the hand instruments or ultrasonic scalers
traditionally used by the profession.

91.  These studies, when taken together, show that the
Er:YAG laser can promote periodontal regeneration
by removing calculus from the root surface, leaving
the root surface smooth and better able to create an
environment for successful attachment of new
connective tissue fibers.
 A distinction must be made here with respect to the
erbium class of dental lasers. There is a great deal of
difference between the effectiveness

92.  American Academy of Periodontology concluded that
‘‘the Er:YAG laser demonstrated the best application
of laser use directly on hard tissue, leaving the least
thermal damage and creating a surface that suggests
biocompatibility for soft tissue attachment.
 The use of barrier membrane and epithelial exclusion
techniques is not new to regenerative periodontal
therapy.
 The question to be raised is whether there is any place
in periodontics for the use of lasers to retard epithelial
downgrowth?

93.  The answer to this question may be found in a series
of publications.
 The first article, by Rossmann et al, used monkeys to
determine the ability of the CO2 laser to prevent
epithelial migration after flap surgery.
 The results showed that epithelialization of the CO2
irradiated side was delayed by at least 7 days,
allowing for new connective tissue to grow. Just as
important, the results showed that the healing of the
connective tissue was not retarded at all.

94.  The investigators concluded that the CO2 laser can be
used to delay the apical downgrowth of epithelium and
that this technique was less technically demanding and
more time efficient than other currently known methods
of epithelial retardation.
 Israel et al used the CO2 laser in a human study. They
performed open de´bridement and placed a notch on the
teeth at the crest of the alveolar bone before closure.
 At reentry 90 days later, every nonlased tooth developed a
long junctional epithelium the length of the root to the
base of the notch. On the lased side, the notch was filled
with connective tissue and some repair cementum.

95.  Rossmann et al refined this technique with a study on beagles
that found similar results. This technique subsequently was
performed clinically by Israel M et al.
 The in vivo human results showed that this CO2 laser de-
epithelialization technique has the ability to obtain new clinical
attachment with bone fill in previously diseased sites.
 The investigators concluded that this technique has shown
significantly better results than the results obtained through
conventional osseous grafting alone.

96.  The results of the CO2 de-epithelialization studies combined
with the Er:YAG studies of the effects on root surfaces lead to
the conclusion that the most effective method of regenerative
periodontal surgical techniques would be a double-wavelength
technique.
 This technique would use the Er:YAG to de´bride the open
surgical site, clean and sterilize the root surface, and prepare
the root surface for the adhesion of fibroblasts.
 The CO2 laser would remove the epithelium, which would
allow the fibroblasts to adhere and proliferate, creating new
attachment This double-wavelength technique shows
tremendous promise in the field of regenerative periodontal
surgery

98. Lasers in surgical periodontics
 Studies on the speed of healing of laser
wounds compared with scalpel wounds are
controversial: several studies suggest faster
healing (Carruth JAS 1982, Hall RR 1971,
Howell RM 1988).
 Some suggest slower healing (Pogrel MA
1990, Pick RM 1990), and still others report
that there is no difference (Rossmann JA,
2002)

99. Argon
 In 1995, Finkbeiner coined the term laser pocket thermolysis
to describe the reduction of pathogens within the periodontal
pocket using an argon laser in conjunction with scaling and
root planing.
 There are reports that this laser is useful in guided tissue
regeneration by the de-epithelialzation of the wound margin.
 At present, the argon laser is useful in the clinical application
of soft tissue welding and soldering. The importance of tissue
welding compared with conventional tissue closure methods
lies in the fact it can be faster, less traumatic, and easier to
apply.

100. Carbon dioxide laser
 The CO2 laser is absorbed by the water
component of dental hard tissues, which could
lead to thermal damage; therefore, contact with
those tissues must be avoided. Any inadvertent
char on hard tissue may inhibit the attachment
of fibroblasts and delay wound healing

101. Nd:YAG laser
 When used in a contact mode, the Nd:YAG laser is
useful in gingivectomy and gingivoplasty procedures.
 The laser is used in a noncontact mode at extremely
low power to denature the proteins of the surface
layer of the lesions, thereby providing a biologic
bandage created with the patient’s own tissues.

102.  This process results in the immediate relief of
pain and there is evidence that the healing time
may be reduced significantly.
 Studies have confirmed the harmful effects of
the Nd:YAG laser when used directly on bone
and root surfaces. These potentially harmful
effects include thermal damage to underlying
bone when this laser is used on thin soft tissues
to perform gingivectomies (Gimble 2000)

103. Diode laser
 The laser may be used in a noncontact mode to
coagulate soft tissues or to provide hemostasis
over an area. As with the CO2 and Nd:YAG
lasers, most soft tissue procedures can be
performed with this wavelength.

104. Holmium lasers
 Holmium lasers can cut and vaporize soft tissue while
providing hemostasis.
 Reasonably good surgical precision and control can
be obtained when cutting or vaporizing with a bare
fiber in a contact or noncontact mode. As with the
CO2 laser, photothermal interactions of soft tissues
with the holmium laser do not rely on hemoglobin or
other tissue pigments for the efficient heating of
tissue (Coluzzi DJ 2000).

105. Erbium lasers
 Erbium lasers can be used to cut and ablate soft tissue
precisely. Cuts are scalpel-like and there is almost no
healing delay.
 The most useful application of these lasers in soft
tissue surgery occurs when they are used to trim
gingival tissues in preparation for caries removal
without the need for analgesia.
 Because these lasers are well absorbed by hard
tissues, the surgeon must protect adjacent tooth
structures in the operative field.

106.  The Er:YAG laser may be used not only to remove
the diseased hard and soft tissue from root surfaces
but also to clean out diseased tissue in root furcations
and infrabony pockets without harming root surfaces.
 Whereas other wavelengths studied (Nd:YAG, CO2)
may leave a char layer on the root surface that
prevents attachment of fibroblasts to the root surface,
the Er:YAG

107. Soft tissue surgery
 Gingivectomy
 Gingivoplasty
 Frenectomy
 Second stage implant surgery
 Free gingival graft

108. A preoperative view of gingival enlargement caused by a calcium channel blocker.

109. Erbium lasers

113. Role of hard tissue lasers in soft tissue ablation
 It must remembered that the primary chromophore of the
erbium family of lasers is water in the target tissue, and the
largest component of soft tissue is water.
 The erbium laser soft tissue removal process results in a
‘‘shaving’’ or ‘‘planing’’ of the tissue that clinically appears
different than the deeper penetrating ablation process seen
with dedicated soft tissue lasers.
 Venugopalan et al postulated that during the cutting of human
mucosa, the Er:YAG targets the water molecules rather than
the collagen matrix. The energy causes the water molecules to
be heated into steam, which in turn strains and fractures the
collagen matrix in the extracellular environment

114.  The collateral damage produced by the
Er:YAG laser is minimal because the energy is
absorbed in water and thermal damage is small
(no charring), which may result in improved
healing of the area.
 Neev et al discovered that there is less
collagen remodeling and, in turn, faster healing
with minimal scar tissue presenting after
erbium laser soft tissue surgeries.

115.  Diode lasers (810–980 nm), unlike the erbium family,
are very well absorbed in melanin and hemoglobin.
These wavelengths will pass through water and
penetrate much deeper into the soft tissue.
 Moreover, these wavelengths achieve hemostasis
much better than the erbium lasers, which are not
well absorbed by these chromophores. The erbium
family, therefore, is not the ideal wavelength for soft
tissue surgeries in which ideal hemostasis is desired.
 The degree of difficulty with hemostasis seems to be
greatest in cases where the soft tissue initially is
inflamed.

116.  Although the erbium laser can be used for
gingivectomies, gingivoplasties, frenectomies,
vestibuloplasties, excisional procedures, crown
lengthenings, incisions and drainages, implant
exposures during second-stage surgery, apthous ulcer
palliative treatments, and the removal of melanin
pigmentation, the clinician must show care to assure
that no iatrogenic damage occurs in adjacent tissues
such as bone, cementum, or dentin due to using the
erbium laser for soft tissue procedures (Stabholz
2003)

117. Osseous resection
 Many full-thickness mucoperiosteal flap procedures include
osseous resection. The only wavelengths cleared by the FDA
for osseous surgery are the erbium family of lasers. Er:YAG
and Er:Cr:YSGG are the only wavelengths that have the ability
to ablate osseous tissue safely.
 For the present, the Er:Cr:YSGG and Er:YAG lasers are
clinically acceptable for use on dental hard tissue.

118.  Liu et al,1999 compared Nd:YAG laser treatment with scaling
and root planing alone in 1999 in a randomized controlled
clinical study. The study assayed for interleukin (IL)-1β, a
known potent stimulator of bone resorption found in crevicular
fluid and responsible for loss of periodontal structures in the
disease process of periodontal disease. The group with the
laser combined with scaling and root planing showed
maximum improvement over time in the reduction of IL-1β.
 Raffetto and Gutierrez showed similar results using an
Nd:YAG laser.
Lasers and proinflammatory cytokines

119. SDF-1α
 Stromal Derived factor (SDF) 1-α levels were
estimated in GCF before and after laser
treatment
 Laser group showed a enhanced reduction of
SDF-1α levels than SRP alone

120. Lasers in implantology
 Nd:YAG has been a particularly popular wavelength
to use for soft tissue second-stage surgery, several
investigators contend that it is contraindicated.
Walsh, Block et al, and Chu et al studied the effects
of this wavelength on implants.
 The specific issues that were studied were the
transmission of heat to the bone from the heated
implant surface, effects of this wavelength on the
metal surface, the potential for pitting and melting,
and the porosity of the implant surface.

121.  Another investigated periodontal use of the
erbium family of lasers is around implants and
for the treatment of peri-implantitis. Walsh and
Schlenk et al examined the role of erbium
lasers in implantology in the early 1990s.
 Kreisler et al discovered that low settings of
both Er:YAG and CO2 lasers could be used
around implants without damage to the
implants; however, diode instruments were
preferred for this procedure in their study.

122.  Schwarz et al in two separate studies, examined the
effects of the Er:YAG laser on the surface structure
of titanium implants. They discovered that using the
erbium lasers on implants resulted in no thermal
damage, did not damage the titanium surfaces, and
did not inhibit or influence the attachment of human
osteoblastlike cells to the implants.

123.  CO2 laser energy, on the other hand, is reflected
away from metal surfaces.
 The failure of implants to absorb the energy of the
CO2 laser is a major advantage of this wavelength.
 Use of the CO2 wavelength minimizes the risk of
temperature-induced tissue damage as a result of
lasing the implant surface.

124.  An article by Mouhyi et al demonstrated that a CO2
laser on a wet implant surface in pulsed mode at
8W(10 milliseconds pulse duration, 20 Hz for 5
seconds) induced a temperature increase of less than
30C, well within the 100C safety margin from 370 C
to 470C. It also should be noted that the hemostatic
properties of CO2 are excellent, which is a
tremendous advantage for its use on soft tissue.

125.  Mouhyi et al found that a combination of citric acid, hydrogen
peroxide, and CO2 laser irradiation seems to be effective for
cleaning and reestablishing the oxide structure of contaminated
titanium surfaces. The highly biocompatible titanium oxide
surface is corrosion resistant, which contributes significantly
to the strength of the bone–implant interface during
osseointegration.
 A study on dogs performed by Deppe et al concluded that peri-
implant defects can be treated successfully by CO2 laser
decontamination without damaging the surrounding tissues.
 Romanos was able to treat successfully 18 ailing implants in
14 patients using mechanical debridement followed by implant
surface decontamination with the CO2 laser and subsequent
grafting of the bony defects with a resorbable barrier.

126.  CO2 lasers have been successful in decontaminating
implant surfaces.
 Kato et al found that this wavelength did not cause
surface alteration, rise of temperature, or serious
damage of connective tissue cells located outside the
irradiation spot or cause inhibition of cell adhesion to
the irradiated area.
 They concluded that irradiation with an expanded
beam may be useful in removing bacterial
contaminants from implant surfaces.

127.  All types of lasers can be used to excise or vaporize
periodontal tissue as needed to expose dental
implants.
 One advantage of the use of lasers in implantology is
that impressions can be taken immediately after
second stage surgery because there is little blood
contamination in the field due to the hemostatic effect
of the lasers.
 There is the potential for obliteration of the attached
gingiva if this technology is overused. It is important
to maintain and preserve attached gingiva around
implants whenever possible.

128.  There also is minimal tissue shrinkage after
laser surgery, which assures that the tissue
margins will remain at the same level after
healing as they are immediately after the
surgery.
 In addition, the use of the laser can eliminate
the trauma to the tissue of flap reflection and
suture placement (assuming adequate zones of
keratinized tissue and the knowledge of where
the implant has been placed).

129.  What are the potential benefits of using lasers
to repair ailing implants?

130.  One of the most interesting uses of lasers in implant
dentistry is the possibility of salvaging ailing implants
by decontaminating their surfaces with laser energy.
A number of clinical studies have been done to
examine how, when, and whether lasers can be used
successfully to help these situations.
 Diode lasers were used in a study by Bach who found
a significant improvement in the 5-year survival rate
when integrating laser decontamination into the
approved treatment protocol.

131.  Dortbudak et al found that the use of low-level laser
therapy with a diode soft laser (690 nm) for 60
seconds after the placement of toluidine blue O for 1
minute on the contaminated surface reduced the
counts of bacteria by a minimum of 92%.
 This reduction was a significant improvement, but
complete elimination of bacteria was not achieved
with this wavelength. The same group was able to
obtain complete bacterial elimination in a study using
the 905-nm diode (also a soft tissue laser) with
toluidine blue O on all types of implant surfaces (ie,
machined, plasma-flame–sprayed, etched, and
hydroxyappatite coated).

132.  Shibli et al found a positive correlation in the
use of a diode laser and toluidine blue O on
experimentally produced peri-implantitis in
dogs before guided tissue regeneration
procedures.
 Their data on several implant surfaces suggest
that lethal photosensitization, through the use
of toluidine blue O to sensitize the cell
membranes to laser light, may have potential
in the treatment of peri-implantitis.

133. Low-level laser therapy in periodontics
 Therapeutic laser treatment, also referred to as
low-level laser therapy (LLLT), offers
numerous benefits.
 Along with the primary benefit of being
nonsurgical, it promotes tissue healing and
reduces edema, inflammation, and pain.

134.  The most recognized theory to explain the effects and
mechanisms of therapeutic lasers is the
photochemical theory. According to this theory, the
light is absorbed by certain molecules, followed by a
cascade of biologic events Enwemeka CS 1999.
 Suggested photoreceptors are the endogenous
porphyrins and molecules in the respiratory chain,
such as cytochrome c-oxidase, leading to increased
ATP production [26]. Karu T 2003
The mechanism

135.  The most popularly described treatment benefit of
LLLT is wound healing. From the studies of Mester
et al, the electron microscope examination showed
evidence of accumulated collagen fibrils and
electrondense vesicles intracytoplasmatically within
the laser-stimulated fibroblasts as compared with
untreated areas.
 Increased microcirculation can be observed with the
increased redness around the wound area; during the
initial treatment stage, the patient can feel the
transient pin-prickling sensation, which is thought to
be evidence of the accelerated wound healing.

136.  The polarization of noncoherent light disappears
shortly after entering tissue. The coherent character of
the laser light is not lost after penetrating the tissue
but is split into small coherent and polarized islands
called speckles. The speckle pattern is maintained
through the irradiated volume of tissue. Steinlechner
C, 1993

137.  Last, the effect of the laser is localized at the
treatment site but can have a more generalized
systemic effect. Infrared lasers have greater
penetration than lasers in the visible range and
are therefore able to affect deeper-lying
conditions (Longo L, 1991)

138.  Postoperative therapy and care
 Temporomandibular disorders.
 Hypersensitive dentin.
 Postextraction and bone-healing therapy
 Orthodontics
 Herpes labialis
 Aphthous ulcers
 Mucositis
Clinical applications

139.  Paresthesia
 Trigeminal neuralgia
 Nausea
 Periodontitis
 Nonbiostimulative effects

140. Hypersensitive dentin
 Hypersensitive dentin. Although many desensitizing
agents treat this condition, more difficult cases can be
treated by the laser. A review of the literature has
been published by Kimura .
 A hypersensitive tooth that does not respond to 4 to 6
J per root in two or three sessions is indicated for
endodontic treatment. The occlusal scheme should be
evaluated as part of the treatment protocol.

141. Periodontitis
 The use of LLLT helps to control the symptoms and
condition of periodontitis. The anti-inflammatory effect
slows or stops the deterioration of periodontal tissues and
reduces the swelling to facilitate the hygiene in
conjunction with other scaling, root planning, curettage,
or surgical treatment. As a result, there is an accelerated
healing and less post-op discomfort.
 Studies report stimulation of human periodontal
fibroblasts, reduced gingivitis index, pocket depth, plaque
index, gingival fluid, and metalloproteinase-8 levels
(Qadri T,Miranda L, Tune´ r J, Gustafsson A,
unpublished data, 2004), and there are positive results
after gingivectomies

142. Conclusion

143. The person who sees science in everything
and everything in science will not be lost
by each other