Lasers in dentistry. sameera

PRESENTED BY:
DR.VENU SAMEERA PANTHAGADA
MDS POSTGRADUATE IN ORAL AND
MAXILLOFACIAL SURGERY

 Lasers are widely used in dentistry for various clinical procedures
like cavity preparation, surgical procedures, scaling and root
planning etc. Since its first use in 1960, lasers are now evolved to
be used in all aspects of dentistry.
 Lasers are effective in ablation of various potentially malignant
disorders, obtaining biopsy, periodontal plastic surgeries and
providing incisions in surgical conditions.
 Technological advances have led to increased use of lasers in
surgery and the laser has become a useful tool in the surgeon’s
armamentarium.

 THEODORE H.MAIMAN built the first laser (synthetic red ruby) at
HUGHES AIRCRAFT RESEARCH LABORATORY.
 One year later MILTON ZARET of NEWYORK UNIVERSITY
SCHOOL OF MEDICINE used a laser to produce ocular lesion in
animals.
 Laser is an acronym for light amplification by the stimulated
emission of radiation.
 Every laser has a laser medium such as ruby ,argon, carbon
dioxide each laser has a source of energy to excite atoms.
 Source can be electrical, chemical, or another light source.

 Photon is the basic of light.
 A laser emits photons of only one wavelength (monochromatic) and
are emitted in parallel (collimation).
 As photons are produced ,they continue to travel with in the laser
chamber, exciting more atoms.
 The intensity of energy increases with in the laser chamber as this
chain reaction continues. This is called amplification.
 The ability to direct the monochromatic, collimated photons is
called coherence.
 The light is delivered from the laser chamber to the tissue in variety
ways.
fibre optic cable
articulated arm system
hollow wave guide

 lasers must be delivered to the tissue by a contact or noncontact
mechanism .
 Most lasers have a handpiece with a lens attchment.
 In noncontact laser systems, lens allows the beam of light to be
focused.
 Some noncontact or free beam laser systems have angled mirrors
to direct the beam either at 90 or 120 degrees.

 Contact laser systems offer the advantage of tactile sense during
operating.
 Some Nd:YAG lasers have interchangeble sapphire or ceramic tip.
 Tip is heated when laser is activated enabling tissue to be cut and
coagulated with a precise light powered scalpel

 When laser light is directed at tissue,compounds with in the tissue
called CHROMOPHORES absorb the wavelength of light.
 Generally four reactions can happen when laser light interacts with
tissue.
1.REFLECTION off the tissue
2.SCATTERING to surrounding tissue
3.TRANSMISSION through the tissue
4.ABSORPTION by tissue chromophores

The balance of these reactions is determined by wavelength of light
and type of tissue.
Amount of absorption determines the amount of selective tissue
destruction.
Amount of scatter determines the amount of peripheral tissue
damage.

 There are five important types of biological effects that can occur
once the laser photons enter the tissue: fluorescence,
photothermal, photodisruptive, photochemical, and
photobiomodulation.
 Fluorescence happens when actively carious tooth structure is
exposed to the 655nm visible wavelength of the Diagnodent
diagnostic device.
 The amount of fluorescence is related to the size of the lesion, and
this information is useful in diagnosing and managing early carious
lesions.

 Photothermal effects occur when the chromophores absorb the
laser energy and heat is generated.
 This heat is used to perform work such as incising tissue or
coagulating blood.
 Photothermal interactions predominate when most soft tissue
procedures are performed with dental lasers.
Photothermal ablation is also at work when CO2 lasers are used on
teeth as hard tissue is vaporized during removal.
Heat is generated during these procedures and great care must be
taken to avoid thermal damage to the tissues.

 Photodisruptive effects (or photoacoustic) can be a bit more
difficult to understand.
 Hard tissues are removed through a process known as
photodisruptive ablation.
 Short-pulsed bursts of laser light with extremely high power
interact with water in the tissue and from the handpiece causing
rapid thermal expansion of the water molecules.
 This causes a thermo-mechanical acoustic shock wave that is
capable of disrupting enamel and bony matrices quite efficiently.

 Erbium lasers’ high ablation efficiency results from these micro-
explosions of superheated tissue water in which their laser energy
is predominantly absorbed.
 Thus tooth and bone are not vaporized but pulverized instead
through the photomechanical ablation process. This shock wave
creates the distinct popping sound heard during erbium laser use.

 Thermal damage is very unlikely as almost no residual heat is
created when used properly, particularly when the concept of
thermal relaxation is considered.
 Photochemical reactions occur when photon energy causes a
chemical reaction. These reactions are implicated in some of the
beneficial effects found in biostimulation

 Photobiomodulation or Biostimulation refers to lasers ability to
speed healing, increase circulation, reduce edema, and minimize
pain.
 Many studies have exhibited effects such as increased collagen
synthesis, fibroblast proliferation, increased osteogenesis,
enhanced leukocyte phagocytosis, and the like with various
wavelengths.
 The exact mechanism of these effects is not clear but it is
theorized they occur mostly through photochemical and
photobiological interactions within the cellular matrix and
mitochondria.
 Biostimulation is used dentally to reduce postoperative discomfort
and to treat maladies such as recurrent herpes and aphthous
stomatitis. Low Level Laser Therapy (LLLT) is another term used to
describe this phenomenon.

 37-60*F = tissue retraction, protein conformational changes
 >60*F = proteins denature and coagulation
 90-100*F =carbonization and char formation
 >100*F =ablation of tissue

STAGES IN LASER PRODUCTION
1 Optical pumping or state of excitation
electric discharge
chemical reaction
xenon or krypton flash lamp
2 Population inversion
3 Stimulated emission
4 Cascade process----collimated beam
5 Amplification –light is coherently amplified after reflection from
mirrors
19

 This is the process in which energy is driven into resonant
chamber or cavity from an external or internal source that is
specific for a laser system .
 For example electric discharge ,chemical reaction or an external
high powered radiant source ,such as xenon or krypton flash lamp.
 This energy is used to change the energy level or quantum state of
lasant species .
20

 OPTICAL PUMPING & POPULATION INVERSION
21

This is the phenomenon when there is a transition of electrons in
whole active medium from low energy to high energy levels after
the absorbtion from external source or optical imaging .
STIMULATED EMISSION
22
After the population inversion of the laser ,there is stimulated emission.
The atoms existing in higher energy state, gradually drop to a lower
energy level and emit photons in the process.

 After stimulated emission ,photons move longitudinally along the
long axis of the laser chamber and stimulate other proximal excited
atoms to emit additional identical photons that will travel with the
same directionality as the stimulated photons with the laser
chamber .
 The cascade of light that is parallel with the long axis of the laser
cavity from a collimated beam of intense radiant energy .
23

 Amplification or oscillation is what is critical in the process
called optical feedback.
 This optical feedback is produced by causing the photons to
bounce between mirrors placed on either side of the optical
cavity.
 As light continues to reflect back and forth making round trips
with in the laser cavity ,the light is coherently amplified by
this process.
25

 Developed by PATEL in 1964
 Wavelength of 10600 nm
 Medium: mixture of co2 ,nitrogen and helium.
 Uses an articulated arm to deliver the beam
 Uses: for excision and ablation of superficial lesions
 for skin resurfacing
 co2 laser is the most commonly used laser in oral cavity reason
being 1.the
chromophore that absorbs the co2 wavelength is water 2.shallow
depth of penetration 0.2mm
 3.little scatter ,reflection, transmission

 Developed by BRIDGES in 1964 at HUGHES AIRCRAFT
RESEARCH LABORATORIES
 Delivers green blue light beam with wavelength of 488-514nm
 Deliveerd with fibre optic cable and hand piece
 Argon beam is highly absorbed by hemoglobin, and is an excellent
hemostatic laser.
 Used to excise gingival soft tissue lesions.
 In the treatment of vascular hemangiomas.

 Developed by GUESIC in 1964
 Wavelength of 1064 nm
 Neodymium yattrium aluminium garnet
 Delivered by fibre optic cable
 Used with specially designed sapphire or ceramic tips and used as
contact laser scalpel or ablation tool, with excellent hemostasis and
cutting abilities.
 Uses: treatment of vascular lesions
 intraoral and extraoral pimented lesions
 open TMJ arthroplasty
 malignant lesion excision

 Modified version of Nd:YAG laser
 Wavelength : 532nm
 Its absorption is similar to that of the argon laser
 Used in treatment of vascular and pigmented lesions, tattoo
removal, blepharoplasty,some endoscopic procedures.

 Holmium yttrium aluminum garnet
 Emits wavelength of 2140 nm.
 An aiming beam with fibre optic cable is used for delivery
 Used in both contct and noncontact mode.
 Well absorbed by synovium and joint surface.
 Extensively used in endoscopic orthopedic surgery
 Used in TMJ for lysis of adhesions and sculpting of
fibrocartilaginous disk tissue.

 Erbium : YAG laser for facial resurfacing and incision and ablation
of soft tissues.
 Wavelength :2940 nm
 Advantage is its ability to remove superficial skin layers even more
precisely than co2 laser.
 It allows reorganization of collagen with less total energy.

 Safety in the surgical theatre is of greater importance when lasers
are used.
 NOMINAL HAZARD ZONE is defined as surgical area in which the
laser is used and could potentially cause injury or damage , usually
related to eye exposure.
 NHZ is determined by wavelength of light, maximum power, type of
delivery system, diameter if the beam.
 Greater the calculated NHZ zone, greater the probability that injury
can occur.

 Laser protective eyewear must be worn by all people in the NHZ.
 Patients should also be provided with scleral shields, when laser is
being used on the face.
 Scleral shields are used when blepharoplasties and facial
resurfacing techniques are used.
 Special surgical laser masks with protective filters are worn to
prevent inhalation of infectious or toxic plume smoke.

 Evacuation systems with high speed suction are used to remove
plume from the field.
 Exposure to skin can be limited by use of noninflammable gowns
that offer maximal body coverage.
 When preparing the patient for surgery, no alcohol based
preparation solutions should be used in order to prevent ignition
and severe burns.

 Wet towels are used to drape the patient, and they should be
moistened throughout the procedure to prevent ignition of drapes.
 An open basin of sterile water with an irrigating syringe should be
available in case fire developes.
 Most inhalational anesthetics are not flammable ,but gases like
oxygen support combustion. Therfore oxygen concentration should
generally be less than 40%.
 PVC endotracheal tubes are highly flammable and not
recommended for use during laser surgery.

 With scalpel there is 200% decrease in elasticity compared with
normal mucous membrane. While with lasers there is only 50%
decrease in elasticity.
 The extraordinary rapid cell vaporization, with loss of intracellular
chemical mediators (cytokines) is posited to result in a markedly
less intense local inflammatory response and consequently, less
local pain, edema and cicatrix formation.
36

 Photocoagulation technique
 Incisional and excisional technique
 Ablation or vaporization technique
 Contact laser technique

 C02 LASER can be used to coagulate or photoablate vessels
smaller than 500 um in diameter.
 Laser is used in defocused mode to a spot size of approx 2mm with
a power density lessthan 5W.
 CO2 LASER is absorbed readily by water, the area must be
relatively dry for effective coagulation of the vessels.

 Increasing the exposure time heats the tissue to critical
temperature needed for hemostasis.
 As hemoglobin is a major chromophore, blood components are
directly lased, surrounding vessel is damaged by collateral heat
after being coagulated.
 Crisscross or circumferential pattern can be used in a defocused
mode.

Carbon dioxide laser is a superb light scalpel.
Near bloodless field allows for excellent visualization of the
specimen during surgical removal.
Point to be considered during biopsy is LATERAL ZONE OF
THERMAL NECROSIS.
Zone of necrosis is generally less than 500um when using the
carbondioxide or contact ND:YAG Laser.

First ,topical, local, general anesthesia is administered as the
procedure indicates.
Area should be dried to increase the accuracy of absorption of
energy.
To outline the specimen, choose single or slow repeating pulse
mode and mark the area of incision.

A row of dots can be used to outline the specimen with desired margin.
Power density is adjusted and incision made to the desired depth.
Gentle tension on the specimen with a forceps is used to deliver the
lesion as it is surgically removed.
Advancing the handpiece in to the incision keeps the spot size and
distace constant.
Hemostasis is achieved.
Lesions can be left open.
Specimen should be handled in usual manner and the pathologist
informed the use of laser.

 One of the greatest advantages of laser is its ability to ablate or
vaporize lesions layer by layer.
 It is useful in removing discrete benign lesions, useful in eradicating
multiple , diffuse lesions of the oral cavity.
 An anesthetic plan is implemented as type of procedure indicated.
 5 to 10 w of power on the carbon dioxide laser is adequate for
efficient and controlled ablation of a lesion layer by layer.
 Lesion is outlined .
 Crisscrossing patterns of horizontal, vertical, and oblique lines can
be used when clearing the wound of char between passes.

 Contact laser has several advantages over traditional beam.
 ND:YAG & HO:YAG LASERS are commonly used contact lasers.
 The specially designed tips of contact lasers allow for transmission
of laser energy to the tissue directly from the tip surface.
 Effect of laser is concentrated to just around the tip surface.
 There is less tissue penetration and less collateral tissue damage.
 Helpful in the lysis of adhesions with in TMJ.
 Benefit of contact laser surgery is WAVELENGTH CONVERSION
EFFECT.

 Laser tissue interaction actually involves many cellular and
subcellular events.
 There is vaporization of intra cellular fluid that helps disintegrate
cell structure almost instantaneously, and the subcellular structures
often vaporized.
 This likely occurs without normal cascade of cytokines seen in
acute inflammation.

 Slower healing due to delayed epithelial migration and decreased
scar formation.
 Nerve endings are histologically sealed which claims of decreased
post op pain.
 Finding of fewer myofibroblasts at wound edges after laser surgery
has been postulated as the reason for lessened scarring.

 INCISIONAL AND EXCISIONAL PROCEDURES
 Gingivectomy , Operculectomy, Frenectomy, Tuberosity reductions
 Co2 laser is well suited for removal of gingival tissue.
 Gingivectomy procedure involves the use of laser beam focused
using smallest spot size.
 Specimen is excised and hemostasis is obtained using
photocoagulation technique.

 Palliation of pericoronitis by excising operculam can be done.
 Frenectomy can be accomplished by grasping the tissue with a
hemostat at its supero inferior attachment .
 Tissue is then excised by directing the laser along the hemostat.

 EPULIS FISSURATUM AND PYOGENIC GRANULOMA AND
GRANULATION TISSUE EXCISION:
 Excision of epulis fissuratum may be performed rapidly without the
loss of vestibuar depth by using carbondioxide laser.
 Traction is applied to the lesion using forceps and it is excised
along its base.
 Granulomatous soft tissue masses are vascular lesions are excised
using co2 laser.

 MUCOCELE AND MUCOUS RETENTION CYST:
 Here minor salivary glands should be bluntly dissected with
scissors and a hemostat and then excised with laser.
 Photocoagulation can be used to obtain hemostasis.
 This minimizes the chance of recuurence of mucocele

 IMPLANT OR TOOTH EXPOSURE:
 Role of lasers in perisurgical implant care has expanded.
 Nd:YAG LASER was shown to have adverse thermal effect on
fixture which then destroyed the surface layer of plasma titanium.
 Lasers are relatively contraindicated for use with hydroxyapatite
coated implants as both ND:YAG AND CO2 lasers remove the
outer coating and expose the metal core.
 RANULA AND SIALOLITH REMOVAL:
 They can be easily marsupialised with the co2 laser and sialoliths
can be easily located and removed with co2 laser.

 VESTUBULOPLASTY:
 CO2 Laser is useful in performing a submucosal and secondary
epithilialization vestibbuloplasty.
 Only the initial incsion for vestibuloplasty with split thickness graft
should be made with laser.
 Deeper extent of incision should not be mad with laser because
laser inhibits epithelial migration.
.

 LASER ASSISTED ASSISTED UVULOPLASTY:
 Done for surgical treatment of chronic snoring, upper airway
resistance syndrome, obstructive sleep apnoea.
 Uvulopalatopharyngoplasty for the treatment of snoring was
intoduced by Ikematsu in 1964.
 Later LAUPP is developed by KAMAMI
 Procedure is described in one stage & multi stage technique

 To perform the procedure , patient is placed in a comfortable ,
upright position.
 Topical anesthetic spray is applied to the nostrils and posterior
oropharynx, including the palate.
 1.5 ml of 2% lidocaine with 1:100000 epinephrine is injected in to
uvula at its base and the junctions of the soft palate.

 In multistage technique, inferior half of the uvula is ablated or
excised.
 Verticle incisions of 10mm are given just lateral to the uvula through
the soft palate.
 In one stage procedure , lateral vertical cuts are initially made in
longer fashions.
 Vertical incisions terminate just prior to the insertion of levator
palatini muscle. Then the uvula is reduced to a normal presurgical
length.

 MAXILLO FACIAL COSMETIC AND DERMATOLOGIC LASER
SURGICAL PROCEDURES:
 Cosmetic laser surgery has recently recieved much attention in the
literature and media.
 Laser makes facial resurfacing more accurate and predictable than
dermaabrasion and chemical peel.

 FACIAL RESURFACING:
 CO2 and ER:YAG Lasers offer excellent results with a more
accurate and reproducing technique.
 Selective photothermolysis is possible with the laser delivery
systems there by decreasing collateral tissue damage.
 Ablation is accurately and repeatedly taken to level of the
midreticular dermis.
 As the tissue heals, new elastic fibres reorganize and realignment
of collagen fibres occur in more parallel fashion

 Laser technique works well for fine wrinkles at areas like perioral
and periorbital areas.
 Deeper wrinkles associated with more muscular actions like
forehead lines respond less favourably.
 Visible contraction of skin is evident as treatment continues.
 Patients with history of radiation therapy in expected treatment
area, and prior use of isotretinoin should usually be excluded from
laser therapy because their healing is completely different.
 Make up can be worn after epithelialization is complete,usually
about 12 to 14 days.
 Complications include scarring, hyopigmentation, erythema ,
induartion , herpes simplex activation, and infection.

 BLEPHAROPLASTY:
 Technique for blepharoplasty can be aided by using a
carbondioxide, KTP, or Nd:YAG laser for the dissection to help
create a blood less field.
 If blepharoplasty alone is planned , IV sedation with LA
INFILTARTION AND topical opthalmic anesthetics are sufficient.
 Corneal shields are placed .

 Initial incision can be made with scalpel and further dissection can
be advanced with laser .
 The fat pads are then removed with co2 laser using a wet cotton tip
applicator.
 Incisions are then closed in standard fashion.
 Instructions to keep the head elavated and to use cold compresses
are important.

 SKIN PIGMENTED LESION REMOVAL:
 Laser treatment ,resurfacing , or ablation can lighten or completely
remove these lesions.
 Melanosomes are the target cells and they absorb variety of
wavelength.
 Lesions that extent in to the dermis require deeper penetration by
the laser and are best treated by longer wavelengths.

 The pulsed tunable dye laser at 510 nm is commonly used to treat
superficial pigmentation such as cafe au lait macules .
 Noncontact ND:YAG laser at 1064nm are used to treat deeper
lesions.
 The area should be evalauted 6 weeks after treatment for signs of
lightening or hyperpigmentation.
 Hyperpigmentation can be resolved by topical applcation of
hydroquinone , glycolic acid.

 Alster and other groups used the pulsed dye laser at 585 nm to
treat various types of scarring, with significant clinical improvement.
 Topical or local anesthetic is usually adequate for patient
comfort,but care must be taken not to inject LA directly in to tissues
as this may change the absorption of laser energy.
 Entire scar is treated and the patiet is instructed to keep the area
clean and bandaged lightly.
 Perioperative acyclovir may be prescribed if the scar is in a region
of previous herpes simplex activation.

 Unger has published extensively on hair transplantation using
micrografts and the added benefits of using ultrapulse co2 laser as
an adjunct.
 Hair transplantation with excised grafts leaves rows of hair that are
easily visible and a hairline that is unnatural.
 The advent of micrografting helped decrease the unsighty
appearance of rows of plugged hair .
 Smaller slits are made to place the microcut hair grafts in place.
 The co2 laser is used to make the recipient sites slighter wider ,
creating even more natural hairline.

 Laser assisted hair removal is currently being evaluated .
 Alexandrite , Nd:YAG and ruby lasers have been selected for their
specificity for the red and near infrared sensitive dermal tissues .
 Carbon based solution applied to the hair bearing area to engulf the
hair papilla , making it susceptible to the heat effects of the laser.
 The heat then destroys the follicle and causes a reduction in hair
producing elements in that area.

 Difficulty of treating some TMJ disorders has been evident since
ANNADALES first surgical attempts in 1887.
 Mccain’s contributions to arthroscopy have advanced the field
significantly.
 Hendler and Koslin described as sculpting fibrocartialginous and
retrodiscal tissue safely and easily with Hol:YAG laser.
 TRAUNER showed that the Hol:YAG laser was less damaging to the
surrounding tissues when sculpting fibrocartilage.
 Hol:YAG laser works well in a saline environment and can be used
with a fibre optic quartz fibre.
 This allows for easy manipulation with in the joint using standard
traiangulation techniques described by McCain.

 In endoscopic brow lift surgery , small incisions are made in the
scalp area to dissect with in a subgaleal or subperiosteal plan or
both to alter the muscular action of the procerus and corrugator
musculature as well as reposition of the brow tissue.
 ENDOSCOPIC LASER LITHOTRIPSY OF SALIVARY GLAND
STONES:
 the endoscope is advanced with in a salivary gland duct to view the
stone , and the laser fibre is advanced to ablate the stone .
 This technique may restore the salivary flow with the advantage of
minimally invasive surgery.

 Photodynamic therapy is currently being evaluated for the
treatment of head and neck ,skin, intraabdominal cancers.
 Lasers have also been used in the microanastomosis of nerve and
vascular tissue with some success.
Summary
 Surgical laser is a powerful tool that adds great dimension to the
oral and maxillofacial surgeon’s practice but one must command
the knowledge and temperament to use it for the proper indications

References:
 Textbook of oral and maxillofacial surgery. RAYMOND
J.FONSECA VOL 1
 Textbook of oral and maxillofacial surgery: NEELIMA
MALIK

Lasers in dentistry. sameera

Recomendados

Recomendados

Más contenido relacionado

La actualidad más candente

La actualidad más candente (20)

Similar a Lasers in dentistry. sameera

Similar a Lasers in dentistry. sameera (20)

Último

Último (20)

Lasers in dentistry. sameera