lasers and its role in endodontics / orthodontic courses by indian dental academy

INDIAN DENTAL ACADEMY

Leader in continuing dental education www.indiandentalacademy.com

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FLOW CHART- INTRODUCTION- HISTORY- EXPLANATION OF TERM – LASER- BASIC COMPONENT OF LASER- CLASSIFICATION OF LASER- LASER DELIVERY SYSTEM & EMISSION MODE- LASER EFFECT ON TISSUE- MEDICAL USES OF LASER- DENTAL USES OF LASER- ROLE OF LASER IN ENDODONTICS- LASER HAZARDS & CONTROL MEASURES


INTRODUCTION• Most patients still associate the sound and vibration of

the drill with pain. However, with the new advancements in this field, several options have become available to progressive dentists to allay fears and offer patients state of the art treatment. One such advancement is the advent of the laser technology presenting new vistas for dentists in fields of dentistry .

• The unique characteristics of the laser are that it is monochromatic, coherent and collimated. This allows concentration of tremendous amount of energy to a small area.


HISTORYThe dental lasers of today have benefited from decades of laser research and have their basis in certain theories from the field of quantum mechanics formulated by Danish physicist Bhor.(1900)

Einstein’s atomic theories on controlled radiation (1917) can be credited as the foundation for laser technology.

40 years later, American Physicist, Townes first amplified microwave frequencies by the stimulated emission process and the acronym MASER. (Microwave amplification by stimulated emission of radiation).

In 1958 they discussed extending the maser principle to the optical portion of the electromagnetic field hence. LASER (Light amplification by the stimulated emission of radiation).

Albert Einstein


L – Light


LASER LIGHT IS MONOCHROMATICREGULAR LIGHT IS POLYCHROMATICwww.indiandentalacademy.com

COLLIMATION:

BEAM HAVING SPECIFIC SPATIAL BOUNDARIES

Constant beam size

Constant shape.


COHERENCY


A- Amplification means that a very bright 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.


S – Stimulated : Means that the photons are amplified by stimulating an atom to releases more photons.

E-Emission refers to the giving off photons. The exited atom emits a photon by absorbing energy.


The term stimulated emission of radiation is based on the quantum theory of physics first postulated by Bohr


R-Radiation mean giving or omitting photons.


THE BASIC COMPONENTS OF

LASER


The wave energy of laser ranges between gamma rays to radio waves.

All the available dental laser devices have emission wave lengths of approximately 0.5µ or 500 nm to 10.6µ in 10,600 nm.


All dental lasers emit either a visible light beam or an invisible infra red light beam in the portions of non-ionizing spectrum called thermal radiation.


CLASSSIFICATION OF LASERS


GAS LASERS Eg: CO2 laser Argon laser


Solid state lasers

Eg: Nd:YAG Laser Ho:YAG Laser Er:YAG Laser DIODE Laser


LASER DELIVERY SYSTEMS AND EMISSION MODES

Delivery systems

Flexible hollow wave guide or tube that has an interior mirror finish.

The laser energy as reflected along this tube and exits through a hand piece at the surgical end, with the beam striking the tissue in a non contact fashion.


The second delivery system is a glass fiberoptic cable.

• It comes in various diameters and sizes ranging from 200-1000µm

• The glass fiber is encased in a resilient sheath, it can be somewhat fragile and cannot be bent into a sharp angle.

• It can be used in a contact or a non contact mode.


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:- large peak energy of laser light are emitted for short time(microsecond) followed by long time when laser is off.


Laser effects on tissue

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.

Reflection : laser beam become more divergent

as distance from handpiece increases.

Can be dangerous


AbsorptionThis 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.

Short wave lengths, from about 500-1000nm are absorbed readily in pigmented tissue.

Argon has high affinity for melanin and hemoglobin. .

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 di-oxide.


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.

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.


Besides photothermal effects there are other effects that lasers have on selected tissue.

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 photodyanamic therapy.


IN 1961 Goldman established the first laser medical laboratory at the university Of Cincinati, he is recognized as the first physician to use laser technology.

L’Esparance was the first to report clinical use of an argon laser in1968 in opthalmology .

In 1972 Strong and Jako reported the first clinical use of Co2 laser in otolaryngyology.

Keifhaber etal documented the first clinical use of Nd:YAG laser in1977 in Gastroenterology.

History


Cardiovascular surgery Dermatology and plastic surgery Gastroenterology General and oncologic surgery Gynecology Neurosurgery Ophthalmology Orthopedic surgery Ornitholaryngology Podiatry Pulmonary medicine Thoracic surgery Urology Vascular surgery


History

In 1960, first working laser , PULSED RUBY LASER , built by Maiman of huges research lab.

During the 1970’s and 1980’s intraoral use of Co2 laser was confined primarily to Specialists such as oral surgeons and some periodontists.

In 1990 Myer and Myer’s developed a pulsed Nd:YAG laser which was recognized as the first laser specifically fo general dentistry called the deLase 300


Intra oral soft tissue application• Ablating, incising, excising, and coagulating Co2, Nd:YAG, Ho:YAG

• Co2 laser has been favorite instrument for oral surgeons b’cos of its wave lengths ready absorption into water (soft tissue).

• Nd:YAG is also used because of its excellent coagulation ability, flexible fibroptic delivery system, ease of use and precision.


LASER – ASSISTED UVULOPLASTY Is a clinical application for the treatment of obstructive sleep apnea and snoring.

Kamami is credited as originator of tech.

CO2 laser is used for this purpose.


Treatment of pathologic conditions

Tuffin and Carruth were the first report on use of Co2 laser in pathologic lesions.

Co2 It is predominantly used.

Nd:YAG laser was also used to treat similar conditions.

Photodynamic therapy


Other conditions

Drug induced hyperplasia Orthodontically induced hyperplasia Apthous ulcers Lichen planus Sialoliths Epulis Mucoceles Ranula Granuloma Haemangioma Papillomatosis Lymphangioma ANUG.


Hard tissue applications

Caries removal, inhibition and detection Cavity preparation Surface modification Calculus removal Bone ablation and cartilage reshaping Dentin desensitization -occlusion of dentinal tubules - nerve analgesia thru depression of nerve tranmission


Analgesia :

- interfere with sodium pump mechanism - change cell membrane permeability - block depolarization of c and Aß fibers

- Other Dental Applications

Laser diagnostics. - laser doppler flowmetry. - flow cytometry.Instrument sterilization

Bio stimulation

♣ He- Ne , diode lasers

♣ Analgesia, pain relief, accelerated wound healing , fibroblast proliferation, enhanced neuron regeneration, bone formation and dentinal hypersensitive.www.indiandentalacademy.com

Lasers used for endodontics

Laser type Wave length (nm)

Argon 488 – 515CO2 10,600

Nd:YAG 1064Diode 800-980Er:YAG 2.94

Er :YSGG 2.79www.indiandentalacademy.com

Argon Laser :-

Active medium of argon gas &delivered fiber optically in continuous-wave &gated pulse modes.

Laser has two emission wavelengths– 488nm (blue) & 514nm (blue-green)

488nm wavelength needed to activate camphoroquinone. Used with other dental materials- light activated impression paste & light

activated bleaching gel. 514nm wavelength peak absorption– red pigment tissue containing hemoglobin, hemosiderin, melanin –intract with laser Surgical laser with excellent hemostatic capabilities Poor absorption into enamel, dentine – advantage when used for cutting

& sculpting gingival tissues thus no damage to tooth structure Both wavelength used for caries detection – orange-red color.

Argon Laser :-


CO2 Laser

• Uses hollow wave guide delivery system

• Has gas active medium, delivered in continuous &gated pulse mode . Wavelength - 10,600nm • Effective in pain reduction & dentin hypersensitivity

• It is used as an adjunct to mechanical root instrumentation The CO2 laser’s ability to act as bactericidal

• It is found effective in removing masses of tissuewww.indiandentalacademy.com

Nd:YAG laser has solid active medium, crystal of Y-A-G doped with Nd

delivered fiber optically in free running pulsed mode, wavelength - 1064nm

Can be used in contact and non – contact modes for cutting and ablating tissue. It can be used on effective adjunct to mechanical root instrumentation.

It is used for curettage.

Has been used in frenectomies, gingivoplasty,crown lengthening,gigivectomy

Excision or destruction of lesions, such as leukoplakia or fibromas.

Used in direct pulp capping , vital pulp amputation,disinfection of infected root canals, apicoectomy, retrograde apical cavity prepration


DIODE LASER

Diode laser have solid active medium

Is solid state semiconductor laser uses combination –aluminum,galium ,&arsenide, to change electric energy to light energy.

delivered fiber optically in continuous-wave &gated pulse mode in contact with tissues. Wavelength - 800nm to 980nm.

Excellent soft tissues surgical laser indicated – cutting, coagulating gingiva,soft tissue curettage

useful adjunct in reducing gingival inflammation and providing analgesic effects. www.indiandentalacademy.com

Different laser systems used in dentistry


ROLE OF LASERS IN ENDODONTICS


VITAL AND NON VITAL DIAGNOSIS OF DENTAL PULP BY LASER

Use of Laser Doppler Flowmetry• EPT uses electric current to stimulate A nerve fibre within pulp.• Intact nerve fibre does not mean pulp is vital.• Teeth that have experienced recent trauma or are in position of the

jaw that has undergone orthognathic surgery.• Laser doppler flowmetry uses specific wave length.• HeNe and Diode laser at a lower power of 1 or 2 mW are used in

laser doppler flowmetry.• Wave length of HeNe laser – 632.8mm

Diode laser – 780 to 820mm


• Prevent reflecting from surrounding gingiva – used under rubber dam.

• Advantages – Allow painless diagnosis - Vital and non vital diagnosis of immature or traumatized teeth.

- Patient sensitive to tooth pain.


Dentinal Hypersensitivity

• It is a short, sharp pain from exposed dentin.

• Erosion, abrasion, attrition, gingival recession are risk factors.

• Management of Dentinal hypersensitivity involves therapies that reduces flow of dentinal fluid.


• Blocking dentinal fluid flow – decreases DH.

• This is obtained by application of Oxalate salt, isobutyl cynoacrylate, fluoride releasing resin, varnish, potassium containing dentifrices, fluoride containing medicaments and agent with 10% strontium chloride.


• Laser induced reduction in dentinal hypersensitivity – 2 mechanism.

1. Direct effect of laser on electric activity of nerve fibre within pulp.2. Modification of tibular structure of dentin by sealing dentinal tubule.

• The laser is used for treatment in 2 groups- Low output power laser (HeNe, diode)- Middle output for laser (Nd:YAG, Co2)


DIFFERENTIAL DIAGNOSIS OF PULPITIS BY LASER STIMULATION

Normal pulp and Acute Pulpitis

• Normal pulp stimulated by Nd: YAG laser at 2W and 20pps at distance 10mm - pain produced within 20-30 sec and disappear a couple of seconds after stimulation is stopped.

• However, in case of acute pulpitis pain is induced immediately after application and continues for 30sec after stopping the stimulation.


Acute Serous Pulpitis and Acute Suppurative Pulpitis

• Obtained by combining the electric current resistance of caries and pain induced by laser stimulation.

• If electric current resistance is greater than 15.1m and patient experience continuous pain for more than 30 sec – acute serous pulpitis.

• If electric current resistance is less than 15 m and pain continuous for more than 30 sec – Acute suppurative pulpitis.


• Because of advantage of control of haemorrhage and sterilisation - DPC

• Diameter of pulpal exposure must be 2mm or less and there must be no infection in pulp.

• CO2 laser can be used for this purpose

TREATMENT BY LASER FOR DIRECT PULP CAPPING


• Laser irradiation performed at 1 or 2W after irrigating alternatively with 8% sodium hypoclhorite & 3% H2O2 for 5 min.

• Ca (OH)2 paste must be used to dress the exposure site.

• After which the cavity is tightly sealed with cement e.g carboxylate cement.

• High success rate because – ability to control haemorrhage, disinfection, sterilization, carbonization and stimulation on dentinal pulp cells.

• Others – Nd:YAG, argon, diode, Er : YAG.


• Closure of dentinal tubule and sedative effect on pulpitis.

• Indication – Deep cavities, hypersensitive cavities & cavities requiring sedative treatment

• Pulsed Nd:YAG laser + air spray used at 2W and 20 pps for 1 sec.

• CO2 can be used for IPC at low energy for 1sec.

Treatment by Laser for Indirect Pulp Capping


ACCESS CAVITY PREPARATION AND ENLARGEMENT OF ROOT CANAL

ORIFICE BY LASER

• Access cavity preparation has been performed - Air turbine

• And Enlargement of canal orifice – Gates Glidden drill.

• Er:YAG and Er, Cr : YSGG laser, which ablate enamel and dentin can replace air turbine.


• Indications – Vital extripation of infected root canal - Gates glidden cannot be inserted

because of difficulty in opening mouth.

- Difficulty to find root canal orifices.

• Access cavity and orifice enlargement is carried out at 5W and 6Hz under water spray.


CLEANING & SHAPING OF ROOT CANAL BY LASER

• Optical fiber of laser can cut enamel &dentin making possible to remove pulp tissue & prepare root canal wall

• Er:YAG laser at 8hz & 2w can be used• Laser tip must slide gently from apical portion to

coronal portion• laser irradiation performed in combination with usual

root canal preparation – shown that smear layer removed completely & dentinal tubules opened.


• One limitation with use of laser – laser is emitted .straight ahead,making it almost impossible to irradiate the lateral canal walls

• Stabholz, et al – reported development of a new tip that can be used with Er:YAG laser system

• This is called as RC Lase side firing tip• The beam of laser delivered through hollow tube, tip

of tube sealed at its far end thus preventing the transmission of irradiation through apical foramen.

• Thus laser is delivered laterally to the walls of canal through spiral slit located along the tip.


LASERS FOR REMOVING PULP REMNANTS & DEBRIS AT APICAL FORAMEN

pulsed Nd:YAG , Er:YAG – recommended A power of 2 – 5 w for 1 sec is recommed Carried out in combination with 5.25% sodium hypochlorite

or 14% EDTA Laser produces cavitation effect similar to ultrasonic Indication - straight , slightly curved canal ,wide root canal


STERLIZATION OR DISINFECTION OF INFECTED ROOT CANAL

laser is effect tool in killing micro organism Nd:YAG in combination with 38% silver ammonium sol. At

2W & 20 pps for 5 sec are recommed. Silver ammonium sol has been used as iontrophoresis of

infected root canal To prevent leakage of 38% silver ammonium sol into

periapical tissue , a cotton pellet is placed in apical 1/3rd of root canal

If no symptom – obturate root canal otherwise – calcium hydroxide intracanal dressing given


• LASER CAN ALSO BE USED FOR APICOECTOMY , RETROGRADE ENDODONTIC APICAL CAVITY PREPARATION, & PERIAPICAL CURETAGE


Laser hazards are basically categorized into a categories according to ANSI or OSHA standards

Class Description

I Low powered lasers that are safe to oral

II Low powered visible lasers that are hazardous when viewed for larger than 0.25sec

III Low powered visible lasers that are hazardous when viewed for larger than 1000sec

IIIa Medium powered lasers that are normally not hazardous if craves for less than 0.25sec without magnifying optics IIIb Medium powered lasers (0.5w) that can be hazardous viewed directly

IV High powered lasers (>0.5w) that produce ocular, skin, and fire hazards.www.indiandentalacademy.com

The lasers generally used for surgical procedures in dentistry fall under class IV.

The types of hazards that may be encountered within clinical practice of dentistry may be grouped as follows.•1. Occular injury•2. Tissue damage•3. Respiratory hazards•4. Fire and explosion •5. Electrical shock


LASER HAZARD CONTROL MEASURES

USE OF PROTECTIVE WEAR THE SMALL FLEXIBLE FIBEROPTIC , HANDPIECES OR Tip MUST BE STEAM STERLIZED IN STERLIZING POUCHES. USE OF SCREEN & CURTAINS SHOULD BE PROMOTED USE OF PROPER CLOTHING USE OF ANTI-FIRE EXPLOSIVE THEIR SHOULD BE PROPER TRANING EDUCATION FOR USE OF LASER


C0NCLUSION

The last 20 years have witnessed many new developments in dental technologies, and

the next 20 years promise to be even richer in technologic advancements. Lasers will be in the forefront of that

growth.


REFRENCES- THE DENTAL CLINICS OF NORTH AMERICA – VOL-44;

NO-4;OCT 2000- TEXT BOOK OF ENDODONTIC – JOHN I INGLE – 5TH

Edi.- www.HOW STUFF WORKS – LASERS- CLEANING AND SHAPING OF ROOT CANALWITH Nd:YAG

LASER:A COMPARATIVE STUDY. J.O.E 18;123-127;1992.- EFFECT OF LASER TREAT ON ROOT CANAL OF HUMAN

TEETH. DENTAL TRAUMATOLOGY 13;139-145;1997.- THE DENTAL CLINIC OF NORTH AMERICA - VOL-48;NO-8;2004


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lasers and its role in endodontics / orthodontic courses by indian dental academy

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