laser endodontics

8/13/2019 Laser Endodontics

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laser in endodonticsINTRODUCTION

The era of laser technology began with the pioneering workof Prokhoruv, Maimen and Towens with the construction ofthe first gas laser in the year 1961. entistry has also beenprompt in e!ploring several potential applications of laserenergy to dental research. The past decade and a half haswitnessed widespread research activity into the dentalapplications of lasers. The use of laser in endodontic therapy

has been e!tensively studied for the last fifteen years. Thefirst laser in endodontics was reported by "eichman and#ohnson $1%, who attempted to seal the apical foramen invitro by means of a high power infra red &'( laser.)ubse*uently attempts were made to seal the apicalforamen using the +d - / laser $(%.0aser is an acronym for 0ight mplification by )timulated2mission of 3adiation4. The wavelength of the laser beam

ranges from the visible to infrared region of the lightspectrum 5 igure 17. The potential benefits derived fromlasers depend largely upon the uni*ue properties of laserenergy at a particular wavelength and its interaction withdental tissues. The inherent properties of laser light such asselective absorption, coagulation, sterili8ation andstimulatory effects on vital structures offer some advantagesover traditional techni*ues, making lasers the treatment ofchoice in certain situations $(%.

Laser device components

. laser medium, which can be a solid, li*uid or gas and


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determines the wavelength of emitted light from the laser.This medium determines the name of the laser.&'( laser.

. n optical cavity or laser tube having two mirrors, one fullyreflective and the other partially transmissive which arelocated at either end of the optical cavity.

. n e!ternal mechanical, chemical or optical power sourcewhich e!cites or :pumps: the atoms in the laser medium to ahigher energy level. toms in the e!cited state emit photonsof which continue to bounce back and forth between the twomirrors in the laser tube striking other atoms and causing

more stimulated emission. Photons of energy of samewavelength and fre*uencyescape through the transmissive mirror and form thelaser beam $;%. laser component is shown in igure (.


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Laser Physics

0aser is a device that converts electrical or chemical energyinto light energy 5 igure ;7. n contrast to ordinary light that isemitted spontaneously by e!cited atoms or molecules, thelight emitted by the laser occurs when an atom or moleculeretains e!cess energy until it is stimulated to emit it. Theradiation emitted by lasers including both visible and invisible

light is more generally termed as electromagnetic radiation. lbert 2instein first proposed the concept of stimulatedemission of light in 191


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> bsorption> )pontaneous emission> )timulated emission.

"hen an atom is struck by a photon 5*uanta of light7, thereis an energy transfer causing increase in energy of the atom.This process is termed as absorption. The photon thenceases to e!ist, and an electron within the atom pumps to ahigher energy level. The atom is thus pumped up to ane!cited state from the ground state. n the e!cited state, theatom is unstable and will soon spontaneously decay back tothe ground state, releasing the stored energy in the form of

an emitted photon. This process is called spontaneousemission. f an atom in the e!cited state is struck by aphoton of identical energy as the photon to be emitted, theemission could be stimulated to occur earlier than it wouldoccur spontaneously. This stimulated interaction causes twophotons that are identical in fre*uency and wavelength toleave the atom. This is a process of stimulated emission $?%.

Classification of Lasers

.Based on the wavelength > The @A laser 5ultraviolet spectrum, appro!. 1?BC?BBnm7> The Aisible laser 5visible spectrum, appro!. ?BBC The laser 5infrared spectrum, appro!. )olid e.g. +d - /, iode.> 0i*uid e.g. ye 5toludine blue7.> /as e.g. &'(, rgon, +itrogen

.Depending pon energy levels


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a. )oft lasers C They are low in energyb. =ard lasers D They are high in energy

A.Based on operation

Continuous wave lasers, Pulsed laser, gated, free running

These terms are generally falling from use and it is nowcalled high power and low power lasers. The termsdestructive and constructive have also been suggested. nterms of dentistry a high power laser is one capable ofproducing ;" and upwards a low power laser up to about1BBm".)oftE lasers are referred to as cold lasers and are emitted atwavelengths believed to stimulate circulation and cellularactivity. The use of lowCpower lasers has created a separatearea of interest, which has recently become known as 0ow

ntensity 0aser Therapy 50 0T7. )oft or low level lasersprovide cold low energy wavelengths with a minortemperature increase of less than B.1B&. These lasers havebeen used to promote tissue regeneration, healing, reduce

inflammation, edema and pain. &linically low level lasershave been used in locali8ed osteitis, apthous ulcers, herpeticulcers, dentinal hypersensitivity, gingivitis, TM# disorders andmore recently for diagnostic procedures. 0asers mostcommonly used for low laser therapy are the diode, heliumneon 5=eC+e7, /allium rsenide 5/aC s7 and /alliumCaluminiumCarsenide lasers.

short selection from the list of 000T applications promotedby some users and manufacturers of 000T devices includes,acceleration of wound healing, enhanced remodelling andrepair of bone, restoration of normal neural function followinginFury, normali8ation of abnormal hormonal function, painattenuation, stimulation of endorphin release, andmodulation of the immune system $G%.


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=ard or hot or thermic lasers been e!clusively used insurgical procedures to cut, coagulate and vapouri8e. =ardlasers produce immediate observable effects on the tissues

irradiated whereas soft lasers appear to cause no visiblechange at the time of lasing. &'( laser, the +d - / laserand the r laser are the common types of hard lasers usedin medical surgeries also.

!ffects of Laser on Tiss e

0asers have four different interactions with the target tissue.These interactions will depend on the optical properties ofthe tissue.

Photo"iologic Interactions

The first effect is reflection, which is simply a beamredirecting itself off the tissue surface, having no effect onthe target tissue. The second interaction is absorption oflaser energy by the intended target tissue. This effect isdesirable and the amount of energy that is absorbed by thetissue depends on the tissue characteristics, such aspigmentation and water content, and on the laserwavelength and emission mode.

rgon has a high affinity for melanin and haemoglobin in softtissue. The third interaction is transmission of the laserenergy directly through the tissue with no effect on the targettissue. The fourth interaction is scattering. )cattering of thereflected light weakens the intended energy and possiblyproduces no useful biological effect.

Photochemical Interactions#

The basic principle of photochemical process is that specificwavelengths of laser light are absorbed by naturally


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occurring chromophores which are able to induce certainbiochemical reactions. Photosensitive compounds whene!posed to laser energy can produce a single o!ygen radicalfor disinfection of endodontic canals.

Photothermal Interactions#

The radiant energy absorbed by tissue substances istransformed into heat energy, which produces the tissueeffect.

Photomechanical and Photo !lectrical Interactions

These include photodisruption, photoplasmolysis andphotoacoustic interactions. n photoacoustic effects, thepulse of laser energy on the dental tissues can produce ashock wave. "hen this shock wave e!plodes or pulveri8esthe tissue, it creates an abraded crater. Photoelectrical effectincludes photo plasmolysis, which describes how the tissueis removed through formation of electrically charged ions.

!ffects of laser light on "acteria and dentinal walls#n endodontics, lasers use the photoCthermal and

photomechanical effects resulting from the interaction ofdifferent wavelengths and different parameters on the targettissues. These are dentine, the smear layer, debris, residualpulp and bacteria in all their various aggregate forms. @singdifferent outputs, all the wavelengths destroy the cell walldue to their photoCthermal effect. Hecause of the structuralcharacteristics of the different cell walls, gramCnegativebacteria are more easily destroyed with less energy andradiation than gramCpositive bacteria. The near infraredlasers are not absorbed by hard dentinal tissues and haveno ablative effect on dentinal surfaces.The thermal effect of the radiation penetrates up to 1mm into


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the dentinal walls, allowing for a decontaminating effect ondeeper dentine layers. The medium infrared lasers are wellabsorbed by the water content of the dentinal walls and

conse*uently have a superficial ablative anddecontaminating effect on the rootcanal surface $6,


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Clinical $pplications of Lasers in !ndodontics

I) Diagnosis Of Pulp Vitality By Laser. A. Laser Doppler flowmetry

Laser Doppler Flowmeter was developed by Tenlandin 1982 and later by Hollway in 1983.This methoduses Helium- eon and diode lasers at a lower powero! 1 or 2 m".Laser Doppler !lowmetry is a noninvasive method o!

assessin# and a$$urately measurin# the rate o! blood!low in a tissue. The pulp is a hi#hly vas$ular tissueand $ardia$ blood !low in the supplyin# artery istransmitted throu#h pulsations.

These pulsations are apparent on the laser dopplermonitor o! vital teeth and absent in the nonvitalteeth.

The blood !lu% level is mu$h hi#her in vital than non

vital teeth. &urrently' the vitality $an be ( interpreted!rom a si#nal on the s$reen)1*+.

B. Heat stimulation by Laser (Thermal testing):

The laser stimulation method by pulsed d, / laserhas been used in order to $he$0 the vitality o! thepulp and is better tolerated than #utta- per$ha)18+.

Differential diagnosis of pulpitis by laserstimulation

a+ ormal pulp and a$ute pulpitis

"hen normal pulp is stimulated by the pulsedd, / laser at 2" and 2 pulses per se$ond )pps+


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at a distan$e appro%imately 1 mm !rom the toothsur!a$e' pain is produ$ed within 2 to 3 se$ondsanddisappears a $ouple o! se$onds a!ter the laserstimulation is stopped. n the $ase o! a$ute pulpitisthepain is indu$ed immediately a!ter laser appli$ationand $ontinues !or more than 3 se$onds a!terstoppin# the laser stimulation.

b+ $ute serous pulpitis and a$ute suppurativepulpitis

Di!!erential dia#nosis o! a$ute serous pulpitisand a$ute suppurative pulpitis $an be obtained by$ombinin# the measurement o! ele$tri$ $urrentresistan$e o! $aries and the pain duration indu$ed bylaser stimulation. ! the ele$tri$ $urrent resistan$e is

#reater than 1 .1 m4 and the patient e%perien$es

$ontinuous pain !or more than 3 se$onds' thedia#nosis is a$ute serous pulpitis ."hen the value o! resistan$e is less than 1 . m4 and there is$ontinuous pain !or more than 3 se$onds' thedia#nosis is a$ute suppurative pulpitis. &ariesimpeden$e o! less than 1 . m4 indi$ates that nohard healthy dentin e%ists between the $aries andthepulp $hamber.

II) Lasers In Pulp Capping

A. Accesory treatment by laser for In irect !ulpcapping


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IV) Laser In Analgesia

&ertain wavelen#ths o! laser ener#y inter!ere

with the sodium pump me$hanism' $han#e $ellmembrane permeability' alter temporarily the

endin#s o! sensory neurons' and blo$0 depolari ationo! & and !ibers o! the nerves. n this area thepulsed :

d, / laser has $ommanded the most attention. The use o! lasers in endodonti$ therapy has beene%tensively studied !or the past 1 years and proventohave many advanta#es over $onventional methods.;esults su##est that the laser is an e!!e$tive tool !orremoval o! debris' the smear layer and obturationmaterials' as well as bein# an e!!e$tive disin!e$tiontool.

Indications And Contra Indications Of Laser

!upport In "ndodonticsLaser-supported endodonti$ treatmentsshould be !avored when treatin# patients that showone or several o! the !ollowin# symptoms.- Teeth with a purulent pulpitis or pulp ne$rosis- Teeth' o! whi$h $rown and root pulp show#an#renous $han#es.- Teeth with peri-api$al lesions )peri-api$al #ap!rom 1mm' up to #ranulomas with a diametero! mm and more+ )


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- bsorption o! the ape% $aused by in!lammationor trauma- Teeth that have been treated !or at least threemonths without su$$ess )with alternatin# rinsin#and medi$inal inlays+.&lear $ontra-indi$ations !or per!ormin# alasersupportedendodonti$ treatment are very advan$edperiodontitis' a deep $rown or root !ra$ture on thetobe-treated tooth' and when obliterated root $anals are dia#nosed on the endodonti$ally treated teeth)19+.

V) Lasers In #oot Canal Treatment.

a) Laser in access ca"ity preparation an root canal orifice enlargement

The primary use o! lasers in ndodonti$s is!o$used on eradi$atin# mi$roor#anisms in the root$hannel' espe$ially in the lateral dentinal tubuli.

r'&r, ( nm+.

Procedure The len#th o! the root $anal' obtainedthrou#h the ?-ray 'is trans!erred to the !iber-opti$alwave #uide to ensure that the !le%ible 2 @m !iberrea$hes the ape%. The laser is a$tivated only a!terthe


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!iber rea$hes the ape% and the !iber is #uided in anapi$al to $oronal dire$tion with rotary movementsand in $onta$t with the root $anal wall)19+."hen the laser !iber is unable to be inserted into the$anals' reamers and !iles are to be used' !ollowed bylasers.


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The laser is an e!!e$tive tool !or 0illin#mi$roor#anisms be$ause o! the laser ener#y andwavelen#th $hara$teristi$s. n!e$ted $anals are anindi$ation !or this treatment but its di!!i$ult ine%tremely $urved and narrow $anals. 5ulsed d, /'ar#on' semi$ondu$tor diode' &6 ' r, / are 2$onsidered !or this treatment./ut0ne$ht et al' 199> a$hieved an avera#e o! 99.927 ba$teri$idal redu$tion in root $anal usin# thepulsed d, / laser with standard settin#s o! 1 Hat 1 mB C1. "' repeated !our times !or -8se$onds.

n 5hotoa$tivated disin!e$tion' tolonium dye isapplied to the in!e$ted area and li#ht is transmittedinto the root $anals at the tip o! a small !le%ibleopti$al!iber that is atta$hed to a disposable hand pie$e.Laser emits 1 m" and does not #enerate su!!i$ient heat to harm the ad a$ent tissues)8+.

L. Eer#mans et al did a study on the e!!e$t o! photoa$tivated disin!e$tion on endodonti$ patho#ense% vivo. They $on$luded that photoa$tivateddisin!e$tion is not an alternative but a possiblesupplement to the e%istin# proto$ols !or root $anal disin!e$tion)9+.

f) Obturation using gutta(perc%a or resin bylaser

/utta-per$ha is thou#ht to be melted by laser)1 '21+ heat ener#y. ni$ and atsumoto attemptedtoinvesti#ate whether it is possible to per!orm the root$anal !illin# usin# se$tioned #utta-per$ha se#ments


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and a pulsed d, / laser. This was shown to bepossible by verti$al $ondensation method' but thete$hniGue reGuired too mu$h time.

g) #emo&al of temporary ca&ity sealingmaterials root canal sealing materials andfractured instruments in root canals.

$$ordin# to e%perimental results' it was easyto remove temporary $avity sealin# materials madeo! in$ o%ide' eu#enol ' or #utta-per$ha by pulsed

d, /' r, /' and r'&r,


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tubules and de$reased permeability)22+.Daniel humberto et al in their laser study!ound the !ollowin# te$hniGues to redu$e dye lea0a#eand thereby $on$luded them to be #ood.

pi$oe$tomy with burs and treatment o! api$alsur!a$e with d, / laser pi$oe$tomy with bur'root end $avity preparation with ultrasound' !illin#with T treatment o! api$al sur!a$e with &6 laser2and api$oe$tomy with r, / laser and treatment o! api$al sur!a$e with d, / laser)1(+.

The advanta#es o! r, / laser over burs arebetter visibility a$$urate api$al rese$tion no$onta$tremoval o! lesion in a shorter time by vapori ationhemostasis no vibration or dis$om!ort and minimalpainand less ba$terial ris0 o! trauma to ad a$ent tissues."hile usin# r'&r,


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postin the root $anal. This treatment $an be per!ormed toa$$elerate wound healin# in $ombination withendodonti$ or sur#i$al treatment. 5ulsed d, / and&6 lasers are re$ommended !or these treatments. 2For the pulsed d, / laser' 2 " and 2 pps are there$ommended parameters and the !iber tip must beinserted into the tra$t and drawn slowly !rom the rootape% to the e%it throu#h the sinus tra$t. Thistreatment#enerally is per!ormed three or !our times durin# onevisit. "hen usin# the &6 laser' the e%it o! draina#e 2

must be ablated as deeply as possible at 1 or 2 "andunder air $oolin# or lo$al anesthesia. Thea!orementioned laser treatments are per!ormed on$eor twi$e a wee0 until the sinus tra$t disappears.

$dvantages of Dental Lasers

17 0asers have many advantages for both the surgeon andthe patient because of the uni*ue manner in which itdestroys the tissue. Precision in tissue destruction ispossible because of good visuali8ation of tissue planes bymeans of operating microscope or the hand piece. Themicroscope provides precise control together withillumination and magnification of the operative field, while thehandpiece is more versatile.

(7 =igh rate of patient acceptance.;7 )elective removal of affected epithelium and minimaldamage to surrounding healthy tissues.?7 0aser beam e!erts a hemostatic effect.G7 )ealing of blood vessels and blockage of lymphatic


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pathway will eliminate tumour cell dissemination.67 3isk of blood borne contamination is dramaticallyreduced.


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J7 +ot available in all hospitals.97 )pecial trained persons needed for operation. Laser %a&ards

0aser ha8ard classification according to the +) 5 merican+ational standards nstitute7 and '=) 5'ccupational)afety and =ealth dministration of the@nited )tates7 $1;%.

Classes and their Description

. 0ow power laser that is safe to view. 0ow powered visible lasers that are ha8ards only when

viewed directly for longer enough than 1.B sec.. 0ow powered visible lasers that are ha8ards only when

viewed directly for longer enough than B.(G secondsv. Medium powered laser that can be ha8ardous if viewed

directly.A. =igh powered laser 5LB.G"7 that produces ocular, skinand fire ha8ards. The types of laser ha8ards that may be

encountered within the clinical practice of dentistry may begrouped as follows 'cular inFury, Tissue damage,3espiratory ha8ard, ire and e!plosion, 2lectric shock.

Laser 'afety

0aser safety is an issue limited not only to the performanceof treatment within the dental operatory, but one that alsoencompasses the interC relationship among the health careproviders educational institutes, government and commercialsector. The responsibility for the safe application of laser indentistry therefore is one that is shared by all thoseconcerned that is the dentist, manufacturer and scientisteach has the role from design and development to thepractical application. 0aser safety control measures


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recommended by +) 5 merican +ational )tandardnstitute7 $1;C16%.

1# !ngineering control

> Protective housing, nter locks, Heam enclosure, )hutters,)ervice panel,> 2*uipment label, "arming system key switch.

( # $dministrative control ( Laser safety officer

> )tandard operating procedures, output limitations,> Training and education, "arming signs, Protective devices,Medical surveillance, ncident reporting, )# Personal Protective !* ipments

> 2ye wear, 'ptical density transmission identification,> Aisibility, &omfort and fit, &lothing, )creen and curtains.

?. 'pecial Controls

C 3epair ire and maintenance, iber delivery system.

There are three factors to laser safety

1. Manufacturing process of the instrument(. Proper operation of the device;. The personal protection of the surgical team and patient

Reg lar $gencies(+o r Organi&ations are given 'afety

of Laser 'ystems,

7 +) 5 merican national standards institute7H7 5 ood and drug dministration7&7 & 3= 5&enter for evices and 3adiological =ealth7

7 ')= 5'ccupational )afety and =ealth dministration7


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? in =unter #/, )ackier #M, editors. Minimally invasivesurgery. +ew -ork Mc/rawC=ill, nc., 199; pp (;C;1.$G% "alsh 0#. The current status of low level laser therapy indentistry. Part 1. )oft tissue applications. us ental #, 199

laser endodontics

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