Biophysics of Lasers - Part II

8/12/2019 Biophysics of Lasers - Part II

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BIOFIZIKA LASERA - II DEO

BIOPHYSICS OF LASERS - PART II

Goran Jovanovi, Nikola Buri, Neboja Kruni

MEDICINSKI FAKULTET, KLINIKA ZA STOMATOLOGIJU, ODELJENJE ZA ORALNU HIRURGIJU, NI, SRBIJA

MEDICAL FACULTY, CLINIC OF STOMATOLOGY, DEP. OF ORAL SURGERY, NI SERBIA

Acta Stomatologica Naissi jun/June 2007, vol. 23, broj/number 55 str./p 679 - 684

Kratak sadraj

Detaljno je obraena biologija lasera koja obuhvata interakciju laser-

skog zraenja sa tkivom i mnogobrojne primarne i sekundarne efekte

iz kojih proizilaze terapijski efekti. Navedene su indikacije i kontrain-

dikacije za primenu lasera u stomatologiji, a na kraju rada ukazano jena tetne efekte koji mogu da nastanu prilikom nestrunog rukovanja

laserskim aparatom.

Kljune rei: laser, biozika, biostimulacija, indikacije, kontraindi-

kacije

Interakcija sa tkivom

Dejstvo lasera na tkivo zavisi u prvomredu od tehnikih karakteristika lasera i odzioloko-hemijskog i biolokog stanja tkiva.

Pod tehnikim karakteristikama podrazumeva-mo tip lasera, talasnu duinu zraenja, frekven-ciju impulsa, energiju i gustinu snage zraenja na

jedinici povrine, irinu laserskog snopa, vrstureima rada itd.1 Anatomo-histoloka graa,intenzitet cirkulacije, toplotna provodnost, stu-

panj hidratisanosti, debljina podsluzokonog ipotkonog tkiva, heterogenost mikrostrukture,pigmentacija, i koecijent apsorpcije/reeksijesu parametri koji spadaju u zioloka stanjatkiva.2

Parametri koji utiu na distribuciju laser-skog zraenja u tkiva su:

PREGLEDNI RADREVIEW ARTICLE

Abstract

In this work has been detailed biology of lasers which includes the in-

teraction of laser radiation with tissue and many primary and second-

ary effects which on the other side cause therapeutic effects. There were

mentioned indications and contraindications for laser usage in den-tistry, and at the end of the work there were mentioned harmful effects

which could appeared by unprofessional usage of laser device.

Key words:laser, biophysics, biostimulation, indications, contraindica-

tions

Interaction with tissue

The effect of laser on tissue depends at rstside on technical characteristics of laser andon physiology-chemical and biologic state of

tissue. Under the technical characteristics wemean the type of laser, frequency of radiation,frequency of impulse, energy and density pow-er of radiation on unit of area, width of laser

beam, kind of working and so on.1Anatomical-histological material, circulation intensity, ther-mal conduction, stage of hydration, thickness ofsubmucous membrane and subcutaneous tissue,heterogeneous of microstructure, pigmentationand coefcient of absorption/reection are pa-rameters which belong to physiological state of

tissue.2

Parameters which inuence on distributionof laser radiation are following:


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a) reeksija - u zavisnosti od ugla delovanjalasersko zraenje se moe manje ili vieodbijati, pri emu se jedan deo energijeod strane tkiva apsorbuje (apsorpcija je

bolja ukoliko je tkivo bogatije vodom,

bilirubinom, melaninom, karotinom, ok-sihemoglobinom i hemoglobinom),2

b) rasejavanje - deo energije koji prodire utkivo se iri i gubi u okolno tkivo, i

c) transmisija lasersko zraenje moe daproe u dublje strukture tkiva na koje sene eli uticaj.

Bioloko dejstvo

1. Primarni efekti

Fotohemijski- stimulie oslobaanje hemi-jskih medijatora (serotonin, bradikinin i hista-min); ubrzava sintezu vitamina A i D; aktivirasistem DNK i RNK i stimulie razmnoavanjeelija; stimulie pretvaranje ADP u ATPubrzavajui elijski metabolizam; i inhibira sin-tezu prostaglandina.35

Fotoelektrini- jako elektrino polje kojese stvara oko laserskih zraka dovodi do norma-lizacije potencijala elijske membrane nervnih

vlakana i onemoguava normalno odvijanjeprocesa depolarizacije (blokira kalijum natri-jumovu pumpu i prenos jona natrijuma i hloras jedne i kalijuma s druge strane, tako da se

prekida prenos nervnih impulsa).6

Fotoenergetski stimulacijom pretvaranjaADF u ATP na nivou mitohondrija poveava seintracelularna energija.7

2. Sekundarni efekti

Stimulacija elijskog metabolizma ogle-

da se u ubrzanoj elijskoj razmeni materija;deobi i diferencijaciji elija; poveanoj intrace-lularnoj energiji u obliku ATP i poveanom pri-livu kiseonika (posledica pojaane mikrocirku-lacije), tako da je stimulisano elijsko disanje,kao i unoenje hranljivih i eliminacija toksinihmaterija.8

Stimulacija mikrocirkulacije stimulieoslobaanje histamina koji paralie prekapila-rni snkter to za posledicu ima arteriolarnudilataciju.9Ovaj efekat se ne zasniva na lokal-

nom poveanju temperature tkiva. Minimalnopoveanje temperature tkiva, do ziolokihgranica, posledica je pojaanog elijskog me-

a) reection in dependence on workingangle, laser radiation can be less or morereected, when one part of energy has

been absorbed by tissue (absorption isbetter if tissue is richer with water, biliru-

bine, melanin, carotene, oxyhemoglobinand hemoglobin)2,b) diffusion one part of energy which pe-

netrates in tissue has been amplied anddisappeared at tissue in surrounding, and

c) transmission laser radiation can passthrough in deeper tissue structure onwhich we dont want to have inuence.

Biological effect

1. Primary effectsPhotochemical it stimulates release of

chemical mediators (serotonin, bradikinin andhistamine); it accelerates synthesis of vitaminA and D; activate DNK and RNK system andstimulates multiplication of cells; stimulatesADP changing in ATP with acceleration of cellsmetabolism; and it inhibits synthesis of prosta-glandin.3-5

Photoelectric strong electric eld whichappeared round laser rays can cause the normali-zation of potential of nerve ber cell membraneand disable normal running of depolarization

process (it blocks potassium sodium pump andtransfer of sodium and chlorine, on one side,and potassium, on the other hand, so the trans-fer of nerve impulses have been interrupted).6

Photoenergetic - by stimulation of ADFchanging in ATP on mitochondria level, intra-cellular energy has been increased.7

2. Secondary effects

Stimulation of cells metabolism it is

shown in accelerate material exchange of cells;ssion and differentiation of cells; increased in-tracellular energy in state of ATP and increasedinux of oxygen (consequence of increased mi-crocirculation), so the cells aspiration as well asthe loading of nourishing material and elimina-tion of toxic material have been stimulated.8

Stimulation of microcirculation it stimu-lates release of histamine which paralyzes overcapillary sphincters. The consequence is arte-riolar dilatation.9This effect has not been based

on local increase of tissue temperature. Mini-mal increase of tissue temperature, until physi-cal limits, is consequence of increased cells me-


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tabolizma i vazodilatacije krvnih sudova. Pred-nost lasera u odnosu na druge zikalne metode(infra-crveno, ultra-violetno zraenje, dijater-mija itd.) jeste da svoj terapijski efekat ostvar-uje bez termikog dejstva, te se moe slobodno

koristiti u inciranom tkivu.3. Terapijski efekti

Analgetiki efekat- nastaje kao posledicafotoelektrinog dejstva i stabilizacije elijskemembrane neurona (blokada prenosa nervnihimpulsa); bra resorpcija zapaljenjskog eksudatasmanjuje pritisak izlivene tenosti na perifernenervne zavretke; aktivna vazodilatacija stvarauslove za bolju ishranu i regeneraciju oteenihnerava; dok poveana produkcija endorna u

likvoru i serumu hiperpolarizuje elijske mem-brane i izaziva centralnu i perifernu akciju naneurohumoralne hemijske medijatore i sintezuendogenih peptida, to takoe ima analgetikodejstvo.1012

Antiinamatorni efekat - stimulie fago-citnu aktivnost neutrolnih leukocita, mikro- imakrofaga; mitotsku aktivnost makrofaga; asveukupno stimulie celularni i humoralni imu-nitet. Efekat lasera na zapaljenje sastoji se i ustimulaciji nespecine humoralne odbrane i

porastu sinteze komplemenata, lizozoma i inter-ferona.8Isto tako, stimulacijom makrofagalnogsistema aktivira se i imunokompetentni sistem(T i B limfociti) sa kojim nastupa specinaimunoloka odbrana.8

Antiedematozni efekat - ubrzava regene-raciju limfnih i venskih sudova i smanjuje in-trakapilarni pritisak, izazivajui bru eliminaci-

ju (apsorpciju) izlivene tenosti.13

Biostimulativni efekat - stimulie rast ireprodukciju broblasta i osteoblasta, sintezu

kolagenih vlakana, regeneraciju nervnih, endo-telnih i epitelnih elija, mitotsku aktivnost ma-krofaga i enzimsku aktivnost elija.13

Indikacije za primenu lasera velikesnage

- precizno seenje i koagulacija tkiva,- biopsija i uklanjanja malignih i benignih

tumorskih lezija,

- hirurke intervencije na temporomandibu-larnom zglobu,- preprotetske hirurke procedure,

tabolism and vasodilatation of blood vessels.The advantage of lasers in comparison with theother physical methods (infrared, ultraviolet ra-diation, diathermia, etc.) is that it achieves itstherapeutic effect without thermal effect, so it

can be used without doubt in infected tissue.

3. Therapeutic effects

Analgetic effect it appears as conse-quence of photoelectrical action and stabiliza-tion of cells membrane of neurons (blockade ofnerve impulses transfer); faster resorption of in-ammatory exudates reduce pressure of moltenliquid on periphery nerve upshot; active vaso-dilatation makes conditions for better nourish-ment and regeneration of disabled nerves; while

increased production of endorphin in liquorand serum hyperpolarize cell membrane andgenerate central and periphery action on neu-rohumoral chemical mediators and synthesis ofendogen peptides, which also has analgetic ef-fect.1012

Anti-inammatory effect it stimulatesphagocyte activity of neutrophil leucocytes, mi-cro- and macrophages; mitotic activity of mac-rophages; and it altogether stimulates cellularand humoral immunity. Laser effect on inam-mation consists also of stimulation nonspecic

humoral defense and increase of complementssynthesis, lisosomes and interpherones.8Like-wise, by stimulation of macrophage systemthere has been activated also immune compe-tent system (T and B lymphocytes) with whicharrive specic immune defense.8

Anti edema effect it accelerates regenera-tion of lymphatic and venous vessels and de-creases intra capillary pressure, provoking fast-er elimination (absorption) of molten liquid.13

Biostimulative effect it stimulates growi-ng and reproduction of osteoblastes, synthesis

of collagen ber, regeneration of nervous, en-dothelial and epithelial cells, mitotic activity ofmacrophages and enzyme activity of cells.13

Indications for the usage of greatpower lasers

- precisely cutting and tissue coagulation,- biopsy and removing of malignant and be-

nignant tumor lesions,

- surgical interventions on temporomandib-ulary joint,- prothetic surgical procedures,

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- uklanjanje infektivnih lezija i hemangio-ma,

- gingivektomija i gingivoplastika,- implantologija,- terapiji mnogih parodontalnih oboljenja,

- kariologija - seenje tvrdih zubnih tkiva iuklanjanje karijesa,- ispitivanje i polimerizacija materijala za

restauraciju,- endodoncija - sterilizacija kanala, i- izbeljivanje zuba.

Indikacije za primenu lasera malesnage

- terapija alveolitisa i drugih bolova u hirur-giji,- pospeuje zaraivanje rana,- smanjuje stvaranja broznog tkiva i oi-

ljaka,- smanjuje postoperativni bol, edem i triz-

mus,- ispitivanje vitaliteta zuba,- terapija hroninih i neuralginih bolova,- kariologija i endodoncija,- dijagnostika i terapija parodontalnih obo-

ljenja (gingivit, afte, herpesne lezije, lihenplanus), i

- terapija hipersenzitivnog dentina.

tetni efekti

Za razliku od lasera velike snage, kojinekvalikovanom i neadekvatnom upotrebomzbog izrazitog termikog dejstva mogu izazvativelika tkivna razaranja, laseri male snage goto-vo da nemaju tetnih uticaja. S obzirom da i pri

prekoraenju doze laserski zraci ne poveavajuznatnije temperaturu tkiva (najee ostaje uziolokim granicama) moe se zakljuiti da nemogu izazvati termika oteenja.

Meutim, reektujui se od ravnih metal-nih povrina (ogledalce, ekarter) laserski zracise odbijaju i mogu otetiti vid. Povrede nastajutako to refrakcioni sistem oka fokusira laser-ske zrake na dno oka, tako da se njihovo dej-stvo moe pojaati i stotinu puta.4 Zatita odovakvih efekata obuhvata upoznavanje osoblja

sa tetnim dejstvom laserskih zraka, struno ioprezno rukovanje laserskim aparatom i oba-vezna upotreba zatitnih naoara.

- removal of infective lesions and heman-gioms,

- gingivictomy and gingivoplastic,- implantology,- therapy of many parodonthic diseases,

- cariology - cutting of hard teeth tissues andremoval of caries,- inspection and polimerisation of materials

for restauration,- endodoncy - canals sterilization, and- teeth whitening.

Indications for low power lasersusage

- therapy of alveolitis and other pains in sur-gery,- it improves overruning of wounds,- reduces appearence of tissue brosis and

scars,- reduces postoperative pain, edema and

trismus,- inspection of teeth vitality,- therapy of chronic and neuralgic pains,- cariology and endodoncy,- diagnosis and therapy of pharadontic dis-

eases (gingivitis, afthes, herpes lesions, li-hen planus), and

- therapy of hypersensitiv dentine.

Harmful effects

In contrast to great power lasers which cancause serious destruction of cells by unqualiedand inadequate usage, low power lasers doesnthave anything harmful effects. Knowing thefact that also with overdosage, laser rays dontincrease tissue temperature considerably (mostoften it is in physical limits), there can be con-cluded that laser rays can not produce thermaldamage.

However, laser rays are reected from atmetal surfaces (mirror, ekarter) and they candamage sense of sight. Injuries appear becauserefractive eye system focuses laser rays to the

bottom of eye, so its effect can be increasedeven for hundred time.4 Defense of such effectsincludes presentation of the laser ray harmful

effects to the personnel, competent and carefulmanaging with laser device and compulsory us-age of glasses.


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LITERATURA / REFERENCES

1. Skobelkin O. Lazeri v hirurgii. Medicina, Moskva,1989.

2. Labat J. Primena lasera u akupunkturi. U (grupaautora): Ka integraciji savremene i tradicionalne medi-cine. ECPD, Beograd, 1995, str. 321-329.

3. Abt E. Biostimulation and Photodynamic Therapy.In: Miserendino L, Pick R. (ed.): Lasers in Dentistry.Quintessence Publishing Co., Chicago-Berlin, London-Tokyo, Sao Paulo-Moscow-Warsaw, 1995, pp. 247-257.

4. Miserendino L, Levy G, Miserendino C. Laser In-teraction with Biologic Tissues. In: Miserendino L, PickR. (ed.): Lasers in Dentistry. Quintessence PublishingCo., Chicago-Berlin, London-Tokyo, Sao Paulo-Mos-cow-Warsaw, 1995, pp. 39-55.

5. Schimizu N, Yamaguchi M, Goseki T, Shibata Y,

Takiguchi H, Iwasawa T, Abiko Y. Inhibition of Prosta-glandin E2 and Interleukin 1-beta Production by Low-

power Laser Irradiation in Stretched Human PeriodontalLigament Cells. J. Dent. Res., 1995, 74: 1382-1388.

6. Lazovi M. Laseroterapija. Prosveta, Ni, 1997.

7. Jovanovi G, Buri N, Kesi Lj. Effects of SoftLaser in Pein Therapy After Root Resection. J Oral LaserApplications, 2003, 3: 83-86.

8. Jovanovi G. Uticaj lasera male snage na zarasta-nje ekstrakcionihi hirurkih rana usne duplje. Doktorska

disertacija, Medicinski fakultet, Ni, 1998.9. Lim H, Lew K, Tey D. A clinical investigation of

the efcacy of low level laser therapy in reducing orth-odontic postadjustment pein. Am J Orthod Orthop, 1995,108: 614-622.

10. Janev J, Peeva M. Primena na laserot vo oralnatahirurgija. Maked Stom Pregl, 1996, 20 (1-4): 71-76.

11. Passarello N, Chiarello A, Denardo L, GiarleoC. Endorne e laserterapia. I Congresso Internazionaledi Laserterapia Medica, Modena, Guinio, 1983. Citat iz:Marii B, Mady L, Hraste J, ua B. Analgetiki uinak

lasera u stomatolokoj terapiji. Acta Stom Croat, 1987,21: 291-301.

12. Jovanovi G. Uticaj lasera male snage na post-operativni edem. Acta Stom Naissi, 2002, 37-38: 26-28.

13. Jovanovi G, Buri N, Kesi Lj. Effect of lowpower laser on postoperative trismus. Facta Universitatis,2004, Vol. 11, No 3, pp. 136-138.

Address for correspondence:Assoc. Prof. Goran Jovanovi, DDS, MSD, Ph. D.

52 Buld. Zorana inia18000 NiSerbia

Phone.: + 381(0)18 226 216

Adresa za korespondenciju:Prof. dr Goran Jovanovi

Bul. Zorana inia 5218000 NiSrbijaTelefon: 018 / 226 216

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Biophysics of Lasers - Part II