lasers in periodontics and it's application

Lasers

1. Lasers and its appLications in p eriodon t o L o g y

2. Co n tents  Introduction.  Historical perspective.  LASER properties.  LASER physics.  LASER parts and delivery systems.  LASER classification.  Biologic rationale: LASER –tissue interactions.  LASERS-  Argon, Diode, Nd:YAG, Er:YAG, Co 2 laser.

3. Contents  Laser Safety.  Applications in dentistry.  Clinical Applications in Periodontics.  Conclusion  References

4. introduction L - Light A - Amplification S - Stimulated E - Emission R - Radiation

5. historicaL perspective  1917- Principle of stimulated emission by Albert Einstein. “Zur Quantern Theorie der Strahlung”  1954: Townes and Gordon- MASER.  1957- Gordon Gould introduced the term LASER.  1960- Theodore Maiman- First LASER- ruby – active medium.  1961- Javan.- He-Ne laser.

6. historicaL perspective  1964- Nd YAG- Geusic.  1965- Co2 Laser- Patel.  1989- Myers and Myers-FDA approval for use of laser in dentistry- Nd YAG laser.  1990- Opthalmic application- ruby laser.  1995- dental use started.

7. properties of Laser

8. parts of a Laser  Active medium/Gain: Gas , solid, liquid suspended in an optical cavity.  Power supply: external energy source- flash lamp/ electrical energy.  Optical resonator: mirrors for amplification.  Cooling system, Control system, Delivery system.

9. active MediuM Phase Example Gas Argon, Co2 Solid Diode Solid Nd:YAG Solid Er:YAG Liquid Red dye Usually defines laser type.

10. optic fiBer  Smaller in diameter with sizes ranging from 200 -1000 μm in diameter  Fits into a handpiece  Used in contact or noncontact mode  Focal point is at or near the tip, which has the greatest energy.

11. Laser deLivery systeMs Delivery system type Articulated arm Hollow tubes, 45 degree mirrors Hollow waveguide Semi-rigid tube with internal reflective pathway Optic fiber/ rigid tip Quartz-silica flexible fiber with quartz, sapphire tip Hand held unit Low power lasers. Erbium family- fibers with low content of OH ion are used. (eg) Zirconium fluoride

12. Modes of operation of Laser  Continuous wave Gated pulsed mode (Physical gating of beam) Free running pulsed mode (Property of the active medium)

13. F oc u sed De -f o cu s ed  Laser beam hits tissue at its focal point- narrowest diameter.  Cutting mode  Beam moved away from its focal point.  Wider area of tissue affected as beam diameter increases.  Ablative mode.  LLLT. Laser operation paraMeters

14. Contact Non- contact  Tip is in contact with tissue.  Concentrated delivery of laser energy.  Char tissue formation at tip.  Tactile feedback is available  Tip is kept 0.5 to 1 mm away from tissue.  Laser energy delivered at the surface is reduced. Laser OperatiOn parameters

15. BiOLOgic ratiOnaLe fOr Laser use Laser-tissue interactiOns LASER-TISSUE INTERACTION: Reflection. Transmission. Scattering. Absorption.

16. a B s O r pt i On  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)

17. 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.

18. r e fLe c t i O n  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.

19. s c a t t e r i ng  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.

20. Benefits Of Laser – tissue interactiOn Soft tissue:      Cut, coagulate, ablate or vaporize target tissue elements Sealing of small blood vessels Sealing of small lymphatic vessels Sterilizing of tissue- Eschar Decreased post-operative tissue shrinkage

21. Laser effects are Due tO:  Photothermal.  Photochemical.  Photoacoustic.  Biostimulation.  Photodynamic.  Phot o v a p o r o l y s i s .  Phot o p l a s m o l y s i s .

22. WHat DOes tHe OperatOr cOntrOL

23. cLassificatiOn Of Laser (periODOntOLOgy 2000, 2009)

24. Classification of LASER- based on safety  Based on the potential of the primary laser beam or the reflected beam to cause biologic damage to the eye or skin.  Four basic classes:  Class I.  Class II: a,b  Class III: a, b  Class IV.

25. cLassificatiOn Of Lasers Class I lasers  Do not pose a health hazard.  Beam is completely enclosed and does not exit the housing.  Max power output: 1/10 th of milliwatt  Eg: CD player. Class II Lasers:  Visible light with low power output.  No hazard- blinking and aversion reaction .  Max power output is 1 mW.  Eg: bar code scanner, laser pointer  Two subdivisions: IIa: dangerous- >1000 sec. IIb: ¼ th of second.

26. Laser cLassificatiOn Class IIIa:  Any wavelength.  Max Output power: 0.1 to 0.5 W.  Danger > ¼ th of a second.  Caution label. Class IIIb:  Hazard to eye- direct or reflected beam, irrespective of time of exposure .  Safe with matted surface and no fire hazard.  Max output power: 0.5 to 5W.

27. cLassificatiOn Of Lasers Class IV lasers:  Hazardous for direct viewing and reflection.  Max output power > 5 W.  Fire and skin hazards .  Use safety glasses  Dental lasers are Class IIIb or Class IV lasers.

28. aBsOrptiOn cHaracteristics Of DentaL Lasers LASER Wavelength Type Chromophore Argon 488-515 nm Gas H e m o g l ob in, melanin He Ne 632 nm Gas Melanin Diode 810-980 nm Solid Melanin, h e m o g l ob in. Nd: YAG 1064 nm Solid Melanin, water Ho: YAG 2120 nm Solid Water, HA. Erbium family 2790-2940 nm Solid Water, HA. Co2 9300, 9600, 10600 nm Gas Water, HA.

29. argOn Laser LASER characteristics Wavelength 488 to 514 nm Active medium Argon Gas Delivery system Optical fiber Mode of operation Continuous wave Chromophore Melanin pigment, hemoglobin, hemosiderin Applications Soft tissue only. Pocket debridement and de- epithelialization for GTR “ Laser Pocket thermolysis ”: Finkbeiner 1995- absorption by black pigmented bacteria- bacterial load reduction in the periodontal pocket. Blue wavelength  488nm  composite curing Green wavelength  510nm  soft tissue procedures, coagulation

30. a r g O n

31. DiODe Laser LASER characteristics Wavelength 810 to 980 nm Active medium Semi-conductor diode Delivery system Optical fiber- quartz or silica Mode of operation Continuous wave, gated pulsed mode. Used in focused and de-focused modes. Chromophore Melanin, hemoglobin. Applications Primarily soft tissue applications- all minor surgical procedures. The chief advantage of the diode lasers is one of a smaller size, portable instrument. HOT TIP EFFECT  heat accumulation at tip  thick coagulating layer Less tissue penetration , Deeper coagulation DIODENT Visible red diode 655nm 1 mW

32. nD:yag Laser LASER characteristics Wavelength 1064 nm Active medium Neodymium in YAG crystal Delivery system Optical fiber Mode of operation Continuous wave, pulsed wave Ch r omo p h o r e Hemoglobin, melanin, water Applications Effective for soft and Hard tissue-> Hemostasis, treatment of apthous ulcers, or pulpal analgesia. Causes more thermal damage Earliest FDA approved laser for dental use. Nd: YAG 1340 nm, Black pigmented tissue absorption. Do not use for disinfection of implant surfaces- damage to sand blasted and acid etched surfaces ( Kreisler et al 2002 ).

33. erBium famiLy Of Lasers  Er YAG- 2940 nm: Zharikov et al 1975 .  Er Cr YSGG- 2780 nm: Zharikov et al 1984 and Moulton et al 1988.  1988: Phagdiwala: Er YAG laser: ability to ablate the dentinal hard tissue.  1989: Pulsed Erbium laser: Keller and Hibst- enamel , dentin and bone.  1995: Commercially available.  1997: introduced for use in dentistry.

34. Wavelength 2940 and 2780 Active medium Erbium ion embedded in YAG or YSGG crystal Delivery system Articulated arm, Hollow wave guide, Water free compound like Zirconium fluoride fiber with air and water in the co-axial cable. Mode of operation Continuous wave, free running pulsed mode. Used in focused and de-focused modes. Chromophore Water, Hydroxyapatite 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.

35.  MOA of Er laser  photoablation  Layers formed  superficial significantly altered intermediate deeper/ less affected  Superficial layer  micro-cracking, disorganization, slight recrystallization of apatite, reduction of surrounding organic matrix  Intermediate layer  micro-explosion due to energy accumulation  Deep  no change

36. Co2 laser Wavelength 9300, 9600, 10600 nm Active medium Carbon dioxide Gas Delivery system Articulated arm Mode of operation Continuous wave, gated pulsed mode. Used in focused and de-focused modes. Chromophore Water, Hydroxyapatite Limitation: High risk of carbonization (water absorption  generates more heat  carbonizes tissue) Advantage : carbonized / charred layer acts as biological dressing

37. Carbonization  Use limited to soft tissue procedures as it produces severe thermal damage, like cracking, melting and carbonization of the adjacent root cementum and dentin Spencer (1996),Israel et al(1997) , Barone et al (2002)  Hi gh l y a b s o r be d b y m a in c o m p o n e n t o f hard tissue, m in e r al e s p e c i a l ly phosphate ions leading to Carbonization of organic components Melting of inorganic ones

38. Disadvantages Advantages  Hemostasis.  Ablation.  Detoxification.  Bactericidal activity.  Osseous tissue removal and contouring easy with Er family  Hard tissue damage (bone)  High cost.  Risk of pulpal damage.  No single wavelength can treat all diseases l a sers

39. eye damage Part of eye damaged Laser type Corneal damage Er Cr YSGG, Ho YAG, Er YAG, Co2 Lens damage Diode, Nd YAG, Ho YAG, Er Cr YSGG, Er YAG Aqueous damage Ho YAG, Er Cr YSGG, Er YAG Retinal damage Argon, He Ne, Diode, Nd YAG

40. appliCations in dentistry  Biopsy.  Apicoectomy.  Teeth preparation.  Epulis fissuratum.  Residual ridge modification.  Bleaching.  Impaction.  Pontic site preparation.  Tori reduction.  Soft tissue modification around laminates.  Impacted teeth exposure- orthodontic movement.  Caries removal.  Root canal disinfection.

41. CliniCal appliCations in periodontiCs  Initial non-surgical pocket therapy.  Frenectomy.  Gingivectomy.  Soft tissue grafting.  De-pigmentation.  Desensitization  Removal of granulation tissue.  Osseous recontouring.  Crown lengthening.  Surgery- implants.  Peri-implantitis.  Operculectomy.

42. L A S E R Conventional methods  Bleeding- surgical field.  Suturing.  Local anesthesia.  Post-operative discomfort.  Healing time.  P os t - o p er a t ive c o mp li c a t i on s.  Infection.  Periodontal dressings.  Effective hemostasis.  No sutures. (concept of tissue welding).  Topical anesthetic- some procedures.  Faster healing.  Minimal/no post operative complications.  Laser sterilization of wound site.  Laser bandage. Why lasers in periodontiCs…

43. non surgiCal therapy Introduction:  Primarily aimed at efficient removal of plaque and calculus and reduction of bacterial load, inflammation.  Conventional therapy limitations:  Incomplete removal of calculus.  Incomplete elimination of inflamed pocket lining. Lasers used: Diode, Nd YAG, Er YAG, Co2 lasers.

44. subgingival CalCulus deteCtion- unique appliCation for laser  Conventional method- tactile feel.  Latest: Er YAG laser with fluorescent feedback system for calculus detection. Rationale:  Difference in the fluorescence emission properties of calculus and dental hard tissue when subjected to irradiation with 655 nm diode laser.

45.  All commercially a v ai l a b l e L LLT sy s t em a r e generally variants of Gallium, Aluminum, Arsenide ( Ga , A l , A s ) whic h e m it in the near infrared spectrum (700 – 940 nm).

46. Low LeveL Lasers  Helium – neon laser  Gallium – aluminum – arsenide diode laser  Gallium – arsenide diode laser  Argon ion laser  Defocused Co 2 laser  Defocused Nd:YAG laser

47. BiostimuLation effects of Low LeveL Laser  Reduction of discomfort / pain (Kreisler MB et al 2004).  Promotion of wound healing (Qadri T et al 2005).  Bone regeneration (Merli LA et al 2005).  Suppression of inflammatory process . (Qadri T et al 2005).  Activation of gingival and periodontal ligament fibroblast (Kreisler M et al 2003), growth factor release (Saygun I et al 2007).  Alteration of gene expression of inflammatory cytokines (Safavi SM et al 2007).  Photobiostimulaation (Garcia et al 2012)

48. Laser assisted new attachment Procedure  LANAP  Gold and Villardi 1994, safe application of the Nd YAG laser for removal of pocket epithelium lini ng without carbonization of the underlying connective tissue.  Approved by FDA for use.  Yukna et al 2007- case series- histologic study- new cementum with new connective tissue attachment on previously diseased root surface.

49. 1 s t pass – laser t r o ugh ing 2 n d pass – long pulse

50. imPLant theraPy- management of Peri- imPLantitis Peri-implantitis – Management options-  Conventional- plastic curettes and antibiotics.  New option- Laser Rationale:  Disinfection and de-contamination of implant surface.  Granulation tissue removal. Lasers used: Diode, Co2, Erbium family. Lasers contra-indicated: Nd YAG (Implant damage).

51. Photodynamic theraPy in Laser Main objective of periodontal therapy: eliminate the deposits of bacteria. incomplete elimination Co n ve n t io n a l mecha n i ca l t h e rapy: due to Anatomical complexity of root. Deep periodontal pockets.

52. recent advances WATERLASE Device that uses laser energized water to cut and coaglate soft and hard tissue. Er, Cr: YSGG laser 2,780nm - available as WATERLASE

53. u s es Full thickness flap Partial thickness flap Split thickness Laser soft tissue curettage Laser removal of diseasd, infected, inflamed, necrosed tissue within the periodontal pocket Rem o va l of in f l a me d t i s sue , o s t e op l as t y , o ss e ous recontouring……

54. concLusion  Lasers in dentistry offer incredible precision, less pain, faster healing and many more advantages.  It is most important for the dental practitioner to become familiar with those principles and choose the proper laser for the intended clinical application.