Principles and uses of lasers in omfs /certified fixed orthodontic courses by Indian dental academy


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Principles and uses of lasers in omfs /certified fixed orthodontic courses by Indian dental academy

  1. 1. PRINCIPLES AND USES OF LASERS IN OMFS INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. • The term laser is an acronym for light amplification by a stimulated emission of radiation, which serves to explain most but not all the critical physical interactions that occur within a laser generating cavity. • Surgeons do not necessarily have to be fully tortured on the complex physics required to create the various forms of laser radiant energy. • However, it is pragmatic to have a general knowledge of stimulated emission so that one can evaluate newer laser technologies and understand how lasers affect biologic tissue.
  3. 3. HISTORY – The possibility of stimulated emission was predicted by Einstein in 1917. – Maiman in 1960 created the first operational laser called Ruby laser and it was employed in treating dermatological lesions. – CO2 laser was fabricated by Patel and colleagues in 1964. – Lasers entered OMFS in 1970.
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  6. 6. LASER PRODUCTION Absorption: electron absorbs energy and transferred to more exited state. Spontaneous emission of radiation: electron returns to its resting state and releases electromagnetic radiation in the form of light.
  7. 7. • When an atom in exited state becomes irradiated with a photon of light of same wavelength and frequency that was previously absorbed, as it returns to its resting state, it will emit 2 photons of light energy of same W.length traveling in the same direction in spatial and temporal phase. • Because of this production of electromagnetic energy it is called LASER ( light amplification by the stimulated emission of radiation)
  8. 8. PROPERTIES OF LASER LIGHT 1. Monochromaticity: with all of energy it produces having same wave length. 2. Directionality : beam can travel considerable distance with a minimal divergence(milliradans). 3. Coherence : is a distinct feature that allows laser beam to remain parallel for long distance and spatially coherent. This helps in extremely fine focusing. 4. Brightness : high brightness- high energy.
  9. 9. PHOTOBIOLOGY • Photobiologic effects: 1.Photocoagulation 2.Photovaporization 3.Photochemical 4.Photophysiological phenomena All these are both wavelength and dose dependent.
  10. 10. • • • • PHOTOCOAGULATION Heating tissues above 60degree c. Whitening of tissues Changes in molecular structure of tissues Collagen shrinkage in blood vessels causes hemostasis . • Laser damage to erythrocytes attracts a population of platelets and causes intraluminal thrombosis.
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  12. 12. PHOTO VAPORIZATION • Intense, highly focused laser radiation produces surface temp exceeding 100 degree C, which causes tissue vaporization of 0.05mm thickness within 1/8 th of a second. • Cellular expansion due to steam production • Over 100deg C destroys cellular proteins • Literally cell explode releasing the confined steam in the form of plumes. • When further heated results in complete or partial combustion and produces smoke and flashes of incandescence.
  13. 13. PHOTOCHEMICAL EFFECT & PHOTOCHEMICAL THERAPY • Here a Radiant energy possessing a multitude of wavelengths is used to treat a host of dermatologic diseases by administrating a Photosensitizing agent to the patient before application of the light. • PSORALENS (Tricyclic Furocoumarins) is used as a Photosensitizing agent in combination with exposure to UV radiations. • Used in the treatment of Psoriasis, Mycosis,Fungoides,Vitiligo, Eczema.
  14. 14. • Systemic administration of Photosensitizing agent offers conveniance,bypasses the barrier to radiant energy alone of the stratum corneum, and may cause a uniform skin concentration of Photoagent. • Because the Photoagent is activated by optical radiant energy, the effects of the Photosensitizer are confined to exposed areas and the penetrative action of the radiant energy is limited to the skin
  15. 15. PHOTODYNAMIC THERAPY (PDT) WITH LAZER • PDT using the laser is similar to the use of photosensitizers and radiant energy, possessing less power and in most cases shorter wavelengths. • Initially PDT used Hematoporphyrin derivative and red light to treat malignant diseases in humans. • PDT therapy requires adequate tissue levels of photosensitizer, oxygen and laser energy.
  16. 16. • The foundation of PDT is the activation of a local or systemically administered photosensitizing agent by radiant energy. • PDT turns on the ability of certain chemicals to accumulate in malignant tissues and to be rendered cellucidal if activated, by exposure to laser energy in the form of low intensity visible or near infrared light. • A range of oral microorganisms responsible for both dental caries and PDL disease are susceptible to the cellucidal effects of PDT.
  17. 17. PHOTOMECHANICAL EFFECT (PHOTODISRUPTION) • Photodisruption is not a laser application sought by OMFS as a way of managing diseased tissues. • Most commonly used by Ophthalmologists.
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  21. 21. LASER DELIVERY MODES W.L In nm CHROMOPHORE 1 CO2 Articulated arm, fibroptic CW, P, UP, Flash scan 10,600 Water 2 Argon Fibroptic CW, P 488-514 Hemoglobin 3 Nd:YAG Fibroptic CW, P Q-Switched 1064 Hb, melanin 4 HOL: YAG Fibroptic P 2150 Synovium 5 KTP Fibroptic P 532 Hb, melanin, tatoo pigments
  22. 22. LASER DELIVERY MODES W.L In nm CHROMOPHORE 6 Er:YAG Fibroptic P, UP 2940 Water 7 Q-switched ruby Articulated arm P 694 Melanin, carbon tatoos 8 Pulsed dye Fibroptic P 4001000 Hb, tatoos, vascular malformations 9 Copper vapor Fibroptic P 578 Hemangiomas Tatoos Vascular malformations 157-355 Cornea 10 Excimer Flexible arm P
  23. 23. • • • • Continous Pulsed mode Superpulsed Ultrapulsed • Free beam • Focused • Contact lasers • Non contact lasers
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  25. 25. HOW TO USE A LASER • Wide variety of procedures by laser can be categorised into: 1.Incisional / Excisional techniques 2.Vaporization/ Ablation 3.Hemostasis/ Coagulation
  26. 26. Incisional & Excisional • Co2 laser is used as a light scalpel and is operated in focused mode (smallest possible spot size of that laser). • Focused mode – High power per unit- Deep cut. • Planned margin should be atleast 0.5mm beyond margins, failure to do this may cause thermal effect to encroach on the lesion and make pathologic interpretation unreliable. Area should be outlined in a slow to moderate intermittent mode. • Cutting in intermittent mode could result in perforation rather than incising.
  27. 27. Incision should be performed in one or two passes at a rapid rate of motion, slowing the laser motion will result in deeper incisions but also lateral thermal damage. Deeper incisions are best achieved by increasing power or performing additional passes rather than slowing the traverse speed which may cause widening the zone.
  28. 28. Care should be taken to ensure that the spot size remains constant during the procedure to achieve the uniform depth incision. Typical parameters: spot size -0.10.5mm, power setting within 4-10 watts
  29. 29. • Suture closure of areas excised with co2 laser is not mandatory. • Excellent hemostasis and less scarring,often allows laser wound to heal secondarily. • Laser wounds are slow to epitheliase. Fibrinous coagulum acts as biological dressing • If sutures are used, it is advisable to leave them in place somewhat longer, than would be the case with scalpel wound.
  30. 30. VAPOURISATION TECHNIQUE • Useful in the management of surface lesions such as hyper keratosis, epithelial dysplasia, lichenplanus etc… • This technique is used in diffused mode where the spot size is increased, and power density and depth of cut is decreased. • After it is outlined the lesion should vaporise in a continuous series of connecting and paralleling “U” s, this method ensures an even lacing of the entire lesion. • After initial pass is performed the surface carbonization should be gently wiped with moist gauze
  31. 31. HEMOSTATIC TECHNIQUE • There are number of laser that are highly absorbed by hemoglobin, therefore an ideal in management of vascular lesions. • Argon, copper vapor, Potassium titanyl phosphate(KTP), Nd: YAG, Co2 laser. • Dry field should be maintained, other wise water content greater than that present intracellularly will absorb the laser energy and negate its effects.
  32. 32. GENERAL PRINCIPLES OF CLINICAL LASER APPLICATION • Careful observation of target tissue • Beam should be directed perpendicular to the target tissue unless dissection of the underlying tissue is desired. • When using the continuous or rapid mode the surgeon should work expenditiously and with even strokes.
  33. 33. • Both the power density and fluence may change with small variations in operative technique and may affect clinical outcome in sensitive areas like facial skin. Be aware of tissue that is in the path of laser beam beyond the target tissue. • Width of laser cut corresponds to beam diameter, the depth depends on power set and degree of coagulation necrosis on duration of laser exposure. • Heat produced sterilizes the operating field, so no transplantation of pathology occurs even in touch technique or with a free beam laser.
  34. 34. RATIONAL BASIS FOR USE OF LASERS • CO2 laser, absorption is proportional to water content. Therefore, tissues with high aqueous content like epithelium, connective tissues or muscles rapidly absorb the incident beam. • Non aqueous tissues like bone, tendon, fat are poor absorbers and produces more heat and makes these tissues more anhydrous . flaming may occur on prolonged application. Ho:YAG lasers can be used here as they have shorter wave length (less heat production). • Argon has affinity for red pigment of hemoglobin and used in photocoagulation of vascular lesions. • Nd: YAG has affinity for dark pigments like melanin and protein and is most useful for ablation of large volume of tissues particularly when strict hemostasis is desired.
  35. 35. SOME OF THE COMMON CILNICAL APPLICATIONS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Incisional and excisional biopsies. Focal hyperkeratosis Nicotinic stomatitis Solar chelitis Leukoplakia Erythroplakia Fordysces granules Verrucos carcinoma Oral papillomatosis Lichenplanus Oral melanotic macules . Oral submucosa fibrosis
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  38. 38. MANAGEMENT BY ANATOMIC REGION • 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. TONGUE: Fibroma Papilloma Granular cell tumor Lingual thyroid Hemangioma Lymphangioma Lingual tonsil Lipoma Pyogenic granuloma Apthous ulcer
  40. 40. • 1. 2. 3. 4. 5. 6. LIPS: Mucocele Pyogenic granuloma Fibroma Actinic cheilitis Hemangioma Apthous .
  41. 41. • 1. 2. 3. 4. 5. 6. 7. BUCCAL MUCOSA: Hyperkeratosis/dysplasia Fibroma Payogenic granuloma Hemangioma/lymphangioma Salivarygland tumors Scar tissues/ hyperplastic tissues Lichen planus.
  42. 42. • 1. 2. 3. 4. 5. 6. 7. FLOOR OF THE MOUTH: Ranula Salivary gland tumors Sailolithiasis Hemangioma Lymphangioma Leukoplakia/dysplasia Ankyloglossia
  43. 43. GINGIVA: 1. 2. 3. 4. 5. 6. Lichenplanus Pyogenic granuloma Fibroma Papilloma Drug induced gingival hyperplasia Hyperplastic gingival tissue
  44. 44. • 1. 2. 3. 4. • 1. 2. 3. 4. 5. SOFT PALATE: Salivary gland tumors Hemangiomas/ lymphangiomas Mucous retention phenomena Palatal/uvular hypertrophy. HARD PALATE: Salivary gland tumors without bony invasion Papillary hyperplasia Pyogenic granuloma Apthous Gingival hyperplasia
  45. 45. • 1. 2. 3. 4. 5. 6. 7. 8. 9. DERMATOLOGICAL USES: Angiofibroma Psoriasis Neurofibroma Erythroplasia Pyogenic granuloma Keloids Tattoo Scar revision Basal cell carcinoma
  46. 46. LASER USE IN ANATOMICALLY DIFFICULT AREAS • 1. 2. 3. 4. Surgery in and around oral cavity and face is complicated by the proximity to number of vital structures. Salivary glands and their ducts. Nerves, blood vessels Near the Commissures of oral cavity Airway.
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  48. 48. LASERS-TMJ 1. 2. 3. 4. Anterior disk displacement Synovectomy Hypermobility Perforated disk
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  50. 50. • LASERS IN MALIGNANT LESIONS OF HEAD AND NECK • Ability of lasers to seal blood vessels, lymphatics, nerve endings, decreased levels of inflammatory mediators and reduced scarring, aids in surgery with limited complications. Carbondioxide & Nd:YAG 1. 2. 3. 4. 5. 6. Premalignant/displastic lesions Carcinoma of tongue Carcinoma of lip Lesions of tonsils & oropharynx Lesions of the palate Verrucous carcinoma
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  53. 53. VASCULAR & PIGMENTED LESIONS Argon laser Nd-Yag laser Pulsed dye lasers Q-switched Nd-Yag lasers Examples Hemangioma Port wine stains Neves
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  57. 57. • Both clinical and laboratory studies demonstrated the CO2 laser produces wounds that heal differently from those made by a scalpel. • Scalpel wounds contracted significantly and developed rolled margins that remained present 42 days later. • Laser wounds also developed rolled margins , but flattening occurred 28 days after lasing. • Histologically, there are fewer mayofibroblasts present, which appears to be responsible for less scar contraction. • In addition, less collagen formation is noted, and epithelial regeneration is delayed.
  58. 58. • The regeneration from the epithelial margins appears to extend over the fibrinous coagulum rather than proliferating beneath the granulation tissue, as when wounds heal by secondary intention. • Reepithelialization appears to be complete in 6 weeks, with the original wound outline visible. • There is minimal scaring, and the overlying surface remains palpably soft.
  59. 59. • Ductal orifices in the lased field do not demonstrate any stenosis on healing. • Laser wounds are thought to produce less post opp pain. • Vaporization of cellular structure, organelles, and cellular chemical mediators, as well as sealing of nerve endings, is considered responsible.
  60. 60. LASER IN WOUND HEALING • Lasers employing low level radiant energy have been claimed to produce a positive effect on the biologic and biochemical processes of wound reconstitution. • Low level radiant energy of lasers have accelerated wound healing, reduced pain and enhanced neural regeneration. • It also brings about more rapid epithelialization, enhances neo vascularisation .
  61. 61. • Role of lasers in 3rd molar surgery reveals although helium-neon laser produced a significant reduction of Trismus, but there is no evidence of it reducing pain. • All the studies of laser wound healing have focused on proliferative phase of wound healing( the period of 10-14 days after wound healing that is characterised by population of proliferating fibroblasts and the initiation of the synthesis of collagen).
  62. 62. COMPLICATIONS • General complications: 1.Post operative infections 2.Contact dermatitis 3.Post operative pain 4.ocular injuries 5.Air way 6.Injuries to staff
  63. 63. • Complications unique to extra oral laser surgery of head and neck: 1.Hyperpigmentation 2.Hypopigmentation 3.Erythema 4.Hypertrophic scarring 5.Milia and acne outbreaks
  64. 64. • Complications unique to intra oral laser procedures: 1.Damage to dentition 2.Damage to oropharyngral tissues.
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  66. 66. SAFETY MEASURES • Shielding devices • Fire hazards : drapes alcohol in surgical field • Specular reflection • Electric shock • Explosive hazards: ether cyclopropane alcohol • Virus particles • Combustion products are carcinogenic • Anesthetic : endotrachial tubes anesthetic gas mixture
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  69. 69. Impacted teeth
  70. 70. freenectomy
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  75. 75. References : • Laser applications in OMFS- Guy A. Catone • Lasers in OMFS-Clinics of North America VOL 16. NO 2. MAY 2004 • Lasers in OMFS and dentistry- Lewis Clayman • Fonseca vol 1.
  76. 76. Thank you