Lasers in orthodontics /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
0091-9248678078



The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.


Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
00919248678078

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Lasers in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. LASERS IN ORTHODONTICS www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. Laser Evolution Laser devices have been used in the past two decades in countless ways to benefit humankind. LASER – Light Amplification by Stimulated Emission of Radiation. 1917-Einstein-if a photon struck a molecule already in an excited state the molecule would fall back to the lower energy and emit a photon of exactly the same size and move in the same direction as the entering photon. 1957-Townes-amplify microwave frequencies-MASER – “Microwave amplification of stimulated emission of radiation”. www.indiandentalacademy.com
  4. 4. 1958 – Schawlow and Townes-extended MASER principle to the optical portion of the electromagnetic field. 1960 – Theodore Hurold Maiman-first succesful operation of a laser device using a synthetic ruby made from aluminium oxide doped with chromium oxide. www.indiandentalacademy.com
  5. 5. Laser Physics What are photons? The basic units or quanta of light- photons. A quantum of light can be depicted as an electromagnetic wave with an electric field oscillating up and down in the plane of the page. Speed- 1 foot/nanosecond ( 1 ns = 1 billionth of a second). www.indiandentalacademy.com
  6. 6. Light Absorption and Emission: When light encounters matter – deflected or absorbed. If a photon is absorbed - energy is not destroyed – but used to increase the energy level of the absorbing molecule. Atom absorbs photon Photon ceases to exist and an electron within atom jumps to higher energy level Atom pumped up to an excited state from resting ground state Atom unstable and spontaneously decay back to the ground state releasing stored energy in the form of emitted photon. www.indiandentalacademy.com “Spontaneous emission”
  7. 7. www.indiandentalacademy.com
  8. 8. Light amplification by stimulated emission of radiation Lasing occurs when an excited atom can be stimulated to emit a photon before the process occurs spontaneously. When a photon of exactly the right wavelength enters the electromagnetic field of an excited atom,the incident photon triggers the decay of the excited electron to lower energy state. Release of stored energy in the form of second photon. Stimulated emission occurs when the incident photon has same energy as released photon.If a collection of atoms include more that are pumped into excited state than resting state,a population inversion exists.-ideal condition for lasing. www.indiandentalacademy.com
  9. 9. The spontaneous emission of a photon by one atom will stimulate the release of a second photon in a second atom and these two photons will trigger the release of two more photons. These four then yield eight; eight yield sixteen and so on. A brief intense flash of monochromatic ( same wavelength) and coherent (same phase) light is produced. www.indiandentalacademy.com
  10. 10. www.indiandentalacademy.com
  11. 11. Principle of Laser Laser works on the principle of generation of monochromatic,coherent and collimated radiation by a suitable medium in an optical oscillator. Monochromatic:Laser light is characterized by radiation in which all waves have same frequency and energy. Coherent:All waves are in a certain phase relationship. Collimated:All emitted waves are near by parallel and the beam divergence is very low. www.indiandentalacademy.com
  12. 12. Components of Laser devices:Laser medium • Solid • Liquid • Gas This medium determines the wavelength of the light emitted from the laser and the laser is named after the medium. An Optical cavity or Laser Tube It consists of two mirrors,one fully and the other partially transmissive which are located at either end of the optical cavity. Some form of External power source This is necessary to excite the atom in the laser medium to a higher www.indiandentalacademy.com energy level for population inversion to take place.
  13. 13. Classification of Lasers According to mode of emission •Fractioned •Continuous •Pulsed According to power •High power laser •Medium power laser •Low power laser www.indiandentalacademy.com
  14. 14. According to emitting material •Gas laser •Solid state laser •Dye laser •Semi conductor diode laser •Ring laser The Carbon dioxide laser The lasing medium contains a mixture of carbon dioxide,nitrogen and helium gases. Nitrogen molecules are pumped up with energy from an electric discharge applied to the lower tube. www.indiandentalacademy.com
  15. 15. Solid state lasers: In solid state lasers,the lasing medium is suspended in a transparent crystal.A garnet crystal made from yttrium and aluminium is commonly used in a variety of surgical lasers call YAG lasers. YAG lasers can be used in combination with three rare earth elements,neodymium,holmium and erbium. Each element has a different arrangement of electron orbitals so that lasing occurs at different wavelengths for each. Argon laser: It is one of the rare gas ion lasers capable of outputs of several watts continuous light in the visible green and blue portion of the spectrum.The active lasing medium is argon gas. www.indiandentalacademy.com
  16. 16. Laser interaction with biologic tissues When radiant energy is absorbed by tissue,four basic types of interactions or responses can occur. Photochemical interactions Photochemical interactions include bio stimulation which describes the stimulatory effects of laser light on biochemical and molecular processes that normally occur in tissues such as healing and repair. Photodynamic therapy which is the therapeutic use of lasers to induce reactions in tissues for the treatment of pathologic conditions and phosphorescent re emission or tissue fluoroscence-used as a diagnostic method to detect light reactive substances in tissue. Photothermal interactions Photothermal interactions manifest clinically as photo ablation or the removal of tissue by vaporization and super heating of tissue www.indiandentalacademy.com fluids,coagulation and hemostasis and photopyrolysis.
  17. 17. Photomechanical Interactions Photmechanical interactions include photodisruption or photodissociation which is the breaking apart of structures by laser light and photo acoustic interactions which involve the removal of tissue with shock wave generation. Photoelectrical Interactions Photo electrical interactions include photo plasmolysis which describes how tissue is removed through the formation of electrically charged ions and particles that exist in a semi gaseous,high energy state. www.indiandentalacademy.com
  18. 18. Laser Effects on Dental Hard Tissues Thermal effects The best known laser effect in dentistry is the thermal vaporization of tissue by absorbing infrared laser light.The laser energy is converted into thermal energy or heat that destroys the tissues.At 100 degrees centigrade the water inside the tissue vaporizes.The absorption of the laser energy increases rapidly. Mechanical effects High energetic and short pulsed laser light can lead to a fast heating of the dental tissues in a very small area.High and fast shock waves lead to mechanical damage of the irradiated tissue. www.indiandentalacademy.com
  19. 19. Chemical effects The basis of the photochemical effect is the absorption of laser light without any thermal effect which leads to an alteration in the chemical and physical properties of the irradiated tissues. Molecules can be dissociated directly with laser light of high photon energies. www.indiandentalacademy.com
  20. 20. Enamel surface response to laser ablation Carbon dioxide medium:Surface fusion,roughness,etching,partially fused crystallites,charred,cracking. Nd:YAG:Terraced surface,rough fused crystallites,charred,cracking. Argon:Reflection of beam produces minimal effect on enamel surface. Ruby:Cratering,irregular cavitation surface,charred. www.indiandentalacademy.com
  21. 21. Uses Of Lasers in Dentistry:Argon laser: • Root planing and curettage • Oral lesion therapy • Laser Tissue welding-fusing vascular tissues by laser thermal welding and for coagulation and hemostasis of bleeding vessels. Carbon dioxide laser:• Biopsies • Tongue lesions • www.indiandentalacademy.com White lesions – vesiculobulbous and premalignant lesions.
  22. 22. • Aphthous ulcers • Herpetic lesions • Coagulation • Exposure of Implants • Distal wedge and tuberosity reduction • Hypersensitivity • Pre prosthetic surgery • Malignant lesions • Gingival troughing Er:YAG laser:• Removal of dental filling materials • Bone ablation and oral soft tissue ablation. www.indiandentalacademy.com
  23. 23. Orthodontic applications of laser: •Gingivectomy/gingivoplasty •Frenectomy •Temperomandibular disorders •Low level laser therapy for arthritic cases •Pain control with LLLT •Etching •Bonding •Debonding •Newer brackets with laser cut bracket bases •Holographic studies www.indiandentalacademy.com
  24. 24. Laser Etching in Orthodontics Laser etching can be done with the help of various types of lasers such as Argon laser,Krypton flouride excimer laser and so on. Arf-193nm,Krf-248nm,Xecl-308 nm Principle The high performance density leads to a locally restricted very strong and fast interaction with the irradiated material that splits the bond of organic and inorganic substances on the surface.This process of microexplosion is called photoablation. Due to the extremely short pulse length of some nanoseconds and sudden removal,there is no efficient heat conductance through the hard substance which shows that there is no harmful increase in the temperature of the pulp. www.indiandentalacademy.com
  25. 25. Bonding Argon laser for light curing adhesives (Mark Kurchak,Bernadette Desantos,John Powers,David Turner) JCO 1997 •The enamel surface was etched with 37% phosphoric acid for 15 seconds. •The surface was treated with Megabond. •Adhesive precoated brckets were placed on enamel surface. •Laser tip was held 0.5mm from the bracket and the light curing wand was kept touching the bracket. •No enamel damage caused by argon lasers at energy levels www.indiandentalacademy.com of 1.6 to 6 watts.
  26. 26. Result •The study demonstrates that 10 seconds of curing with argon laser produces bond strenghts comparable to those achieved with 20 to 40 seconds of curing with a conventional high intensity light. •The time savings involved in bonding a full arch is significant with the help of Laser. www.indiandentalacademy.com
  27. 27. Bond strengths of two ceramic brackets using argon laser,light and chemically cured resin systems (Sergio J Weinberger,Timothy F Foley,Robert J McConell,Gerald Z Wright) AJO 1998 Three methods were used to bond the brackets to the teeth. •First method consisted of a light cured microfilled resin and laser energy for curing. •Second method consisted of light cured microfilled resin and visible light curing unit for curing. •Third method involved a one step no mix chemically cured adhesive. •Debonded samples were examined under a stereo microscope and bond strengths measured with the help of Instron machine. www.indiandentalacademy.com
  28. 28. Result •There were no differences noted in the bond strength between light and laser cured brackets. •Upon debonding,no enamel fractures occurred among chemically cured brackets.Light and laser cured brackets exhibited a 10% rate of enamel fracture on debonding. www.indiandentalacademy.com
  29. 29. Laser Debonding of Ceramic Orthodontic brackets (Robert M Tocchio,Peter T Williams,Franz J Mayer,Kenneth G Standing) AJO 1993 Laser light has been shown to degrade resins by thermal softening or photo ablation. •Both polycrystalline alumina and single crystal alumina (saphire) ceramic orthodontic brackets were bonded to the labial surface of lower deciduous teeth with regular acid etch technique. •Under externally applied stress of 0.8Mpa,the brackets were debonded by irradiating the labial surfaces of the brackets with laser light at wavelengths of 248nm,308nm,1060nm. •Debonding times were measured and the surfaces created by debonding were examined with both light and scanning electron microscopy to determinewww.indiandentalacademy.com the extent of bracket and enamel damage.
  30. 30. Results •No enamel bracket damage in any sample. •The debonding of polycrystalline brackets is caused by thermal softening of the bonding resin resulting from heating of the bracket. The hot bracket then slides off the tooth. •Ideal debonding time – 0.5 seconds shows no pulp reaction,Pulp irritation increases only with increased lasing time. •No enamel tear outs and catastrophic bracket failures were observed. •Lasers used are Nd:YAG laser and carbon dioxide laser. •Porosity suggestive of gas production in a molten resin was observed in a few locations. www.indiandentalacademy.com
  31. 31. Newer Bracket Systems Newer brackets with laser reinforced structured bases enable the force to be applied even closer to the crown. The patented laser structured base of brackets guarantees an excellent bond during the entire treatment period. Laser markings help in easy identification of brackets.When compared with conventional markings,laser markings cannot be abraded and does not contain harmful colouring agents. www.indiandentalacademy.com
  32. 32. Efficacy of low level laser therapy ( LLLT) in reducing orthodontic post adjustment pain LLLT has been shown to produce analgesic effects in many clinical applications. Terminology included soft laser,mid laser,low energy laser,cold laser. Defined as laser treatment in which the energy output is low enough so as not to cause a rise in the temperature of the treated tissue above 36.5 degrees centigrade or normal body temperature. Biostimulatory effects of LLLT have been attributed to its anti inflammatory and neuronal effects. Harris proposed that LLLT has benign stimulatory influence on depressed neuronal and lymphocyte respiration. www.indiandentalacademy.com
  33. 33. •Stabilization of membrane potential and release of neuro transmitters. •Laser unit used was Class 3B Galium diode laser probe with a wavelength of 830 nm. Result: Although LLLT was found to be unable to provide immediate pain relief,it could have a potential in reducing the intensity of pain during its time course with just one or two applications. www.indiandentalacademy.com
  34. 34. Laser in Holography Hans Rydin and Bielkhagen(1982) developed a new method for comparing the tooth positions on the dental casts at different stages.Holograms of the casts were prepared using Helium Neon laser Burstone C.J.T.W.Every and R.J.Pryputneiwiz (1982)based on pulsed laser hologram inferometry studied the dynamics of incisor extrusion. Procedure: The output from the laser is split into two parts by beam splitter.One part was expanded by a beam expander and is used to illuminate the object. www.indiandentalacademy.com The scattered wave from the object is called object wave.
  35. 35. The second part was expanded by a beam expander,reflected by a mirror and a wave called reference wave is formed which forms the hologram. www.indiandentalacademy.com
  36. 36. Laser Safety in Dental Practice Tissue hazards • Laser induced damage to the skin and other non target tissue can result from thermal interaction of radiant energy with tissue proteins. • Temperature elevations of 21 degrees centigrade above the normal body temperature can produce cell destruction by denaturation of cellular enzymes and structural proteins. • Histologically thermal coagulation necrosis is produced. • During ablation of oral tissue with carbon dioxide laser a carbonized layer of tissue or char layer forms.This char layer is a strong absorbent of different wavelengths of laser light and the extent of collateral damage increases with this www.indiandentalacademy.com layer.Mechanical removal of char layer is essential.
  37. 37. Environmental hazards • Potential inhalation of airborne hazardous materials that may be released as a result of laser therapy. • Some lasers contain inert gases (argon, krypton or xenon) mixed with toxic gases such as fluorine or hydrogen chloride as the active medium. • Inhalation of toxic material in the form of aerosols has been found potentially damaging to the respiratory system. • Standard surgical masks and surgical smoke evacuation equipment is used in the theatre. • Greatest producers of smoke – carbon dioxide and Nd:YAG laser. www.indiandentalacademy.com
  38. 38. Combustion Hazards •Flammable solids,liquids and gases used within the surgical setting can be easily ignited if exposed to the laser beam. •The use of flame resistant materials and other precautions therefore is recommended •Flammable materials found in dental treatment areas. Solids Liquids Clothing Ethanol Oxygen Paper Products Acetone Nitrous oxide Plastics Methylmethacrylate General anesthetics Waxes and Resins Solvents www.indiandentalacademy.com Gases Aromatic Vapours
  39. 39. Electrical hazards •Electrical hazards of lasers can be grouped as electrical shock hazards,electric fire hazards or explosion hazards. •Insulated circuitry,shielding,grounding and housing of high voltage electrical components provide protection under most circumstances from electrical injury. www.indiandentalacademy.com
  40. 40. Personal Protective Equipment Eye protection Light produced by lasers presents potential hazard for occular damage by either direct viewing or reflection of the beam. Adequate eye protection must be worn by the operator as well as the patient. They are available in the form of safety goggles or screening devices.Laser protective eyewear filters are specified according to their optical density which takes into account the wavelength,power and diameter of the beam. Laser filtration masks – prevents air borne contamination. Foot pedal control switch with protective hood prevents accidental depression by surgical staff. www.indiandentalacademy.com
  41. 41. www.indiandentalacademy.com
  42. 42. CONCLUSION With technology and science reaching new heights it is needless to say that lasers would soon become a necessity in every field of science .Orthodontics has also been captured into this magical spell of laser which would enable us to reach new goals. www.indiandentalacademy.com
  43. 43. Thank you www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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