Laser in Medicine PDF

Laser in medicine By: Abdullah Munqith Principles of Laser LASER Light Amplification by Stimulated Emission of Radiation Principles of Laser Atomic transitions Electron energy levels, allowed states E4 E3 E2 electron hf ΔE E1 Before excitation Excited states Atom: excited state E2 E1 E0 Photon energ...

Laser in medicine By: Abdullah Munqith Principles of Laser LASER Light Amplification by Stimulated Emission of Radiation Principles of Laser Atomic transitions Electron energy levels, allowed states E4 E3 E2 electron hf ΔE E1 Before excitation Excited states Atom: excited state E2 E1 E0 Photon energy ΔE=hf (energy absorbed) E2 Ground state E1 After excitation Principles of Laser Ordinarily more atoms in the ground state than excited state Population inversion happens if there are more atoms in the excited state than the ground state Principles of Laser Atomic transitions Spontaneous emission (10-8sec) Atom: excited state Atom: ground state E2 E2 ΔE E1 E1 Before de-excitation hf=ΔE After de-excitation Stimulated emission Atom: excited state E2 ΔE hf=ΔE Before E1 Atom: ground state E2 hf hf After E1 Excited atom returns to ground state and hence emits a 2nd photon of the same energy Principles of Laser Stimulated emission photons properties: Excited atom returns to ground state and hence emits a 2nd photon of the same energy Both photons are in phase and have the same energy (color) (wavelength) Both photons can stimulate other atoms to emit photons that in turn stimulate the emission of more photons. Laser Typical Characteristics Uni-directional; same direction. Single wavelength in visible region; same frequency. Same phase. Intense beam. General Applications CD players Pointers Printers Eye surgery (reshaping cornea). Soft tissue procedures excision of tumors/lesions, incision/ excision biopsies, burns tumours and so forth. Control of bleeding in vascular lesions. Arthroscopic joint surgery. Cuts metal Cuts patterns (many layers of cloth at once) Telecommunications (sent down optical fibers) Power of Laser 1-5 mW 30- 100 W laser pointers surgical lasers 100-3000 W in industry; laser cutting 1.3 PW (1.3 x 1015 W) most powerful produced at Lawrence Livermore Lab. Laser Dental Applications 1-Reshape gum tissue (reduce prominence) Gum reshaping or contouring for some people who their gums may cover up too much of their teeth, that can make their teeth look smaller, and for some, it holds them back from smiling. This surgery can involve the use of a scalpel, a laser or radiosurgery. Gum reduction surgery requires a local anesthetic. Your dentist will assess the area that needs treatment and will choose the best method for it. Laser Dental Applications Surgical gingivectomy : Local anaesthetic is used to keep the patient comfortable during the procedure. The technique is completed with a surgical scalpel and involves trimming and removing the tissue around the teeth. The remaining gums are reattached in and around the teeth by sutures (stitches), and the area is cleaned with saline. After the procedure is completed, a surgical dressing, or pack, is placed in and around the teeth and gums. This dressing is left in place for about a week. Laser Dental Applications Laser gingivectomy : Dental lasers, and in particular diode lasers, are being increasingly used, and gingivectomy is the most common procedure performed with dental lasers. Several laser wavelengths can be used to precisely to incise gingiva for restorative, cosmetic, and periodontal indications; however, diode lasers come with smaller set up and often better price. Rapid healing and reduced pain are commonly seen postoperatively and patients rarely need periodontal packing or sutures. Laser Dental Applications The Laser types include: Nd:YAG (Neodymium: Yttrium Aluminium Garnet) laser CO2 laser Diode laser Laser Dental Applications 2-Laser aided teeth whitening Laser teeth whitening is a bleaching procedure done in a dentist’s office. It’s different from other teeth whitening methods, as the procedure involves a bleaching gel and laser. A laser is a beam of high intensity light. designed to brighten your teeth. It’s also known as laser teeth bleaching. During the procedure, a bleaching gel is applied to your teeth. A laser is then directed onto your teeth, which heats up the gel. This activates its whitening properties and alters stain molecules on the teeth. The goal of laser teeth whitening is to reduce discoloration and make your teeth look whiter. Laser Dental Applications Tooth discoloration can happen for many reasons, including: Consuming certain foods and drinks, like coffee and tea. Using tobacco. Aging. Injury to the mouth. Certain medications, like antihistamines and chemotherapy. Laser Dental Applications 3. Laser Drill Preparation for fillings. Capable of killing bacteria located in a cavity. No vibration. - Laser: Erbium Yag (Er: YAG) Wavelength 2940 nm, light of this wavelength highly absorbed by water. Laser beam absorbed by decayed tissue because of large water content compared with healthy enamel. ✓ Result : Selective ablation of decay Conservation of healthy tooth No increase in pulp temperature