Sandoval MC, Mattiello-Rosa SM, Soares EG, Parizotto NA.
School of Physical Therapy, Industrial University of Santander, Bucaramanga, Columbia.
Photomed Laser Surg. 2009 Feb 2 [PMID: 19187016]
Abstract Objective: The purpose of this study was to evaluate the effects of low-level laser (LLL) energy on the clinical signs of inflammation and the cellular composition of synovial fluid (SF) in the inflamed knee of the rabbit.
Background Data: There are few findings related to the effects of LLL on SF in inflammatory processes and there is little knowledge about the optimal parameters for reducing joint inflammation.
Materials and Methods: Inflammation in the right knee of 36 rabbits was induced by intracapsular injection (0.2 mL) of Terebinthina commun (Tc). The animals were randomly assigned to three groups: acute experimental group (AEG), chronic experimental group (CEG), and control group (CG), which only received Tc. Each group was divided in two subgroups of six animals each. The AEG and CEG groups began to receive laser treatment 2 and 5 d after the induction of inflammation, respectively. Laser irradiation at a wavelength of 830 nm, power output of 77 mW, and power density of 27.5 W/cm(2) was applied daily for 7 d for either 0.12 sec or 0.32 sec, resulting in doses of 3.4 J/cm(2) and 8 J/cm(2), respectively. Body mass, joint perimeter, joint temperature, and the morphology of the SF were analyzed.
Results: There was no statistically significant differences between groups in the body mass, joint perimeter, and SF morphology.
Conclusion: Laser irradiation with the selected parameters produced only a few subtle differences in the inflammatory signs and the SF. The lack of effects may have been due to the short irradiation time.
by Richard Martin, BS, CLT
Practical Pain Management, Nov/Dec 2003
Injured cells and tissues have greater affinity for LLLT than healthy cells and tissues. LLLT in the treatment of inflammation, pain and healing is a highly integrated process, but the author separates those processes categorically for identification.
Acute Inflammation Reduction(flowchart provided in the original article) – After injury, tissues initiate a series of biological responses and cellular membrane reactions which manifest in a combination of edema, inflammation, pain and functional debility. LLLT mediates by: (1) Stabilizing cellular membranes; (2) Enhancing molecule ATP production and synthesis; (3) Stimulating vasodilation via increased Histamine, Nitric Oxide and Serotonin; (4) Accelerating leukocytic activity; (5) Increasing Prostaglandin synthesis; (6) Reducing Interleukin-1; (7) Enhancing lymphocyte response; (8) Increasing angiogenesis; (9) Modulation temperature; (10) Enhancing superoxide dismutase levels; and (11) Decreasing C-reactive protein and neopterin levels.
Pain Reduction(flowchart provided in the original article) – Evidence justifies a conclusion that LLLT reduces pain by combination of processes: (1) Increase in b-Endorphins; (2) Blocked depolarization of C-fiber afferent nerves; (3) Increased nitric oxide production; (4) Increased nerve cell action potential; (5) Axonal sprouting and nerve cell regeneration; (6) Decreased Bradykinin levels; (7) Increased release of acetylcholine; and (8) Ion channel normalization.
Tissue Healing – LLLT enhances wound healing by: (1) Enhanced leukocyte infiltration; (2) Increased macrophage activity; (3) Increased neovascularization; (4) Increased fibroblast proliferation; (5) Keratinocyte proliferation; (6) Early epithelialization; (7) Growth factor increases; (8) Enhanced cell proliferation and differentiation, and (9) Greater healed wound tensile strength.Click for Main Studies Page
de Morais NC, Barbosa AM, Vale ML, Villaverde AB, de Lima CJ, Cogo JC, Zamuner SR.
Laboratory of Inflammation, Institute of Research and Development, University of Vale do Paraí ba , Sáo José dos Campos, Brazil.
Photomed Laser Surg. 2009 Sep 25. [PMID: 19780633]
Abstract Objective: The aim of this work was to investigate the effect of low-level laser therapy (LLLT) and light-emitting diode (LED) on formation of edema, increase in vascular permeability, and articular joint hyperalgesia in zymosan-induced arthritis.
Background Data: It has been suggested that low-level laser and LED irradiation can modulate inflammatory processes.
Material and Methods: Arthritis was induced in male Wistar rats (250-280 g) by intra-articular injection of zymosan (1 mg in 50 muL of a sterile saline solution) into one rear knee joint. Animals were irradiated immediately, 1 h, and 2 h after zymosan administration with a semiconductor laser (685 nm and 830 nm) and an LED at 628 nm, with the same dose (2.5 J/cm(2)) for laser and LED. In the positive control group, animals were injected with the anti-inflammatory drug dexamethasone 1 h prior to the zymosan administration. Edema was measured by the wet/dry weight difference of the articular tissue, the increase in vascular permeability was assessed by the extravasation of Evans blue dye, and joint hyperalgesia was measured using the rat knee-joint articular incapacitation test.
Results: Irradiation with 685 nm and 830 nm laser wavelengths significantly inhibited edema formation, vascular permeability, and hyperalgesia. Laser irradiation, averaged over the two wavelengths, reduced the vascular permeability by 24%, edema formation by 23%, and articular incapacitation by 59%. Treatment with LED (628 nm), with the same fluence as the laser, had no effect in zymosan-induced arthritis.
Conclusion: LLLT reduces inflammatory signs more effectively than LED irradiation with similar irradiation times (100 sec), average outputs (20 mW), and energy doses (2 J) in an animal model of zymosan-induced arthritis. The anti-inflammatory effects of LLLT appear to be a class effect, which is not wavelength specific in the red and infrared parts of the optical spectrum.
Freddo AL, Rodrigo SM, Massotti FP, Etges A, de Oliveira MG.
School of Dentistry, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Rio Grande do Sul, Brazil.
Lasers Med Sci. 2009 Sep;24(5):721-8. Epub 2008 Nov 15. [PMID: 19011949]
This study evaluated the use of red and infrared lasers on tissue surrounding the femurs of 60 rats randomly divided into three groups after implantation of bioabsorbable plates. The control group were not subjected to laser irradiation; group A was treated with red laser [indium-gallium-aluminum-phosphide (InGaAlP) laser, wavelength 685 nm, 35 mW, continuous wave (CW), Ø = 0.06 cm, 2.23 min], and group B was subjected to infrared laser [gallium-aluminum-arsenium (GaAlAs) laser, wavelength 830 nm, 50 mw, CW, Ø = 0.06 cm, 1.41 min], both at 10 J/cm(2). Samples were stained with hematoxylin and eosin (H&E) and examined microscopically. Results showed that the laser irradiation had had a positive photobiomodulation effect on inflammation, confirmed by a better histologic pattern than that of the control group at 3 days and 7 days. Semiquantitative analysis revealed that groups A and B had a histologic score significantly greater than that of the control group at 3 days. At 21 days, histomorphometric analysis revealed a more intense inflammation in the red laser group than in the other groups. We concluded that low-level laser therapy (LLLT) has positive effects on the photobiomodulation of inflammation in the tissues surrounding the poly-L-lactic/polyglycolic acid (PLLA/PGA) bioabsorbable plate. It stimulated vascularization, fibroblast proliferation, and collagen deposition.Click for Main Studies Page
Maver-Biscanin M, Mravak-Stipetic M, Jerolimov V.
Department of Prosthodontics, Clinical Hospital Centre, Zagreb, Croatia. firstname.lastname@example.org
Photomed Laser Surg. 2005 Jun;23(3):328-32. [PMID: 15954824]
OBJECTIVE: The purpose of our report is to present the effect of low-level laser therapy on Candida albicans growth and palatal inflammation in two patients with denture stomatitis.
BACKGROUND DATA: The most common oral mucosal disorder in denture wearers is denture stomatitis, a condition that is usually associated with the presence of the yeast Candida albicans. Different treatment methods have been suggested to treat this symptom, none of which is proven to be absolutely effective.
METHODS: Two denture-wearing patients, both with palatal inflammation diagnosed as Newton type II denture stomatitis were treated with low-power semiconductor diode laser (BTL-2000, Prague, Czech Republic) at different wavelengths (685 and 830 nm) for 5 d consecutively. In both patients, palatal mucosa and acrylic denture base were irradiated in noncontact mode (probe distance of 0.5 cm from irradiated area) with different exposure times-5 min (830 nm, 3.0 J/cm2, 60 mW) and 10 min (685 nm, 3.0 J/cm2, 30 mW). The effect of laser light on fungal growth in vivo was evaluated after the final treatment using the swab method and semiquantitative estimation of Candida albicans colonies growth on agar plates. The severity of inflammation was evaluated using clinical criteria.
RESULTS: After lowlevel laser treatment, the reduction of yeast colonies on the agar plates was observed and palatal inflammation was diminished.
CONCLUSION: LLLT is effective in the treatment of denture stomatitis. Further placebo controlled studies are in progress.
Fikácková H, Dostálová T, Vosická R, Peterová V, Navrátil L, Lesák J.
Institute of Biophysics and Informatics, 1st Medical Faculty, Charles University, Prague, Czech Republic. email@example.com
Photomed Laser Surg. 2006 Aug;24(4):522-7. [PMID: 16942435]
OBJECTIVE:: This case report describes the treatment of a patient with arthralgia of the temporomandibular joint (TMJ) caused by disc displacement.
BACKGROUND DATA: The goal of the treatment of TMJ arthralgia is to decrease pain by promotion of the musculoskeletal system's natural healing ability.
METHODS:: This report describes the complex treatment of TMJ arthralgia. Low-level laser therapy (LLLT) was chosen for its antiinflammatory and analgesic effects. Laser therapy was carried out using the GaAlAs diode laser with an output power of 400 mW, emitting radiation with a wavelength of 830 nm, and having energy density of 15 J/cm2; the laser radiation was applied by contact mode on four targeted spots in 10 sessions. Physiotherapy was recommended to this patient to prevent the injury of intraarticular tissue caused by incorrect movement during opening of the mouth. Splint stabilization and prosthetic treatment were used to reduce overloading of the TMJ, resulting from unstable occlusion and to help repositioning of the dislocated disc.
RESULTS: Five applications of LLLT led to decrease of pain in the area of the TMJ on the Visual Analog Scale, from 20 to 5 mm. The anti-inflammatory effect of the laser was confirmed by thermographic examination. Before treatment, the temperature differences between the areas of the normal TMJ and TMJ with arthralgia was higher than 0.5 degrees C. However, at the conclusion of LLLT, temperatures in the areas surrounding the TMJ were equalized.
CONCLUSION: This study showed the effectiveness of complex non-invasive treatment in patients with arthralgia of the TMJ. The analgesic and anti-inflammatory effects of LLLT were confirmed by infrared thermography.
Sato T, Kawatani M, Takeshige C, Matsumoto I.
Department of Anesthesiology, Saitama Medical College, Saitama, Japan.
Acupunct Electrother Res. 1994 Jun-Sep;19(2-3):141-51. [PMID: 7863838]
A Ga-Al-As diode system that produces low-energy red light (830 nm, 40 mW) has been used for the treatment of many kinds of pain. The mechanism of action of this new laser irradiation for analgesia was studied in anesthetized rats. The effect of laser irradiation of the saphenous nerve was studied by recording neuronal activity at the L4 dorsal root filaments after the injection of a chemical irritant, turpentine. Laser irradiation inhibited both the asynchronous firing by that was induced by turpentine and increased part of the slow components of the action potentials. Thus, the laser irradiation selectively inhibited nociceptive signals at peripheral nerves.Click for Main Studies Page