• 대한치과의사협회지
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• 제49권11호
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• pp.679-687
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• 2011

Low-level laser therapy (LLLT) is the application of light to pathology to promote tissue regeneration, reduce inflammation, and relieve pain. LLLT has a photochemical effect whereby the light is absorbed and exerts a chemical change. The clinical applications of LLLT include improvement in wound and bone healing processes, control of pain and tooth hypersensitivity, modulation of periodontal inflammation, the prevention and treatment of cancer therapy-induced oral mucositis, management of burning mouth syndrome, and improvement in temporomandibular disorder symptoms. Further research is needed to better elucidate the cellular mechanisms of LLLT and provide a solid scientific basis for the clinical application of LLLT in dentistry.

• Korean Journal of Acupuncture
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• 제32권1호
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• pp.30-38
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• 2015

Objectives : The aim of the study is to investigate the effects of low level laser treatment (LLLT) on the gait behavior in the rat model of arthritis. Methods : Knee arthritis was induced by the injection of $125{\mu}l$ of Complete Freund's Adjuvant(CFA) into the right hind knee joint cavity. Arthritic rats were divided 3 groups; arthritis group was used for control(CON), 10 min of laser treated group(LSR10), and 30 min of laser treated group(LSR30). LLLT was applied to KI 1 for 11 times under gaseous anesthesia. We performed several analyses under catwalk test including stand and swing time, duty cycle of paw steps, intensity and print area of steps, and stride length. Results : Stand and duty cycle of paw steps were increased significantly at 12 days after arthritis induction in LSR30 group. Swing time was decreased significantly at 12 days after arthritis induction in LSR10 group. In the analysis of intensity, print area and stride length, however, results did not show statistical significance during the time point of experiments. Conclusions : The data suggest that LLLT on the rat model of CFA induced arthritis showed beneficial effects by increase of stand time and duty cycle of paw steps and decrease of swing time. Therefore, LLLT could be useful option to improve gait discomfort in arthritis patients.

• Tissue Engineering and Regenerative Medicine
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• 제15권6호
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• pp.793-801
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• 2018

BACKGROUND: The aim of this study was to evaluate the combined effect of low-level laser treatment (LLLT) and recombinant human bone morphological protein-2 (rhBMP-2) applied to hypoxic-cultured MC3T3-E1 osteoblastic cells and to determine possible signaling pathways underlying differentiation and mineralization of osteoblasts under hypoxia. METHODS: MC3T3-E1 cells were cultured under 1% oxygen tension for 72 h. Cell cultures were divided into four groups: normoxia control, low-level laser (LLL) alone, rhBMP-2 combined with LLLT, and rhBMP-2 under hypoxia. Laser irradiation was applied at 0, 24, and 48 h. Cells were treated with rhBMP-2 at 50 ng/mL. Alkaline phosphatase activity was measured at 3, 7, and 14 days to evaluate osteoblastic differentiation. Cell mineralization was determined with Alizarin red S staining at 7 and 14 days. Western blot assays were performed to evaluate whether p38/protein kinase D (PKD) signaling was involved. RESULTS: The results indicate that LLLT and rhBMP-2 synergistically increased alkaline phosphatase (ALP) activity and mineralization. Western blot analyses showed that expression of type I collagen, runt-related transcription factor 2 (RUNX2), and Osterix (Osx), increased and expression of hypoxia-inducible factor 1-alpha ($HIF-1{\alpha}$), decreased more in the LLLT and rhBMP-2 combined group than in the rhBMP-2 or LLL alone groups. Moreover, LLLT and rhBMP-2 stimulated p38 phosphorylation and rhBMP-2 and LLLT increased Prkd1 phosphorylation. CONCLUSION: Combined treatment with rhBMP-2 and LLL induced differentiation and mineralization of hypoxic-cultured MC3T3-E1 osteoblasts by activating p38/PKD signaling in vitro.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.230-243
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• 1996

Root surface exposure due to gingival recession after periodontal surgery, dentin exposure after root planing elicit pain response when exposed to mechanical, heat, chemical or osmotic stimulation. Especially, patients treated with periodontal surgery, show high frequency and there have been reports showing the 1 out of 7 patients have dentin hypersensitivity. There have been many studies on the clinical effects of various materials on the treatment of dentin hypersensitivity. but, none could provide absolute clinical efficacy. In this study, 45 teeth from 30 patients, who had had periodontal surgery and showed dentin hypersensitivity after surgery were chosen for the experimental group and they were illuminated with laser, 15teeth were chosen for the control group and they were not exposed to laser. After this dentin hypersensitivity was elicited by tactile, compressed air, cold water and then, the degree was evaluated using NRS(Numerical Rating Scale). And during LLLT(Low Level Laser Therapy) semiconductor laser using Gallium - Arsenide as a diode was illuminated for 180 seconds at a frequency of 7(500Hz). This therapy was done 10 times, and each time the changes in dentin hypersensitivity was evaluated using NRS. The results were as follows : 1. After treat with LLLT on dentin hypersensitivity due to periodontal surgery, 22.2% showed total loss of dentin hypersensitivity, 60.0% showed loss of tactile dentin hypersensitivity, 48.8% showed loss of compressed air dentin hypersensitivity, 22.2% showed loss of cold water dentin hypersensitivity. 2. As a result of clinical evaluation of dentin hypersensitivity using NRS, there was significant increase in improvement of dentin hypersensitivity in the experimental group compare to the control group(P<0.05). And there was almost no natural loss of dentin hypersensitivity in the control group. 3. In comparison of the stages of evaluation, there was significant difference in between experimental and control group. after the second visit(P<0.05), and the difference increased with each visit.

• 대한의생명과학회지
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• 제13권3호
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• pp.223-230
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• 2007

Low power laser and neuromuscular electrical stimulation have been utilized in many clinical applications for the treatment of musculoskeletal lesion. This study was to investigate the effects of low power He-Ne IR laser and neuromuscular electrical stimulation on the change of the serum biochemical components in experimentally induced muscle injured rats. The twenty Sprague-Dawley male rats were randomly assigned to the 4 groups: the normal group (n=5), the control group (n=5), the low power laser irradiation group (LLI) (n=5) and the neuromuscular electrical stimulation group (NMES) (n=5). The experimentally induced muscle injury was induced by the subcutaneous injection of a 0.1 ml Freund's Complete Adjuvant into the right hind paw and calf muscles in control, LLI and NMES groups. The LLI group was irradiated with He-Ne IR laser for 5 minutes every day during 10 days. Also, the NMES group was electrically stimulated 15 minutes every day during 10 days. The normal and control groups were not received with any therapeutic intervention. The authors performed tests which were the concentration of the serum biochemical components to detect the effects of therapeutic interventions. The results were as follows: 1. The level of the aspartate aminotransferase (AST) was significantly decreased in the LLI and NMES groups compare to the control group. 2. The level of the serum lactate dehydrogenase (LDH) was significantly decreased in the LLI and NMES groups compare to the control group. 3. The level of the serum creatine kinase (CK) was significantly decreased in the LLI and NMES groups compare to the control group. From the results, we could come to the conclusion that low power laser and neuromuscular electrical stimulation could be accelerating healing processes of skeletal muscle injury and further clinical work will be required.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권2호
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• pp.120-124
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• 2009

The concept of biostimulation of wounds by low-level laser therapy(LLLT) is attracting considerable attention. Although its effect on whole tissues has been studied quite extensively, the biological and cellular mechanisms underlying LLLT have not been clarified. In an experimental radius fracture in rabbits, Tang and Chai reported that LLLT enhanced the activity of red blood cells, macrophages, fibroblasts, chondrocytes, and osteoclasts within the fracture area. The purpose of the present study was to evaluate the effect of LLLT with a GaAlAs diode laser device on bone healing in rabbit mandibular fractures. We use 12 rabbits for this study. All rabbits were fractured mandible angle area using saw in anesthetic condition. In control group(n=6), none treatment was performed at fracture site. In experimental group(n=6), LLLT with a GaAlAs diode laser was radiated at fracture site daily for 7 days. All rabbits were sacrificed at 6 weeks later from performed fracture day. We studied the immunohistochemical staining of CD34 and Vimentin and the histochemical analysis for calcium and phosphorus content. The results were as follows. 1. In the histological and immunohistological staining, after 6week, fibroblasts, osteogenic cells and collgen fibers were observed more in experimental group than in control group. 2. In the histochemical analysis, the amount of calcium and phosphorus contents of the experimental group were more than the control group. From the results obtained, we suggest that the bone healing is stimulated by low-level laser irradiation in bone fractures.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.514-515
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• 2008

Low level laser therapy has various therapy effects. This paper performed the basic study for developing the Low Level Laser Therapy Equipment for medical treatment. The apparatus has been fabricated using the laser diode and microprocessor unit. This equipment was fabricated using a micro-controller and a laser diode, and designed to enable us to control light time, frequency and so on. In this study, the designed device was used irradiation to find out how 850 nm laser diode affected the cell proliferation of RAT bone-marrow cells. Experiment was performed to irradiation group and non-irradiation group for Rat bone marrow cells. MTT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590 nm transmittance of micro plate reader. As a result, the cell increase of Rat bone marrow cells was verified in irradiation group as compared to non-irradiation group. The fact that specific wavelength irradiation has an effect on cell vitality and proliferation is known through this study.

• Journal of Oral Medicine and Pain
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• 제17권2호
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• pp.129-149
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• 1992

In order to verify the acceleration effect of low level laser (LLL) on oral mucosal wound healing process at cell biological level, the author studied growth pattern and ultrastructure in human gingival fibroblasts flashed by GaAlAs LLL-830 nm, 15mW for 10 minutes/flash one to three times at interval of 3-4 days through the evaluation of cell growth rate, protein conent/cell, DNA content/cell and ultrastructural changes for 14 days. The results were as follows : 1. The growth rate in gingival fibloblasts treated by LLL showed 4 orderly stages-decreasing stage after LLL treatment, acute increasing stage 3 days after LLL treatment, restring stage and recovering stage. 2. The effect of multiple flashes on LLL at interval of 3 days more or less was not proportional to times of flash on acceleration of growth in gingival fibroblasts. 3. The total protein content per gingival fibroblast was not significantly changed by LLL treatment in comparison with control group. But some kinds of protein which might be cell growth promoting factors were decreased immediately after LLL treatment, thereafter were acutely increased in cellular protein profile. 4. In ultrastructural changes of gingival fibroblasts treated by LLL, more prominent rough endoplasmic reticulum, mitochondrial hyperplasia/hypertrophy and increased extracellular fibrillar matrix were observed in comparison with control group under same experimental period.

• Journal of Periodontal and Implant Science
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• 제38권4호
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• pp.657-668
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• 2008

Purpose: In this study, we compared low-power $CO_2$ laser treatment to ultrasonic scaling, which is generally approved as a power-driven mechanical instrumentation, and evaluated both of these treatments regarding their clinical effectiveness and change in the volume of in GCF. Material and methods: 20 patients who had gingivitis were selected. all of patients has no systemic problems. Randomly selected, one quadrant received ultrasonic scaling only, another quadrant received ultrasonic scaling and $CO_2$ laser irradiation, the other quadrant received $CO_2$ laser irradiation only. Clinical parameters measured at baseline, 1 weeks, 2weeks, 4weeks and 8weeks. Result: Pocket probing depth and clinical attachment level were not changed during study period. Gingival index of all group were improved after treatment. At 1 weeks after treatment, Gingival index of ultrasonic scaling group was only significantly different compared to control group. At 2 weeks after treatment, gingival index of all experimental group were significantly different compared to control group. At 4 and 8 weeks after treatment, gingival index of all group were increased, but experimental group were lower than control group. Sulcus bleeding index was similar to the results of gingival index. At 1 weeks after treatment, all experimental group were significantly different compared to control group and it maintained during study. At 2 weeks after treatment, sulcus bleeding index of all group were lowest during study. Gingival crevicular fluid were measured with $Periotron^{(R)}$ 8000($Oraflow^{(R)}$, Inc. USA). At baseline, all group were showed moderately severe condition. At 1 week after treatment, laser treatment only group was reduced quantity of gingival crevicular fluid mostly, and all group were reduced quantity of gingival crevicular fluid. At 2 weeks after treatment, all group were health state. At 4 and 8 weeks after treatment, all group were showed recurrent of inflammation, and control group was the most significantly increased. Conclusion: This study showed that the effects of $CO_2$ laser treatment were similar to conventional ultrasonic scaling and this result remained longer than plaque control only. These results suggest possibility of $CO_2$ laser treatment for altered periodontal therapy.

• Medical Lasers
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• 제10권4호
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• pp.207-213
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• 2021

Background and Objectives This study was undertaken to assess the stability and efficacy of laser therapy (808 nm), Liquiband (a commercial topical skin adhesive product), and a combination treatment, for application in oral ulcers. Materials and Methods The oral ulcer rat animal model was used to determine the efficacy of photobiomodulation, Liquiband, or combination therapy. Ulcers were induced by injecting 60% acetic acid in the oral mucosa. Three days after ulcer confirmation, the chemically induced ulcers were treated with either laser (808 nm), Liquiband, or a combination of both, every two days for 8 days (4 sessions). Combination therapy was performed by first treating with laser followed by application of the Liquiband. Reduction in ulcer area size was subsequently determined, and animals were sacrificed at 5 and 10 days after the last administration, for histological observation of the extracted oral ulcer tissue samples. Results In this study, treatment with either laser (808 nm) or commercial Liquiband product as well as the combined treatment significantly enhanced oral ulcer healing in the rat animal model. The effect of laser treatment is mainly attributed to collagen synthesis, whereas application of the Liquiband promotes vascularization and formation of granulation tissue. Our results indicate that further optimization of the combined therapy could synergistically and significantly enhance oral ulcer healing. Conclusion Laser or Liquiband treatment of oral ulcer in the rat animal model exert different outcomes, but both methods confirm significant effects relative to the untreated group. The combined treatment group with laser and Liquiband showed marked oral ulcer healing, but further optimization is required to get highly significant results and establish the potential synergistic effect of the combination therapy, as compared to the individual enhancing effects of healing oral ulcers.