Effects Of Low-level Laser Irradiation Research Articles

In Vitro Effect of Low-Level Lasers on Total Bilirubin Concentration in Human Blood Plasma Using 375 and 650 nm Lasers.

Background: The current research extends previous laboratory investigations by investigating the effects of low-level laser irradiation (LLLI) on human blood plasma. Total bilirubin is of special importance because of its potential biostimulatory and modulatory actions. Objective: This study aims to analyze changes in total bilirubin content as a consequence of LLLI on human blood plasma. This study aims to determine how changes in exposure duration and laser wavelength affect these adjustments. Methodology: Plasma was isolated from a healthy adult donor's whole blood using the anticoagulant ethylenediaminetetraacetic acid (EDTA). Plasma samples were exposed to LLLI at 375 and 650 nm for 5, 10, 15, 20, and 25 min. Total bilirubin concentrations were measured both before and after irradiation using spectrophotometric analysis. The difference between 375 and 630 nm lasers was also investigated. Results: Five, 10, 15, 20, and 25 min of exposure to LLLI at 375 and 650 nm wavelengths resulted in statistically significant differences in total bilirubin content (p ˂ 0.05, p ˂ 0.001, p ˂ 0.0001). There was no statistically significant difference in total bilirubin concentration between the 375 and 630 nm lasers. Conclusions: Human blood plasma total bilirubin levels were considerably lower following LLLI at 375 and 630 nm than controls. Multiple exposures provide the same results. These findings demonstrate the role of biostimulation by laser irradiation in blood plasma applications and suggest that low-level laser treatment may control total bilirubin levels, particularly at 375 and 630 nm.

Effect of Low-Level Laser Irradiation (810 nm) on the Proliferation and Differentiation of Osteoblast-Like Cells Cultured on SLA Titanium Discs Exposed to a Peri-implantitis Environment.

Introduction: Elimination of inflammation and re-osseointegration are the major objectives of peri-implantitis therapy. Existing data, however, do not support any decontamination approach. Thus, the present in vitro study aims to assess whether the air-debriding decontamination method with erythritol powder restores the biocompatibility of infected titanium discs and to investigate the potent biomodulatory ability of diode laser (810 nm) irradiation to promote cell proliferation and differentiation of premature osteoblast-like cells (MG63) towards osteocytes. Methods: The experimental groups consisted of cells seeded on titanium discs exposed or not in a peri-implantitis environment with or without biomodulation. Infected discs were cleaned with airflow with erythritol powder. Cell cultures seeded on tricalcium phosphate (TCP) surfaces with or without biomodulation with a laser (810 nm) were used as controls. The study evaluated cell viability, proliferation, adhesion (SEM) at 24, 48 and 72 hours, and surface roughness changes (profilometry), as well as the effects of low-level laser therapy (LLLT) on ALP, OSC, TGF-b1, Runx2, and BMP-7 expression in MG63 cells' genetic profile on days 7, 14, and 21. Results: The MTT assay as well as the FDA/PI method revealed that cell proliferation did not show significant differences between sterile and decontaminated discs at any timepoint. SEM photographs on day 7 showed that osteoblast-like cells adhered to both sterile and disinfected surfaces, while surface roughness did not change based on amplitude parameters. The combination of airflow and LLLT revealed a biomodulated effect on the differentiation of osteoblast-like cells with regard to the impact of laser irradiation on the genetic profile of the MG63 cells. Conclusion: In all groups tested, osteoblast-like cells were able to colonize, proliferate, and differentiate, suggesting a restoration of biocompatibility of infected discs using airflow. Furthermore, photomodulation may promote the differentiation of osteoblast-like cells cultured on both sterile and disinfected titanium surfaces.

The effect of low-level laser irradiation on the proliferation, osteogenesis, inflammatory reaction, and oxidative stress of human periodontal ligament stem cells under inflammatory conditions

Periodontitis often causes damage to the periodontal tissue and affects the function of human periodontal ligament stem cells (hPDLSCs). Low-level laser therapy (LLLT) has been used for periodontal treatment and can upregulate the proliferation and osteogenesis of hPDLSCs. The purpose of this study was to investigate the effects of LLLT on the proliferation, osteogenic differentiation, inflammatory reaction, and oxidative stress of hPDLSCs in an inflammatory environment (pPDLSCs). We designed one control group and three testing groups (treated with Nd:YAG laser at 4, 8, and 16J/cm2) of hPDLSCs from periodontitis patients who were diagnosed with stable phase periodontitis. Cell proliferation was measured by colony-forming unit fibroblast (CFU-F) assays and 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assays. The osteogenic capacity of the cells was determined by alkaline phosphatase (ALP) staining, ALP activity assays, Alizarin Red S staining and the mRNA transcript levels of runt-related transcription factor 2 (Runx2), ALP, and osteocalcin (OCN). The effects of LLLT on the secretion of tumor necrosis factor-α (TNF-α) and interleukin (IL)-1β by PDLSCs were measured by enzyme-linked immunosorbent assay (ELISA). We also evaluated the oxidative stress of hPDLSCs and pPDLSCs by measuring the reactive oxygen species (ROS) level, malondialdehyde (MDA) level, and superoxide dismutase (SOD) activity after treatment with LLLT at 4, 8, and 16J/cm2. Our results demonstrated that LLLT could modulate the osteogenic potential of pPDLSCs at 8J/cm2. Inflammatory stimuli induced excess ROS release, and LLLT at 4-8J/cm2 promoted oxidative stress levels in hPDLSCs but decreased the expression of inflammatory cytokines and ROS levels in pPDLSCs. Moreover, LLLT at 16J/cm2 could significantly suppress proliferation and osteogenic differentiation and promote inflammatory cytokines and ROS levels in pPDLSCs. In conclusion, LLLT could regulate proliferation, osteogenesis, inflammatory reaction, and oxidative stress of human periodontal ligament stem cells under inflammatory conditions.

Effects of Low-Level Laser Irradiation on Mammalian Cell Cultures: Comparative Experimental Studies with Different Types of Lasers at 1260-1270 nm

Abstract The effects observed under near-infrared laser irradiation of mammalian cells have been demonstrated to depend to a large extent on the type of irradiation source. In our experiments, we have measured concentration of reactive oxygen species in cell cultures of different origin (rodent and human, cancerous and non-cancerous) exposed to the radiation of low-level lasers at 1265 nm. Surprisingly, the radiation effects of narrowband laser occur to be more pronounced compared with those provided by the lasers of broader linewidth. Also, we have found that the aggressive types of cancer require a more accurate selection of irradiation parameters and laser operation regime.

Effects of Low-Level Laser Irradiation and Dry Needling on the Symptoms of Myofascial Pain Syndrome: A Controlled Pilot Study

Introduction: This study aimed to compare the effects of Low-Level Laser Therapy (LLLT) combined with Dry Needling (DN) with DN alone on pain and neck disability index following myofascial pain syndrome.
 Materials and Methods: Sixteen women with active Trigger Points (TrPs) in their upper trapezius muscles participated in this study. They were divided into two groups: Experimental and control. The experimental group received one session of the DN plus the LLLT with 6 j/ cm2 energy at their TrPs. The patients in the control group were under a similar procedure, but they did not receive any energy by the LLLT (placebo). The pain score was assessed before, immediately, and 48 hours after the treatment. Neck Disability Index (NDI) was assessed before and 48 hours after the treatment.
 Results: There was a significant improvement in pain intensity and NDI scores 48 hours after the treatment in both groups compared with the baseline scores (P<0.05). The pain was also significantly reduced at the patients following laser therapy immediately after the treatment (P=0.01).
 Conclusion: A combination of the LLLT and DN might be more effective compared with using DN alone, and reduce immediate pain at the patients with the active TrPs. There was no difference between the groups 48 hours after the treatment. It seems that LLLT has no considerable effect on NDI and pain intensity 48 hours after the treatment.

Effect of Low-Level Laser Irradiation on Accommodation and Visual Fatigue.

PurposeThis study used low-level laser irradiation on auricular points for the eyes of junior college teenagers with myopia to observe the changes in refractive errors and eye accommodation. According to the Sterner’s study, we used the relationship between the amplitude and subjective symptoms to assess the degree of improvement in visual fatigue caused by changes in accommodation.MethodsParticipants were 49 healthy junior college teenagers, with an average age of 16.04±0.80 years old, and the refractive errors of both eyes were between −1.50 D and −5.00 D. All participants underwent refractive error tests before and after class and after a 30-min break. In a 30-min break, all participants underwent two tests of with (experimental group) and without (control group) low-level laser irradiation on the auricular points. Then, refractive error tests were conducted to evaluate the participants’ eye accommodation.ResultsThe results revealed that with treatment of the auricular points with and without low-level laser irradiation, the refractive error of the participants’ binocular left and right eyes decreased by −0.12 D (−0.18 D) in the experimental grou and by −0.05 D (−0.02D) in the control group. For the amplitudes of accommodation (AA) examination, the AA of the participants’ binocular in the experimental group became 7.98 ± 1.35 D (7.65 ± 1.37 D). The AA of participants’ binocular can recover to the level before the class.ConclusionThe results indicated that low-level laser irradiation at auricular points restored the eye accommodation faster than did natural closing of the eyes.

EFFECTS OF LOW-LEVEL LASER IRRADIATION ON THE GROWTH OF THE RAT MANDIBULAR CONDYLE IN ORGAN CULTURE

<h3>Objective</h3> The present study was carried out to histologically, immunohistochemically, and histometrically investigate the effect of low-level laser irradiation by a diode laser on the growth of the rat mandibular condyle in organ culture. <h3>Methods</h3> The mandibular condyles were removed from rats' embryos on the 21st day and then cultured for 8 days. The 20 cultured condyles were divided into 4 groups: F−L− group (serumless BGJb); F+L− group (serumless BGJb with bFGF 100 ng/mL); F−L+ group (serumless BGJb and laser irradiation); and F+L+ group (serumless BGJb with bFGF 100 ng/mL and laser irradiation). The laser irradiation (output 1.3 W/cm² and wavelength 633 nm) was performed on the cultured condyle for 30 seconds every 24 hours for 5 days. Immunohistochemically, PCNA was used to analyze cell proliferation. <h3>Results</h3> The mesenchymal cells in the layer of differentiation and hypertrophy in the F+L+ group showed a marked increase in cell number and the size of the condyle. The positive cell number of PCNA in F+L− and F+L+ group was significantly higher compared with the control group. <h3>Conclusions</h3> Our data showed that low-level laser irradiation promotes cell proliferation in the cultured condyle same as in bFGF addition. It is suggested that low-level laser irradiation by a diode laser (wavelength 633 nm) stimulated the proliferation of mesenchymal cells, which resulted in an increase in the number of chondrocytes in the layers of differentiation and hypertrophy by leading to the enlargement of the condylar size.

Protective effect of low-level laser irradiation on lipopolysaccharide-mediated inflammatory injury of human periodontal ligament fibroblasts.

To study the effect and mechanism of low-level laser irradiation (LLLI) on lipopolysaccharide (LPS)-induced inflammatory injury of human periodontal ligament fibroblasts (hPDLFs). hPDLFs were inoculated into well plates and randomly divided into the normal group, LPS group, and LPS+LLLI group. The cells in the normal group were cultured in conventional medium. The hPDLFs in the LPS and LPS+LLLI groups were cultured in RPMI1640 medium containing 1 mg·L-1 LPS. The three subgroups of the LPS+LLLI group were exposed to different LLLI. After 4 days, the cell apoptosis, viability, and intracellular free Ca2+ concentration of each group were measured. The contents of tumor necrosis factor-α (TNF-α), interleukin (IL)-8, IL-1β, and IL-6 were measured by enzyme linked immunosorbent assay (ELISA). Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the expression of matrix metalloproteinase (MMP)-2, MMP-3, and MMP-9 genes and proteins of hPDLFs in each group. Compared with the normal group, the LPS group showed increased apoptosis rate of hPDLFs and intracellular free Ca2+concentration and decreased cell viability (P<0.05). The TNF-α, IL-8, IL-1β, and IL-6 levels were higher in the cell supernatant (P<0.05), and the expression of MMP-2, MMP-3, and MMP-9 genes and proteins of hPDLFs was significantly increased (P<0.05). Compared with the LPS group, the LPS+LLLI group showed significantly decreased apoptosis rate and intracellular free Ca2+ concentration and significantly increased cell viability (P<0.05). The TNF-α, IL-8, IL-1β, and IL-6 levels in the supernatant of cells and the expression of MMP-2, MMP-3, and MMP-9 genes and proteins of hPDLFs were significantly decreased (P<0.05). LLLI has a protective effect on the inflammatory injury of hPDLFs induced by LPS, and the effect is most obvious when the irradiation intensity is 4 J·cm-2.

Therapeutic Window of Photodynamic Treatment (PDT) in Conservative Periodontal Therapy -Analysis of Cell Migration Within A Three Dimensional Collagen Matrix-

Objectives: The aim of the present study was to investigate the effect of low-level laser irradiation as photodynamic therapy (PDT) on proliferation and differentiation of a human fibroblast cell line, determining the therapeutic window of toluidine blue O (TBO) using the 3-D collagen matrix assay with fibroblasts.

Low-level laser irradiation in the comprehensive treatment of acute renal damage

Background. The discussed topic is worth attracting attention because of its high mortality rate in patients with acute renal damage which is caused by urological and surgical diseases. The membrane-destructive component in damaged renal tissues is manifested with decreased glomerular filtration rate, increased endotoxin level and lipid aberrations. The standard infusion and antibacterial therapy does not fully compensate the severity of pathological changes.Purpose. To study the effectiveness of low-level laser irradiation at endotoxicosis and lipid metabolism indicators in acute renal damage in acute experimental peritonitis.Material and methods. Lipid peroxidation, membrane-destructive processes in renal tissues as well as lipid metabolism and endotoxicosis were studied in the experiment with dogs. The effectiveness of infusion and antibiotic therapy and combined therapy with laser light were compared.Basic results: the experiment has demonstrated that acute renal damage was caused by systemic inflammatory diseases of non-urological profile. The applied low-level laser irradiation (LLLI) promoted more rapid correction of pathological processes which were manifested with increased concentration of cholesterol esters, total phospholipids, phosphatidylserine; LLLI decreased levels of cholesterol, phosphatidylcholine, triacylglycerol, phosphatidylinositol, triacylglycerol, phosphatidylinositol, diacylglycerol, lysophospholipids, free fatty acids and endotoxicosis parameters.Conclusion: the obtained results reliably indicate a LLLI positive effect at the organism’s potentials to recover when LLLI is included into the comprehensive therapy (under experiment). This is evidently seen in the restoration of lipid component in elements of renal parenchyma and in the decrease of lipid peroxidation activity.

Effect of low-level laser irradiation on cytotoxicity of benzene in human normal fibroblast cells.

Benzene is volatile organic hydrocarbon which is widely used in a wide range of industries. Studies have shown that exposure to benzene consequences serious health risks for human. Understanding the effect and risks of environmental hazard materials in the laser therapy of skin is interesting which can show useful or harmful role of these effects in therapies. In this study, the effect of low-level laser therapy was investigated on benzene-induced cytotoxicity on human skin fibroblast cells (HU02). Human skin fibroblast cells (HU02) were exposed to various concentrations of benzene (0-100μg/mL) and incubated for 2h. Then the effect of low-level laser therapy (LLLT) at 660-nm wavelength with 3J/cm2 energy for 90s was investigated on the viability of the cells exposed to benzene using MTT assay and inverted light microscope. The effect of low-level laser therapy on the viability of the cells was positive at concentrations 0-15μg/mL but negative at higher concentrations than 15μg/mL. Low-level laser therapy in low concentrations of benzene decreases the cytotoxicity caused by benzene and maintains cell viability. At high concentrations and in the presence of low-level laser therapy, the cell viability decreased compared to dark experiment. The morphology study of the cells using inverted light microscopy has confirmed the MTT results.

THE EFFECT OF LOW-LEVEL LASER IRRADIATION ON FREE RADICAL PROCESSES IN THE MITOCHONDRIAL FRACTIONS INDUCED BY THE BISPHENOL A ADMINISTRATION

Bisphenol A (BPA), the xenoestrogen and plasticizer, can induce mitochondrial dysfunction via the shift in the balance between oxidants and antioxidants. Low-level laser irradiation may influence oxidative stress parameters by changing the activity of antioxidant enzymes and the production of ROS. Our study aimed to investigate the effect of low-level laser irradiation on oxidative stress parameters in hepatic mitochondrial fractions of rats under the conditions of BPA administration. The BPA was administered per os daily for 3 days at a dose of 50 mg/kg body weight. Low-level laser irradiation was performed after each or last administration of xenobiotic. The activity of antioxidant enzymes and the content of free radicals was spectrophotometrically determined in the mitochondrial fraction of the liver. Short-term BPA exposure results in the induction of free radical processes in hepatic mitochondria by the enhanced generation of O2• – and decreased activity of antioxidant enzymes. At the same time, low-level laser irradiation reduces the prooxidant effect of this xenobiotic in mitochondria by the enhancement of the antioxidant activity, which is primarily associated with conformational changes induced by a short-term increase in the temperature of lightabsorbing biomolecules. This effect was observed only in the case of LLLI after BPA exposure.

Effect of low-level laser irradiation on the bisphenol a-induced free radical processes

One of these novel application areas is LLLT for drug-induced liver injury. LLLI employs visible (generally red) or near-infrared light generated from a laser or light-emitting diode (LED) system. The light is typical of narrow spectral width between 600-1000 nm. Despite significant research efforts around the effects and molecular mechanisms of LLLT in various cells or tissues, the appropriate doses of radiation, energy densities, time, and irradiation conditions as well as the appropriate individual settings in the various laser devices, which will predictably lead to optimal therapeutic effects, have not been clarified yet. In the present study, the effect of low-level laser irradiation on oxidative stress parameters in rats under the conditions of BPA administration was investigated. Toxic liver injury induced by bisphenol A (BPA) administration at 50 mg/kg body wt by gavage for 3 days once a day. Low-level laser irradiation was performed after each administration of xenobiotic. A laser diode (50 mW) with 650 nm continuous wavelength was applied to the skin surface at the anatomical site of the liver. The administration of BPA leads to the evaluated of free radical generation and decrease in SOD, CAT and GPx activities in the liver of bisphenol A-exposed animals. The enhanced processes of the generation of superoxide radicals and nitric oxide and exhausting level of antioxidant enzymes under the conditions of BPA administration leads to the increased oxidative damage of lipid and protein in subcellular fraction. The low-level laser irradiation of BPA-treated animals leads to the increase of enzymatic activity of antioxidant defences system, a decrease of free-radical production and oxidative protein and lipid damage in microsome and cytosol.

Effectiveness of Low-Level Laser Irradiation in Reducing Pain and Accelerating Socket Healing After Undisturbed Tooth Extraction.

Introduction: This study aimed to determine the effect of low-level laser therapy (LLLT) on reducing complications following tooth extraction. Methods: This randomized clinical trial consisted of 40 subjects who underwent lower molar extraction. The patients were randomly assigned to 4 groups. Group 1 was irradiated with a 660 nm laser (200 mW, 30 seconds radiation to lingual, buccal and occlusal surfaces of the socket, 6 J/area). In group 2, an 810 nm laser was applied similar to group 1. In group 3, a combination of 660 and 810 nm lasers was used. The patients in group 4 served as a placebo group. LLLT was performed after 0.5-1 hour of extraction and 2 days later. The participants were asked to record pain degree using a visual analogue scale (VAS) over 7 days. The amount of wound healing was evaluated on the third and seventh days. Results: There was no significant difference in pain scores among the groups at any of the assessment intervals (P >0.05). The between-group differences in wound healing scores were small and insignificant (P >0.05). Conclusion: LLLT with 660 nm or 810 nm lasers or their combination had no greater effect than the placebo laser for reducing the complications of tooth extraction.

The effect of low level-laser irradiation on antioxidant enzymes and mineral levels in serum of patients with type 2 diabetes mellitus

Background: The control and management of type 2 diabetes mellitus is the most important way to prevent health consequences of the disease. Oxidative stress derived from diabetes mellitus is an important cause of these symptoms in uncontrolled diabetic patients. The consumption of functional foods containing antioxidants and trace minerals can help prevent these consequences and control diabetes mellitus.Objective: In this study, we examined whether low-level laser therapy could have an effect on levels of antioxidant enzymes and minerals in the serum of patients with type 2 diabetes mellitus.Methods: Thirty individuals with type 2 diabetes and thirty healthy individuals, as controls, were selected as participants for this study. The levels of antioxidant enzymes glutathione peroxidase, catalase, superoxide dismutase; biochemical parameters, such as glucose and hydrogen peroxide; minerals iron, zinc, magnesium, copper; and selenium binding protein 1 (as an indicator of selenium) were studied before and after low level-laser therapy.Results: The levels of antioxidant enzymes and some minerals significantly increased in control and diabetic patients after low level-laser therapy. The levels of glucose, hydrogen peroxide, and selenium binding protein 1, however, were unchanged after low-level laser therapy.Conclusions: Low level-laser therapy may be an important tool for reducing oxidative stress caused by type 2 diabetes mellitus due to its ability to increase levels of antioxidant enzymes and mineral content.Keywords: Laser Irradiation; Antioxidant; Functional Foods/Bioactive Compounds; Diabetes Mellitus.

Low-level laser irradiation potentiates anticancer activity of p-coumaric acid against human malignant melanoma cells.

p-Coumaric acid (PCA) is a kind of phenolic compound, and as one of the cinnamic acid derivatives, it has many biological functions such as antioxidants, anti-inflammatory, antiplatelet, and anticancer activity. Low-level laser irradiation has received increasing interest in the fields of tissue regeneration and wound healing. In this study, the effect of low-level laser irradiation on human fibroblast cells (human dermal fibroblast) and human melanoma cancer cells (A375 and SK-MEL-37) treated with PCA was investigated. The human dermal fibroblast, A375, and SK-MEL-37 cells were exposed to low-level laser at 660-nm wavelength with 3 J/cm for 90 s, and then the cells were treated with different concentrations of PCA (0-1000 μg/ml for 24 h), separately. In another experiment, first the cells were treated by PCA and then irradiated with low-level laser as described before. The effect of various irradiation energy (1-6 J/cm) on the melanoma cells, which were then treated by PCA, was studied. The cell viability using MTT assay and lactate dehydrogenase assay was determined. Morphological changes owing to apoptosis induction by irradiation and PCA were detected by fluorescence microscopy using acridine orange/ethidium bromide double staining. The results showed that pretreatment with low-level laser irradiation and then PCA reduced the survival and growth of melanoma cells more than the early treatment with PCA and then low-level laser irradiation. Lactate dehydrogenase activity was reduced significantly by preirradiation and then PCA treatment in comparison with the dark group in melanoma cells. The cell cytotoxicity at different irradiation energy and then IC50 concentration of PCA was increased up to 3 J/cm and then decreased following increasing irradiation energy. The morphology study with light microscopy and apoptotic assay using acridine orange/ethidium bromide dual staining confirmed the MTT results. This study showed that low-level laser irradiation alone is not able to kill human normal fibroblast and human melanoma cancer cells. Preirradiation followed by treatment with PCA did not change the cell viability in human fibroblast significantly but reduced the cell viability in melanoma cells presumably through the apoptosis pathway.

The effect of low-level laser radiation and doxycycline on the levels of osteoprotegerin and receptor activator of nuclear factor kappa-B ligand.

The present in vitro study was conducted to investigate the effect of low-level laser (LLL) radiation and doxycycline on the levels of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-B ligand (RANKL) derived from MG-63 osteosarcoma cell line. MG-63 cells were divided into four groups. In the first group, 2mg/mL of doxycycline was injected into the cell culture medium. Diode laser (810nm, 100mw, 75s) was radiated to the culture medium of the second group. The third group received both doxycycline and laser radiation. In the fourth group (control), the culture medium was replaced daily, similar to the above three groups. Mentioned interventions were performed once a day for 4 consecutive days. Then, on the sixth day, the levels of OPG and RANKL mediators were measured using real-time polymerase chain reaction by isolating the cells from the samples. OPG expression had the highest to lowest levels in the laser + doxycycline, doxycycline, laser, and control groups, respectively. The level of OPG was significantly different between all the study groups (p < 0.05) except in the doxycycline + laser and doxycycline groups (p = 0.061). The highest to lowest levels of RANKL was observed in the doxycycline, laser + doxycycline, control, and laser groups, respectively. The RANKL expression was not significantly different between all the study groups (p > 0.05). The results of this study revealed that LLL and doxycycline reduced the RANKL/OPG ratio derived from the MG-63 osteosarcoma cell line, which may result in the diminished activity of osteoclasts and osteoclastogenesis.

Therapeutic and photobiomodulation effects of low-level laser irradiation on Egyptian patients with carpal tunnel syndrome: a placebo-controlled study

Background/Aim Carpal tunnel syndrome (CTS) is the most prevalent mononeuropathy, where the median nerve is entrapped in the hand; it affects women more than men and is diagnosed by clinical and electrophysiological examination. Low-level laser therapy (LLLT) was suggested for conservative treatment of CTS. The aim of this study was to evaluate the role of LLLT in the treatment of CTS. Patients and methods The study was carried out on 40 female patients with CTS. Patients were recruited from Neurology and Rheumatology clinics at National Research Centre, Egypt. The patients were randomly divided into two groups (20 patients each). The first group was subjected to active LLLT, and the second group was subjected to placebo (sham) LLLT. The patients of the first group were treated with real LLLT by gallium-aluminum-arsenide laser (905 nm) with touch sensor guide light +8 diodes of power output of 100 MW each (800 MW total), and pulsed mode of frequency of 10 000 Hz over two areas, one extends from the proximal palmer crease to the distal wrist crease and the other over the thenar area, for three times per week for 4 weeks (12 sessions). All patients were subjected to clinical and nerve conduction studies evaluations. Results LLLT showed significant reduction in erythrocyte sedimentation rate and visual analog scale and significant improvement in functional status scale and symptom severity scale (P Conclusion This study confirmed the safety and positive effects of LLLT on pain, inflammation, functional capacity, and electro-neurophysiological aspects of median nerve in patients with CTS.

Low-level laser-aided orthodontic treatment of periodontally compromised patients: a randomised controlled trial

Low-level laser irradiation (LLLI) shows effects in orthodontic pain relief and periodontal inflammation control. The aim of this article is to investigate the analgesic and inflammation-modulatory effects of low-level laser irradiation among orthodontic patients with compromised periodontium. A randomised controlled trial with split-mouth design was conducted in 27 adults with treated and controlled chronic periodontitis over 6 months. One side of the dental arch underwent repeated treatment under a 940-nm diode laser (EZlase; Biolase Technology Inc.) with a beam size of 2.8 cm2 for 60 seconds at 8.6 J/cm2, whilst the other side received pseudo-laser treatment. Laser irradiation was applied repeatedly for 8 times during the first 6 weeks after bracket bonding and monthly thereafter until the end of orthodontic treatment. Subjective pain (assessed by visual analogue scale in pain diary and by chairside archwire activation), periodontal status (assessed by periodontal clinical parameters), cytokines in gingival crevicular fluid (interleukin 1β, prostaglandin E2, substance P) and periodontopathic bacteria (Porphyromonas gingivalis and Treponema denticola) in supragingival plaque were assessed. The intensity of pain was lower on the laser-irradiated side at multiple follow-up visits (P < 0.05). The pain subsided 1 day earlier on the laser side, with a lower peak value during the first week after initial archwire placement (P < 0.05). The laser side exhibited a smaller reduction in bite force during the first month (mean difference = 3.17, 95% CI: 2.36–3.98, P < 0.05 at 1-week interval; mean difference = 3.09, 95% CI: 1.87–4.32, P < 0.05 at 1-month interval). A smaller increase was observed in the plaque index scores on the laser side at 1-month (mean difference = 0.19, 95% CI: 0.13–0.24, P < 0.05) and in the gingival index scores at the 3-month follow-up visit (mean difference = 0.18, 95% CI: 0.14–0.21, P < 0.05). Laser irradiation inhibited the elevation of interleukin-1β, prostaglandin E2 and substance P levels during the first month (P < 0.05). However, no intergroup difference was detected in the bacteria levels. Low-level laser irradiation exhibits benefits in pain relief and inflammation control during the early stage of adjunctive orthodontic treatment in periodontally compromised individuals.

Influence of Pulsed He-Ne Laser Irradiation on the Red Blood Cell Interaction Studied by Optical Tweezers.

Optical Tweezers (OT), as a revolutionary innovation in laser physics, has been extremely useful in studying cell interaction dynamics at a single-cell level. The reversible aggregation process of red blood cells (RBCs) has an important influence on blood rheological properties, but the underlying mechanism has not been fully understood. The regulating effects of low-level laser irradiation on blood rheological properties have been reported. However, the influence of pulsed laser irradiation, and the origin of laser irradiation effects on the interaction between RBCs remain unclear. In this study, RBC interaction was assessed in detail with OT. The effects of both continuous and pulsed low-level He–Ne laser irradiation on RBC aggregation was investigated within a short irradiation period (up to 300 s). The results indicate stronger intercellular interaction between RBCs in the enforced disaggregation process, and both the cell contact time and the initial contact area between two RBCs showed an impact on the measured disaggregation force. Meanwhile, the RBC aggregation force that was independent to measurement conditions decreased after a short time of pulsed He–Ne laser irradiation. These results provide new insights into the understanding of the RBC interaction mechanism and laser irradiation effects on blood properties.