Effect Of Low-level Laser Research Articles

Antiproliferative effect of low-level laser/ photobiomodulation on gingival fibroblasts derived from calcium channel blocker-induced gingival overgrowth

The aim of this study was to evaluate the antiproliferative properties of low-level laser therapy (LLLT) on gingival fibroblasts obtained from calcium channel blocker-induced gingival overgrowth (GO). Gingival fibroblasts of patients with GO were compared to healthy gingival fibroblasts (H). Both cells were exposed to LLLT (685 nm wavelength, 25mW power, diode laser) and compared to those not treated with LLLT. Cell proliferation and viability were measured with MTT assay at baseline and after 24 and 72 h. TGF-β1, CTGF, and collagen Type 1 levels were evaluated with Enzyme-Linked Immunosorbent Assay (ELISA). LLLT significantly decreased the proliferation of GO fibroblasts (p < 0.05) while leading to a significantly higher proliferation in H fibroblasts compared to the untreated cells (p < 0.05). GO cells showed significantly higher CTGF, TGF-β, and collagen Type 1 expression than the H cells (p < 0.05). LLLT significantly reduced CTGF levels in GO cells compared to the control group (p < 0.05). In H cells, CTGF and TGF-β levels were also significantly decreased in response to LLLT compared to the control group (p < 0.05). While LLLT significantly reduced collagen expression in the H group (p < 0.05), it did not significantly impact the GO cells. LLLT significantly reduced the synthesis of the growth factors and collagen in both groups with an antiproliferative effect on the gingival fibroblasts from calcium channel blocker-induced GO, suggesting that it can offer a therapeutic approach in the clinical management of drug-induced GO, reversing the fibrotic changes.

Effect of Pulsed Low-Level Lasers on Adult versus Neonatal Human Retinal Pigment Epithelial Cells: An in-vitro Study.

To investigate the short-term effects of low-level lasers (LLLs; also known as low-power laser therapy) on the structure, genetic, and phenotype of cultured human retinal pigment epithelial (hRPE) cells from both adult and neonatal sources. Cultivated adult and neonatal hRPE cells were irradiated with two types of LLL (630 nm and 780 nm), 1 min daily for five consecutive days. An increase in doubling time was observed in 630 nm-irradiated adult hRPE cells (P = 0.032). The gene expression profile revealed increased expression of retinoid isomerohydrolase RPE65 (RPE65) (P 0.01 for 630 nm laser, P 0.001 for 780 nm laser) and nestin (NES) (P 0.01 for 630 nm laser) in neonatal hRPE cells, upregulation of RPE65 (P 0.001 for 780 nm laser) and paired box 6 (PAX6) (P 0.001 for 780 nm laser) genes in adult hRPE cells, and reduced expression of actin alpha 2 (ACTA2) in 780 nm-irradiated adult hRPE cells (P 0.001). Except the significant increase of -SMA in 780 nm-irradiated neonatal hRPE cells, no significant change was noted in the expressions of other investigated proteins. Short-term irradiation of neonatal and adult hRPE cells with LLLs may induce multipotency at the transcriptional level. Irradiation of neonatal hRPE cells with LLLs can be associated with increased risk of myofibroblastic transformation; however, adult hRPE cells irradiated with the 780 nm laser have minimal risk of myofibroblastic differentiation. It seems that the 780 nm laser may be a promising option for future photobiomodulation in retinal degenerations in adults.

Therapeutic Effects of Low-Level Laser Combined with LED on Post-operative Hand

Therapeutic Effects of Low-Level Laser Combined with LED on Post-operative Hand

Correction to: Evaluate and compare the effectiveness of low-level laser (diode) therapy and occlusal splints in TMJ pain-pilot study

Correction to: Evaluate and compare the effectiveness of low-level laser (diode) therapy and occlusal splints in TMJ pain-pilot study

Near infrared low-level laser effect on electron radiation therapy of non-melanoma human squamous cell cancer: An in-vitro study

PurposeThe aim is to assess the efficacy of combined electron-laser radiation therapy on non-melanoma Squamous cell carcinoma (SCC) cancer cells in an in-vitro model. Material and methodsThe human SCC cancer line (TSCC-1) was purchased from the Iranian Biological Resources Center (IBRC) and cultured according to the standard protocol. The groups of this study were control; only electron radiation; only Low-Level Laser Therapy (LLLT); and combined laser-electron radiation. Irradiation with a 980 nm 50 mW laser was performed in a single session with energy doses of 1 and 1.5 J/cm2. Electron radiation was carried out using a Varian accelerator with a radiation dose of 2 and 4 Gy. 24 h after laser treatment of cancer cells, combined electron irradiation was performed. MTT and flow cytometry bioassays were performed and analyzed to check their effectiveness. ResultsThe cell viability assay for irradiation with 980 nm 50 mW NIR laser in a single session with an irradiation time of 20 and 30 s in combination with 2 and 4 Gy electrons showed a significant difference (P-value <0.01). Flow cytometry test of the electron-radiated samples showed that the sum of early and late apoptosis was the highest. However, for the combination of electron-laser radiation of 30 s with 2 and 4 Gy electrons, the maximum percentage of apoptosis and necrosis was obtained close to the electron alone. Except for the control group, the quantitative interval of induced necrosis of all the groups evaluated by electron alone, laser alone, and combined electron laser was almost equivalent. ConclusionsThis study showed that the physical parameters of a 980 nm NIR LLLT might not have a synergy effect on treatment response in combination with an electron ionizing beam on SCC cancer cells. It is critical to consider the effect of light irradiation parameters for combination therapy in more extensive studies.

Effect of Low-Level Laser on The Pain PerceptionFollowing Dental Extraction

The goal of this study was to determine the effectiveness of a single dose of low-level laser therapy (LLLT) on the pain of patients after tooth extraction. Thirty patients in total were divided into two treatment groups. Each group consists of fifteen patients. Group A received a single dose of LLLT 20 minutes after tooth extraction with (0.3 W, 30 sec, 9 J/cm2) diode laser. The irradiation was extra-orally 1 cm away from the site of interest. Group B is the control group. The patients' level of pain was assessed. Visual analog scale (VAS) was utilized to quantify pain intensity in the 2nd and 7th days after extraction. Results indicated that (Group A) had significantly decreased VAS values than (Group B) on postoperative day 7. The current study suggested that there is a significant effect of single dose (LLLT) on lowering pain following tooth extraction.

Short-term effects of low-level laser versus ultrasound therapy on children’s neck posture after long-term use of electronic devices

The purpose of the study was to compare the effect of low-level laser therapy (LLLT), ultrasound therapy (US), and strengthening and stretching exercise in children diagnosed with cervical straightening caused by long-term use of electronic devices. A total of 60 patients from 12 to 18 years of both gender diagnosed with straight neck syndrome which is losing the normal C shape of cervical vertebrae. Patients were randomized into three groups. In group A, patients received LLLT plus exercise, while in group B, they received US plus exercise, and group C received exercise. In group A and B, Cobb angle and VAS showed a significant improvement (more significant in group A) with P < 0.001, while in group C P = 0.006. LLLT, US, and exercise improved the cervical straight curve, and reduced pain with maximum effect was done by LLLT.

Effects of low level laser on periodontal tissue remodeling in hPDLCs under tensile stress

This study aimed to investigate the effect of Low-Level Laser Therapy (LLLT) on human Periodontal Ligament Cells (hPDLCs) under tension stress. Primary hPDLCs were obtained using the tissue culture method, and P3 cells were utilized for the subsequent experiments. The study comprised four groups: a blank control group (Group B), a laser irradiation group (Group L), a tension stress group (Group T), and a laser + tension stress group (Group LT). Mechanical loading was applied using an in-vitro cell stress loading device at a frequency of 0.5 Hz and deformation of 2% for two hours per day for two days. Laser irradiation at 808 nm GaAlAs laser was administered 1 h after force loading. Cell samples were collected after the experiment. Bone and fiber remodeling factors were analyzed using PCR and Western blot. Flow cytometry was employed to assess the cell cycle, while ROS and Ca2+ levels were measured using a multifunctional enzyme labeling instrument. The results revealed that laser intervention under tension stress inhibited the expression of osteogenic differentiation factors, promoted the expression of osteoclast differentiation factors, and significantly increased the production of collagen factors, MMPs, and TIMPs. The LT group exhibited the most active cell cycle (P < 0.05). LLLT not only enhanced Ca2+ expression in hPDLCs under tension stress, but also stimulated the production of ROS. Overall, our findings demonstrate that LLLT effectively accelerated the proliferation of hPDLCs and the remodeling of periodontal tissue, possibly through the regulation of ROS and Ca2+ levels in hPDLCs.

Effects of low-level laser on the expression of interleukin-6, tumor necrosis factor‑α, osteoprotegerin, and receptor activator of nuclear factor-κB ligand in human periodontal ligament cells.

This study aims to determine the effects of low-level laser (LLL) on the expression of interleukin-6 (IL-6), tumor necrosis factor (TNF)-α, osteoprotegerin (OPG), and receptor activator of nuclear factor-κB ligand (RANKL) in human periodontal ligament cells (HPDLCs) stimulated by high glucose; and identify the molecular mechanism of LLL therapy in the regulation of periodontal inflammation and bone remodeling during orthodontic treatment in diabetic patients. HPDLCs were cultured in vitro to simulate orthodontic after loading and irradiated with LLL therapy. The cultured cells were randomly divided into four groups: low glucose Dulbecco's modification of Eagle's medium (DMEM)+stress stimulation (group A), high glucose DMEM+stress stimulation (group B), hypoglycemic DMEM+LLL therapy+stress stimulation (group C), and hyperglycemic DMEM+LLL therapy+stress stimulation (group D). Groups C and D were further divided into C1 and D1 (energy density: 3.75 J/cm2) and C2 and D2 (energy density: 5.625 J/cm2). Cells in groups A, B, C, and D were irradiated by LLL before irradiation. At 0, 12, 24, 48, and 72 h, the supernatants of the cell cultures were extracted at regular intervals, and the protein expression levels of IL-6, TNF-α, OPG, and RANKL were detected by enzyme-linked immunosorbent assay. 1) The levels of IL-6 and TNF-α secreted by HPDLCs increased gradually with time under static pressure stimulation. After 12 h, the levels of IL-6 and TNF-α secreted by HPDLCs in group A were significantly higher than those in groups B, C1, and C2 (P<0.05), which in group B were significantly higher than those in groups D1, and D2 (P<0.01). 2) The OPG protein concentration showed an upward trend before 24 h and a downward trend thereafter. The RANKL protein concentration increased, whereas the OPG/RANKL ratio decreased with time. Significant differen-ces in OPG, RANKL, and OPG/RANKL ratio were found among group A and groups B, C1, C2 as well as group B and groups D1, D2 (P<0.05). 1) In the high glucose+stress stimulation environment, the concentrations of IL-6 and TNF-α secreted by HPDLCs increased with time, the expression of OPG decreased, the expression of RANKL increased, and the ratio of OPG/RANKL decreased. As such, high glucose environment can promote bone resorption. After LLL therapy, the levels of IL-6 and TNF-α decreased, indicating that LLL therapy could antagonize the increase in the levels of inflammatory factors induced by high glucose environment and upregulate the expression of OPG in human HPDLCs, downregulation of RANKL expression in HPDLCs resulted in the upregulation of the ratio of OPG/RANKL and reversed the imbalance of bone metabolism induced by high glucose levels. 2) The decrease in inflammatory factors and the regulation of bone metabolism in HPDLCs were enhanced with increasing laser energy density within 3.75-5.625 J/cm2. Hence, the ability of LLL therapy to modulate bone remodeling increases with increasing dose.

Therapeutic Effects of Low-Level Laser on Male Infertility: A Systematic Review.

Introduction: The objective of this study was to assess the effectiveness and safety of photobiomodulation (PBM) in the treatment of male infertility. Methods: We searched Google Scholar, PubMed, and the reference sections of relevant papers published from January 1, 2000 to September 23, 2022. We retrieved all publications related to the impact of PBM on male infertility. After reviewing the titles, abstracts, and full texts, we included fifteen papers in the research. The studies involved 477 semen samples (in vitro studies) and 70 male participants (randomized clinical trials). Results: All 14 in vitro studies that evaluated effectiveness reported that PBM was successful in increasing the proportion of progressive sperms in semen samples. Various methods were used to evaluate the safety. One study with a sample size of 58 concluded that PBM was not a safe treatment, whereas the other ten studies confirmed its safety. Only one clinical trial evaluated the effect of laser acupuncture on male infertility and found improvements in sperm progressive motility without any serious adverse effects. Conclusion: All 15 studies evaluating effectiveness reported that the low-level laser was effective for increasing the proportion of progressive sperm in semen samples and that it was safe to use. However, due to the heterogeneity of population characteristics, source characteristics, duration of exposure, sample size, and instruments for measuring safety and efficacy, we cannot conclude that the positive results obtained from the reviewed studies are solely attributable to the low-level laser on the sperm samples.

The effects of low-level laser therapy and photodynamic therapy on oral health of fixed orthodontics patients. A systematic review and meta-analysis

Objective To investigate the effect of low-level laser and photodynamic therapy on the oral health, and periodontal tissue of fixed orthodontic patients and the effect of using photobiomodulation methods compared to routine plaque removal methods and the amount of plaque in fixed orthodontic patients.Method and materials First, the title and summary of related articles were collected by using the search strategy electronic databases PUBMED, EMBASE, Cochrane's CENTRAL, Scopus, ISI and all the articles that were published from the beginning to February 2023 were evaluated. The title, abstracts and full texts of all the relevant studies were reviewed respectively, and those meeting the criteria were entered into our study. Finally, the quality of the studies was examined and the results of the studies were pooled by means of random effects inverse variance meta-analysis.Results Eighteen randomized studies, conducted between 2015 and December 2022, were selected for meta-analysis. Five studies were conducted as split-mouth, twelve as parallel-group, and one as a cross-over design. Among the studies, five examined the effects of low-level laser therapy and twelve assessed the effects of photodynamic therapy. The meta-analysis revealed that photodynamic therapy significantly reduced probing depth compared to scaling (MD=-0.2 mm, P<0.001), though the difference does not seem to be clinically significant. But no significant differences between photodynamic therapy and scaling or low-level laser therapy and control groups in terms of plaque index, or bleeding on probing, gingival crevicular fluid volume, gingival recession, clinical attachment loss, bacterial load and concentrations of inflammatory substances across multiple follow-up periods.Conclusion Moderate evidence indicates that photodynamic therapy (PDT) is comparable to conventional methods in improving oral health, as measured by periodontal indices, inflammatory proteins, bacterial colonies, and white spot lesions, making it a suitable alternative. Limited evidence suggests low-level laser therapy (LLLT) may improve oral health, particularly addressing caries, but further research is needed.

Effect of low-level laser therapy on quadriceps and foot muscle fatigue in children with spastic diplegia: a randomized controlled study

Spastic diplegia is the most common form of cerebral palsy; children with spastic diplegia are suffering from muscle fatigue and spasticity which lead to decreasing power of muscles, impaired motor control, and many functional abilities. The effect of low-level laser (LLL) has a good result as it improves muscles pain and spasticity and in decreasing lactate levels. Forty children were selected with spastic diplegia and were divided into two groups: A and B. Group A received low-level laser treatment (LLLT) with physiotherapy treatment. Group B got physiotherapy sessions. Pain intensity was assessed by the visual analog scale (VAS) of pain which is reliable from age 5, before treatment and after 1-month follow-up. Muscle fatigue and power were assessed by maximum voluntary isometric contraction (MVIC) before treatment and after 1-month follow-up. Also, we tested blood lactate level in both groups; all evaluations were done before treatment and after 1-month follow-up. We found a significant difference between the two groups in VAS and MVIC and blood lactate level test regarding low-level therapy after 1-month follow-up. There is a good effect of low-level laser in increasing muscle power, decreasing blood lactate level, and improving pain.

Evaluation of photobiomodulation effect on cesarean-sectioned wound healing: a clinical study.

The effects of low-level laser on the wound healing and burn injuries have been previously examined to demonstrate some satisfactory results. Despite there are a few articles available to study photobiomodulation (PBM) effects on the pain relief of cesarean sectioned wound, however no systematic examination has been carried out so far regarding its healing. Here, the aim of this clinical study was to evaluate PBM effect on the cesarean-sectioned wound healing. PBM effects of semiconductor lasers are investigated at 658 and 660 nm with 100, 150 and 350 mW output powers on 40 patients. Due to the global increasing number of cesarean sections, we have decided to investigate the effect of laser as a reliable technique to recover the wounds fast. We considered women as the target group who had their first delivery giving the birth of their children by cesarean section. We selected patients are who treated by laser therapy using indium gallium aluminum phosphide (InGaAlP) semiconductor linear scanning type with beam cross section of 12 cm2 and the output power of 100 mW at 658nm exposing a therapeutic dose of 2J/cm2. The purpose is to accelerate the healing process of the wounds after delivery as an intervention group against the people who chose the conventional methods (using ointments, pills, etc.) to heal their cesarean sectioned wounds as the control group. Regarding the wounds of these two groups, the questionnaires were filled by patients to assess the severity of pain from visual analogue scale (VAS) based on the healing of wounds from redness, edema, ecchymosis, discharge, and distance between the two edges of the wound (REEDA) scale in the early hours after surgery and the post-treatment follow-up on the third, seventh, and the tenth days. The data collected by these questionnaires were analyzed using statistical package for social science)SPSS( as a statistical software to give out the comparative histograms. This study reports a clinical examination of PBM under intervention group of 40 patients ranging 18-40years old with body mass index (BMI) of 29-36, during post-cesarean surgery to elucidate successful healing of the wounds and scars against conventional methods which considered as control group. Comparison of mean REEDA scores on the third day (p = 0.035), seventh day (p = 0.03), and tenth day (p = 0.02) after delivery exhibits that the two groups benefit a statistically significant difference with each other. For instance, the mean wound healing score in the intervention group was almost half of the mean wound healing score on the tenth day in the control group (1.09 ± 0.586 vs. 2.25 ± 0.422). The post-cesarean follow-up indicates that the patients treated by the laser therapy (intervention group) encounter better recovery than the control group.

Effect of Low-Level Laser of 650nm on Viability of Porphyromonas Gingivalis with and with Out Photosensitizers: An Invitro Study

Effect of Low-Level Laser of 650nm on Viability of Porphyromonas Gingivalis with and with Out Photosensitizers: An Invitro Study

Effect of Low level laser on miniscrew displacement during canine retraction: A randomized controlled clinical trial

Background: Anchorage is an important consideration for successful orthodontic treatment. Skeletal anchorage by miniscrews provided better anchorage control then the ordinary extra-oral and intra-oral appliances. However, the stability of the miniscrews is still questionable since they might move under orthodontic loading. Objectives: The aim of this study was to evaluate the effect of Low Level Laser on the miniscrew displacement when subjected to orthodontic force during canine retraction using CBCT. Methods: Twelve patients who required bilateral extraction of upper first premolar and absolute anchorage were recruited from the outpatient clinics of the Department of Orthodontics, Faculty of Dentistry, Beirut Arab University of age ranging 14-28 years. Twenty-four miniscrews were assessed; two miniscrews were inserted into the buccal alveolar bone between the second premolar and first molar on the right and left side for each patient in a 60o oblique direction at the mucogingival junction to avoid root injury. They were divided into 2 sides; test side and a control side, the test side received 4 application of low-level laser therapy during the first twelve days of insertion with a 60 seconds for each application. While the control side did not receive any laser application. After waiting a period of twelve days from miniscrew insertion to allow for soft tissue healing, the upper right and left canines were retracted by 150g of nickel-titanium (NiTi) closed coil springs. A cone-beam computed tomography was taken to evaluate the miniscrew position before application of the force at baseline (T0) and after canine retraction at 6 months (T1). Results: There was no statistically significant difference of miniscrew head and tail displacements of the test side and a sta- tistically significant difference of the heads for the control sides when compared to baseline. Conclusions: Miniscrews used in the current study with the suggested protocol underwent non-significant displacement when using low level laser. The miniscrews remained stable throughout the follow-up period (6 month) without any significant displacement on the test side.

Low-Level Laser Therapy Facilitates Post-Contraction Recovery with Ischemic Preconditioning.

Despite early development of muscle fatigue, ischemic preconditioning is gaining popularity for strength training combined with low-load resistance exercise. This study investigated the effect of low-level laser (LLL) on post-contraction recovery with ischemic preconditioning. Forty healthy adults (22.9 ± 3.5 years) were allocated into sham (11 males, 9 females) and LLL (11 males, 9 females) groups. With ischemic preconditioning, they were trained with three bouts of intermittent wrist extension of 40% maximal voluntary contraction (MVC). During the recovery period, the LLL group received low-level laser (wavelength of 808 nm, 60 Joules) on the working muscle, whereas the sham group received no sham therapy. MVC, force fluctuations, and discharge variables of motor units (MU) for a trapezoidal contraction were compared between groups at baseline (T0), post-contraction (T1), and after-recovery (T2). At T2, the LLL group exhibited a higher normalized MVC (T2/T0) (86.22 ± 12.59%) than that of the sham group (71.70 ± 13.56%)(p = .001). The LLL group had smaller normalized force fluctuations (LLL: 94.76 ± 21.95%, Sham: 121.37 ± 29.02%, p = .002) with greater normalized EMG amplitude (LLL: 94.33 ± 14.69%, Sham: 73.57 ± 14.94%, p < .001) during trapezoidal contraction. In the LLL group, the smaller force fluctuations were associated with lower coefficients of variation of inter-spike intervals of MUs (LLL: .202 ± .053, Sham: .208 ± .048, p = .004) with higher recruitment thresholds (LLL: 11.61 ± 12.68 %MVC, Sham: 10.27 ± 12.73 %MVC, p = .003). Low-level laser expedites post-contraction recovery with ischemic preconditioning, manifesting as superior force generation capacity and force precision control for activation of MUs with a higher recruitment threshold and lower discharge variability.

Investigating the Effectiveness of Low-Level Laser in Reducing Root Resorption of the Upper Incisors During Intrusion Movement Using Mini-Implants in Adult Patients With Deep Overbite: A Randomized Controlled Clinical Trial.

Deep bite is a common characteristic of malocclusion, and many methods are used to treat it, including mini-implants used for the intrusion of the upper incisors. Orthodontically induced inflammatory root resorption (OIIRR) is an inevitable and unexpected side effect of orthodontic therapy. However, resorption of the root could be affected by the type of tooth movement, such as intrusion. Several studies have indicated the effectiveness of low-level laser therapy (LLLT) in accelerating orthodontic movement, but studies that have evaluated the role of this laser in reducing the risk of OIIRR have been limited. This trial aimed to investigate the effectiveness of LLLT in reducing the resorption of the roots of the upper incisors during their intrusion in the context of deep bite correction. Thirty patients (13 males, 17 females; mean age 22.4±3.37 years) with deep overbite were recruited and allocated to the laser or the control groups. Mini-implants were inserted between the roots of the upper central incisors and the lateral incisors from the labial aspect at the gingival-mucosal junction on both sides with a force of 40 g on each side through an NiTi coil spring. A low-level laser (Ga-Al-As) with 808 nm wavelength in a continuous mode, with the parameters250 milliwattpower output, 4 Joules/point energy density, and 16 seconds irradiation per point, was applied to the root of each of the upper incisors. The laser was applied on the first day of the upper incisor intrusion (T1), then on days 3, 7, and 14 of the first month. In the second month, the laser was applied every 15 days, adjusting the spring strength every four weeks until the end of the intrusion stage (T2), which was determined by reaching a normal overbite. As for patients in the control group, the strength of the nickel-titanium springs was adjusted every four weeks to the required strength of 40 g on each end until reaching a normal overbite. There was a volumetric decrease in both groups' upper central and lateral incisors roots, and this decrease was statistically significant (P<0.001). However, the difference between the two groups was not statistically significant in each central and lateral incisor volume root (P=0.345 and 0.263 for U1 and U2, respectively). Also, both groups had a linear decrease in upper central and lateral incisors roots, which was statistically significant (P<0.001). At the same time, the difference between the two groups was not statistically significant in each central and lateral incisor root length (P=0.343 and 0.461for U1 and U2, respectively). The low-level laser irradiation using the current protocol did not significantly affect the amount of root resorption induced by incisor intrusion in the experimental group compared to the control group.

Evaluate and compare the effectiveness of low-level laser (diode) therapy and occlusal splints in TMJ pain-pilot study

Evaluate and compare the effectiveness of low-level laser (diode) therapy and occlusal splints in TMJ pain-pilot study

Effect of Low-Level Laser with and without Shoulder Mobilization in Treating Shoulder Impingement

Effect of Low-Level Laser with and without Shoulder Mobilization in Treating Shoulder Impingement

The effects of low-level laser in the treatment of myofascial pain syndrome: systematic review

The effects of low-level laser in the treatment of myofascial pain syndrome: systematic review