Effect Of Laser Photobiomodulation Research Articles

Effect of LASER photobiomodulation on the cell viabilities of periodontal ligament fibroblasts of older and younger individuals - An in vitro study.

Fibroblasts form the major cell type of the periodontal ligament and most often studied for periodontal regeneration. The aim of the present study was to investigate the effects of photobiomodulation (PBM) on aged periodontal fibroblasts and compare the viability of periodontal fibroblasts of older and younger individuals. A total of 32 patients were divided into four groups: A, B, C, and D. Groups A and C and B and D comprised of extracted teeth of older (>60 year) and younger individuals (<25 year), respectively. Extracted teeth from Groups A and B received PBM, (diode laser, 660 nm, 100 mW at 4J) whereas Groups C and D did not. Tissue from extracted teeth of all groups was processed and cultured and subjected to 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay to assess their viability. The difference between the groups in terms of viability was significant (P < 0.0001). The mean viability of A and B (PBM) was 1.04 and 1.19, respectively. The mean viability for C and D (non-PBM) was 0.95 and 0.85, respectively. Older fibroblasts have lower viability than younger fibroblasts. PBM improves viability in both older and younger fibroblasts and more so in younger fibroblasts. However, more than one PBM would be required to sustain the effect longer.

Comparative study of the effectiveness of ozone therapy and laser photobiomulation upon experimental wound repair: systematic review

Laser photobiomodulation and ozone therapy are therapeutic possibilities for antimicrobial control and biomodulation of tissue repair. This study aimed to compare the effect of laser photobiomodulation with that of ozone gas in wound healing of experimental lesions on animal's tissues. It was a systematic literature review, which aimed to search for articles of the animal model experimental study according the PRISMA guidelines. The search was made through the electronic articles indexed in the databases: PubMed, BVSalud, Cochrane, Scielo and Google Scholar, based on the DeCS/MeSH descriptors in English and Portuguese. The sample included studies from 2013 to 2020 and methodological quality was assessed using the ARRIVE guideline. A total of 329 of records indentified through database searching. Five studies were selected for the present systematic review according to the inclusion and exclusion criteria outlined for the research. All studies performed histological analysis of the treated tissue sections. Ozone therapy and laser showed a significant difference in favor of repair in different tissues when compared to the findings of the control groups in all studies. When compared to each other, ozone showed superiority over laser in two of the five studies, in addition to two studies having similar results between these two therapies. Regarding the ARRIVE guideline, in the most studies, the meeting criteria was high, with good methodological quality. Most studies highlighted the lack of uniformity in the therapy protocol as the greatest difficulty encountered, although they were unanimous in stating that laser photobiomodulation and ozone therapy contributed to the improvement of the healing pattern.

Effects of Laser Photobiomodulation on TGF-ß and VEGF Expression in Burn Wound: Systematic Review and Meta-Analysis in the Animal Model

Laser photobiomodulation (laser PBM) is known to be able to accelerate burn wound healing in the animal model; however little evidence exists on the action of laser PBM on the expression of important proteins in wound healing in the animal model, such as VEGF and TGF-ß1. The aim of this study was to carry out a systematic review in order to analyse the effect of laser PBM on VEGF and TGF-ß expression during burn wound repair in the animal model. A systematic review was carried out of the EMBASE, PubMed/ MEDLINE and LILACS databases. The studies included were preclinical studies that analysed the action of laser PBM on the expression of VEGF and TGF-ß (1, 2, 3) during burn wound repair in the animal model. The SYRCLE risk of bias tool was used. Random effect models were used to estimate the combined effect. Increased VEGF expression was observed with the use of laser PBM at 4.93 J/cm2 per point in the first two weeks after induction of the burn wound, with greater size of effect in the second week (SDM = 5.72; 95% CI: 3.14 to 8.31, I2 = 0 %; very low certainty of evidence). We also observed that the effect of laser PBM on TGF-ß1 expression was greater than in the control in the first week (SDM = -0.45; 95% CI: -1.91 to 1.02, I2 = 51 %; very low certainty of evidence), but diminished in the third week after induction of the lesion (SDM = -2.50; 95% CI: 3.98 to -1.01, I2 = 0 %; very low certainty of evidence). Laser PBM has an effect on TGF-ß1 and VEGF expression, promoting burn wound repair in the animal model.

Immediate effects of red (660 nm) and infrared (808 nm) photobiomodulation therapy on fatigue of the orbicularis oris muscle: a randomized clinical study.

To compare the immediate effects of laser photobiomodulation at wavelengths of 660 nm and 808 nm on fatigue of the orbicularis oris. This is a randomized study with 60 women aged between 19 and 43 years. The participants were divided into four groups. Group RG received photobiomodulation with a laser wavelength of 660 nm at four points of the orbicularis oris; group IRG received photobiomodulation with a laser wavelength of 808 nm at the same points; the control group did not receive light treatment; and the placebo group underwent the same procedures as RG and IRG but with the equipment switched off. The irradiation was performed with a laser of 100 mW of power, 4 J of energy per point and 133.3 J/cm2 of fluency. An electromyography evaluation was performed before and after the irradiation, concomitantly with the exercise of lip protrusion maintained until the sensation of fatigue. Fatigue was evaluated by a median frequency using the electromyographic fatigue index. The amplitude of the signal was evaluated, examining the root mean square, and the values were normalized by the peak. The difference in amplitude between the upper and lower lips was also analyzed. All variables were compared before and after irradiation. No significant difference was found between the measures taken before and after irradiation. Photobiomodulation with the parameters investigated in this study had no immediate effect on orbicular oris fatigue.

Effects of laser photobiomodulation in the management of oral lichen planus: a literature review.

This review aims to understand whether Photobio-modulation (PBM) therapy is a valid aid in the management of Oral Lichen Planus (OLP) and its symptoms. Moreover, an analysis to determine whether it is a valid replacement for conventional therapies and whether standardized protocols can be used in PBM sessions or whether these should be changed depending on the type of injury has been made. Finally, an evaluation to determine whether PBM may induce transformation of dysplastic oral keratinocytes into squamous cell carcinoma has been made. Searches were conducted on two search databases for relevant publications released between 1992 and 2019. The databases used were: Pubmed "Medline", and Google Scholar. Forty-four articles complied with the inclusion criteria and were included for quality assessment and data extraction. All the studies reported positive effects of PBM; how-ever, there was wide heterogeneity in the laser parameters used in the management of the OLP. The effective dose ranges from 2 to 3 J/cm2, in order to see the desired biological effects. PBM is useful in controlling algal sensation and can be used in cases of OLP lesions that are not responsive to conventional therapies or when corticosteroid doses are too high for the patient, resulting in possible side effects. Standardized biostimulation protocols with further scientific insights are therefore required.

Laser photobiomodulation effect on fibroblasts viability exposed to endodontic medications

Aim: The literature has not yet reported investigations about the effect of laser photobiomodulation (LPBM) over the cytotoxicity of drugs for endodontic treatments. Thus, the aim of this study was to evaluate, in vitro, the effect of the association between LPBM and intracanal medications on fibroblasts viability in different exposure times. Methods: Calcium hydroxide (Ca(OH)2) and iodoform (IO) were used pure or associated to LPBM. Eluates of medications were prepared and placed in contact with the cells in three different periods: 24h, 48h and 72h. Laser irradiation (emitting radiation λ 660nm, power density of 10mW, energy density of 3 J/cm²) has been performed in two sessions within a six hour interval, for 12s per well. After each experimental time, the colorimetric assay (MTT) has been performed. Statistical analysis was applied for Mann-Whitney test with 5% α error admitted test. Results: At 24h, the use of LPBM did not increase cell viability while after 72h cell proliferation was stimulated in the group without medications. LPBM application did not increase cell viability in Ca(OH)2 group and IO at any tested time. Ca(OH)2 cytotoxicity at 24h was higher than iodoform, while at 72h not difference was observed. Therefore, after 72 hours was no statistical difference between the IO and Ca(OH)2 groups. Conclusion: LPBM was able to increase cell viability in 72h in the group without medication, although no improvement was observed in the other groups. Thus, LPBM was not able to reduce the cytotoxic effects of the materials on fibroblasts in vitro.

A Comprehensive Review on the Effects of Laser Photobiomodulation on Skeletal Muscle Fatigue in Spastic Patients

Peripheral muscle fatigue is a common experience in daily life. Every individual at some point in their life has realized the inability to maintain muscle contraction, a phenomenon known as fatigue. Interestingly, neurological patients with peripheral sequelae such as spastic muscle contraction are able to remain in a pattern of muscle contraction for prolonged periods. The effects of laser therapy are already recognized in muscle contraction to delay skeletal muscle fatigue, prolong physical activity, and reduce delayed onset muscle soreness. However, the effects of photobiomodulation on neurological patients with muscular spasticity are still not well established. The present literature review seeks to recognize articles about the application of laser irradiation, also known as photobiomodulation, to patients with muscle fatigue and/or spastic palsy. To perform a literature review, we used the systematic review methodology for the literature search. The following keywords were searched: (skeletal muscle fatigue) AND (spastic patients) AND (low-level laser therapy OR low intensity laser therapy OR low energy laser therapy OR LLLT OR LILT OR LELT OR infrared laser OR IR laser OR diode laser), and these were used for search on the following databases: PubMed, Embase, Web of Science, BIREME, Scopus, and SciELO. Besides that, a literature review concerning on muscle physiology, fatigue, and LLLT was made. No language filter was applied, and altogether, 689 papers were identified. A group of 3 physiotherapists and 01 pharmaceutical scientist performed the literature review, and every exclusion was confirmed by at least two reviewers. After inclusion and exclusion criteria, 128 studies were included in this review. Conclusion, the LLLT can contribute to the recovery of spastic patients and muscles in fatigue. However, the real effect of laser photobiomodulation on muscle spasticity remains to be established. Only a much reduced number of clinical trials have been performed with a small number of participants. There is a lack of clinical trials from different research groups that could help to understand and elucidate the effects of laser in prolonged muscle contraction in spastic palsy.

Gene Expression Analysis of Chondrogenic Markers in Hair Follicle Dermal Papillae Cells Under the Effect of Laser Photobiomodulation and the Synovial Fluid.

Introduction: Regarding the limited ability of the damaged cartilage cells to self-renew, which is due to their specific tissue structure, subtle damages can usually cause diseases such as osteoarthritis. In this work, using laser photobiomodulation and an interesting source of growth factors cocktail called the synovial fluid, we analyzed the chondrogenic marker genes in treated hair follicle dermal papilla cells as an accessible source of cells with relatively high differentiation potential. Methods: Dermal papilla cells were isolated from rat whisker hair follicle (Rattus norvegicus) and established cell cultures were treated with a laser (gallium aluminum arsenide diode Laser (λ=780 nm, 30 mW) at 5 J/cm2 ), the synovial fluid, and a combination of both. After 1, 4, 7, and 14 days, the morphological changes were evaluated and the expression levels of four chondrocyte marker genes (Col2a1, Sox-9, Col10a1, and Runx-2) were assessed by the quantitative real-time polymerase chain reaction. Results: It was monitored that treating cells with laser irradiation can accelerate the rate of proliferation of cells. The morphology of the cells treated with the synovial fluid altered considerably as in the fourth day they surprisingly looked like cultured articular chondrocytes. The gene expression analysis showed that all genes were up-regulated until the day 14 following the treatments although not equally in all the cell groups. Moreover, the cell groups treated with both irradiation and the synovial fluid had a significantly augmented expression in gene markers. Conclusion: Based on the gene expression levels and the morphological changes, we concluded that the synovial fluid can have the potential to make the dermal papilla cells to most likely mimic the chondrogenic and/or osteogenic differentiation, although this process seems to be augmented by the irradiation of the low-level laser.

Characterization of Skeletal Muscle Strain Lesion Induced by Stretching in Rats: Effects of Laser Photobiomodulation

Unusual and exhaustive physical exercise can lead to muscle lesions depending on the type of contraction, intensity, duration, age, and level of conditioning. Different therapies have been proposed to prevent or reduce exercise-induced muscle damage. In this study, we investigate the effects of low-level laser therapy on skeletal muscle strain in an experimental model in rats. Male Wistar rats (200 g) were used. The animals were randomized into groups of six animals. We performed tibialis muscle elongation using a previously described protocol. The animals were anesthetized and submitted to passive stretching of the anterior tibial muscle attached to a weight corresponding to 150% of the body mass of the animal for 20 min, rested for 3 min, and received a second traction for 20 min. The cytokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, and IL-10, edema, and C-reactive protein (CRP) levels were determined in the tibialis anterior muscle. Plasma extravasation of groups treated with different doses of laser energy, lesion +1 J (2.61 ± 0.46), lesion +3 J (2.33 ± 0.13), lesion +6 J (2.92 ± 0.91), and lesion +9 J (2.80 ± 0.55), shows a significant reduction of extravasation when compared with the injury group (5.46 ± 1.09). Laser therapy was able to significantly reduce CRP and cytokine levels (TNF-α, IL-1β, IL-6, and IL-10). Laser photobiomodulation reduced skeletal muscle edema as well as cytokines and CRP, leading to a significant reduction in inflammatory markers.

Effect of laser photobiomodulation on wound healing and postoperative pain following free gingival graft: A split-mouth triple-blind randomized controlled clinical trial

Background and AimFree gingival graft (FGG) is one of the most predictable techniques for gingival augmentation. However, patient's discomfort and pain during healing period are significant concerns. The aim of this study was to assess if laser photobiomodulation (PBM) was effective in terms of enhancing wound healing and reducing postoperative pain. Methods and MaterialsTwelve patients participated in this split-mouth randomized controlled clinical trial. Each patient had a 30-day interval between the two procedures. In the test group, donor and recipient sites received diode laser (660nm, 200mW, continuous mode, time of irradiation:32s, energy density: 4J/cm2, spot size:0.5cm) immediately after FGG surgery, and 1,2,4 and 7days later. The control side received the same sequence of irradiation with the laser-off. Complete wound epithelialization of donor site and clinical wound healing and visual analogue scale (VAS) pain score of donor and recipient sites were evaluated after surgery. ResultsAt 14 and 21days after surgery, the number of donor sites with complete epithelialization was greater in laser group compared to the placebo. After 21days, all donor sites in the test group were epithelialized completely, while at the same time, only eight donor sites in the control group showed complete epithelialization (P value=0.05). In terms of clinical healing of the recipient and donor sites, the test and control groups did not show any significant difference during the 45-day period, except at days 1 (for recipient site) and 14 (for donor site), when the test group showed better results (P values: 0.01 and 0.03, respectively). The VAS pain score did not show statistically significant difference between two groups during the study period, except for the first 3h after procedure when laser group showed greater VAS pain score (P values<0.05). ConclusionPBM following FGG procedure with the parameters used in this study could accelerate the rate of epithelialization at the donor site. However, it did not reduce postoperative pain.

Effect of IR laser photobiomodulation on the repair of bone defects grafted with organic bovine bone

A major problem on modern dentistry is the recovery of bone defects of different etiologies. Biomaterials are used to improve the repair of these defects. Previous studies have shown positive effects of Laser Photobiomodulation (LPBM) on the repair of both soft and bone tissues. This study assessed histologically the effect of LPBM on the repair of surgical defects on the femur of rats filled with lyophilized bovine bone. The animals were divided into three groups: group I (control); group II (graft); group III (graft + LPBM). The animals on the irradiated groups received 16 J/cm(2) per session divided into four points around the defect being the first irradiation immediately after surgery and repeated at every 48 h during 2 weeks. Animal death occurred 15, 21, and 30 days after surgery. The specimens were routinely processed and stained with H/E and Sirius red and analyzed by light microscopy. There was histological evidence of improved collagen fiber deposition at early stages of the healing; increased amount of well-organized bone trabeculae at the end of the experimental period on irradiated animals. It is concluded that LPBM has positive biomodulative effect on the healing process bone defects.