Effects Of Low-level Light Therapy Research Articles

Thermal effect on eyelid and tear film after low-level light therapy and warm compress

ABSTRACT Clinical relevance The warming effect of low-level light therapy may contribute to its therapeutic mechanism which is beneficial for dry eye management. Background Low-level light therapy is proposed to work via cellular photobiomodulation and a potential thermal effect in dry eye management. This study examined the change in eyelid temperature and tear film stability after low-level light therapy compared to warm compress. Methods Participants with no to mild dry eye disease were randomised into control, warm compress, and low-level light therapy groups. The low-level light therapy group was treated with Eyelight mask (633 nm) for 15 minutes, the warm compress group with Bruder mask for 10 minutes, and the control group with an Eyelight mask having inactive LEDs for 15 minutes. Eyelid temperature was measured using the FLIR One® Pro thermal camera (Teledyne FLIR, Santa Barbara, CA, USA), and clinical measures of tear film stability were evaluated before and after treatment. Results Thirty-five participants (mean age ± SD, 27.3 ± 4.3 years) completed the study. Eyelid temperatures for external upper, external lower, internal upper and internal lower eyelids were significantly greater in the low-level light therapy and warm compress groups immediately after treatment compared to the control group (all p < 0.001). No difference in temperature was observed between the low-level light therapy and warm compress groups at all time points (all p > 0.05). Tear film lipid layer thickness was significantly greater after treatment (mean (95% CI), 13.1 nm (5.3 to 21.0), p < 0.005) but not different between groups (p > 0.05). Conclusion A single treatment of low-level light therapy increased eyelid temperature immediately after treatment, but the increase was not significantly different from warm compress. This suggests that thermal effects may in part contribute to the therapeutic mechanism of low-level light therapy.

A Novel, Hand-Held, and Low-Level Light Therapy Device for the Treatment of Acne Vulgaris: A Single-Arm, Prospective Clinical Study

There is an increasing demand for low-level light therapy devices for the treatment of dermatologic conditions, such as acne, hair loss, undesirable body hair, and skin aging. This study evaluated the safety and effectiveness of a novel hand-held low-level light therapy device with a 680 nm red laser diode and a 450 nm blue light-emitting diode for the treatment of mild-to-moderate acne. A prospective clinical study was conducted on 57 patients with mild-to-moderate acne and Fitzpatrick skin types II–IV. Treatments were self-administered by the patients at home daily for 4 weeks. Conventional treatment was restricted during the study period. The number of inflammatory and noninflammatory lesion counts, Investigator’s Global Assessment grade, patients’ self-assessment, and adverse events were measured every two weeks, and follow-ups were performed until four weeks after the final treatment. Moreover, we evaluated the bactericidal effect of low-level light therapy on Cutibacterium acnes, a causative agent of acne vulgaris, in vitro. The mean number of inflammatory acne lesions decreased statistically at weeks 4 ( ∗ ∗ ∗ p &lt; 0.001 ) and 8 ( ∗ ∗ ∗ p &lt; 0.001 ). The proportion of Investigator’s Global Assessment grade 3, indicating moderate acne severity, decreased significantly at the final visit. No severe adverse reactions were reported. Furthermore, there was a significant reduction in the viability of Cutibacterium acnes following low-level light therapy exposure in vitro. The results of this study demonstrate that this novel, hand-held, and low-level light therapy device are safe and effective for the treatment of inflammatory acne, with good adherence.

Assessment of Effects of Low-Level Light Therapy on Scalp Condition and Hair Growth.

The appearance of the scalp and hair is very important aesthetically regardless of age or sex. Although there are many drugs and treatment methods for scalp problems and hair loss, the treatment response is still insufficient. To evaluate the efficacy of low-level light therapy in a helmet-like device. This study was designed as a 24-week trial with 50 participants. All participants used a helmet-shaped device emitting 630-690, 820-880, and 910-970 nm light wavelengths, for 20 minutes, daily for 24 weeks. A phototrichogram for hair density and thickness, Global Aesthetic Improvement Scale score, erythema index, and sebum secretions of the scalp were evaluated at baseline and at 12 and 24 weeks. After 24 weeks of treatment, hair density and hair thickness were found to have significantly increased (P <.01 and P =0.013, respectively) and sebum secretion of vertex area had decreased significantly (P <.01). Of 49 participants, 73.47% of the participants showed improvement in the overall appearance of the scalp (n = 36). A helmet-like low-level light therapy device can improve the appearance of the hair, with thickening and increase in the density of the hair, and can improve scalp condition by decreasing sebum secretion.

Low-level laser therapy prevents medication-related osteonecrosis of the jaw-like lesions via IL-1RA-mediated primary gingival wound healing

BackgroundMedication-related osteonecrosis of the jaw (MRONJ) is a serious debilitating disease caused by anti-resorption and anti-angiogenesis drugs, significantly affecting patients' quality of life. Recent studies suggested that primary gingival wound healing may effectively prevent the development of MRONJ. This study aimed to evaluate the effects of low-level light therapy (LLLT) on promoting gingival wound healing in extraction sockets of MRONJ-like mice and preventing the occurrence of MRONJ. Furthermore, we explored underlying mechanisms.MethodsMice were randomly divided into the Ctrl, Zol, and Zol + LLLT groups. Administration of zoledronate and tooth extraction of bilateral maxillary second molars were used to build the MRONJ model, and LLLT was locally administered into the tooth sockets to examine the effect of LLLT. Next, to explore the function of IL-1RA, we performed LLLT with interleukin-1 receptor antagonist (IL-1RA) neutralizing antibody (named Zol + LLLT + IL-1RA NAb group) or negative control antibodies for tooth extraction in subsequent rescue animal experiments. Stereoscope observations, micro-computed tomography, and histological examination were conducted to evaluate gingival wound healing and bone regeneration in tooth sockets. The effects of LLLT on the migration capacities of zoledronate-treated epithelial cells were assessed in vitro.ResultsLLLT promoted primary gingival wound healing without exposed necrotic bone. Micro-computed tomography results showed higher bone volume and mineral density of the tooth sockets after LLLT. Histology analysis showed complete gingival coverage, obvious bone regeneration, and reduced soft tissue inflammation, with down-regulated pro-inflammation cytokines, like interleukin-1 beta (IL-1β) and tumor necrosis factor-α (TNF-α), and up-regulated IL-1RA expression in the gingival tissue in the LLLT group. The rescue assay further showed that the effects of LLLT promoting gingival wound healing and preventing MRONJ might be partially abolished by IL-1RA neutralizing antibodies. In vitro studies demonstrated that LLLT accelerated zoledronate-treated epithelial cell migration.ConclusionsLLLT might promote primary gingival wound healing and contribute to subsequent bone regeneration of the tooth extractions in MRONJ-like lesions via IL-1RA-mediated pro-inflammation signaling suppression.

Effect of Low-level Light Therapy on Post-operative Healing of Secondary Chronic Osteomyelitis of the Jaws - A Prospective Study.

Osteomyelitis of the jaws is a common disease of the maxillofacial region. The goal of treatment is to alleviate pain, reduce infection, inhibit the progression of the disease and induce bone and mucosal healing. In addition to surgical management and antibiotic and oxygen hyperbaric therapy, new therapeutic strategies for the treatment of osteomyelitis are developed. One of the novel approaches is photobiomodulation therapy or low-level light therapy (LLLT). After surgical treatment, experimental group patients (n = 4) were treated with LLLT for five sessions with an extraoral pulsed 635-nm LED lamp (Repuls7, Repuls Lichtmedizintechnik GmbH, Austria), maximum output power: 140 mW/cm2, frequency: 2.5 Hz, duty cycle: 50%. Clinical achievement and patient pain perception (through Visual Analogue Scale score) were evaluated at 1-, 3- and 6-month follow-up appointments and compared with control group (n = 4) patients, treated with standard therapy. At three and six months, clinical achievement was better in patients treated with LLLT. Pain and discomfort resolution was significantly greater in the experimental group. Taking into consideration the results of this study, it can be concluded that LLLT shows potential for improving clinical outcome of surgical and medical treatment of secondary chronic osteomyelitis of the jaws. Furthermore, pain and discomfort were significantly reduced in patients treated with LLLT. Further research with a larger sample size is needed to obtain a more accurate insight into this promising field.

Low level light therapy/photobiomodulation for diabetic peripheral neuropathy: protocol of a systematic review and meta-analysis

IntroductionDiabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes that strongly impact the patients’ quality of life and working ability. Evidence indicated that low level light...

Effect of low-level light therapy before radiotherapy in oral squamous cell carcinoma: An in vitro study.

Radiation therapy for head and neck squamous cell carcinoma (HNSCC) is associated with several complications. Although photobiomodulation (PBM) has radioprotective effects in normal tissue, it could also enhance the growth of neoplastic cells. Thus, the present study aimed to investigate the cellular response of oral squamous cell carcinoma with pre-exposure to low-level phototherapy before radiotherapy. SCC9, Cal-27, A431, and HaCaT cell lines were subjected to low-level light therapy and radiotherapy. The cells were treated with a single energy density (300 J/cm2) of a light-emitting diode (660 nm) prior to ionizing radiation at different doses (0, 2, 4, and 6 Gy). After 24 h, wound scratch, proliferation, clonogenic cell survival, cell death, and reactive oxygen species (ROS) analyses were performed to evaluate cell response. The cell lines pre-exposed to PBM at the analyzed dosage were radiosensitive. The treatment significantly reduced cell proliferation and clonogenic cell survival. Migration and cell death assays also revealed positive results, with the treatment group showing lower rate of migration and higher cell death than did the control group. Moreover, PBM effectively increased the intracellular levels of ROS. PBM at 300 J/cm2 is a promising radiosensitizing modality to reduce the radiation dose and avoid the intolerable side effects of radiotherapy for HNSCC, thus increasing the probability of successful treatment. However, further studies are needed to support and confirm the results.

Effect of low-level light therapy in patients with dry eye: a prospective, randomized, observer-masked trial

To evaluate the efficacy of low-level light therapy (LLLT) with near-infrared light-emitting diodes (LED-LLLT) for the treatment of dry eye. 40 patients were randomly assigned with a 1:1 allocation ratio to receive LED-LLLT (LLLT group, n = 20) or placebo treatment (placebo group, n = 20). Patients in the LLLT group received LLLT twice a week for 3 weeks, for a total of 6 treatment sessions. The primary endpoint was the changes in the fluorescein corneal staining (FCS) score. The secondary endpoints were the changes in the ocular surface disease index (OSDI) score, lissamine green conjunctival staining (LGCS) scores, tear film break-up time (TBUT), Schirmer test, and the meibomian gland dysfunction (MGD) index. These were evaluated before treatment and 4 weeks after start of treatment. The mean difference of score change in primary endpoint revealed significant improvement in the LLLT group, compared to the placebo. Among secondary endpoints, LGCS, Schirmer's test, upper meibography scores showed significant improvements, while TBUT, lid debris, lid swelling, lid telangiectasia, meibomian gland secretion and expressibility scores had slight improvement without significant differences. No serious adverse events were observed. The use of LED-LLLT for the treatment of dry eye and MGD appears to be safe and beneficial.

Effects of low-level light therapy on xerostomia related to hyposalivation: a systematic review and meta-analysis of clinical trials

Hyposalivation is a condition represented by a reduced salivary flow and may include symptoms such as mouth dryness (xerostomia), loss of taste, pain, dysphagia, and dysphonia, all of which greatly affect an individual's quality of life.The aim of the present study was to systematically review the effects of low-level light therapy irradiation (photobiomodulation) on salivary gland function in patients with hyposalivation.The main question of the systematic review was: "Does low-level light irradiation therapy of the salivary glands affect salivary flow rate or indicators of salivary function (ion and protein concentrations) in patients with xerostomia or hyposalivation?" The question was based on the PICO (participant, intervention, control, outcome) principle and followed the PRISMA guidelines. Databases were explored and papers published between the years 1997 and 2020 were reviewed for the following Mesh-term keywords and their corresponding entry terms in different combinations: "Low-level light therapy," "Xerostomia," "Saliva," "Salivary glands," "Salivation."The initial sample consisted of 220 articles. Of those, 47 articles were used for full-text analysis and 18 were used for a systematic review, 14 were used in meta-analysis. According to their individual quality, most articles were classified as high quality of evidence according to the GRADE score. Meta-analysis of the evidence observed increase of unstimulated salivary flow 0.51 SMD compared to placebo (95% CI: 0.16-0.86), I2 = 50%, p = 0.005.The findings of our review revealed evidence of a beneficial effect of photobiomodulation therapy on salivary gland function. The therapy alleviates xerostomia and hyposalivation. However, these effects are reported short term only and did not induce lasting effects of photobiomodulation therapy on patients' quality of life.

Investigation of Effect of Low-Level Light Therapy by Continuous Wave and Pulse Wave Through Dry Skull by Using Mathematical Modeling

Investigation of Effect of Low-Level Light Therapy by Continuous Wave and Pulse Wave Through Dry Skull by Using Mathematical Modeling

The Effect of Low-Level Light Therapy on Capsaicin-Induced Peripheral and Central Sensitization in Healthy Volunteers: A Double-Blinded, Randomized, Sham-Controlled Trial.

IntroductionSeveral clinical trials have demonstrated that low-level light therapy (LLLT), a method of photobiomodulation, is an effective analgetic treatment. However, the mechanism of action has not yet been finally clarified. In particular, unanswered questions include whether it only affects peripheral or whether it also affects the spinal or supraspinal level. This study aimed to evaluate the effect of low-level light therapy on primary and secondary hyperalgesia in a human pain model.MethodsThis study was planned as a randomized, sham-controlled, and double-blinded trial with repeated measures within subject design. Capsaicin was applied on both forearms of ten healthy volunteers to induce peripheral and central sensitization. One forearm was treated with low-level light therapy; the other served as sham control.ResultsLow-level light therapy significantly increased the mechanical pain threshold, heat pain threshold, and decreased pain intensity.ConclusionsOur data indicate that low-level light therapy is effective at reducing the heat and mechanical pain threshold in a human pain model, pointing to a significant modulating effect on peripheral and central sensitization. These effects—especially in the absence of reported side effects—make low-level light therapy a promising tool in pain management. The application of low-level light therapy to treat chronic pain should be considered for further clinical trials.

Effect of Transcranial Low-Level Light Therapy vs Sham Therapy Among Patients With Moderate Traumatic Brain Injury

Preclinical studies have shown that transcranial near-infrared low-level light therapy (LLLT) administered after traumatic brain injury (TBI) confers a neuroprotective response. To assess the feasibility and safety of LLLT administered acutely after a moderate TBI and the neuroreactivity to LLLT through quantitative magnetic resonance imaging metrics and neurocognitive assessment. A randomized, single-center, prospective, double-blind, placebo-controlled parallel-group trial was conducted from November 27, 2015, through July 11, 2019. Participants included 68 men and women with acute, nonpenetrating, moderate TBI who were randomized to LLLT or sham treatment. Analysis of the response-evaluable population was conducted. Transcranial LLLT was administered using a custom-built helmet starting within 72 hours after the trauma. Magnetic resonance imaging was performed in the acute (within 72 hours), early subacute (2-3 weeks), and late subacute (approximately 3 months) stages of recovery. Clinical assessments were performed concomitantly and at 6 months via the Rivermead Post-Concussion Questionnaire (RPQ), a 16-item questionnaire with each item assessed on a 5-point scale ranging from 0 (no problem) to 4 (severe problem). The number of participants to successfully and safely complete LLLT without any adverse events within the first 7 days after the therapy was the primary outcome measure. Secondary outcomes were the differential effect of LLLT on MR brain diffusion parameters and RPQ scores compared with the sham group. Of the 68 patients who were randomized (33 to LLLT and 35 to sham therapy), 28 completed at least 1 LLLT session. No adverse events referable to LLLT were reported. Forty-three patients (22 men [51.2%]; mean [SD] age, 50.49 [17.44] years]) completed the study with at least 1 magnetic resonance imaging scan: 19 individuals in the LLLT group and 24 in the sham treatment group. Radial diffusivity (RD), mean diffusivity (MD), and fractional anisotropy (FA) showed significant time and treatment interaction at 3-month time point (RD: 0.013; 95% CI, 0.006 to 0.019; P < .001; MD: 0.008; 95% CI, 0.001 to 0.015; P = .03; FA: -0.018; 95% CI, -0.026 to -0.010; P < .001).The LLLT group had lower RPQ scores, but this effect did not reach statistical significance (time effect P = .39, treatment effect P = .61, and time × treatment effect P = .91). In this randomized clinical trial, LLLT was feasible in all patients and did not exhibit any adverse events. Light therapy altered multiple diffusion tensor parameters in a statistically significant manner in the late subacute stage. This study provides the first human evidence to date that light therapy engages neural substrates that play a role in the pathophysiologic factors of moderate TBI and also suggests diffusion imaging as the biomarker of therapeutic response. ClinicalTrials.gov Identifier: NCT02233413.

The effect of low-level light therapy on orthodontic tooth movement rate, heat shock protein 70, and matrix metallopreteinase 8 expression: Animal study

The aim of this study was to determine the effect of low-level light therapy (LLLT) on orthodontic tooth movement (OTM) rate, heat shock protein 70 (HSP-70) expression, and matrix metalloproteinase 8 (MMP-8) expression. In this experimental study twenty-four male guinea pigs were randomly divided into three groups (n = 8): control group (K) without orthodontic force and LLLT; treatment group 1 (T1) with orthodontic force, and treatment group 2 (T2) with orthodontic force and LLLT. The labial surfaces of both maxillary central incisors in treatments groups were installed with single-wing bracket before being inserted with close coil spring to give 10 g/cm2 orthodontic force. For the T2 group, 4 J/cm2 of LLLT was administered in the mesial-distal and labial-palatal regions for 3 min every day. On day 14, the gap between teeth was measured and immunohistochemistry staining was done to determine HSP-70 and MMP-8 expression. Data were analyzed using (IBM, New York, (ANOVA), followed by Turkey's HSD test to determine the differences between groups. Nonnormal distributed data would be analyzed using Kruskal-Wallis test, followed by Mann-Whitney test with P < 0.05 being performed. The gap between teeth in the T2 group was greater compared to T1 group (P = 0.00). However, there was a significant decrease of HSP-70 and MMP-8 expression in T2 group compared to T1 group in the tensile and compressive sides. LLLT intervention during orthodontic treatment could accelerate OTM rate and decreased HSP-70 and MMP-8 expression both in tension and in compressive side. Thus, LLLT interventions can be used as adjuvant therapy to shorten orthodontic treatment duration.

Effects of Low-level Light Therapy at 740 nm on Dry Eye Disease In Vivo

Effects of Low-level Light Therapy at 740 nm on Dry Eye Disease <i>In Vivo</i>

Photobiomodulation in Periodontology and Implant Dentistry: Part 1.

(Part 2 of this article can be located at www.liebertpub.com/doi/10.1089/photob.2019.4731.) Objective: Finding evidence-based treatment strategies for low-level light therapy (LLLT) and the correct incorporation of these treatment methods in the clinical practice of periodontics. Background: Photobiomodulation has been shown to have biostimulatory, anti-inflammatory and analgesic effects that can be beneficial in periodontal and dental implant treatment procedures. Methods: In this review we have addressed some clinical questions regarding the potential clinical application of low-level light irradiation and its photobiomodulatory effects in periodontology and implantology. The literature was searched for in vivo (animal or clinical) articles written in English in four electronic databases of PubMed, Scopus, Google Scholar, and Cochrane Library until April 2019. Only studies with low irradiation doses without any thermal effects used only for their photobiomodulatory purposes were included. Results: We were able to find relevant studies for all of our questions, and positive effects for the application of light therapy were reported in most of the studies. However, there is still great deal of heterogeneity in terms of study designs and most importantly in light irradiation devices and the parameters used. Owing to this issue it was not possible to reach specific evidence-based irradiation protocols for the questions addressed in this review. Conclusions: Based on our search results, an obvious positive effect of LLLT on stimulation of healing of periodontal soft and hard tissues and reduction of inflammation can be seen. Future well-designed randomized control studies with the same irradiation settings and systematic reviews evaluating the studies found on the questions mentioned are necessary to reach evidence-based recommendations.

Photobiomodulation in Periodontology and Implant Dentistry: Part 2.

(Part 1 of this article can be located at www.liebertpub.com/doi/10.1089/photob.2019.4710.) Objective: Finding evidence-based treatment strategies for low-level light therapy and the correct incorporation of these treatment methods in the clinical practice of periodontics. Background: Photobiomodulation has been shown to have biostimulatory, anti-inflammatory, and analgesic effects that can be beneficial in periodontal and dental implant treatment procedures. Methods: In this review, we have addressed some clinical questions regarding the potential clinical application of low-level light irradiation and its photobobiomodulatory effects in periodontology and implantology. The literature was searched for in vivo (animal or clinical) articles written in English in four electronic databases of PubMed, Scopus, Google Scholar, and Cochrane Library until April 2019. Only studies with low irradiation doses without any thermal effects used only for their photobiomodulatory purposes were included. Results: We were able to find relevant studies for all of our questions, and positive effects for the application of light therapy were reported in most of the studies. However, there is still a great deal of heterogeneity in terms of study designs and most importantly in light irradiation devices and the parameters used. Due to this issue, it was not possible to reach specific evidence-based irradiation protocols for the questions addressed in this review. Conclusions: Based on our search results, an obvious positive effect of low-level light therapy on stimulation of healing of periodontal soft and hard tissues and reduction of inflammation can be seen. Future well-designed randomized control studies with the same irradiation settings and systematic reviews evaluating the studies found on the questions mentioned are necessary to reach evidence-based recommendations.

Low level light therapy for the treatment of recalcitrant chalazia: a sample case summary.

PurposeTo evaluate the effects of low-level light therapy (LLLT) on the resolution of recalcitrant chalazia.Patients and MethodsThis was a single-site retrospective chart review of patients with chalazia, all of whom were unresponsive to previous pharmaceutical therapy or surgical intervention, who received a 15 min LLLT treatment in conjunction with a standard pharmaceutical regimen. A second treatment was applied 24 hrs to as late as 2 months if there was no evidence of progression of resolution in appearance.ResultsA total of 26 eyes of 22 patients with relevant history and treatment were reviewed, all with a history of prior pharmaceutical treatment for their chalazia. After a single 15 min LLLT treatment, followed by a standard pharmaceutical regimen, 46% of eyes (12/26) showed resolution of their chalazia. Resolution was noted from 3 days to one-month post-treatment. With a second treatment, the chalazia resolved in 92% of eyes (24/26). Only two eyes of the 26 (8%) required incision and curettage after LLLT treatment.ConclusionThe use of LLLT for the treatment of recalcitrant chalazia appears to be beneficial in patients who have failed topical and/or systemic therapy, significantly reducing the likelihood of requiring surgical intervention.

Local and systemic effects of low-level light therapy with light-emitting diodes to improve erythema after fractional ablative skin resurfacing: a controlled study.

Therapy with light-emitting diodes (LED) has been associated with the reduction of erythema and accelerated wound healing. LED phototherapy has been used in various clinical practices including post-laser wound healing enhancement. Fractional laser resurfacing is one of the popular dermatological procedures; however, the duration and degree of downtime may limit daily life activity and studies on the effect of LED low-level light therapy (LED-LLLT) on post-ablative laser wound care are still limited. To evaluate local and systemic effects of LED-LLLT on post-ablative laser erythema and wound healing acceleration after fractional ablative laser resurfacing. The study was divided into two arms. First, a prospective split-face randomized controlled and single-blinded study involved 17 patients (split-face group) to determine the local and systemic effect of LED-LLLT. Patients with acne scars or rhytides were treated with a single session of fractional CO2 laser followed by 830/590nm LED-LLLT on one side of their faces. The duration of post-laser erythema, the erythema index, and transepidermal water loss were collected at baseline, and compared with 7-daily follow-up visits posttreatment for the non LED- and LED-treated sides. The second controlled arm of the study was performed on an additional 19 subjects (CO2 group). The patients received a single fractional CO2 laser treatment without any LED-LLLT with the same follow-up protocol. All measurements were compared with the results from the patients from the split-face group. In the split-face group, the duration of erythema post laser was equal (7.4 ± 2.8days). No significant reduction in the erythema index and transepidermal water loss was seen in the LED-treated vs the non-treated side (p values = 0.99 and 0.78 respectively). For the second part of the study that compared the results between the split-face group and the control CO2 only group, the duration of the post-laser erythema was comparable (p value = 0.32). However, the percentage difference of the erythema index from baseline in the split-face group was significantly lower than the CO2 group on days 1, 4, 5, and 7 post-laser treatment (p value = 0.03 on days 1, 4, 5, and 0.04 on day 7) and the LED-treated side provided the lowest percentage difference of the erythema index followed by the non LED-treated side compared with the control CO2 only group. 830/590nm LED-LLLT may provide both local and systemic effects on the degree of post-ablative laser erythema in human skin, however, appropriate protocol settings should be considered to achieve a significant clinical outcome.

Slow oscillations of cerebral hemodynamics changes during low-level light therapy in the elderly with and without mild cognitive impairment: An fNIRS study

Low-level light therapy (LLLT) is used to stimulate cell function or reduce pain by applying light emitting diodes (LED) to the skin. LLLT is known to contribute to the neuronal recovery during the reconstruction of brain tissue for the treatment of degenerative disorders. This research aims to confirm the slow oscillations of cerebral hemodynamics changes when LLLT is applied to the elderly and patients with mild cognitive impairment (MCI). Eight patients with MCI and 7 healthy elderly participated in this study. They were randomly divided into four groups; carotid artery stimulation, vertebral artery stimulation, simultaneous carotid and vertebral artery stimulation, or sham stimulation. The subjects received LLLT using Color DNA ® (Color Seven Co.) with a LED light source for 30 minutes a day during 20 days. The hemodynamic responses were recorded by an fNIRS system (NIRScout ® ) with 74 channels at the first and the 20th intervention days, before, during, and after the LLLT. The spectral power density over the very low-frequency oscillations (VLFO) of cerebral hemodynamics was calculated using Welch technique. In both healthy and MCI patients, VLFO increased in the whole cerebral area during LLLT compared to the resting state, and these changes are more contrasting in the condition with simultaneous carotid and vertebral artery stimulation condition. These characteristics were observed in both the first and 20th intervention days however, VLFO in the 20th intervention day were more increased than the first day. Increase of very low frequency oscillations demonstrated increasing spontaneous activity of cerebrovascular tone and neuronal activation. These findings may suggest a possibility of modulating effect of LLLT on neuronal activity and blood vessel reconstruction.

Velocity of orthodontic active space closure with and without photobiomodulation therapy: a single-center, cluster randomized clinical trial

The objective of this two-arm, parallel randomized clinical trial was to assess the effectiveness of low-level light therapy (photobiomodulation) using an intraoral light-emitting diode (LED) device with respect to accelerating premolar extraction space closure during en masse retraction. This trial was conducted between January 2013 and February 2014 at the European Univeristy College Department of Orthodontics. The study included 60 orthodontic patients (age range, 11.3–47.1 years; mean age, 20.4 years) with premolar extractions. Patients (n = 60) were randomized into the photobiomodulation (PBM) group (n = 30) or the control group (n = 30). Eligibility criteria included no active caries, good oral hygiene, and an extraction orthodontic treatment plan. Extraction spaces were closed using NiTi closed springs utilizing 150 g of force. Extraction spaces were measured on study models at the beginning of en masse retraction (T1) and at space closure completion (T2). All measurements were obtained by a single investigator who was blinded to the group allocation of study models. The primary outcome was the velocity of extraction space closure (mm/month) during the period of en masse retraction. Treatment allocation was implemented using randomization with 2 major blocks of 30 patients, by asking each patient to draw a sealed envelope (n = 60) indicating allocation to the PBM or control group. The allocation ratio was 1:1. The PBM group of patients (n = 30) was treated with intraoral infrared LED light therapy for 3 min per arch per day using OrthoPulse™ (Biolux Research®, Vancouver, Canada) producing a continuous 850-nm wavelength and a power density of 33 mW/cm2 per arch per day to achieve a total energy density of approximately 6 J/cm2 at the surface of the device during the en masse retraction phase; patients were required to maintain over 80% compliance with daily device use. Compliance was monitored by the device controller’s onboard computer. Sixty patients were randomized between the two groups. Fifteen patients dropped out during the study period, but were accounted for in the primary analysis as an intention to treat (ITT) analysis through multiple imputations. Mean age for the PBM and control groups were 20.7 and 22 years, respectively. Patients treated with PBM exhibited a statistically significant higher velocity of space closure by 0.22 mm/month (95% confidence interval [CI], 0.09–0.49; p < 0.01). The mean velocity of space closure in the PBM group was 1.08 mm/month (SD 0.54) compared with the control group’s 0.86 mm/month (SD 0.42). A secondary analysis was conducted on the 45 patients that reached the primary outcome and did not deviate from the study protocol (15 dropout patients removed), providing 123 extraction spaces for the analysis—23 patients from the PBM group and 22 patients from the control group. No serious harms due to treatments were encountered during the study period. The results of this study suggest that PBM therapy accelerated the rate of orthodontic space closure during en masse retraction. This trial and its protocol were not registered on a publicly accessible registry.