Showing papers in "Lasers in Medical Science in 2017"

Effect of wavelength and beam width on penetration in light-tissue interaction using computational methods

Abstract: Penetration depth of ultraviolet, visible light and infrared radiation in biological tissue has not previously been adequately measured. Risk assessment of typical intense pulsed light and laser intensities, spectral characteristics and the subsequent chemical, physiological and psychological effects of such outputs on vital organs as consequence of inappropriate output use are examined. This technical note focuses on wavelength, illumination geometry and skin tone and their effect on the energy density (fluence) distribution within tissue. Monte Carlo modelling is one of the most widely used stochastic methods for the modelling of light transport in turbid biological media such as human skin. Using custom Monte Carlo simulation software of a multi-layered skin model, fluence distributions are produced for various non-ionising radiation combinations. Fluence distributions were analysed using Matlab mathematical software. Penetration depth increases with increasing wavelength with a maximum penetration depth of 5378 μm calculated. The calculations show that a 10-mm beam width produces a fluence level at target depths of 1–3 mm equal to 73–88% (depending on depth) of the fluence level at the same depths produced by an infinitely wide beam of equal incident fluence. Meaning little additional penetration is achieved with larger spot sizes. Fluence distribution within tissue and thus the treatment efficacy depends upon the illumination geometry and wavelength. To optimise therapeutic techniques, light-tissue interactions must be thoroughly understood and can be greatly supported by the use of mathematical modelling techniques.

Beneficial neurocognitive effects of transcranial laser in older adults

Abstract: Transcranial infrared laser stimulation (TILS) at 1064 nm, 250 mW/cm2 has been proven safe and effective for increasing neurocognitive functions in young adults in controlled studies using photobiomodulation of the right prefrontal cortex. The objective of this pilot study was to determine whether there is any effect from TILS on neurocognitive function in older adults with subjective memory complaint at risk for cognitive decline (e.g., increased carotid artery intima-media thickness or mild traumatic brain injury). We investigated the cognitive effects of TILS in older adults (ages 49–90, n = 12) using prefrontal cortex measures of attention (psychomotor vigilance task (PVT)) and memory (delayed match to sample (DMS)), carotid artery intima-media thickness (measured by ultrasound), and evaluated the potential neural mechanisms mediating the cognitive effects of TILS using exploratory brain studies of electroencephalography (EEG, n = 6) and functional magnetic resonance imaging (fMRI, n = 6). Cognitive performance, age, and carotid artery intima-media thickness were highly correlated, but all participants improved in all cognitive measures after TILS treatments. Baseline vs. chronic (five weekly sessions, 8 min each) comparisons of mean cognitive scores all showed improvements, significant for PVT reaction time (p < 0.001), PVT lapses (p < 0.001), and DMS correct responses (p < 0.05). The neural studies also showed for the first time that TILS increases resting-state EEG alpha, beta, and gamma power and promotes more efficient prefrontal blood-oxygen-level-dependent (BOLD)-fMRI response. Importantly, no adverse effects were found. These preliminary findings support the use of TILS for larger randomized clinical trials with this non-invasive approach to augment neurocognitive function in older people to combat aging-related and vascular disease-related cognitive decline.

Ultrapulsed fractional ablative carbon dioxide laser treatment of hypertrophic burn scars: evaluation of an in-patient controlled, standardized treatment approach.

Abstract: In this study, we aimed to quantify the effects of fractional ablative carbon dioxide laser therapy in the treatment of widespread hypertrophic burn scars. While many different pilot studies have described the potential of the technology and expert groups and current guidelines, alike, recommend its use, the level of evidence for the efficacy of fractional CO2-laser treatment for burn scars is currently very low. Ten patients (three male, seven female) with hypertrophic burn scars were treated with a single course of fractional CO2-laser therapy in an in-patient controlled setup, using a standardized treatment paradigm. Documentation was based on modern scar scales and questionnaires, like the Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (POSAS), and Dermatology Life Quality Index (DLQI), as well as state of the art clinical measurements (PRIMOS, Cutometer). Over the course of 6 months after treatment, VSS and POSAS scores showed significant improvement in the rating of scar parameters, as did the quality of life rating according to the DLQI. In the treated scars, surface relief improved significantly, as S max decreased by 1893 μm (-36.92%) (p = 0.0273) and S z by 1615 μm (-36.37%) (p = 0.0488). Scar firmness in treated scars could be reduced by 30% after one treatment session, as R 0 improved by 0.0797 mm (+30.38%) (p = 0.0212). Fractional ablative CO2-laser treatment is a safe and efficacious option for the treatment of hypertrophic burn scars. While more treatment sessions are required for satisfying results, significant improvement is already apparent after a single course of treatment.

Effect of laser on pain relief and wound healing of recurrent aphthous stomatitis: a systematic review

Abstract: The aim of this systematic review was to assess a potential benefit of laser use in the treatment of recurrent aphthous stomatitis (RAS). The primary outcome variables were pain relief, duration of wound healing and reduction in episode frequency. A PICO approach was used as a search strategy in Medline, Embase and Cochrane databases. After scanning and excluding titles, abstracts and full texts, 11 studies (ten RCTs and one non-randomised controlled trial) were included. Study selection and data extraction was done by two observers. Study participants varied between 7-90 for the laser and 5-90 for the control groups. Laser treatment included Nd:YAG laser ablation, CO2 laser applied through a transparent gel (non-ablative) and diode laser in a low-level laser treatment (LLLT) mode. Control groups had placebo, no therapy or topical corticosteroid treatment. Significant pain relief immediately after treatment was found in five out of six studies. Pain relief in the days following treatment was recorded in seven studies. The duration of RAS wound healing was also reduced in five studies. However, criteria of evaluation differed between the studies. The episode frequency was not evaluated as only one study addressed this outcome parameter, but did not discriminate between the study (LLLT) and control (corticosteroid) groups. Jadad scores (ranging from 0 to 5) for quality assessment of the included studies range between 0 and 2 (mean = 1.0) for studies analysing pain relief and between 0 and 3 (mean = 1.1) for studies evaluating wound healing. The use of lasers (CO2 laser, Nd:YAG laser and diode laser) to relieve symptoms and promote healing of RAS is a therapeutic option. More studies for laser applications are necessary to demonstrate superiority over topical pharmaceutical treatment and to recommend a specific laser type, wavelength, power output and applied energy (ablative versus photobiomodulation).

Transoral laser microsurgery versus radiotherapy for T1 glottic carcinoma: a systematic review and meta-analysis

Abstract: Transoral laser microsurgery (TLM) and radiotherapy (RT) are both accepted treatment modalities for glottic cancer. The objective of the study was to assess the oncologic outcomes and life quality of TLM in comparison with RT for T1 glottic carcinoma. We searched Medline/PubMed, Web of knowledge, EMBASE, the Cochrane Library, the Wiley online library, Springer, Google, China National Knowledge Infrastructure (CNKI), etc. We screened the literature, assessed the quality of the studies, and extracted the relevant data through the establishment of inclusion and exclusion criteria. Meta-analysis was done using the Cochrane collaboration' s RevMan 5.0 for data analysis. A total of 11 studies were included in this meta-analysis. The laryngeal preservation for patients undergoing TLM was significantly better than that for RT (P < 0.00). The laser surgery significantly improved the overall survival of patients with T1 glottic carcinoma (P = 0.04). No statistically significant differences were found between TLM and RT regarding the local control (P = 0.91). The funnel plot demonstrates no apparent publication bias in the overall survival and laryngeal preservation comparison. Our meta-analysis suggested that laser surgery was a preferred method than radiotherapy with respect to significantly better overall survival and laryngeal preservation. But the local control was not significant different. Further prospective randomized controlled studies will be needed.

Low-level laser therapy as an adjunct to conventional therapy in the treatment of diabetic foot ulcers

Abstract: Foot ulcers are serious complications of diabetes mellitus (DM) and are known to be resistant to conventional treatment. This study was conducted to evaluate the efficacy of low-level laser therapy (LLLT) for the treatment of diabetic foot ulcers in a tertiary care centre (Department of Surgery, Mahatma Gandhi Memorial Medical College and Maharaja Yashwantrao Hospital, A.B. Road, Indore). A total of 30 patients with type 2 DM having Meggitt-Wagner grade I foot ulcers of more than 6 weeks duration with negative culture were studied. Patients were randomized into two groups of 15 each. Patients in study group received LLLT (660 ± 20 nm, 3 J/cm2) along with conventional therapy and those in control group were treated with conventional therapy alone. The primary outcome measure was the absolute and relative wound size reduction at 2 weeks compared to the baseline parameter. Percentage ulcer area reduction was 37 ± 9% in the LLLT group and 15 ± 5.4% in the control group (p < 0.001). For ∼75% of wounds of the treatment group, wound area reduction of 30–50% was observed. In contrast, for the control group, ∼80% of wounds showed a wound area reduction of <20% on day 15. Further, the wounds with initial wound area 1000–2000 mm2 seems to have better final outcome than the groups with larger areas. The treated groups showed higher amount of granulation than the control group. The results suggest that LLLT is beneficial as an adjunct to conventional therapy in the treatment of diabetic foot ulcers.

Effectiveness of low-level laser therapy on pain intensity, pressure pain threshold, and SF-MPQ indexes of women with myofascial pain

Abstract: Women with temporomandibular disorders (TMD) frequently report pain areas in body regions. This process is associated with central sensitization phenomena, present in chronic pain. The low-level laser therapy (LLLT) has been reported as a therapeutic option for the painful TMD treatment. The aim of this study was to analyze the effect of LLLT on pain intensity (visual analogue scale, VAS), pain sensitivity in orofacial and corporal points (pressure pain threshold, PPT), and on Short Form-McGill Pain Questionnaire (SF-MPQ) indexes of women with myofascial pain (subtype of muscle TMD). Ninety-one women (18-60 years) were included in the study, among which 61 were diagnosed with myofascial pain (Research Diagnostic Criteria for Temporomandibular Disorder-Ia and Ib) and were divided into laser (n = 31) and placebo group (n = 30), and 30 were controls. The LLLT was applied at pre-established points, twice a week, eight sessions (780 nm; masseter and anterior temporal = 5 J/cm2, 20 mW, 10 s; TMJ area = 7.5 J/cm2, 30 mW, 10 s). Pain intensity, pain sensitivity, and the SF-MPQ indexes were measured at the baseline, during laser sessions, and 30 days after treatment. For intra-group comparisons, the Friedman test was performed, and for inter-group, the Mann-Whitney test. Increased pain sensitivity was found in women with myofascial pain when compared to controls (p 0.05). Active laser and placebo reduced the indexes of sensory, total pain, and VAS, maintaining the results after 30 days; there was a reduction in the affective pain rating index for both groups, with no maintenance after 30 days for placebo, and the present pain intensity decreased in the laser group and did not change in the placebo after LLLT. In conclusion, the LLLT active or placebo are effective in reducing the overall subjective perception of myofascial pain (VAS and SF-MPQ indexes); however, they have no effectiveness in reducing the pain sensitivity in orofacial and corporal points (PPT increase).

Effects of photobiomodulation therapy, pharmacological therapy, and physical exercise as single and/or combined treatment on the inflammatory response induced by experimental osteoarthritis

Abstract: Osteoarthritis (OA) triggers increased levels of inflammatory markers, including prostaglandin (PG) E2 and proinflammatory cytokines. The elevation of cytokine levels is closely associated with increased articular tissue degeneration. Thus, the use of combination therapies may presumably be able to enhance the effects on the modulation of inflammatory markers. The present study aimed to evaluate and compare the effects of photobiomodulation therapy (PBMT), physical exercise, and topical nonsteroidal anti-inflammatory drug (NSAID) use on the inflammatory process after they were applied either alone or in different combinations. OA was induced by intra-articular papain injection in the knee of rats. After 21 days, the animals began treatment with a topical NSAID and/or with physical exercise and/or PBMT. Treatments were performed three times a week for eight consecutive weeks, totaling 24 therapy sessions. Analysis of real-time polymerase chain reaction (RT-PCR) gene expression; interleukin (IL)-1β, IL-6, and tumor necrosis factor alpha (TNF-α) protein expression; and PGE2 levels by enzyme-linked immunosorbent assay (ELISA) was conducted. Our results showed that PBMT alone and Exerc + PBMT significantly reduced IL-1β gene expression (p < 0.05) while no treatment changed both IL-6 and TNF-α gene expression. Treatment with NSAID alone, PBMT alone, Exerc + PBMT, and NSAID + PBMT reduced IL-1β protein expression (p < 0.05). All therapies significantly reduced IL-6 and TNF-α protein expression (p < 0.05) compared with the OA group. Similarly, all therapies, except Exerc, reduced the levels of PGE2 (p < 0.05) compared with the OA group. The results from the present study indicate that treatment with PBMT is more effective in modulating the inflammatory process underlying OA when compared with the other therapies tested.

Gold-coated magnetic nanoparticle as a nanotheranostic agent for magnetic resonance imaging and photothermal therapy of cancer

Abstract: Because of their great scientific and technological potentials, iron oxide nanoparticles (IONPs) have been the focus of extensive investigations in biomedicine over the past decade. Additionally, the surface plasmon resonance effect of gold nanoparticles (AuNPs) makes them a good candidate for photothermal therapy applications. The unique properties of both IONPs (magnetic) and AuNPs (surface plasmon resonance) may lead to the development of a multi-modal nanoplatform to be used as a magnetic resonance imaging (MRI) contrast agent and as a nanoheater for photothermal therapy. Herein, core–shell gold-coated IONPs (Au@IONPs) were synthesized and investigated as an MRI contrast agent and as a light-responsive agent for cancer photothermal therapy. The synthesized Au@IONPs were characterized by UV–visible spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis. The transverse relaxivity (r 2) of the Au@IONPs was measured using a 3-T clinical MRI scanner. Through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the cytotoxicity of the Au@IONs was examined on a KB cell line, derived from the epidermal carcinoma of a human mouth. Moreover, the photothermal effects of Au@IONPs in the presence of a laser beam (λ = 808 nm; 6.3 W/cm2; 5 min) were studied. The results show that the Au@IONPs are spherical with a hydrodynamic size of 33 nm. A transverse relaxivity of 95 mM−1 S−1 was measured for the synthesized Au@IONPs. It is evident from the MTT results that no significant cytotoxicity in KB cells occurs with Au@IONPs. Additionally, no significant cell damage induced by the laser is observed. Following the photothermal treatment using Au@IONPs, approximately 70% cell death is achieved. It is found that cell lethality depended strongly on incubation period and the Au@IONP concentration. The data highlight the potential of Au@IONPs as a dual-function MRI contrast agent and photosensitizer for cancer photothermal therapy.

Effect of low-level laser therapy on angiogenesis and matrix metalloproteinase-2 immunoexpression in wound repair

Abstract: Low-level laser therapy (LLLT) induces anti-inflammatory and angiogenic activities in wound healing. However, the mechanism of action and optimal parameters require further clarification. In this study, we investigated the effects of LLLT on wound healing matrix metalloproteinase (MMP)-2 immunoexpression and angiogenic processes. Twenty female Wistar rats were randomly divided into four groups (n = 5) according to the treatments as follows. CG7 and CG14 were control groups at days 7 and 14, respectively, which received physiological saline (0.9 % NaCl daily). LG7 and LG14 were laser therapy groups at days 7 and 14, respectively, which received two (LG7) or four (LG14) LLLT applications (40 mW; 660 nm; 4 J/cm2). A dorsal skin sample in the wound area (measuring 2 cm2) was removed after the experimental period, and then the animals were euthanized. The specimens were processed for qualitative and quantitative histological analyses and measurement of MMP-2 expression in the dermis and epidermis. A persistent crust and moderate number of inflammatory cells were found in CG7 and CG14 groups. In the LG14 group, wounds demonstrated complete re-epithelization at the remodeling phase. Angiogenesis and MMP-2 expression were higher in LLLT-treated groups, particularly the LG14 group, which correlated according to the Spearman correlation test. LLLT improves wound healing by enhancing neocollagenesis, increasing the amount of new vessels formed in the tissue (neoangiogenesis), and modulating MMP-2 expression. Epidermal overexpression of MMP-2 was correlated to angiogenic processes.

Efficacy of pulsed Nd:YAG laser in the treatment of patients with knee osteoarthritis: a randomized controlled trial.

Abstract: The purpose of this study was to investigate the effects of pulsed Nd:YAG laser plus glucosamine/chondroitin sulfate (GCS) in patients with knee osteoarthritis (KOA) by examining changes in pain and knee function, as well as synovial thickness (ST) and femoral cartilage thickness (FCT). Sixty-seven male patients participated, with a mean (SD) age of 53.85 (4.39) years, weight of 84.01 (4.70) kg, height of 171.51 (3.96) cm, and BMI of 28.56 (1.22). Group 1 was treated with high-intensity laser therapy (HILT), GCS, and exercises (HILT + GCS + EX). Group 2 was treated with GCS plus exercises (GCS + EX), and group 3 received placebo laser plus exercises (PL + EX). The outcomes measured were pain level and functional disability using the visual analog scale (VAS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), respectively. ST and FCT were measured by ultrasound examination. Statistical analyses were performed to compare differences between baseline and after 6 weeks of treatment and then after 3 months of follow-up. Statistical significance was set at p < 0.05. VAS and WOMAC were significantly decreased in all groups after 6 weeks, with nonsignificant differences between 6 weeks and 3 months of follow-up. ST was significantly decreased in the HILT + GCS + EX group posttreatment, with nonsignificant decreases in the GCS + EX and PL + EX groups, as well as nonsignificant differences to FCT in all groups. Overall, pulsed Nd:YAG laser combined with GCS and exercises was more effective than GCS + EX and exercises alone in the treatment of KOA patients.

Non-ablative erbium YAG laser for the treatment of type III stress urinary incontinence (intrinsic sphincter deficiency).

Abstract: The objective of this pilot study was to determine the safety and efficacy of a new non-ablative erbium YAG laser procedure for the treatment of type III stress urinary incontinence (intrinsic sphincter deficiency) in women. Twenty-two patients with a Valsalva leak point pressure less than 60 cm H2O were recruited and treated with a non-ablative erbium laser delivering low fluence pulses inside the whole length of the urethra through a specially designed cannula. Treatment consisted of two treatment sessions with a 3-week interval in-between. Therapeutic efficacy, as assessed by a questionnaire addressing quality of life during urinary incontinence and the 1-h pad test, was measured at 3 and 6 months after the procedure. Both methods of assessment showed similar levels of improvement in terms of incontinence severity and improvement in quality of life. All patients tolerated the therapy well and adverse effects were mild and transient. The results of this pilot study showed significant improvement of type III stress urinary incontinence. Despite the limitations of this study, being small patient number and short follow-up, this non-ablative intraurethral erbium YAG laser procedure seems to be a safe and efficacious alternative for patients with type III stress urinary incontinence. More controlled studies should be performed to confirm this data and to evaluate the long-term effects.

Effects of photodynamic laser and violet-blue led irradiation on Staphylococcus aureus biofilm and Escherichia coli lipopolysaccharide attached to moderately rough titanium surface: in vitro study

Abstract: Effective decontamination of biofilm and bacterial toxins from the surface of dental implants is a yet unresolved issue. This study investigates the in vitro efficacy of photodynamic treatment (PDT) with methylene blue (MB) photoactivated with λ 635 nm diode laser and of λ 405 nm violet-blue LED phototreatment for the reduction of bacterial biofilm and lipopolysaccharide (LPS) adherent to titanium surface mimicking the bone-implant interface. Staphylococcus aureus biofilm grown on titanium discs with a moderately rough surface was subjected to either PDT (0.1% MB and λ 635 nm diode laser) or λ 405 nm LED phototreatment for 1 and 5 min. Bactericidal effect was evaluated by vital staining and residual colony-forming unit count. Biofilm and titanium surface morphology were analyzed by scanning electron microscopy (SEM). In parallel experiments, discs coated with Escherichia coli LPS were treated as above before seeding with RAW 264.7 macrophages to quantify LPS-driven inflammatory cell activation by measuring the enhanced generation of nitric oxide (NO). Both PDT and LED phototreatment induced a statistically significant (p < 0.05 or higher) reduction of viable bacteria, up to -99 and -98% (5 min), respectively. Moreover, besides bactericidal effect, PDT and LED phototreatment also inhibited LPS bioactivity, assayed as nitrite formation, up to -42%, thereby blunting host inflammatory response. Non-invasive phototherapy emerges as an attractive alternative in the treatment of peri-implantitis to reduce bacteria and LPS adherent to titanium implant surface without causing damage of surface microstructure. Its efficacy in the clinical setting remains to be investigated.

Laser-assisted topical corticosteroid delivery for the treatment of keloids.

Abstract: Laser-assisted drug delivery has generated intense interest. The objectives of this study are to evaluate the clinical benefit of laser-assisted corticosteroid delivery and to compare this technique to corticosteroid intralesional injection, a standard treatment for keloids. Patients with keloids on the left shoulder after BCG vaccination were enrolled in this study. The entire lesion was first treated with an ablative fractional erbium-YAG laser. After this treatment, the lesion was divided into two halves. The first half received an intralesional injection of corticosteroid, whereas the second half received topical application of corticosteroids that were occluded for 3 hours. Four treatment sessions were conducted, with treatments occurring once every 6 weeks. Treatment outcomes were evaluated using the Vancouver Scar Scale (VSS). Pain was self-assessed by the patient during the procedure. The mean keloid VSS score before treatment was 8.59 ± 1.23 for the corticosteroid injection site and 8.31 ± 2.09 for the topical site. After treatment, the mean keloid VSS score was decreased on both sides (4.56 ± 1.09 vs 5.02 ± 0.87, respectively, P > 0.05). Patients rated their satisfaction level as “moderate” on both sides. However, the mean pain score was 1.1 out of 10 on the topical side versus 6.1 on the corticosteroid injection site. The combination of ablative fractional laser treatment and topical corticosteroid application is a promising modality for the treatment of keloids. Moreover, this procedure was not associated with any serious adverse reactions or unbearable pain.

The use of low-level light therapy in supportive care for patients with breast cancer: review of the literature.

Abstract: Breast cancer is the most common cancer in women worldwide, with an incidence of 1.7 million in 2012. Breast cancer and its treatments can bring along serious side effects such as fatigue, skin toxicity, lymphedema, pain, nausea, etc. These can substantially affect the patients' quality of life. Therefore, supportive care for breast cancer patients is an essential mainstay in the treatment. Low-level light therapy (LLLT) also named photobiomodulation therapy (PBMT) has proven its efficiency in general medicine for already more than 40 years. It is a noninvasive treatment option used to stimulate wound healing and reduce inflammation, edema, and pain. LLLT is used in different medical settings ranging from dermatology, physiotherapy, and neurology to dentistry. Since the last twenty years, LLLT is becoming a new treatment modality in supportive care for breast cancer. For this review, all existing literature concerning the use of LLLT for breast cancer was used to provide evidence in the following domains: oral mucositis (OM), radiodermatitis (RD), lymphedema, chemotherapy-induced peripheral neuropathy (CIPN), and osteonecrosis of the jaw (ONJ). The findings of this review suggest that LLLT is a promising option for the management of breast cancer treatment-related side effects. However, it still remains important to define appropriate treatment and irradiation parameters for each condition in order to ensure the effectiveness of LLLT.

Effects of photobiomodulation on experimental models of peripheral nerve injury.

Abstract: Phototherapy has demonstrated positive effects in the treatment of peripheral nerve injury, but there is a need to investigate the dosimetric parameters. Thus, the aim of the present study was to conduct a literature review on the effects of photobiomodulation with the use of low-level laser therapy (LLLT) on the treatment of peripheral nerve injury in experimental models. The databases of PubMed/MEDLINE, SCOPUS, and SPIE Digital Library were searched for articles on the use of LLLT in experimental models of peripheral nerve injury published in English between January 2007 and March 2016. The laser parameter variability was wavelength (632.8 to 980 nm), power (10 to 190 mW), and total energy (0.15 to 90 J) in pulsed or continuous wave and single or multiple points. Eighteen original articles demonstrating the effects of LLLT on the acceleration of functional recovery, morphological aspects as well as the modulation of the expression inflammatory cytokines, and growth factors were selected. LLLT is a viable phototherapeutic modality for the treatment of peripheral nerve injury, demonstrating positive effects on the neuromuscular repair process using either red or infrared light. The majority of studies used a power of up to 50 mW and total energy of up to 15 J administered to multiple points. The determination of these parameters is important to the standardization of a LLLT protocol to enhance the regeneration process following a peripheral nerve injury.

Efficacy of low-level laser therapy in management of symptomatic oral lichen planus: a systematic review

Abstract: Oral lichen planus (OLP) is a chronic inflammatory disease of unknown etiology and indefinite cure This systematic review assessed the efficacy of low-level laser therapy in the treatment of symptomatic OLP Electronic databases (PubMed, Scopus, and Web of Science) were searched from date of inception till and including December 2016, using various combinations of the following keywords: oral lichen planus, laser therapy, low-level laser therapy, and phototherapy Owing to heterogeneity of data, no statistical analyses were conducted Initially, 227 publications were identified After selection, only six studies were included in this systematic review In these studies, the laser wavelengths, power output, and duration of irradiation ranged between 630–980 nm, 20–300 mW, and 10 s–15 min, respectively All of the included studies found laser to be effective in management of OLP, without any reported adverse effects The results of the included studies confirm that low-level laser therapy is effective in management of symptomatic OLP and can be used as an alternative to corticosteroids However, due to variety of methods and substantial variations in laser parameters among these studies, more randomized clinical trials with large sample sizes are highly warranted

Microstructure and corrosion behavior of laser surface-treated AZ31B Mg bio-implant material

Abstract: Although magnesium and magnesium alloys are considered biocompatible and biodegradable, they suffer from poor corrosion performance in the human body environment. In light of this, surface modification via rapid surface melting of AZ31B Mg alloy using a continuous-wave Nd:YAG laser was conducted. Laser processing was performed with laser energy ranging from 1.06 to 3.18 J/mm2. The corrosion behavior in simulated body fluid of laser surface-treated and untreated AZ31B Mg alloy samples was evaluated using electrochemical technique. The effect of laser surface treatment on phase and microstructure evolution was evaluated using X-ray diffraction and scanning electron microscopy. Microstructure examination revealed grain refinement as well as formation and uniform distribution of Mg17Al12 phase along the grain boundary for laser surface-treated samples. Evolution of such unique microstructure during laser surface treatment indicated enhancement in the corrosion resistance of laser surface-treated samples compared to untreated alloy.

Role of lasers as an adjunct to scaling and root planing in patients with type 2 diabetes mellitus: a systematic review.

Abstract: The aim of the study was to assess the efficacy of adjunctive use of laser therapy (LT) alone or antimicrobial photodynamic therapy (aPDT) to improve clinical periodontal and HbA1c levels in patients with both chronic periodontitis (CP) and type 2 diabetes mellitus (T2DM). Electronic search of the MEDLINE, PubMed, EMBASE, Science Direct, and SCOPUS databases were combined with hand searching of articles published from 1975 up to and including March 2016 using relevant MeSH terms. Six studies were selected for this review. In these six studies, laser treatment was applied, after scaling and root planing (SRP), in two ways: Three studies used laser alone and three studies used laser with photosensitizer. All the six included studies reporting clinical periodontal and glycemic parameters showed that LT and aPDT were effective in the treatment of CP in T2DM subjects at follow-up. Two studies showed significantly better periodontal outcomes for LT as an adjunct to SRP as compared to SRP alone, whereas four studies showed comparable periodontal outcomes among adjunctive LT or aPDT with SRP. Two studies showed significant reduction of HbA1c levels in LT and aPDT as compared to SRP, whereas three studies showed comparable percentage levels at follow-up. It remains debatable whether LT or aPDT as adjunct to SRP is more effective as compared to SRP alone in the improvement of clinical periodontal and glycemic control in patients with both CP and T2DM, given that the scientific evidence is weak.

Low-level laser therapy in the treatment of pressure ulcers: systematic review

Abstract: The aim of this study was to evaluate the effects of low-level laser therapy (LLT) in pressure ulcers (PU) in humans through a systematic review of randomized studies. The search includes the databases MEDLINE, PEDro, Cochrane CENTRAL, and Lilacs, as well a manual search until May, 2016. This included randomized clinical trials of LLT compared with other interventions, different types of LLT, LLT placebo, or control in the treatment of PU. The outcomes evaluated were the ulcer area, healing rate, and overall healing rate. The risk of bias was evaluated using the tool of the Cochrane Collaboration, and the results were analyzed descriptively. From the 386 articles identified, only four studies were included, with two LLT used with single wavelength (1: 904 nm vs. control and 2: 940 nm vs. 808 nm vs. 658 nm vs. placebo) and two LLT used to probe cluster. One study compared to different single wavelengths showed a significant 71% reduction of the PU and an improved healing rate in which 47% of PU healed completely after 1 month of therapy with the use of LLT with a wavelength of 658 nm compared with other lengths. The other analyzed wavelengths were not significant in the assessed outcomes. Significant results were observed in the use of LLT with a 658 nm wavelength, and no evidence was found for use of wavelengths above that for the treatment of PU. Therefore, we also found no evidence in the laser used to probe the cluster. Registration number: CRD42016036648.

The effect of low-level laser therapy on tooth movement during canine distalization

Abstract: The aim of the study is to determine the effects of low level laser therapy on tooth movement during canine distalization by evaluating IL-1β, TGF-β1 levels in gingival crevicular fluid. Maxillary first premolars of the 15 Angle Class II division I patients (12–19 years old) were extracted. Right maxillary canines were distalized by standard protocol as control group whereas the left maxillary canines distalized by laser application. A gallium-aluminum-arsenide diode laser with an output power of 20 mW was applied as five doses from the buccal and the palatal side on the day 0, and the 3rd, 7th, 14th, 21th 30th, 33st, 37th, 60th, 63th, and 67th days. Gingival crevicular fluid samples were obtained with filtration paper at the initial, 7th, 14th, and 21th days, and the IL-1s and TGF-s1 cytokine levels were analyzed. Orthodontic models and periodontal indices were taken initially and on the days 30th, 60th, and 90th of canine distalization period. Tooth movement was assessed by scanning models (3Shape). The amount of tooth movement in the laser group was 40% more than the control group. First day IL-1s levels were statistically higher than initial and 21st day levels (P= 0.003, P = 0.012). The rise in IL-1s levels caused the negative correlations between 7th day IL-1β and 21st day TGF-β1 levels describes the tissue effects of laser application. Periodontal indices showed no sign of gingival inflammation during canine distalization period. As conclusion, laser does accelerate tooth movement and could shorten the whole treatment duration.

Role of low-level laser therapy added to facial expression exercises in patients with idiopathic facial (Bell's) palsy.

Abstract: The aim of the present study was to investigate the efficacy of low-level laser therapy in conjunction with conventional facial exercise treatment on functional outcomes during the early recovery period in patients with facial paralysis. Forty-six patients (mean age 41 ± 9.7 years; 40 women and 6 men) were randomized into two groups. Patients in the first group received low-level laser treatment as well as facial exercise treatment, while patients in the second group participated in facial exercise intervention alone. Laser treatment was administered at a wavelength of 830 nm, output power of 100 Mw, and frequency of 1 KHz using a gallium-aluminum-arsenide (GaAIAs, infrared laser) diode laser. A mean energy density of 10 J/cm2 was administered to eight points of the affected side of the face three times per week, for a total of 6 weeks. The rate of facial improvement was evaluated using the facial disability index (FDI) before, 3 weeks after, and 6 weeks after treatment. Friedman analysis of variance was performed to compare the data from the parameters repeatedly measured in the inner-group analysis. Bonferroni correction was performed to compare between groups as a post hoc test if the variance analysis test result was significant. To detect the group differences, the Bonferroni Student t test was used. The Mann-Whitney U test was used to compare numeric data between the groups. In the exercise group, although no significant difference in FDI scores was noted between the start of treatment and week 3 (p < 0.05), significant improvement was observed at week 6 (p < 0.001). In the laser group, significant improvement in FDI scores relative to baseline was observed at 3 and 6 weeks (p < 0.001). Improvements in FDI scores were significantly greater at weeks 3 and 6 in the laser group than those in the exercise group (p < 0.05). Our findings indicate that combined treatment with low-level laser therapy (LLLT) and exercise therapy is associated with significant improvements in FDI when compared with exercise therapy alone.

Hard tissue debris removal from the mesial root canal system of mandibular molars with ultrasonically and laser-activated irrigation: a micro-computed tomography study

Abstract: This study is to investigate the efficacy of different irrigant activation techniques on removal of accumulated hard tissue debris (AHTD) in mesial roots of human mandibular molars. Extracted human mandibular molars with an isthmus between the mesial root canals were selected based on micro-CT (μCT) scans. The mesial canals were instrumented to an apical diameter ISO30 using ProTaper rotary files. Teeth were randomly assigned to three irrigant activation groups (n = 10): ultrasonically activated irrigation (UAI) using a size 20 Irrisafe for 3 × 20 s, laser-activated irrigation (LAI) with an Er:YAG laser (2940 nm) and plain 300 μm fiber tip inside the canal (20 mJ, 20 Hz, 3 × 20 s), and laser-activated irrigation with identical parameters with a 400 μm photon-induced photoacoustic streaming (PIPS) tip held at the canal entrance. All teeth were scanned with μCT before and after instrumentation and after irrigant activation. After reconstruction and image processing, the canal system volume filled with hard tissue debris before and after irrigant activation was calculated. Changes in hard tissue debris volumes were compared between groups using one-way ANOVA. The percentage volume of hard tissue debris (vol%) was significantly lower after irrigant activation in all groups. Although the lowest debris values were observed in the laser groups, no significant differences in the vol% of accumulated hard tissue debris after activation were observed between groups. Accumulated hard tissue debris was reduced significantly in all activation groups. Ultrasonically and laser-activated irrigation regimens performed similarly in this respect. None of the tested methods was able to render the root canal systems free of debris.

Photobiomodulation of wound healing via visible and infrared laser irradiation

Abstract: Fibroblast cells are known to be one of the key elements in wound healing process, which has been under the scope of research for decades. However, the exact mechanism of photobiomodulation on wound healing is not fully understood yet. Photobiomodulation of 635 and 809 nm laser irradiation at two different energy densities were investigated with two independent experiments; first, in vitro cell proliferation and then in vivo wound healing. L929 mouse fibroblast cell suspensions were exposed with 635 and 809 nm laser irradiations of 1 and 3 J/cm2 energy densities at 50 mW output power separately for the investigation of photobiomodulation in vitro. Viabilities of cells were examined by means of MTT assays performed at the 24th, 48th, and 72nd hours following the laser irradiations. Following the in vitro experiments, 1 cm long cutaneous incisional skin wounds on Wistar albino rats (n = 24) were exposed with the same laser sources and doses in vivo. Wound samples were examined on 3rd, 5th, and 7th days of healing by means of mechanical tensile strength tests and histological examinations. MTT assay results showed that 635 nm laser irradiation of both energy densities after 24 h were found to be proliferative. One joule per square centimeter laser irradiation results also had positive effect on cell proliferation after 72 h. However, 809 nm laser irradiation at both energy densities had neither positive nor negative affects on cell viability. In vivo experiment results showed that, 635 nm laser irradiation of both energy densities stimulated wound healing in terms of tensile strength, whereas 809 nm laser stimulation did not cause any stimulative effect. The results of mechanical tests were compatible with the histological evaluations. In this study, it is observed that 635 nm laser irradiations of low energy densities had stimulative effects in terms of cell proliferation in vitro and mechanical strength of incisions in vivo. However, 809 nm laser irradiations at the same doses did not have any positive effect.

Evaluation of different treatment protocols for dentin hypersensitivity: an 18-month randomized clinical trial

Abstract: This randomized and longitudinal in vivo study aimed to assess different protocols for the treatment of dentin hypersensitivity with low-power laser (with different doses), high-power laser, and a desensitizing agent, for a period of 12 and 18 months. The lesions from 32 patients (117 lesions), who were submitted to the inclusion and exclusion criteria, were divided into nine groups (n = 13): G1: Gluma Desensitizer (Heraeus Kulzer), G2: low-power laser with low dose (three points of irradiation in vestibular portion and an apical point 30 mW, 10 J/cm2, 9 s per point with the wavelength of 810 nm, with three sessions with an interval of 72 h), G3: low-power laser with high dose (one point in the cervical area, and one apical point 100 mW, 40 J/cm2, 11 s per point with the wavelength of 810 nm in three sessions with an interval of 72 h), G4: low-power laser with low dose + Gluma Desensitizer, G5: low-power laser with high dose + Gluma Desensitizer, G6: Nd:YAG laser (Power Laser™ ST6, Research® in contact 1.0 W, 10 Hz and 100 mJ, ≈85 J/cm2, with the wavelength of 1064 nm), G7: Nd:YAG laser + Gluma Desensitizer, G8: low-power laser with low dose + Nd:YAG laser, and G9: low-power laser with high dose + Nd:YAG laser. The level of sensitivity of each volunteer was assessed by visual analog scale of pain (VAS) with the aid of air from the triple syringe and exploration probe, 12 and 18 months after treatment. All analyses were performed separately for air and probe stimulus. The level of significance was considered for values of p < 0.05. After statistical analysis, all treatments were shown to be effective in reducing dentinal hypersensitivity, and the results were considered not statistically different from those at 12 months. Therefore, until the 18-month evaluation, it could be said that no statistical differences were observed in the sensitivity levels for all treatments.

Radiological and biochemical effects (CTX-II, MMP-3, 8, and 13) of low-level laser therapy (LLLT) in chronic osteoarthritis in Al-Kharj, Saudi Arabia.

Abstract: Inflammation of synovial membrane and degeneration of articular cartilage in osteoarthritis (OA) lead to major changes in joint space width (JSW) and biochemical components such as collagen-II telopeptide (CTX-II) and matrix metallo protineases (MMP-3, 8, and 13). Low-level laser therapy (LLLT) is thought to have an analgesic effect as well as biomodulatory effect on microcirculation and cartilage regeneration in animal studies. The objective of this study was to examine the analgesic and biochemical effect of LLLT in patients with knee osteoarthritis. Subjects (n = 34) who fulfilled the selection criteria were randomly divided into active group (n = 17) and placebo group. Subjects in active group were irradiated laser with the frequency of 3 days per week for 4 weeks with the specific parameters on 8 different points on the joint at 1.5 J per point for 60 s for 8 points for a total dose of 12 J in a skin contact method. The placebo group was treated with the same probe with minimum emission of energy. Visual analog scale for pain intensity, joint space width, collagen-II telopeptide, and matrix metallo protinease-3, 8, and 13 was measured before treatment and at 4 and 8 weeks following treatment. Data are analyzed with mean values and standard deviation with p 0.05) in both groups which shows homogeneity. After 4- and 8-week treatment, active laser group shows more significant difference (p 0.05). Our results show that low-level laser therapy was more efficient in reducing pain and improving cartilage thickness through biochemical changes.

Odontogenic differentiation and biomineralization potential of dental pulp stem cells inside Mg-based bioceramic scaffolds under low-level laser treatment.

Abstract: This study aimed to investigate the potential of low-level laser irradiation (LLLI) to promote odontogenic differentiation and biomineralization by dental pulp stem cells (DPSCs) seeded inside bioceramic scaffolds Mg-based, Zn-doped bioceramic scaffolds, synthesized by the sol–gel technique, were spotted with DPSCs and exposed to LLLI at 660 nm with maximum output power of 140 mw at fluencies (a) 2 and 4 J/cm2 to evaluate cell viability/proliferation by the MTT assay and (b) 4 J/cm2 to evaluate cell differentiation, using real-time PCR (expression of odontogenic markers) and a p-nitrophenylphosphate (pNPP)-based assay for alkaline phosphatase (ALP) activity measurement Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were used for structural/chemical characterization of the regenerated tissues Exposure of the DPSCs/scaffold complexes to the proposed LLLI scheme was associated with statistically significant increase of odontogenesis-related markers (bone morphogenetic protein 2 (BMP-2): 224-fold, dentin sialophosphoprotein (DSPP): 284-fold, Osterix: 185-fold, and Runt-related transcription factor 2 (Runx2): 34-fold) ALP activity was significantly increased at 3 and 7 days inside the irradiated compared to that in the non-irradiated SC/DPSC complexes, but gradually decreased until 14 days Newly formed Ca-P tissue was formed on the SC/DPSC complexes after 28 days of culture that attained the characteristics of bioapatite Overall, LLLI treatment proved to be beneficial for odontogenic differentiation and biomineralization of DPSCs inside the bioceramic scaffolds, making this therapeutic modality promising for targeted dentin engineering

Transcranial LED therapy on amyloid-β toxin 25–35 in the hippocampal region of rats

Abstract: Excessive Aβ deposition in the brain is associated with the formation of senile plaques, and their diffuse distribution is related to Alzheimer’s disease. Thirty rats (EG) were irradiated with light-emitting diode (photobiomodulation (PBM)) in the frontal region of the skull after being inoculated with the Aβ toxin in the hippocampus; 30 rats were used as the control group (CG). The analysis was conducted at 7, 14, and 21 days after irradiation. We observed a decreased in Aβ deposits in treated animals compared with animals in the CG. The behavioral and motor assessment revealed that the EG group covered a larger ground distance and explored the open field than the CG group on days 14 and 21 (p < 0.05). The EG group was statistically significant in the spatial memory test compared to the CG group on day 14. The use of PBM significantly reduced the presence of Aβ plaques and improved spatial memory and behavioral and motor skills in treated animals on day 21.

Does photobiomodulation therapy is better than cryotherapy in muscle recovery after a high-intensity exercise? A randomized, double-blind, placebo-controlled clinical trial.

Abstract: This study aimed to determine the effectiveness of photobiomodulation therapy (PBMT) and cryotherapy, in isolated and combined forms, as muscle recovery techniques after muscle fatigue-inducing protocol. Forty volunteers were randomly divided into five groups: a placebo group (PG); a PBMT group (PBMT); a cryotherapy group (CG); a cryotherapy-PBMT group (CPG); and a PBMT-cryotherapy group (PCG). All subjects performed four sessions at 24-h intervals, during which they submitted to isometric assessment (MVC) and blood collection in the pre-exercise period, and 5 and 60 min post-exercise, while the muscle fatigue induction protocol occurred after the pre-exercise collections. In the remaining sessions performed 24, 48, and 72 h later, only blood collections and MVCs were performed. A single treatment with PBMT and/or cryotherapy was applied after only 2 min of completing the post-5-min MVC test at the first session. In the intragroup comparison, it was found that exercise led to a significant decrease (p < 0.05) in the production of MVC in all groups. Comparing the results of MVCs between groups, we observed significant increases in the MVC capacity of the PBMT, CPG, and PCG volunteers in comparison with both PG and CG (p < 0.05). We observed a significant decrease in the concentrations of the biochemical markers of oxidative damage (TBARS and PC) in all groups and muscle damage (creatine kinase-CK) in the PBMT, PCG, and CPG compared with the PG (p < 0.01). The clinical impact of these findings is clear because they demonstrate that the use of phototherapy is more effective than the use of cryotherapy for muscle recovery, additionally cryotherapy decreases PBMT efficacy.

Impact of low-level laser therapy on hyposalivation, salivary pH, and quality of life in head and neck cancer patients post-radiotherapy.

Abstract: Late effects of radiotherapy for head and neck cancer treatment have been increasingly investigated due to its impact on patients' quality of life. The purpose of this study was to evaluate the effect of low-level laser therapy on hyposalivation, low salivary pH, and quality of life in head and neck cancer patients post-radiotherapy. Twenty-nine patients with radiation-induced xerostomia received laser sessions twice a week, during 3 months (24 sessions). For this, a continuous wave Indium-Gallium-Aluminium-Phosphorus diode laser device was used punctually on the major salivary glands (808 nm, 0.75 W/cm2, 30 mW, illuminated area 0.04 cm2, 7.5 J/cm2, 10 s, 0.3 J). Six extraoral points were illuminated on each parotid gland and three on each submandibular gland, as well as two intraoral points on each sublingual gland. Stimulated and unstimulated salivary flow rate, pH (two scales with different gradations), and quality of life (University Of Washington Quality of Life Questionnaire for Patients with Head and Neck Cancer) were assessed at baseline and at the end of the treatment. There were significant increases in both mean salivary flow rates (unstimulated: p = 0.0012; stimulated: p < 0.0001), mean pH values (p = 0.0002 and p = 0.0004), and mean score from the quality of life questionnaire (p < 0.0001). Low-level laser therapy seems to be effective to mitigate salivary hypofunction and increase salivary pH of patients submitted to radiotherapy for head and neck cancer, thereby leading to an improvement in quality of life.