Over the past decade, dramatic progress has been made in dental research areas involving laser therapy. The photobiomodulatory effect of laser light regulates the behavior of periodontal tissues and promotes damaged tissues to heal faster. Additionally, photobiomodulation therapy (PBMT), a non-invasive treatment, when applied in orthodontics, contributes to alleviating pain and reducing inflammation induced by orthodontic forces, along with improving tissue healing processes. Moreover, PBMT is attracting more attention as a possible approach to prevent the incidence of orthodontically induced inflammatory root resorption (OIIRR) during orthodontic treatment (OT) due to its capacity to modulate inflammatory, apoptotic, and anti-antioxidant responses. However, a systematic review revealed that PBMT has only a moderate grade of evidence-based effectiveness during orthodontic tooth movement (OTM) in relation to OIIRR, casting doubt on its beneficial effects. In PBMT-assisted orthodontics, delivering sufficient energy to the tooth root to achieve optimal stimulation is challenging due to the exponential attenuation of light penetration in periodontal tissues. The penetration of light to the root surface is another crucial unknown factor. Both the penetration depth and distribution of light in periodontal tissues are unknown. Thus, advanced approaches specific to orthodontic application of PBMT need to be established to overcome these limitations. This review explores possibilities for improving the application and effectiveness of PBMT during OTM. The aim was to investigate the current evidence related to the underlying mechanisms of action of PBMT on various periodontal tissues and cells, with a special focus on immunomodulatory effects during OTM.
Humans ; Inflammation ; Low-Level Light Therapy/adverse effects* ; Orthodontics ; Root Resorption/therapy* ; Tooth Movement Techniques

At present, current stimulation, ultra-sound, and light therapy have become effective methods to promote wound healing. Among them, infrared light is the most widely used method and is one of the important methods to promote wound healing. The therapeutic effect of infrared light on wounds is related to the effect of photobiomodulation on cells and molecules on the skin surface, but the mechanism by which photobiomodulation of infrared light promotes wound healing has not been fully elucidated. Therefore, it is necessary to study the action characteristics and the mechanism of photo-biomodulation of infrared light in promoting wound healing. This article reviews the effect of different types of infrared light on wound healing and the mechanism of infrared light in promoting wound healing.
Infrared Rays ; Low-Level Light Therapy/methods* ; Wound Healing/physiology*

OBJECTIVE: To evaluate the effect of photobiomodulation (PBM) on the drainage of brain interstitial fluid (ISF) and to investigate the possible mechanism of the positive effect of PBM on Alzheimer's disease (AD). METHODS: Twenty-four SD male rats were randomly divided into PBM group (n=12), sham PBM group (n=6), and negative control group (n=6). According to the injection site of tracer, the PBM group was further divided into PBM-ipsilateral traced group (n=6) and PBM-contralateral traced group (n=6). Rats in the PBM group and the sham PBM group were exposed to the dura minimally invasively on the skull corresponding to the frontal cortical area reached by ISF drainage from caudate nucleus region. The PBM group was irradiated by using 630 nm red light (5-6 mW/cm²), following an irradiation of 5 min with a 2 min pause, and a total of 5 times; the sham PBM group was kept in the same position for the same time using the light without power. The negative control group was kept without any measure. After PBM, tracer was injected into caudate nucleus of each group. The changes of ISF drainage in caudate nucleus were observed according to the diffusion and distribution of tracer molecule by tracer-based magnetic resonance imaging, and the structural changes of brain extracellular space (ECS) were analyzed by diffusion rate in ECS-mapping (D_ECS-mapping) technique. Finally, parameters reflecting the structure of brain ECS and the drainage of ISF were obtained: volume fraction (α), tortuo-sity (λ), half-life (T_1/2), and D_ECS. The differences of parameters among different groups were compared to analyze the effect of PBM on brain ECS and ISF. One-Way ANOVA post hoc tests and independent sample t test were used for statistical analysis. RESULTS: The parameters including T_1/2, D_ECS, and λ were significantly different among the PBM-ipsilateral traced group, the PBM-contralateral traced group, and the sham PBM group (F=79.286, P < 0.001; F=13.458, P < 0.001; F=10.948, P=0.001), while there was no difference in the parameter α of brain ECS among the three groups (F=1.217, P=0.324). Compared with the sham PBM group and the PBM-contralateral traced group, the PBM-ipsilateral traced group had a significant decrease in the parameter T_1/2 [(45.45±6.76) min vs. (76.01±3.44) min, P < 0.001; (45.45±6.76) min vs. (78.07±4.27) min, P < 0.001], representing a significant acceleration of ISF drainage; the PBM-ipsilateral traced group had a significant increase in the parameter D_ECS [(4.51±0.77)×10^-4 mm²/s vs. (3.15±0.44)×10^-4 mm²/s, P < 0.001; (4.51±0.77)×10^-4 mm²/s vs. (3.01±0.38)×10^-4 mm²/s, P < 0.001], representing a significantly increased molecular diffusion rate of in the brain ECS; the PBM-ipsilateral traced group had a significant decrease in the parameter λ (1.51±0.21 vs. 1.85±0.12, P=0.001; 1.51±0.21 vs. 1.89±0.11, P=0.001), representing a significant decrease in the degree of tortuosity in the brain ECS. CONCLUSION PBM can regulate the brain ISF drainage actively, which may be one of the potential mechanisms of the effect of PBM therapy on AD. This study provides a new method for enhancing the brain function via ECS pathway.
Animals ; Male ; Rats ; Alzheimer Disease ; Brain ; Drainage ; Extracellular Fluid ; Gadolinium DTPA/metabolism* ; Low-Level Light Therapy ; Rats, Sprague-Dawley

Hearing loss is very common and economically burdensome. No accepted therapeutic modality for sensorineural hearing loss is yet available; most clinicians emphasize rehabilitation, placing hearing aids and cochlear implants. Photobiomodulation (PBM) employs light energy to enhance or modulate the activities of specific organs, and is a popular non-invasive therapy used to treat skin lesions and neurodegenerative disorders. Efforts to use PBM to improve hearing have been ongoing for several decades. Initial in vitro studies using cell lines and ex vivo culture techniques have now been supplanted by in vivo studies in animals; PBM protects the sensory epithelium and triggers neural regeneration. Many reports have used PBM to treat tinnitus. In this brief review, we introduce PBM applications in hearing research, helpful protocols, and relevant background literature.
Animals ; Cell Line ; Cochlear Implants ; Culture Techniques ; Epithelium ; Hearing Aids ; Hearing Loss ; Hearing Loss, Sensorineural ; Hearing ; In Vitro Techniques ; Low-Level Light Therapy ; Neurodegenerative Diseases ; Regeneration ; Rehabilitation ; Skin ; Tinnitus

BACKGROUND: Pain, limitations in opening, asymmetrical jaw movements, and temporomandibular joint (TMJ) sounds are the most common findings in temporomandibular joint disorders (TMDs), which causes excruciating pain, inflammation of the surrounding muscles, posterior fibers, and synovial fluid. This study aimed to evaluate and compare the effects of ultrasound heat therapy and low-level laser therapy (LLLT) in reducing TMD-related pain. METHODS: This prospective study included 42 patients (age range, 25–45 years), who were divided into two groups of 21 patients each. All patients were prescribed a non-steroidal anti-inflammatory drug (NSAID) twice a day for 5 days for temporary relief of pain prior to the commencement of treatment. Patients were kept on a soft diet and asked to restrict mouth opening during the same period. Fifteen sessions of LLLT (Group A) or ultrasound therapy (Group B) were administered to the affected side. RESULTS: Post-therapy, the mean visual analog scale score for group A and group B was 4.81 (2.01) and 6.19 (1.20), respectively; the difference was statistically significant and favoring the LLLT group. Similarly, the mean mouth opening for group A and group B was 3.99 (0.40) and 3.65 (0.41), respectively; the difference was statistically significant and favoring the LLLT group. CONCLUSION: Our study recommends LLLT for treating TMD-related pain with no underlying bony pathology.
Diet ; Hot Temperature ; Humans ; Inflammation ; Jaw ; Low-Level Light Therapy ; Mouth ; Muscles ; Pathology ; Prospective Studies ; Synovial Fluid ; Temporomandibular Joint Disorders ; Temporomandibular Joint ; Ultrasonic Therapy ; Ultrasonography ; Visual Analog Scale

No abstract available.
Coronary Artery Bypass ; Coronary Vessels ; Low-Level Light Therapy

BACKGROUND: The aim of this study was to evaluate the combined effect of low-level laser treatment (LLLT) and recombinant human bone morphological protein-2 (rhBMP-2) applied to hypoxic-cultured MC3T3-E1 osteoblastic cells and to determine possible signaling pathways underlying differentiation and mineralization of osteoblasts under hypoxia. METHODS: MC3T3-E1 cells were cultured under 1% oxygen tension for 72 h. Cell cultures were divided into four groups: normoxia control, low-level laser (LLL) alone, rhBMP-2 combined with LLLT, and rhBMP-2 under hypoxia. Laser irradiation was applied at 0, 24, and 48 h. Cells were treated with rhBMP-2 at 50 ng/mL. Alkaline phosphatase activity was measured at 3, 7, and 14 days to evaluate osteoblastic differentiation. Cell mineralization was determined with Alizarin red S staining at 7 and 14 days. Western blot assays were performed to evaluate whether p38/protein kinase D (PKD) signaling was involved. RESULTS: The results indicate that LLLT and rhBMP-2 synergistically increased alkaline phosphatase (ALP) activity and mineralization. Western blot analyses showed that expression of type I collagen, runt-related transcription factor 2 (RUNX2), and Osterix (Osx), increased and expression of hypoxia-inducible factor 1-alpha (HIF-1α), decreased more in the LLLT and rhBMP-2 combined group than in the rhBMP-2 or LLL alone groups. Moreover, LLLT and rhBMP-2 stimulated p38 phosphorylation and rhBMP-2 and LLLT increased Prkd1 phosphorylation. CONCLUSION: Combined treatment with rhBMP-2 and LLL induced differentiation and mineralization of hypoxiccultured MC3T3-E1 osteoblasts by activating p38/PKD signaling in vitro.
Alkaline Phosphatase ; Anoxia ; Blotting, Western ; Cell Culture Techniques ; Collagen Type I ; Humans ; In Vitro Techniques ; Low-Level Light Therapy ; Miners* ; Osteoblasts* ; Oxygen ; Phosphorylation ; Phosphotransferases ; Transcription Factors

OBJECTIVES: The purpose of this study was to evaluate the synergic effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) and low-level laser therapy (LLLT) on bisphosphonate-treated osteoblasts. MATERIALS AND METHODS: Human fetal osteoblast cells (hFOB 1.19) were cultured with 100 µM alendronate. Low-level Ga-Al-As laser alone or with 100 ng/mL rhBMP-2 was then applied. Cell viability was measured with MTT assay. The expression levels of receptor activator of nuclear factor kappa-B ligand (RANKL), macrophage colony-stimulating factor (M-CSF), and osteoprotegerin (OPG) were analyzed for osteoblastic activity inducing osteoclastic activity. Collagen type and transforming growth factor beta-1 were also evaluated for bone matrix formation. RESULTS: The results showed that rhBMP-2 and LLLT had a synergic effect on alendronate-treated osteoblasts for enhancing osteoblastic activity and bone matrix formation. Between rhBMP-2 and LLLT, rhBMP-2 exhibited a greater effect, but did not show a significant difference. CONCLUSION: rhBMP-2 and LLLT have synergic effects on bisphosphonate-treated osteoblasts through enhancement of osteoblastic activity and bone formation activity.
Alendronate ; Bone Matrix ; Bone Morphogenetic Protein 2 ; Cell Survival ; Collagen ; Humans* ; Low-Level Light Therapy ; Macrophage Colony-Stimulating Factor ; Osteoblasts* ; Osteoclasts ; Osteogenesis ; Osteoprotegerin ; Transforming Growth Factors

OBJECTIVE: To compare the effects of low intensity ultrasound (LIUS), traditional exercise therapy (TET), low level laser therapy (LLLT) and TET on temporomandibular joint (TMJ) pain and trismus following recovery from head and neck cancer (HNC). METHODS: Sixty participants following, who had experienced HNC, were randomly allocated to three groups of 20 people each. Each group received different therapy. Group A received LIUS and TET; group B received LLLT and TET; while group C received TET. All 60 participants were evaluated under the visual analog scale (VAS), the University of Washington Quality of Life questionnaire (UW-QOL) and the Vernier caliper scale (VCS) at the beginning of the therapies and after 4 weeks. RESULTS: ANOVA test revealed significant improvements across all three groups with outcomes of p < 0.05. The results of the UW-QOL questionnaire showed a significant difference between groups A, B and C in favor of group A (p < 0.05). The VAS results showed a more improvement in group A as compared to group B (p < 0.05), while there was no statistical difference between groups B and C (p>0.05). The VCS results showed more improvement for the individuals in group B as compared to those in group C (p < 0.05), while there was minimal difference between groups A and B (p>0.05). CONCLUSION: The LIUS and TET are more effective than LLLT and/or TET in reducing TMJ pain and trismus following HNC.
Exercise Therapy ; Exercise* ; Head and Neck Neoplasms* ; Head* ; Low-Level Light Therapy ; Quality of Life ; Temporomandibular Joint* ; Trismus* ; Ultrasonics ; Ultrasonography* ; Visual Analog Scale ; Washington

OBJECTIVE: The aim of this study was to assess the analgesic effect of a single application of low-level laser therapy (LLLT) on spontaneous pain and pain on chewing after placement of initial archwires. METHODS: Forty-two patients (26 women, 16 men) were randomly recruited for this split-mouth randomized clinical trial. Each patient received super-elastic nickel-titanium (NiTi) initial archwires (0.012, 0.014, 0.016, and 0.018-inch [in]) in the maxilla for leveling and alignment for an interval of 4 weeks between archwires. One side of the mouth was randomly designated as experimental, while the other side served as placebo. After insertion of each archwire, the experimental side was irradiated with a diode laser for 3 seconds each on 5 points facially and palatally per tooth, from the central incisor to first molar. On the placebo side, the laser device was held the same way but without laser application. A numerical rating scale was used to assess the intensity of spontaneous and masticatory pain for the following 7 days. The Mann-Whitney U test was used to compare pain scores between sides. RESULTS: Patients in the LLLT group exhibited significantly lower mean scores for spontaneous pain after insertion of the initial two archwires (0.012-in and 0.014-in NiTi; p < 0.05), while there was no significant difference for 0.016-in and 0.018-in wires between the LLLT and placebo groups. LLLT significantly reduced chewing pain scores (p < 0.05) for all archwires. CONCLUSIONS: A single dose of LLLT considerably lessened postoperative pain accompanying the placement of super-elastic NiTi wires for initial alignment and leveling.
Female ; Humans ; Incisor ; Lasers, Semiconductor ; Low-Level Light Therapy* ; Mastication ; Maxilla ; Molar ; Mouth ; Pain, Postoperative ; Tooth