Titanium scaffold osteogenesis in healthy and osteoporotic rats is improved by the use of low-level laser therapy (GaAlAs)

The effect of photobiomodulation therapy on implant stability: A systematic review and meta-analysis

This study was designed to determine the effect of photobiomodulation therapy on dental implant stability. A complete systematic search was performed in PUBMED/MEDLINE, COCHRANE library databases, EMBASE, SCOPUS, and Google Scholar databases on articles published until June 2024. All the RCTs and CCTs reported the solo impact of photobiomodulation on dental implant stability in humans were included. The means and standard deviation for implant stability and sample size were extracted for the meta-analysis. The statistical analysis was conducted using Stata 17 software, and random effect models were applied to assess the source of heterogeneity. The I2 statistic was used to estimate the significance of any discrepancies in the therapy result. After a full-text inspection, 17 articles were qualified for systematic review, and 14 were included in the meta-analysis. Statically significant differences in implant stability were observed between the laser and the control groups on weeks 2 in ISQ reporting groups (p = 0.01, CI 95%) and weeks 4 and 8 in PTV reporting groups (p < 0.001, CI 95%). Despite limitations, the study suggests that PBM therapy benefits patients with dental implants at different periods, particularly during the early phases of healing.

The Potential Effects of Light Irradiance in Glaucoma and Photobiomodulation Therapy

Human vision is mediated by the retina, one of the most critical tissues in the central nervous system. Glaucoma is a complex retinal disease attributed to environmental, genetic, and stochastic factors, all of which contribute to its pathogenesis. Historically, glaucoma had been thought of primarily as a disease of the elderly; however, it is now becoming more problematic as the incidence rate increases among young individuals. In recent years, excessive light exposure has been suggested as contributing to the rise in glaucoma among the younger generation. Blue light induces mitochondrial apoptosis in retinal ganglion cells, causing optic damage; red light increases cytochrome c oxidase activity in the electron transport system, reducing inflammation and increasing antioxidant reactions to promote cell regeneration. In conclusion, the minimization of blue light exposure and the general application of red light treatment strategies are anticipated to show synergistic effects with existing treatments for retinal disease and glaucoma and should be considered a necessary prospect for the future. This review introduces the recent studies that support the relationship between light exposure and the onset of glaucoma and discusses new treatments, such as photobiomodulation therapy.

Effect of photobiomodulation therapy with different wavelengths on bone mineral density in osteoporotic rats

Osteoporosis is associated with severe pain, bone deformity, fracture, and bone loss. It is important to find strategies to prevent bone resorption and treat osteoporosis. This study sought to assess the effect of photobiomodulation therapy (PBMT) with different wavelengths on bone mineral density (BMD) in osteoporotic rats. This animal study evaluated 63 adult female rats. The rats underwent ovariectomy to induce osteoporosis. Ovariectomized rats were randomly divided into 9 groups of control (OC), treatment with zoledronic acid alone (0.02 mg/kg), and treatment with 660 nm, 810 nm, and 940 nm PBMT alone (3 times a week for 6 weeks, energy density of 4 J/cm2), and combined with zoledronic acid. The healthy control group (HC) only underwent sham surgery. The rats underwent cone-beam computed tomography (CBCT) 52 days after the first treatment session to measure their BMD according to the gray value (GV) of images. To assess the biomechanical properties of bone, the resected bones were subjected to 3-point bending test (3-PBT). The experimental groups had significant differences with the OC group regarding radiographic and biomechanical properties of bone (P < 0.05), indicating a healing course. No significant difference was noted between the experimental groups treated with different laser wavelengths and those treated with zoledronic acid (P > 0.05). In the condition of this study, it was found that PBMT at a constant energy density of 4 J/cm2 with 660-, 810-, and 940-nm wavelengths is effective for enhancement of bone mineral density and biomechanical properties. No significant difference was noted between different wavelengths of diode laser regarding radiographic and biomechanical properties of bone.

Photobiomodulation in 3D tissue engineering

SIGNIFICANCE

The method of photobiomodulation (PBM) has been used in medicine for a long time to promote anti-inflammation and pain-resolving processes in different organs and tissues. PBM triggers numerous cellular pathways including stimulation of the mitochondrial respiratory chain, alteration of the cytoskeleton, cell death prevention, increasing proliferative activity, and directing cell differentiation. The most effective wavelengths for PBM are found within the optical window (750 to 1100 nm), in which light can permeate tissues and other water-containing structures to depths of up to a few cm. PBM already finds its applications in the developing fields of tissue engineering and regenerative medicine. However, the diversity of three-dimensional (3D) systems, irradiation sources, and protocols intricate the PBM applications.

AIM

We aim to discuss the PBM and 3D tissue engineered constructs to define the fields of interest for PBM applications in tissue engineering.

APPROACH

First, we provide a brief overview of PBM and the timeline of its development. Then, we discuss the optical properties of 3D cultivation systems and important points of light dosimetry. Finally, we analyze the cellular pathways induced by PBM and outcomes observed in various 3D tissue-engineered constructs: hydrogels, scaffolds, spheroids, cell sheets, bioprinted structures, and organoids.

RESULTS

Our summarized results demonstrate the great potential of PBM in the stimulation of the cell survival and viability in 3D conditions. The strategies to achieve different cell physiology states with particular PBM parameters are outlined.

CONCLUSIONS

PBM has already proved itself as a convenient and effective tool to prevent drastic cellular events in the stress conditions. Because of the poor viability of cells in scaffolds and the convenience of PBM devices, 3D tissue engineering is a perspective field for PBM applications.

Effect of Photobiomodulation Therapy Associated With Biphasic Phosphate Calcium on Bone Repair: A Histomorphometric Study in Rats

Introduction: This study aimed to investigate the effects of photobiomodulation (PBM) therapy associated with biphasic calcium phosphate on calvaria critical defects in rats. Methods: Forty-eight (90 days old) adult male rats (Rattus norvegicus, Albinus variation, Wistar) received critical defects of 5 mm in diameter, which were made on their skull, and they were randomly assigned into the following groups: C-blood clot, B-biphasic calcium phosphate, L-photobiomodulation therapy, and B + L-biphasic calcium phosphate + photobiomodulation therapy. A low-level a gallium aluminum arsenide (GaAlAs) laser was applied in a single dose during surgery, in a wavelength of 660 nm and total energy density of 45 J/cm². On 30^th and 60^th days, the animals from each group were euthanized. Histological and histomorphometric analyses were performed. Results:In 30 days, almost all specimens (C, L, B and B + L) showed bone neoformation areas in regions near the borders of the surgical defect. In 60 days, in many specimens (C, L, B, B + L), it was possible to see a narrow neoformed bone structure along almost the whole extension of the surgical defect, though it was thinner than the original calvary bone. Data were recorded as mean ± standard deviation, and after normality was tested, a suitable statistical test was applied (α = 5%). On day 60, there was a statistically significant difference when comparing the proportion of neoformation area between group L (0.52%±0.13) and group B+L (0.20%±0.08). Group L showed a difference compared with all the groups when we compared the remaining distance between the edges of neoformed bone (C×L, P=0.0431; B × L, P=0.0386; L×B+L, P=0.0352), demonstrating a great defect closure. Conclusion: Our findings suggest that although biphasic calcium phosphate exerts some osteogenic activity during bone repair, PBM therapy is not able to modulate this process.

An Evaluation of the Effects of Photobiomodulation Therapy on the Peri-Implant Bone Healing of Implants with Different Surfaces: An In Vivo Study

(1) Background: This study evaluates the effects of photobiomodulation (PBM) therapy on the peri-implant bone healing of implants with a machined surface (MS) and treated surface (TS). (2) Methods: Topographic characterization of the surfaces (scanning electron microscopy [SEM]- energy dispersive X-ray spectroscopy [EDX]) was performed before and after implant removal. Twenty rabbits were randomly divided into four groups: MS and TS groups (without PBM therapy) and LMS and LTS groups (with PBM therapy). After implant placement, the stability coefficient (ISQ) was measured. In the periods of 21 and 42 days, the ISQ was measured again, followed by biomechanical analysis. (3) Results: The surfaces of the TS implants showed topographic differences compared with MS implants. The ISQ values of the LMS were statistically significant when compared with those of the MS at 42 days (p < 0.001). The removal torque values of the LMS were statistically significant when compared with those of the MS at 21 days (p = 0.023) and 42 days (p = 0.023). For SEM, in general, the LMS, TS and LTS presented high bone tissue coverage when compared to MS. (4) Conclusions: The PBM therapy modulated the osseointegration process and was evidenced mainly on the machined surface.

Photobiomodulation stimulates surrounding bone formation and increases stability of titanium alloy miniscrews in ovariectomized rats

The number of older individuals (> 60 years) treated in orthodontic dental practice is constantly growing, and osteoporosis is a common disease within this age range. Orthodontic treatment for this group tends to be challenging, often requiring the use of mini-implants. Mini-implants are important accessories in orthodontic treatment that provide solutions to complex cases. Despite the high level of success, these devices are prone to failure if insufficient bone stability is achieved. This study aimed to evaluate the effects of photobiomodulation on bone neoformation around mini-implants using fluorescence analysis in ovariectomized rats. A total of 12 female rats (Wistar) were ovariectomized and divided into three groups: two groups of low-level laser therapy irradiation in two different protocols, as follows: in the PBM1 group, applications were performed using 2 J, for 20 s each for 48 h, 6 irradiations in total, and in the PBM2 group, a single application of 4 J was performed for 40 s, and the third group represented the control group, and no laser therapy was applied. Each rat received two mini-implants placed immediately behind the upper incisors, and 0 g of force was applied using a NiTi spring. All rats received two bone markers, tetracycline (days 0-4) and alizarin (days 7-10), for 5 days each. Both markers were bound to calcium, allowing visualization of bone neoformation through fluorescence microscopy. After 12 days, euthanasia was performed; the results revealed that both irradiated groups showed significantly greater bone neoformation compared to the control group (p < 0.05). Mini-implant stability was measured in all animals using the Periotest device on day 0 and on the day of euthanasia. A significant increase in stability was observed in the group that received more laser application (p < 0.05). Photobiomodulation had a positive effect on bone neoformation around mini-implants in ovariectomized rats, with an increase in stability when more irradiation was performed.

Rotary Jet-Spun Polycaprolactone/Hydroxyapatite and Carbon Nanotube Scaffolds Seeded with Bone Marrow Mesenchymal Stem Cells Increase Bone Neoformation

Clinically, bone tissue replacements and/or bone repair are challenging. Strategies based on well-defined combinations of osteoconductive materials and osteogenic cells are promising to improve bone regeneration but still require improvement. Herein, we combined polycaprolactone (PCL) fibers, carbon nanotubes (CNT), and hydroxyapatite (nHap) nanoparticles to develop the next generation of bone regeneration material. Fibers formed by rotary jet spinning (RJS) instead of traditional electrospinning (ES) with embedded bone marrow mesenchymal stem cells (BMMSCs) showed the best outcomes to repair rat calvarial defects after 6 weeks. To understand this, it was observed that different morphologies were formed depending on the manufacturing method used. RJS fibers presented a particular topography with rough fibers, which allowed for better cellular growth and cell spreading in vitro around and into a three-dimensional (3D) mesh, while fibers made by ES were more smooth and cellular growth was only measured on the 3D mesh surface. The fibers with incorporated nHap/CNT nanoparticles enhanced in vitro cell performance as indicated by more cellular proliferation, alkaline phosphatase activity, proliferation, and deposition of calcium. Greater bone neoformation occurred by combining three characteristics: the presence of nHap and CNT nanoparticles, the topography of the RJS fibers, and the addition of BMMSCs. RJS fibers with nanoparticles and seeded with BMMSCs showed 10 136 mm³ of bone neoformation, meaning a 10-fold increase compared to using RJS only and BMMSCs (0.853 mm³) and a 5-fold increase from using ES only (2054 mm³) after 6 weeks of implantation. Conversely, none of these approaches used individually showed any significant difference for in vivo bone neoformation, suggesting that their combination is essential for optimizing bone formation. In summary, our work generated a potential material composed of well-defined combinations of suitable scaffolds seeded with BMMSCs for enhancing numerous orthopedic tissue engineering applications.

Laser-photobiomodulation on titanium implant bone healing in rat model: comparison between 660- and 808-nm wavelength

Laser-photobiomodulation (L-PBM) has been widely studied and its biomodulatory effects have been established on irradiated cells, increasing viability and proliferation and on damaged tissues. In addition, L-PBM may reduce and modulate the inflammatory process. The effect of 660-nm and 808-nm laser-photobiomodulation on bone repair around titanium dental implants placed in rat's femur was evaluated by histomorphometry. Twenty-seven Wistar rats were divided into 3 groups of nine animals: group C - non-irradiated control; group R - λ=660nm irradiated; and group IR - λ=808nm irradiated. Each group was further divided in 3 subgroups of three animals each, according to histomorphometry analysis in 3 days, 7 days, and 14 days after irradiation. Histological H.E.-stained slides were photographed, and bone matrix measured in new-formed bone area. Bone matrix histomorphometry analysis indicates that at 7 days in the irradiated groups (R and IR), a bigger area matrix was observed in relation to control group (C) (p=0.04 and p=0.048 respectively). On the other hand, at 14 days, control group (C) presented a bigger area than infrared irradiated (IR) (p=0.001) and red irradiated group (R) also showed a bigger area than infrared irradiated group (IR) (p=0.019). Histological analysis indicates that irradiated groups (R and IR) exhibited a faster bone tissue matrix production than control group.

Electrospun Poly(butylene-adipate-co-terephthalate)/Nano-hyDroxyapatite/Graphene Nanoribbon Scaffolds Improved the In Vivo Osteogenesis of the Neoformed Bone

Electrospun ultrathin fibrous scaffold filed with synthetic nanohydroxyapatite (nHAp) and graphene nanoribbons (GNR) has bioactive and osteoconductive properties and is a plausible strategy to improve bone regeneration. Poly(butylene-adipate-co-terephthalate) (PBAT) has been studied as fibrous scaffolds due to its low crystallinity, faster biodegradability, and good mechanical properties; however, its potential for in vivo applications remains underexplored. We proposed the application of electrospun PBAT with high contents of incorporated nHAp and nHAp/GNR nanoparticles as bone grafts. Ultrathin PBAT, PBAT/nHAp, and PBAT/nHAp/GNR fibers were produced using an electrospinning apparatus. The produced fibers were characterized morphologically and structurally using scanning electron (SEM) and high-resolution transmission electron (TEM) microscopies, respectively. Mechanical properties were analyzed using a texturometer. All scaffolds were implanted into critical tibia defects in rats and analyzed after two weeks using radiography, microcomputed tomography, histological, histomorphometric, and biomechanical analyses. The results showed through SEM and high-resolution TEM characterized the average diameters of the fibers (ranged from 0.208 µm ± 0.035 to 0.388 µm ± 0.087) and nHAp (crystallite around 0.28, 0.34, and 0.69 nm) and nHAp/GNR (200-300 nm) nanoparticles distribution into PBAT matrices. Ultrathin fibers were obtained, and the incorporated nHAp and nHAp/GNR nanoparticles were well distributed into PBAT matrices. The addition of nHAp and nHAp/GNR nanoparticles improved the elastic modulus of the ultrathin fibers compared to neat PBAT. High loads of nHAp/GNR (PBATnH5G group) improved the in vivo lamellar bone formation promoting greater radiographic density, trabecular number and stiffness in the defect area 2 weeks after implantation than control and PBAT groups.

Interaction between Laser Light and Osteoblasts: Photobiomodulation as a Trend in the Management of Socket Bone Preservation-A Review

Simple Summary

Dental implants are becoming an accepted tool, and thousands of implants are placed every year by specialists and general practitioners. However, more than 10% of bone surgeries and related procedures can show healing complications as a consequence of infections, tissue damage, or inadequate blood supply. In particular, a deficient blood supply impacts on the optimal healing process because of altered oxygen delivery to cells in the wound and a decrease in their energy supply. Researchers showed how red and infrared light affects key cellular pathways by interacting with specific photoacceptors located within the cell, particularly in mitochondria. Low-level laser therapy or photobiomodulation (PBM), as the recent medical subject heading defines it, is based on a light–cell interaction, which modifies cell metabolism by increasing oxygen consumption and ATP production through mitochondria. Although not all aspects of this interconnection are completely described, many in vitro and in vivo studies showed the benefit of PBM in wound defect management. For instance, treatment of bone with PBM results in a greater amount of new-formed osteoblasts and matrix, an increase in collagen synthesis, and microvascular reestablishment. In our review, we highlight the osteoblast–light interaction, and the in vivo therapeutic tool of PBM for socket preservation is discussed.

Abstract

Bone defects are the main reason for aesthetic and functional disability, which negatively affect patient’s quality of life. Particularly, after tooth extraction, the bone of the alveolar process resorbs, limiting the optimal prosthetic implant placement. One of the major pathophysiological events in slowly- or non-healing tissues is a blood supply deficiency, followed by a significant decrease in cellular energy amount. The literature shows that photons at the red and infrared wavelengths can interact with specific photoacceptors located within the cell. Through this mechanism, photobiomodulation (PBM) can modify cellular metabolism, by increasing mitochondrial ATP production. Here, we present a review of the literature on the effect of PBM on bone healing, for the management of socket preservation. A search strategy was developed in line with the PRISMA statement. The PubMed and Scholar electronic databases were consulted to search for in vivo studies, with restrictions on the year (<50 years-old), language (English), bone socket preservation, and PBM. Following the search strategy, we identified 269 records, which became 14, after duplicates were removed and titles, abstract and inclusion-, exclusion-criteria were screened. Additional articles identified were 3. Therefore, 17 articles were included in the synthesis. We highlight the osteoblast–light interaction, and the in vivo therapeutic tool of PBM is discussed.

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.

Photobiomodulation therapy (PBMT) in bone repair: A systematic review

BACKGROUND

Photobiomodulation therapy (PBMT) using low-level laser influences the release of several growth factors involved in the formation of epithelial cells, fibroblasts, collagen and vascular proliferation, besides accelerating the synthesis of bone matrix due to the increased vascularization and lower inflammatory response, with significant increase of osteocytes in the irradiated bone. Considering its properties, beneficial effects and clinical relevance, the aim of this review was to analyze the scientific literature regarding the use of PBMT in the process of bone defect repair.

METHODS

Electronic search was carried out in PubMed/MEDLINE^Ⓡ and Web of Science databases with combination of the descriptors low-level laser therapy AND bone repair, considering the period of publication until the year 2018.

RESULTS

The literature search identified 254 references in PubMed/MEDLINE and 204 in Web of Science, of which 33 and 4 were selected, respectively, in accordance with the eligibility requirements. The analysis of researches showed articles using PBMT in several places of experimentation in the subjects, different types of associated biomaterials, stimulatory effects on cell proliferation, besides variations in the parameters of use of laser therapy, mainly in relation to the wavelength and density of energy. Only four articles reported that the laser did not improve the osteogenic properties of a biomaterial.

CONCLUSIONS

Many studies have shown that PBMT has positive photobiostimulatory effects on bone regeneration, accelerating its process regardless of parameters and the use of biomaterials. However, standardization of its use is still imperfect and should be better studied to allow correct application concerning the utilization protocols.

Systemic and local effects of radiotherapy: an experimental study on implants placed in rats

OBJECTIVES

Evaluate the modulating effect of ionizing radiation, blood cytokine levels, and bone remodeling of the interface around the implant to understand the radiation mechanisms which can impair the implants receptor site.

MATERIAL AND METHODS

Sixty rats were submitted to grade V titanium implants in the femurs and were divided into the following groups: no-irradiation (N-Ir): control group with implant only; early-irradiation (E-Ir): implant + irradiation after 24 h; late-irradiation (L-Ir): implant + irradiation after 4 weeks; and previous-irradiation (P-Ir): irradiation + implant after 4 weeks. The animals in the E-Ir, L-Ir, and P-Ir groups were irradiated in two fractional stages of 15 Gy. At 3 days, 2 weeks, and 7 weeks after the final procedure, five animals were randomly euthanized per group. Serum levels of TNF-ɑ, IL-1β, TGF-β, IL-6, M-CSF, and IL-10 were measured from blood collected prior to euthanasia using the ELISA test. The pieces containing the implants were subjected to immunohistochemical labeling using the tartrate acid resistant to phosphatase, osteocalcin, and caspase-3 markers and mCT. The ANOVA test was used for statistical analysis, and the Tukey multiple comparison test (p < 0.05) was applied.

RESULTS

The results indicated that ionizing radiation modifies the production of pro- and anti-inflammatory serum cytokines, the expression of proteins involved in bone remodeling and cellular apoptosis, as well as changes in bone formation.

CONCLUSIONS

The results suggests that a longer period between radiotherapy and implant placement surgery when irradiation occurs prior to implant installation would allow the recovery and renewal of bone cells and avoid future failures in osseointegration.

CLINICAL RELEVANCE

The search for modifications caused by ionizing irradiation in bone tissue can indicate the ideal period for implant placement without affecting the osseointegration process.

Molecular impacts of photobiomodulation on bone regeneration: A systematic review

Photobiomodulation (PBM) encompasses a light application aimed to increase healing process, tissue regeneration, and reducing inflammation and pain. PBM is specifically aimed to modify the expression of cellular molecules; however, PBM impacts on cellular and molecular pathways especially in bone regenerative medicine have been investigated in scattered different studies. The purpose of the current study is to systematically review evidence on molecular impact of PBM on bone regeneration. A comprehensive electronic search in Medline, Scopus, EMBASE, EBSCO, Cochrane library, web of science, and google scholar was conducted from January 1975 to October 2018 limited to English language publications on administrations of photobiomodulation for bone regeneration which evaluated biological factors. In addition, hand search of selected journals was done to retrieve all articles. This systematic review was performed based on PRISMA guideline. Among these studies, five articles reported in vitro results, twelve articles were in vivo, and three of them were clinical trials. The data tabulated according to the type of markers (osteogenic markers, angiogenic markers, growth factors, and inflammation mediators). PBM's effects depend on many parameters which energy density is more important than the others. PBM can significantly enhance expression of osteocalcin, collagen, RUNX-2, vascular endothelial growth factor, bone morphogenic proteins, and COX-2. Although since the heterogeneity of the studies and their limitations, an evidence-based decision for definite therapeutic application of PBM is still unattainable, the findings of our review can help other researchers to ameliorate their study design and elect more efficient approach for their investigation.

The effect of pulsed electromagnetic field exposure on osteoinduction of human mesenchymal stem cells cultured on nano-TiO2 surfaces

Human bone marrow-derived mesenchymal stem cells (hBM-MSCs) are considered a great promise in the repair and regeneration of bone. Considerable efforts have been oriented towards uncovering the best strategy to promote stem cells osteogenic differentiation. In previous studies, hBM-MSCs exposed to physical stimuli such as pulsed electromagnetic fields (PEMFs) or directly seeded on nanostructured titanium surfaces (TiO₂) were shown to improve their differentiation to osteoblasts in osteogenic condition. In the present study, the effect of a daily PEMF-exposure on osteogenic differentiation of hBM-MSCs seeded onto nanostructured TiO₂ (with clusters under 100 nm of dimension) was investigated. TiO₂-seeded cells were exposed to PEMF (magnetic field intensity: 2 mT; intensity of induced electric field: 5 mV; frequency: 75 Hz) and examined in terms of cell physiology modifications and osteogenic differentiation. Results showed that PEMF exposure affected TiO₂-seeded cells osteogenesis by interfering with selective calcium-related osteogenic pathways, and greatly enhanced hBM-MSCs osteogenic features such as the expression of early/late osteogenic genes and protein production (e.g., ALP, COL-I, osteocalcin and osteopontin) and ALP activity. Finally, PEMF-treated cells resulted to secrete into conditioned media higher amounts of BMP-2, DCN and COL-I than untreated cell cultures. These findings confirm once more the osteoinductive potential of PEMF, suggesting that its combination with TiO₂ nanostructured surface might be a great option in bone tissue engineering applications.

Photobiomodulation Therapy (PBMT) in Peripheral Nerve Regeneration: A Systematic Review

Photobiomodulation therapy (PBMT) has been investigated because of its intimate relationship with tissue recovery processes, such as on peripheral nerve damage. Based on the wide range of benefits that the PBMT has shown and its clinical relevance, the aim of this research was to carry out a systematic review of the last 10 years, ascertaining the influence of the PBMT in the regeneration of injured peripheral nerves. The search was performed in the PubMed/MEDLINE database with the combination of the keywords: low-level laser therapy AND nerve regeneration. Initially, 54 articles were obtained, 26 articles of which were chosen for the study according to the inclusion criteria. In the qualitative aspect, it was observed that PBMT was able to accelerate the process of nerve regeneration, presenting an increase in the number of myelinated fibers and a better lamellar organization of myelin sheath, besides improvement of electrophysiological function, immunoreactivity, high functionality rate, decrease of inflammation, pain, and the facilitation of neural regeneration, release of growth factors, increase of vascular network and collagen. It was concluded that PBMT has beneficial effects on the recovery of nerve lesions, especially when related to a faster regeneration and functional improvement, despite the variety of parameters.