Photobiomodulation therapy in improvement of harmful neural plasticity in sodium salicylate-induced tinnitus.

Tinnitus is a common annoying symptom without effective and accepted treatment. In this controlled experimental study, photobiomodulation therapy (PBMT), which uses light to modulate and repair target tissue, was used to treat sodium salicylate (SS)-induced tinnitus in a rat animal model. Here, PBMT was performed simultaneously on the peripheral and central regions involved in tinnitus. The results were evaluated using objective tests including gap pre-pulse inhibition of acoustic startle (GPIAS), auditory brainstem response (ABR) and immunohistochemistry (IHC). Harmful neural plasticity induced by tinnitus was detected by doublecortin (DCX) protein expression, a known marker of neural plasticity. PBMT parameters were 808 nm wavelength, 165 mW/cm2 power density, and 99 J/cm2 energy density. In the tinnitus group, the mean gap in noise (GIN) value of GPIAS test was significantly decreased indicated the occurrence of an additional perceived sound like tinnitus and also the mean ABR threshold and brainstem transmission time (BTT) were significantly increased. In addition, a significant increase in DCX expression in the dorsal cochlear nucleus (DCN), dentate gyrus (DG) and the parafloccular lobe (PFL) of cerebellum was observed in the tinnitus group. In PBMT group, a significant increase in the GIN value, a significant decrease in the ABR threshold and BTT, and also significant reduction of DCX expression in the DG were observed. Based on our findings, PBMT has the potential to be used in the management of SS-induced tinnitus.

Evaluation of the Effect of Photobiomodulation on Radiation-Induced Xerostomia in Head and Neck Cancer Patients: A Randomized Clinical Trial.

Introduction: Radiotherapy-induced xerostomia is an important side effect of head and neck cancer (HNC) treatment. Photobiomodulation (PBM) is one of the new emerging methods for preventing or reducing this problem. The aim of this study is to evaluate the effect of PBM on radiation-induced xerostomia in HNC patients. Methods: Thirty-seven patients with HNC who were referred for radiotherapy to Mashhad cancer center. In the case group, an infrared diode laser was used in contact mode on 16 points (covering minor and major salivary glands). The device emitted a wavelength of 810 nm and operated at the power of 200 mW and continuous wave mode. Each area was irradiated for 4 seconds in contact mode with gentle pressure, and the laser energy was 0.8 J with an energy density of 2.85 J/cm2 at the surface of the probe (spot size, 0.28 cm2 ). The total dose was 45.6 J/cm2. The power density was 714.2 w/cm2. In the control group, the sham laser device was used. Subjective xerostomia was evaluated through the LENT SOMA scale (LSS). Stimulated and unstimulated saliva was also assessed. Data were analyzed with SPSS ver22 statistical software. Results: The study included 26 men and 11 women with a mean age of 55.6±15.3 years. In the sixth week, the case group produced more stimulated saliva than the control group (P=0.006). They also had less subjective xerostomia than the control group in weeks four to six. Conclusion: In the present study, PBM had a preventive effect on stimulated saliva and subjective xerostomia and can be recommended as an adjunctive treatment. Further studies with a higher sample size and the use of a low-level laser in more sessions are needed for definitive comment.

Photoinactivation Effects of Curcumin, Nano-curcumin, and Erythrosine on Planktonic and Biofilm Cultures of Streptococcus mutans.

Introduction: This in vitro study was conducted to assess the phototoxic effects of curcumin, nano-curcumin, and erythrosine on the viability of Streptococcus mutans (S. mutans) in suspension and biofilm forms. Methods: Various concentrations of curcumin (1.5 g/L, 3 g/L), nano-curcumin (3 g/L), and erythrosine (100 µM/L, 250 µM/L) were examined for their impact on planktonic and biofilm cultures of S. mutans, either individually or in conjunction with light irradiation (photodynamic therapy or PDT). A blue light-emitting diode (LED) with a central wavelength of 450 nm served as the light source. The results were compared to 0.12% chlorhexidine digluconate (CHX) as the positive control, and a solution containing neither a photosensitizer (PS) nor a light source as the negative control group. The dependent variable was the number of viable microorganisms per experiment (CFU/mL). Results: Antimicrobial PDT caused a significant reduction in the viability of S. mutans in both planktonic and biofilm forms, compared to the negative control group (P<0.05). The highest cell killing was observed in PDT groups with curcumin 3 g/L or erythrosine 250 µmol/L, although the difference with PDT groups using curcumin 1.5 g/L or erythrosine 100 µmol/L was not significant (P>0.05). Antimicrobial treatments were more effective against planktonic S. mutans than the biofilm form. Conclusion: PDT with either curcumin 1.5 g/L or erythrosine 100 µmol/L may be suggested as an alternative to CHX to inactivate the bacteria in dental plaque or deep cavities. Nano-curcumin, at the selected concentration, exhibited lower efficacy in killing S. mutans compared to Curcumin or erythrosine.

Effect of photobiomodulation on postoperative endodontic pain: A systematic review of clinical trials.

Background: This review aims to perform a complete evaluation of the impact of photobiomodulation (PMB) on postoperative endodontic pain. Materials and Methods: The PRISMA checklist was used to perform this systematic review. The electronic databases were searched, including Google Scholar, PubMed, and Embase. Sixty-three papers were obtained through a main electronic search and a hand search. Nine trials met the criteria after screening the titles, abstracts, and/or full texts. Results: Seven out of nine studies showed that PMB has a significant impact on relieving postoperative endodontic pain, with no statistically significant difference in the severity of pain between the laser and control groups in the two remaining studies. In addition, eight studies showed no adverse effects, indicating that we can remove the adverse effects of drugs such as nonsteroidal anti-inflammatory drugs. However, one study showed evidence of the consequences of PMB application on teeth with symptomatic irreversible pulpitis. Therefore, it can be concluded that PMB should not be used in teeth with pain because of irreversible pulpitis. Conclusion: Although there is some understanding from a cellular viewpoint of the effects of PMB, there is still some uncertainty about whether these cell-level modifications impact reducing the postendodontic pain.

Skin wound healing in diabetic rat model using low-dose photodynamic therapy.

Chronic wound is one of the major challenges in medicine and imposes a heavy financial burden on the healthcare of different countries. Diabetic foot ulcers as one of the important examples for chronic wounds can lead to lower limb amputation, disability, and death in diabetics. In this regard, novel technology with low side effects got attention in recent years. Low-dose photodynamic therapy (LDPDT) is one of the noninvasive techniques that can be considered for wound healing in diabetic wounds. In this experiment, we aim to study the effect of LDPDT on diabetic rats' wound healing and compare it to healthy rats. In this in vitro experimental study, 32 male rats were used. Rats in both normal and diabetic (streptozotocin injection) groups after being wounded (two wounds [0.8 × 0.8 cm]) on the back of each rat were randomly divided into four groups, including the control group (without treatment), radiation-only (660 nm-1  J/cm2 ) group, 5-ALA-only (1 µg/mL) group, and LDPDT-recipient group. The procedure has been done for 2 days, and at the end of Days 3, 7, 14, and 21, the wound sample was sent to the histopathology laboratory, and the wound size and tissue indices in these groups were evaluated by histology and microscopy techniques. The impact of low concentrations of 5-ALA and low irradiation energy density in both normal and diabetic rats were positive, which accelerated the wound-healing process as seen in the histology study. In diabetic rats treated with only radiation and LDPDT, the process of epithelial regeneration, collagen production, reduction of mast cells, and production of follicles was more as compared to the normal group. The results suggest that LDPDT can have a positive impact on the diabetic rat model wound healing.

Comparative Effects of Cognitive Rehabilitation and Photobiomodulation on Drug Craving in Treatment-Seeking Opioid Addicts.

Background: Drug addiction refers to a maladaptive pattern of drug use that frequently leads to substance abuse problems and accompanying cognitive and behavioral symptoms. Among the crucial criteria of drug addiction, craving stands out as a potent factor contributing to ongoing drug abuse and relapse following period of abstinence. To date, there is no definitive method for eradicating opioid cravings. The introduction of novel neurocognitive interventions, such as cognitive rehabilitation and photobiomodulation (PBM), into the realm of psychiatric treatments holds promise due to the parallels between drug addiction and other psychiatric disorders. These innovative techniques offer potential value in addressing drug addiction. Objective: This study aimed to assess and compare the efficacy of cognitive rehabilitation and PBM in alleviating drug cravings among individuals undergoing addiction treatment in clinical settings. Methods: The research used randomized clinical trial as the chosen research method. The statistical population encompassed all clients receiving treatment for addiction at clinics, selected through the convenience sampling method, with α = 0.05 significance level and an effect size of 85%. Gpower software was utilized to determine three equal groups. Sixty-three participants, each having a mean total score higher than 3 out of 5 on the Desire for Drug Questionnaire (DDQ), were randomly assigned to two experimental groups (n = 21 each) and a control group (n = 21). For the assessment of immediate and periodic opioid craving, the DDQ and the Obsessive Compulsive Drug Use Scale were used. In the low-level laser group, an 810 nm wavelength with continuous irradiation was applied twice a week at a distance of 1 cm by 1 cm to the prefrontal part of the brain for duration of 6 weeks (12 sessions). In the brain rehabilitation group, the stop signal and n-back tasks software were used twice a week for period of 6 weeks (comprising 12 sessions, each lasting 30 min). Results: The results demonstrated that each intervention significantly reduced drug craving in both the post-test and follow-up phases compared to the control group. The Bonferroni post hoc test indicated that PBM was more effective than cognitive rehabilitation in terms of working memory (WM) and inhibitory control for reducing drug craving (p < 0.05). Conclusions: While both PBM and cognitive rehabilitation targeting WM and inhibitory control effectively reduced opioid drug craving, low-level laser therapy proved to be more effective than cognitive rehabilitation in this regard.

High-Power Laser Application for Immediate Implant Placement in Infected Sites: A Systematic Review.

Objective: The purpose of this study was to review the literatures regarding the treatment outcomes of applying laser to the infected sites in immediate implant placement. The review tended to primarily target a question: does applying high-power laser have any positive effect on infected sites in immediate implant placement? Background: Although immediate placement of dental implants has been referred to as a predictable and successful procedure, it is prone to the presence of infection that interferes with the healing process, and triggers the failure of implants. Materials and methods: A thorough electronic database search was conducted on PubMed/Medline, Embase, Web of Science, Google Scholar, and the Cochrane library in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Two writers worked separately on screening the eligible studies, assessing whether there was a risk of bias, and extracting the required data. Results: Five out of the 60 studies nominated by the database search matched the inclusion criteria. The studies were carried out on a total of 192 patients with 296 implants in all. Ultimately, the study focused on 245 implants whose infected bed had been already decontaminated and prepared with the help of the high-intensity laser, used either alone or in combination with other approaches before implantation. With only nine failures, the implants inserted in infected and irradiated areas had a 96.3% overall survival rate. Conclusions: Taking the limitations of the review into account, the authors arrived at the conclusion that high-power laser irradiation can be beneficial for immediate implant placement in infected sites.

Antimicrobial photodynamic therapy against Lactobacillus casei using curcumin, nano-curcumin, or erythrosine and a dental LED curing device.

This study aimed to investigate the photodynamic effects of curcumin, nanomicelle curcumin, and erythrosine on Lactobacillus casei (L. casei). Various concentrations of curcumin (1.5 g/L, 3 g/L), nano-curcumin (3 g/L), and erythrosine (100 µM/L, 250 µM/L) were tested either alone or combined with light irradiation (PDT effect) against L. casei in planktonic and biofilm cultures. The light was emitted from a light-emitting diode (LED) with a central wavelength of 450 nm. A 0.12% chlorhexidine digluconate (CHX) solution served as the positive control, and a solution containing neither photosensitizer nor light was the negative control group. The number of viable microorganisms was determined using serial dilution. There was a significant difference in the viability of L. casei in both planktonic and biofilm forms (P < 0.05). In the planktonic culture, the antibacterial effects of CHX and PDT groups with curcumin 3 g/L and erythrosine 250 µM/L were significantly greater than the other groups (P < 0.05). For L. casei biofilms, the greatest toxic effects were observed in CHX and PDT groups with curcumin 3 g/L, erythrosine 250 µmol/L, erythrosine 100 µmol/L, and nanomicelle curcumin 3 g/L, with a significant difference to other groups (P < 0.05). The antibacterial effects of all photosensitizers (except erythrosine 250 µmol/L at planktonic culture) enhanced significantly when combined with light irradiation (P < 0.05). PDT with curcumin 3 g/L or erythrosine 250 µmol/L produced comparable results to CHX against L. casei at both planktonic and biofilm cultures. Alternatively, PDT with erythrosine 100 µmol/L or nanomicelle curcumin 3 g/L could be suggested to kill L. casei biofilms.

Polyphenolic natural products as photosensitizers for antimicrobial photodynamic therapy: recent advances and future prospects.

Antimicrobial photodynamic therapy (aPDT) has become a potent contender in the fight against microbial infections, especially in the context of the rising antibiotic resistance crisis. Recently, there has been significant interest in polyphenolic natural products as potential photosensitizers (PSs) in aPDT, given their unique chemical structures and inherent antimicrobial properties. Polyphenolic natural products, abundant and readily obtainable from natural sources, are generally regarded as safe and highly compatible with the human body. This comprehensive review focuses on the latest developments and future implications of using natural polyphenols as PSs in aPDT. Paramount polyphenolic compounds, including curcumin, hypericin, quercetin, hypocrellin, celastrol, riboflavin, resveratrol, gallic acid, and aloe emodin, are elaborated upon with respect to their structural characteristics, absorption properties, and antimicrobial effects. Furthermore, the aPDT mechanism, specifically its targeted action on microbial cells and biofilms, is also discussed. Polyphenolic natural products demonstrate immense potential as PSs in aPDT, representing a promising alternate approach to counteract antibiotic-resistant bacteria and biofilm-related infections.

Antimicrobial photodynamic therapy with dendrosomal curcumin and blue laser against Porphyromonas gingivalis.

BACKGROUND: Periodontitis is a chronic inflammatory disease that leads to the loss of tooth-supporting structures. Porphyromonas gingivalis is one of the main pathogens responsible for periodontitis. Because of the limitations of antibiotic use, various alternative approaches have been developed. Antimicrobial photodynamic therapy uses photosensitizers and light to eliminate pathogens. Curcumin is a promising photosensitizer, but has low bioavailability and water solubility. However, dendrosomes can efficiently encapsulate curcumin, overcoming these obstacles. This study aimed to evaluate the efficacy of photodynamic therapy with blue laser and dendrosomal curcumin against Porphyromonas gingivalis. METHODS: In this in vitro experiment, the minimum inhibitory concentration (MIC) of dendrosomal curcumin was determined using a serial dilution approach. Porphyromonas gingivalis suspensions were subjected to blue laser irradiation (447 nm, output power 100 mW) for 30 to 180 s. Finally, several subMIC dendrosomal curcumin concentrations and blue laser irradiation periods were applied to the bacterial suspensions. The negative control group received no therapy, whereas the positive control group was treated with 0.2% chlorhexidine. Consequently, the colony count of each group was calculated. RESULTS: Treatment of Porphyromonas gingivalis with dendrosomal Curcumin at concentrations of 8-250 µg/mL significantly reduced bacterial growth compared to untreated group. 90 second exposure to a blue laser (31.8 J/cm2) completely inhibited the growth of Porphyromonas gingivalis. Blue laser irradiation for 60 s (21.2 J/cm2) markedly reduced bacterial growth but did not completely prevent its survival. Photodynamic therapy using dendrosomal curcumin at concentrations of 2-4 µg/mL and irradiation for 30-90 s resulted in complete eradication of Porphyromonas gingivalis compared to controls (P < 0.05). CONCLUSION: The reduction in survival of Porphyromonas gingivalis following photodynamic therapy with dendrosomal curcumin and blue laser indicates that this technique could be a useful approach to eradicate Porphyromonas gingivalis infections.

Management of recurrent aphthous ulcers with therapeutic Nd:YAG laser, using two different methods.

BACKGROUND: Low-level laser therapy (LLLT) has been applied for the management of craniomaxillofacial disorders, including intraoral wounds, as well as recurrent aphthous stomatitis (RAS) lesions. However, the proper combination of laser features and tissue characteristics remains the major challenge in the realm of photobiomodulation (PBM). OBJECTIVES: The aim of the present study was to assess the feasibility of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser therapy in treating RAS lesions, and to compare 2 techniques, different with regard to the distance between the fiber tip and the ulcer. MATERIAL AND METHODS: A total of 138 patients (94 males and 44 females) with untreated RAS were divided into 3 groups: focused laser (energy density: 48 J/cm2; power density: 0.797 W/cm2; spot size: 0.1256 cm2); defocused laser (energy density: 21 J/cm2; power density: 0.354 W/cm2; spot size: 0.2826 cm2); and placebo. In the focused group, laser irradiation was performed with the laser tip kept 1 mm away from the lesion. Acrylic cylinders were prepared to precisely fit the handpiece tip and hold it in the proper position. In the defocused group, acrylic cylinders were prepared to set the laser tip 6 mm away from the lesion to obtain defocused irradiation. Finally, in the placebo group, a routine laser therapy procedure was carried out with a helium-neon (He-Ne) red light laser. The lesion size, and pain intensity and duration were recorded. RESULTS: Photobiomodulation showed a significantly more efficient pain relief as compared to the placebo group (p < 0.001) and also significantly better results in decreasing pain duration (p < 0.001). Besides, the diameter of the lesions in the exposed cases decreased during the 3 consecutive days of the study, while an increase in the diameter of the lesions was noticed in the placebo group. CONCLUSIONS: The Nd:YAG laser therapy, with the conditions and adjustments of the present study, may be successfully applied to manage RAS lesions, using either focused and defocused scanning techniques.

Gingivectomy with Diode Laser Versus the Conventional Scalpel Surgery and Nonsurgical Periodontal Therapy in Treatment of Orthodontic Treatment-Induced Gingival Enlargement: A Systematic Review.

Background and objective: Some studies support the superiority of diode laser gingivectomy to scalpel surgery and nonsurgical treatments. However, a systematic review on this topic is lacking. This study aimed to compare gingivectomy with diode laser versus the conventional scalpel surgery and nonsurgical periodontal therapy (NSPT) in the treatment of orthodontic treatment-induced gingival enlargement (GE). Materials and methods: In this systematic review, an electronic search of the relevant literature was conducted in Web of Science, Medline/PubMed, Scopus, Cochrane Central Register of Controlled Trials, and ProQuest with no language restriction. Randomized clinical trials published between 1985 and 2020 on comparative treatment of orthodontic treatment-induced GE by diode laser gingivectomy and scalpel surgery or NSPT regarding intraoperative and postoperative bleeding and/or pain were included. Risk of bias was assessed by the Cochrane 1 tool. Results: Of the initially retrieved 288 articles, 40 were duplicates and excluded; 236 articles were excluded following title and abstract screening, and 5 others were excluded following full-text assessment. Finally, 7 studies underwent systematic review. In the risk-of-bias assessment, 5 studies scored 2, and 2 studies scored 3 out of 6. Intraoperative and postoperative bleeding and pain were found to be significantly lower in the laser group. Conclusions: Within the limitations of this systematic review and with respect to the quality of evidence, the present results revealed lower level of pain and bleeding in diode laser gingivectomy compared with the conventional scalpel surgery and NSPT for treatment of orthodontic treatment-induced GE.

Comparing Circumferential Supracrestal Fiberotomy with Surgical Scalpel Versus Photobiomodulation in Orthodontic Relapse Reduction: A Clinical Trial.

Objective: This investigation aimed to compare the efficacy of circumferential supracrestal fiberotomy (CSF) with surgical scalpel, laser CSF, and photobiomodulation for reduction of relapse after orthodontic tooth rotation. Background: Relapse is the tendency of teeth to move back to their preoperative position after removal of orthodontic appliances. Materials and methods: This randomized controlled clinical trial was conducted on 90 rotated teeth at the final stages of fixed orthodontic treatment. The teeth were randomly divided into six groups (n = 15) of (1) control (no intervention), (2) photobiomodulation alone (wavelength of 940 nm, 0.2 W, and 4 J/cm2), (3) conventional CSF, (4) laser CSF (wavelength of 940 nm, 1.5 W, and 4 J/cm2, and power density of 160 mW/cm2), (5) conventional CSF plus photobiomodulation, and (6) laser CSF plus photobiomodulation. Measurements were made on clinical photographs and dental casts using the AutoCAD software. Level of pain of patients was measured within the first 24 h after fiberotomy using a visual analog scale. Data were analyzed by ANOVA and Kruskal-Wallis test (α = 0.05). Results: The magnitude (p = 0.014) and percentage (p = 0.035) of relapse were significantly different among the six groups, and they were the highest in the control group followed by photobiomodulation alone, laser CSF, conventional CSF, conventional CSF plus photobiomodulation, and finally, laser CSF plus photobiomodulation. Moreover, photobiomodulation plus laser CSF and photobiomodulation plus conventional CSF had significantly different results from the other groups. The six groups had no significant difference in sulcus depth changes, gingival recession (difference in primary and secondary crown height), or pain score (p > 0.05). Conclusions: This study suggests that utilizing photobiomodulation combined with laser CSF or conventional CSF can be effective in reducing relapse. However, further clinical trials are required to support this idea. Iranian Registry of Clinical Trials (IRCT20210621051653N1).

Acoustic and optoacoustic stimulations in auditory brainstem response test in salicylate induced tinnitus.

As a common debilitating disorder worldwide, tinnitus requires objective assessment. In the auditory brainstem response (ABR) test, auditory potentials can be evoked by acoustic or optoacoustic (induced by laser light) stimulations. In order to use the ABR test in the objective assessment of tinnitus, in this study, acoustic ABR (aABR) and optoacoustic ABR (oABR) were compared in the control and tinnitus groups to determine the changes caused by sodium salicylate (SS)-induced tinnitus in rat. In both aABR and oABR, wave II was the most prominent waveform, and the amplitude of wave II evoked by oABR was significantly higher than that of aABR. Brainstem transmission time (BTT), which represents the time required for a neural stimulation to progress from the auditory nerve ending to the inferior colliculus, was significantly shorter in oABR. In the tinnitus group, there was a significant increase in the threshold of both ABRs and a significant decrease in the amplitude of wave II only in the oABR. Based on our findings, the ABR test has the potential to be used in the assessment of SS-induced tinnitus, but oABR has the advantages of producing more prominent waveforms and significantly reducing the amplitude of wave II in tinnitus.

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.

Angiogenetic and anti-inflammatory effects of photobiomodulation on bone regeneration in rat: A histopathological, immunohistochemical, and molecular analysis.

Post-surgical bone defects require new alternative approaches for a better healing process. For this matter, photobiomodulation therapy (PBMT) has been used in order to improve the process of healing, pain, and inflammation reduction and tissue rejuvenation. This study is set to evaluate the effect of PBMT on angiogenic and inflammatory factors for bone regeneration in rat post-surgical cranial defects. Thirty male Wistar rats were distributed accidentally into two groups (Subdivided into 3 groups according to their follow-up durations). During operation, an 8-mm critical-sized calvarial defect was made in each rat. A continuous diode laser was used (power density 100 mW/cm2, wavelength 810 nm, the energy density of 4 J/cm2). Bone samples were assessed histomorphometrically and histologically after hematoxylin and eosin (H&E) staining. ALP, PTGIR, OCN, and IL-1 levels were measured by RT-PCR. VEGF expression was studied by immunohistochemistry analysis. The level of IL-1 expression decreased significantly in the PBMT group compared to the control after 7 days (p < 0.05), while, the PTGIR level was improved significantly compared to the control group after 7 days. Furthermore, levels of OCN and ALP improved after PBM use; however, the alterations were not statistically meaningful (p > 0.05). Evaluation with IHC displayed a significant rise in VEGF expression after 3 days in the PBMT group compared to the control (p > 0.05). In this study's conditions, the results showed a meaningful alteration in osteogenic, inflammatory, and angiogenic mediators in post-surgical calvarial defect following PBMT. It appears that PBM can accelerate angiogenesis in the bone healing procedure which can be helpful in bone tissue engineering.

Effect of red and near-infrared irradiation on periodontal ligament stem cells: ROS generation and cell cycle analysis.

Reconstruction of lost tooth structures and the periodontium with the help of tissue engineering has found a special place in dentistry in recent years with reports of great therapeutic success. Stem cells from the periodontal ligament have the potential for high differentiation into the bone and periodontal ligament cells and are therefore a suit candidate for regenerative therapies of the periodontium and other tissues. In this regard, the use of photobiomodulation on these cells by light irradiation can be effective in increasing the efficiency of these regenerative methods. The effect of red and near-infrared lasers was investigated in pulsed and continuous modes on the cell viability, ROS production and the cell cycle of Periodontal Ligament Stem cells (PDLSCs) using MTT assay and flowcytometry techniques. The result shows that both red and near-infra-red (NIR) irradiations at 3 J/cm2 maintain cell viability. ROS generation assay indicated that in PDL stem cells irradiated with NIR laser (940 nm), ROS production was greater than in the red (660 nm) irradiated groups. Cell cycle analysis revealed that NIR irradiation can enhance the proportion of S-phase cells and declinedecline the proportion of G1-phase cells compared to the red laser irradiation groups. Moreover, this enhancement was greater in the pulsed group compared to the continuous mode group. Overall, the current study results showed that photobiomodulation can support the cell viability of PDLSCs and could affect the ROS production and cell cycle. This effect was more with 940 nm (NIR) irradiation pulsed mode compared to 660 nm (red).Communicated by Ramaswamy H. Sarma.

Efficacy of Adjunctive Photobiomodulation in the Management of Medication-Related Osteonecrosis of the Jaw: A Systematic Review.

Background: Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse medication response that manifests as progressive bone necrosis in the craniofacial area. There is still no clear treatment protocol for the management of MRONJ. The purpose of this study was to conduct a systematic review to assess the efficacy of photobiomodulation (PBM) as an adjunct to MRONJ therapy. Methods: In line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement, a literature search was performed on PubMed/MEDLINE, Scopus, Web of Science, and Cochrane databases. Two examiners examined eligibility and risk of bias separately before extracting data. Results: Two hundred sixty-nine articles were found through electronic search, out of which only 11 met the inclusion criteria and were included in qualitative synthesis (9 retrospectives, 1 prospective, and 1 case series). A total number of 759 patients and a mean age ranging from 54 to 74 years were reviewed. Females were the most frequent gender in all of the selected studies (72% females to 28% males), and the most frequent stage in the studies mentioned above was stage II (66%). Most of the studies had shown a significant improvement when PBM was used as an adjunctive treatment. Conclusions: Based on the results of this study, PBM as an adjuvant therapy can significantly improve the outcomes of each treatment plan. However, surgical intervention for the complete healing of the lesions is suggested.

Photobiomodulation therapy in mood disorders: a systematic review.

Mood disorders are common, debilitating and impose a high-cost burden on society. Side effects and resistance to psychiatric drugs justify finding new treatment methods. Photobiomodulation therapy (PBMT) uses photons of light to repair, modulate and improve the function of target tissue. The purpose of this study is to systematically review the use of PBMT for the treatment of mood disorders and to identify the useful parameters of PBMT, the level of evidence of its effectiveness, and the degree of its practical recommendation. "Google scholar," "Pub Med," "Scopus," and "Science direct" online databases were searched based on Preferred Reporting Items for Systematic Reviews and meta-analyses (PRISMA) guidelines. The human or animal studies written in English and published from January 2009 to August 2021 were included. Sixteen studies, which included four randomized controlled trials (RCTs), met the inclusion criteria. Infrared wavelength ranges from 800 to 830 nm, power density of 250 mW/cm2 and energy density of 60 to 120 J/ cm2 were the most used PBMT parameters. Bias risk assessment was performed to evaluate the quality of RCTs in which 2 out of 4 RCTs were evaluated as high quality. Based on grade practice recommendations, PBMT can be classified as strongly recommended for moderate grade of major depressive disorder (MDD) and recommended for anxiety disorder. In bipolar disorder, further studies are needed to recommend this therapeutic method.

NIR irradiation of human buccal fat pad adipose stem cells and its effect on TRP ion channels.

The effect of near infrared (NIR) laser irradiation on proliferation and osteogenic differentiation of buccal fat pad-derived stem cells and the role of transient receptor potential (TRP) channels was investigated in the current research. After stem cell isolation, a 940 nm laser with 0.1 W, 3 J/cm2 was used in pulsed and continuous mode for irradiation in 3 sessions once every 48 h. The cells were cultured in the following groups: non-osteogenic differentiation medium/primary medium (PM) and osteogenic medium (OM) groups with laser-irradiated (L +), without irradiation (L -), laser treated + Capsazepine inhibitor (L + Cap), and laser treated + Skf96365 inhibitor (L + Skf). Alizarin Red staining and RT-PCR were used to assess osteogenic differentiation and evaluate RUNX2, Osterix, and ALP gene expression levels. The pulsed setting showed the best viability results (P < 0.05) and was used for osteogenic differentiation evaluations. The results of Alizarin red staining were not statistically different between the four groups. Osterix and ALP expression increased in the (L +) group. This upregulation abrogated in the presence of Capsazepine, TRPV1 inhibitor (L + Cap); however, no significant effect was observed with Skf96365 (L + Skf).