Journal of Lasers in Medical Sciences

Introduction: Photobiomodulation (PBM) is beneficial to biological tissues; depending on the optical dose that is absorbed by tissues, it can function as a bio-stimulative, analgesic, and anti-inflammatory mediator. Thus, the current research aimed to assess the impacts of PBM and Calcium aluminosilicate-based material on direct pulp capping (DPC) of dogs’ permanent teeth through histological analysis.
Methods: To study DPC of dogs’ teeth, we separated 24 canines and premolars obtained from mature, healthy mongrel dogs into four equal groups: group 1, which served as the control (exposed pulp was covered with a sterile polytetrafluoroethylene, Teflon tape); group 2, which received PBM treatment using a 980 nm diode laser with a 100 mw output power for one minute; group 3: Calcium aluminosilicate-based material; group 4: Calcium aluminosilicate+PBM. In accordance with the assessment period, each group was divided into three equal subcategories: (A) 1 week; (B) 2 months; (C) 3 months. The teeth were evaluated histologically for inflammatory response and dentine bridge formation.
Results: Statistical analysis detected that there was a significant difference between PBM, Calcium aluminosilicate cement, and the combination group of PBM and Calcium aluminosilicate related to the control group in variant evaluation periods regarding the inflammatory response and dentine bridge thickness through the histological analysis. In relation to the inflammatory response after one week, the combined group (Calcium silicate cement+PBM) exhibited a significantly decreased intensity of inflammation compared to other groups at an identical time. As for dentin bridge creation, the PBM+calcium aluminosilicate group detected thicker dentine bridge creation at three months than other studied groups.
Conclusion: Combined with calcium aluminosilicate-based material, PBM using a 980 nm diode laser with an output power of 100 mw for one minute decreased the initial inflammatory response and enhanced a complete thick dentine bridge formation.

Introduction: Intensity is one of the important parameters of laser radiation in photodynamic therapy. Effective treatment requires the selection of a suitable power of laser. This study aimed to evaluate laser effectiveness in photodynamic therapy via high and low intensity by the analysis of the gene expression profiles of the treated cells.
Methods: The gene expression profiles of human SK-ChA-1 cells which are treated by 500mW and 50mW laser radiation were retrieved from the Gene Expression Omnibus (GEO) database. Data were assessed by the GEO2R program, and the significant differentially expressed genes (DEGs) were investigated via expression examination and protein-protein interaction (PPI) network analysis.
Results: Analyses revealed that the higher intensity of radiation is associated with wide gene expression changes relative to the lower mode. 196 significant DEGs were identified and assessed. The extremely dysregulated DEGs except MMP1 were down-regulated. STAT1, IRF7, IL1B, DDX58, ISG15, RSAD2, DHX58, OASL, OAS1, STAT2, DDX60, OAS2, USP18, and IFI44L were introduced as hubs of the main component of the PPI network. Final analysis showed that STAT1, IRF7, IL1B, DDX58, and STAT2 are the critical DEGs.
Conclusion: Compared to the 50 mW mode of radiation, 500 mW laser intensity effectively changed apoptosis, differentiation, cell proliferation and angiogenesis, regulation of other inflammation-related molecules, innate immunity, and maintaining immune homeostasis.

Introduction: Photobiomodulation (PBM) and Akkermansia muciniphila have been shown to be effective in improving inflammatory conditions with positive effects on increasing the population of anti-inflammatory M2 macrophages (MQs). In this study, gliadin-stimulated THP-1 derived MQs were treated with A. muciniphila and PBM to evaluate their effects on promoting the polarization of M2 MQs.
Methods: The human monocyte cell line (THP-1) was differentiated into MQs. MQs were stimulated with 200 μg/mL gliadin for 24 hours and then treated with PBM 810 nm alone and in combination with A. muciniphila for the following 24 hours to evaluate their effects on MQs polarization. THP-1 derived MQs were also treated with PBM and A. muciniphila to evaluate their effects on non-stimulated MQs. CD11b, CD80, and CD206 levels were evaluated by using the flow cytometry technique. Moreover, the expression of some M1 and M2-related cytokines was determined.
Results: PBM therapy of gliadin-stimulated MQs decreased IL-6 and increased TGF-β, IL-10 and TNF-α expression compared with gliadin-exposed MQs. PBM along with A. muciniphila treatment induced IL-6, TNF-α, and IL-10 expression in MQs in comparison to the untreated group. It also elevated TGF-β, IL-10, and TNF-α levels in gliadin-triggered MQs in comparison to gliadin-stimulated MQ cells.
Conclusion: This study showed the potential of PBMT and A. muciniphila for modulating inflammatory responses and MQs polarization. This may open new perspectives to find possible therapeutic targets for celiac diseases.

Introduction: Unhealthy lifestyle choices such as alcohol, chemicals, and heat stress can worsen male infertility. Heat stress can cause damage to the essential structure known as the blood testis barrier (BTB). Photobiomodulation therapy (PBMT) has been employed in various studies to enhance sperm quality in individuals with genital inflammatory conditions in recent times. The current research sought to study how laser therapy affects spermatogenesis and the structure of the BTB in a mouse model of scrotal heat exposure.
Methods: Thirty adult male NMRI mice, 8 weeks old, were divided into three groups: Control, Hyperthermia, and Hyperthermia+Laser 0.03 J/cm2. The animals in the hyperthermia group had their testicles exposed to water at 43 °C for 20 minutes five times every other day. Then, the testicles were exposed to laser radiation every other day for 35 days, lasting 3 minutes each time, with an energy density of 0.03 J/cm2. Animals were sacrificed, and sperm parameters, reactive oxygen species (ROS) and glutathione (GSH) levels, stereological parameters, and gene expression were assessed in the end.
Results: The study showed that PBMT could significantly enhance sperm quality, the quantity of spermatogenic cells, testicular volume, levels of ROS and GSH, and gene expression related to the blood testis barrier.
Conclusion: Currently, PBMT is a novel approach to addressing male infertility by preserving the integrity of the BTB in Sertoli cells, which in turn supports the growth and specialization of germ cells.

Introduction: The elderly population wants to improve skin function and maintain a youthful appearance without wrinkles. Laser is one of the highly developed and widely used therapeutic modalities for skin aging, as it stimulates dermal collagen formation. Picosecond laser therapy is performed on skin with wrinkles to determine the mechanism of wrinkle improvement with a picosecond laser through an increase in tissue inhibitor of metalloproteinases 1 (TIMP-1), and a decrease in matrix metalloproteinase-1 (MMP-1), which was confirmed by collagen density.
Methods: The study was started from March 2021 to July 2021 at URJ Dr. Soetomo Hospital Surabaya and Surabaya Skin Centre. Twenty patients meeting the inclusion criteria of being 36-55 years of age and having a wrinkle in the forearm were enrolled by random sampling. Each sample data was recorded, the average TIMP-1, MMP-1, collagen density, and clinical wrinkles were calculated, and the laser was performed using a picosecond 755 nm laser.
Results: All patients showed a moderate pre-test wrinkle scale. The figure for TIMP-1 and MMP1 after therapy was higher. The MMP-1/TIMP-1 ratio in wrinkles treated by using a picosecond laser was lower but insignificant than before. The picture of collagen density indicates that collagen density after laser therapy was higher than before.
Conclusion: The result of clinical examination, histopathology, and immunohistochemistry in this research explained that a picosecond 755 nm laser with DLA is an effective therapy for wrinkles in Indonesian patients without any adverse effects.

Introduction: Photobiomodulation (PBM) is considered a promising adjunctive approach in regenerative medicine. This study aimed to investigate the proliferation and adhesion of human gingival fibroblast (HGF) cells to a collagen membrane following PBM.
Methods: Cultured HGF cells on a collagen membrane received PBM at wavelengths of 808 nm, 915 nm (2 and 4 J/cm2), and 660 nm (2.1 and 4.2 J/cm2) in interventional groups, while non-irradiated cells served as the control. On days 1 and 3 post-irradiation, cell proliferation was measured by MTT assay and adhesion to the membrane was assessed under the scanning electron microscope (SEM).
Results: Cell proliferation significantly increased in interventional groups compared to the control, with the most significant increase at 915 nm (4 J/cm2) in both time points. On the first day, the 808 nm and 660 nm lasers demonstrated similar results, significantly lower than the 915 nm laser (2 J/cm²). On day 3, the 660 nm, 808 nm, and 915 nm (2 J/cm²) groups showed comparable results. Qualitative analysis by the SEM identified spindle-shaped cells with multiple extended projections in 915 nm groups, especially at an energy density of 4 J/cm2. Groups of 660 nm and 808 nm (4 J/cm2) showed spindle-shaped cell morphology. No distinct cellular morphology indicative of enhanced adhesion was observed at 808 nm (2 J/cm2).
Conclusion: The most effective PBM setup for promoting HGF proliferation and adhesion to a collagen membrane was identified at 915 nm (4 J/cm2)

Introduction: The most common causes of fiber post-failure are inadequate restorations and dislodgement. This study aimed to evaluate fiber post-bond strength to dentin following Er, Cr: YSGG laser irradiation.
Methods: A total of 65 human mandibular premolars with single roots were included. The 14 mm root length was instrumented with the rotary system using the crown-down technique. Gutta-percha was used for obturation, followed by conventional post-space preparation. The samples were divided into two major groups: control (A) and Er, Cr: YSGG (2780 nm) laser group (B). The laser group was subdivided into (B1) 1.25 W, (B2) 1.5 W, and (B3) 1.75 W. All laser groups were set at 20 Hz, 10% and 30% water/air ratio. Fiber posts were cemented with selfadhesive cement. Each sample was divided horizontally into two slices, coronal and apical. The universal testing equipment was used to conduct a push-out test. All groups were examined by SEM and temperature changes. The statistical analysis was performed by using one-way ANOVA and Tukey HSD tests.
Results: SEM images of all laser groups revealed the elimination of the smear layer and opened dentinal tubules, which was particularly noticeable in the apical region with no thermal risk to the periodontal tissue. In the push-out test, all laser groups had highly significant (P<0.001) increases in the bond strength of fiber post-to-dentin. The failure mode of the control group was a predominantly adhesive failure, whereas the laser groups were a predominantly mixed type.
Conclusion: The three laser protocols can be used safely in the surface treatment of the fiber post space of endodontically treated teeth. Laser helps to increase the bond strength of fiber post to dentin, especially in the apical area.

Introduction: Striae distensae (SD) is a skin disorder characterized by linear atrophic depression of the dermis due to stretching of the skin. There are various SD therapy modalities, namely topical therapy, peeling, microneedling, platelet-rich plasma, and laser. Until now, there has been no standard therapy for SD, but several therapeutic modalities can reduce clinical symptoms, so knowledge about the current management of SD is needed.
Methods: The research method used an experimental research design with consecutive sampling technique in SD patients at the Dermatology, Venereology and Aesthetics clinic of Mohammad Hoesin Hospital, Palembang, during the research period. This study aimed to determine the effectiveness of combination therapy with fractional CO2 laser and Centella Asiatica in SD.
Results: This study included 22 SD patients who met the inclusion criteria and received combination therapy with fractional CO2 laser and Centella asiatica. The results of the analysis of differences in the Index of Striae Distensae Assessment (INA) score, Dermatology Life Quality Index (DLQI) score and VAS score revealed that there was a significant difference in the mean decrease in the INA score between the baseline and week 12 (P=0.014), as well as in the DLQI score between the baseline and week 12 (P=0.000). There was a significant difference in the mean VAS score between the baseline and week 4 (P=0.000).
Conclusion: These findings indicate that the combination of fractional CO2 laser and topical Centella asiatica effectively reduces the severity of SD, improves patients’ quality of life, and decreases associated pain. Further studies could explore long-term effects and optimize treatment protocols for even better outcomes.

Introduction: With an alarmingly growing number of patients diagnosed with colorectal cancer, adopting innovative anti-cancer approaches has recently garnered great attention. One interesting concept is the co-administration of cytotoxic agents and safer modalities such as photodynamic therapy (PDT), which can subsequently improve therapeutic efficacy and potentially reduce the risks of severe adverse effects and drug resistance. In the course of PDT, a locally injected photosensitizer (PS) is irradiated with a light source, which subsequently generates reactive oxygen species (ROS) and induces programmed cell death in tumor cells.
Methods: In this study, to evaluate the potential anti-cancer effects of chemotherapy combined with PDT, in comparison to each alone, we employed PDT, comprising methylene blue (MB) and diode lasers at 630 and 810 nm wavelengths, in conjunction with the chemotherapeutic agent doxorubicin (DOX).
Results: The MTT assay showed that the viability of colorectal cancer HT-29 cells decreased significantly following DOX+PDT treatment. Similarly, lactate dehydrogenase (LDH) release and lipid peroxidation rates were substantially higher in DOX+PDT treatment groups. Lastly, the catalase (CAT) assay indicated that the combination reduced the ability of CAT in the detoxification of H2O2.
Conclusion: Our study suggests that MB-mediated PDT combined with chemotherapy might provide a promising avenue to improve therapeutic efficacy and potentially reduce the risk of adverse effects and drug resistance. Without a doubt, further investigations need to delve into the pharmacological advantages and disadvantages of PTD.

Introduction: Diabetes is a highly prevalent disease worldwide. Despite routine treatments, there is no effective treatment approach for patients with diabetic foot ulcers (DFUs). A new approach to reduce complications and control DFU is low-level laser therapy (LLLT). In the present study, we evaluated the therapeutic effects of LLLT on the symptoms of DFU patients.
Methods: Sixty diabetic patients with DFU were included in this randomized clinical trial and were randomly allocated into two groups of laser (n=30) and control (n=30) with signed written consent. The LLLT group underwent visible and infrared laser therapy and conventional medical treatment, while the control group received only conventional medical treatment. The total laser irradiation sessions of the patients were 20 sessions, (three sessions a week) and each session lasted for 30 minutes over the entire surface of the wound. The power density per session for each laser was calculated to be 35.65 mW/cm2 with an energy density of 64.17 J/cm2.
Results: The mean area of ulcers in the LLLT group reduced significantly (P<0.001) from 441.7±365.5 mm2 before LLLT to 163.9±213.9 mm2 from the baseline up to the last session of LLLT, indicating a 62.99% reduction in mean ulcer area. In the control group, the mean ulcer area did not change significantly. Wagner’s classification of the patients in the LLLT group reduced to lower grades significantly (P<0.01), while the classification moved towards higher grades in the control group (P<0.08).
Conclusion: In this study, we showed the effectiveness of LLLT in the reduction of the surface and depth of DFUs. The results documented that patients experienced significant improvements in the healing of their foot ulcers after laser therapy. It is recommended that the LLLT be considered as a non-invasive method for the treatment of DFU patients.

Introduction: Atopic dermatitis is a common inflammatory skin disease which is treated with narrowband ultraviolet B (NB-UVB). Exploring the critical targeted genes in patients by UV radiation is the main aim of this study.
Methods: Gene expression profiles of lesional and non-lesional skin samples of atopic dermatitis patients after treatment with NB-UVB and the non-irradiated samples were extracted from the Gene Expression Omnibus (GEO) database and analyzed via protein-protein interaction (PPI) network analysis to find the critical targeted genes.
Results: A total of 357 significant differentially expressed genes (DEGs) were included in the PPI network. CTNNB1, SRSF1, YWHAB, SMC3, GNB2, ARF3, UBL7, RAB2A, YWHAE, EIF5B, SNRPE, PPIG, RC3H2, CFL1, SMARCB1. LAPTM5, PRPF40A, and RBBP4 were introduced as hub bottlenecks.
Conclusion: In conclusion, five central genes including SMC3, ARF3, EIF5B, SMARCB1, and LAPTM5 were highlighted as critical genes in response to NB-UVB radiation in the skin of the treated atopic dermatitis patients. The introduced crucial genes are involved in essential cellular functions such as apoptosis, cell cycle, cell proliferation, and inflammation. It seems that applied NB-UVB radiation is a suitable therapeutic method for atopic dermatitis disease.

Introduction: White spots are a common complication of orthodontic treatment. Several prevention methods such as fluoride therapy and laser irradiation have been proposed, but there is still no conclusive evidence. Therefore, this study aimed to evaluate the combined application of diode laser and fluoride varnish in preventing white spots.
Methods: Thirty-nine sound human premolars were extracted for orthodontic purposes and randomly divided into three groups of thirteen teeth each (C: Control, FV: fluoride varnish (5% sodium fluoride), and FV+L: fluoride varnish+980 nm diode laser (2 W)). The freshly extracted teeth were disinfected in a 0.5% chloramine T solution and stored in saline at room temperature. Each tooth was coated with nail polish, leaving a 2×3 mm2 window on the midbuccal. Surface
treatments were applied, and primary Vickers microhardness was evaluated in the gingival sections. Then, the samples were immersed in alternating demineralizing (6 hours/day) and remineralizing (18 hours/day) solutions and incubated at 37 °C for 9 days to produce artificial caries. Afterward, the samples were immersed in a remineralizing solution for one day. Finally, secondary microhardness was measured. The data were analyzed using one-way ANOVA.
Results: The primary microhardness was higher in groups C and FV than in group FV+L. The lowest secondary microhardness was recorded in group C, and there was no significant difference between the other two groups. The change in microhardness was greater in group C, while no difference was observed between the FV and FV+L groups.
Conclusion: Within the limitations of this study, the combined application of laser irradiation and fluoride varnish may not improve white spot lesion (WSL) prevention compared to the use of fluoride varnish alone.

Introduction: Genitourinary syndrome of menopause (GSM) is a common complication secondary to estrogen depletion which leads to tissue changes in the female genitourinary tract. Here, we sought to investigate the short- and long-term effects of CO2 laser therapy on symptoms of GSM in postmenopausal women.
Methods: In this clinical trial, 47 postmenopausal women with symptoms of GSM were included. Participants underwent vaginal and extra-vaginal CO2 fractional laser treatment in three sessions, with intervals of one month between each session. Symptom severity, including itching, dyspareunia, vaginal discharge, and dryness, was assessed at each session using a modified Vaginal Health Index (VHI), where the intensity was rated on a Visual Analog Scale (VAS) from 1 to 10 (1 indicating minimal symptoms and 10 representing maximum severity). Additionally, the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF) was administered. Patients were followed for one to three years after the final laser treatment session.
Results: The scores of all subscales, including itching, dyspareunia, urinary incontinence, vaginal discharge, and dryness, improved significantly following three sessions of CO2 fractional laser (p values<0.001). However, except for the urinary incontinence domain (P=0.058), none of the symptoms maintained improved after one to three years from the last intervention.
Conclusion: CO2 fractional laser treatment is appropriate for treating symptoms related to GSM. But it seems that it needs to be used continuously for the maintenance effect on itching, dyspareunia, urinary incontinence, vaginal discharge, and dryness. The exact timing of laser sessions should be identified in further studies since the beneficial outcomes of the intervention seem temporary.

Introduction: Recently, the positive effects of photobiomodulation (PBM) and nano-bone on bone regeneration have garnered significant attention. The purpose of the research was to assess the impact of PBM and nano-bone on the process of mandibular bone repair in mice.
Methods: A 4-mm diameter bone defect was created in the left mandibular angle of 24 mice separated into 4 equal groups: group I: control; group II: PBM by irradiation at 100 mW of a 980 nm diode laser for one minute (three sessions per week; day on and day off); group III: nano-bone; group IV: PBM with nano-bone. Every group was sectioned into 3 equal subgroups corresponding to the evaluation method period: (A) one week, (B) two weeks, and (C) four weeks. Histological examination was done with hematoxylin, eosin, and Masson’s Trichrome after one, two and four weeks for inflammation, bone defect coverage, vascularization within the newly formed bone, and new bone formation. A statistical analysis of the data was done, and the percentage values were presented using chi-square. The significance level was set at a P-value≤0.05 within all tests.
Results: In general, by histological examination of the mandibular bone defect of the rats, the intensity of inflammation was the least in group IV when compared with groups II and III and the control group at all evaluation periods (P<0.001). Also, group IV showed a high significant rise in the percentage of new bone formation following four weeks when compared with the control (P≤ 0.001) and groups II and III (P<0.001).
Conclusion: The present research results confirmed that the combination of PBM and nano-bone can aid in the repair of mandibular bone abnormalities. This animal study suggests that the use of PBM and nano-bone should be investigated further in clinical studies.

Introduction: This study aimed to evaluate the efficacy of the orifice-level passive ultrasonic activation (OL-PUA) technique in removing debris from the mesial root canals of mandibular molars, besides comparing it with other approaches, including manual dynamic agitation (MDA), EndoActivator, and laser-activated irrigation (LAI).
Methods: Ninety mesial roots of mandibular molars were prepared up to 25.06 using the Race rotary system, filled with 3% sodium hypochlorite (NaOCl), and then they were randomly assigned to 5 groups (n=15) based on the activation protocol: MDA, EndoActivator, OL-PUA, LAI (using a diode laser), and needle irrigation (no activation). Moreover, one group served as the negative control using normal saline as the final irrigant. The roots were decalcified and sectioned into coronal, middle, and apical cross-sections. After histological staining, the remaining debris was assessed with an optical microscope and measured in the canals and isthmuses using histomorphometric analysis. Statistical analyses were performed by using one-way ANOVA and Tukey’s HSD post hoc test (P=0.05).
Results: Although less residual debris was observed after OL-PUA/LAI than using the EndoActivator/
MDA methods, no significant difference was found between the four activation techniques at
any root third (P>0.05). The OL-PUA/LAI group harbored significantly less remaining debris
than the needle-irrigated samples at all root thirds (P<0.05). Debris accumulation increased
from the coronal to the apical root thirds.
Conclusion: No statistical difference was detected between the four activation techniques in terms of debris-removal performance, and none of them resulted in completely debris-free canals. Orifice-level PUA proved to be a promising approach with significant efficacy in removing debris compared to control groups.

Introduction: Periodontitis is an inflammatory disease due to bacterial origin; it has a chronic course and progresses by immunosuppressive therapy. However, adjuvant therapies such as photobiomodulation (PBM) and melatonin can reduce the severity of the inflammation and inhibit the progression of periodontitis. Therefore, the present study evaluated the effects of PBM (PBM) and melatonin, as adjuvant therapies, on periodontal healing in immunosuppressed rats with periodontitis.
Methods: Random allocation was performed on 36 albino Wistar rats, divided into the following groups: control, periodontitis, immunosuppressant only, immunosuppressant+PBM, immunosuppressant+melatonin, and immunosuppressant+melatonin+PBM. Periodontitis caused by ligature in all groups, except for the control group. Subcutaneous administration of dexamethasone was performed in the immunosuppressant groups for immunosuppression. All the groups except the control group received scaling and root planning (SRP). Each group was subdivided into three equal subgroups according to the evaluation period: (A), one week, (B) two weeks (C), 4 weeks. Histological examination was done with hematoxylin & eosin and Masson’s Trichrome for inflammation and periodontal healing. Statistical Analysis of the data was done by using the chi-square test. The significance level was set at P≤0.05.
Results: Regarding the inflammatory response and periodontal healing, histological examination revealed a statistically significant difference in all treated groups in comparison with the control untreated immunosuppressed group (P<0.001). The combined application of melatonin and PBM resulted in the best histological response presented by a lower inflammatory response and better periodontal healing when compared with all other treated groups (P<0.001).
Conclusion: After considering the circumstances of this research, the combination of melatonin and PBM by a 650 nm diode laser with an output power of 100 MW for one minute for three sessions appeared to be a beneficial adjunct in periodontal healing in immunosuppressed rats with periodontitis.

Introduction: Chondrocytes are the major cells in hyaline cartilage playing a crucial role in maintaining the mechanical resilience of the tissue. We assessed the effect of an 808nm diode laser on the proliferation of human chondrocytes.

Methods: This study was conducted on human chondrocytes in vitro. The cells were divided into 5 cases and one control group. The cells were irradiated by low-level laser 808 nm, with energy levels of 1, 2, 3 J/cm² (0.2 W, for 5, 10, and 15 seconds), 4 J/cm² (0.3 W,13 s), and 5 J/ cm² (0.4 W,12 s). The culture was incubated for 24 hours. The MTT assay was performed to determine the cell viability. After 72 hours of incubation, the procedure was reperformed to assess the effect of incubation duration. The cell viability in terms of incubation duration and irradiation parameters were investigated by a two-way ANOVA test. Pairwise comparisons were performed using the Bonferroni test.

Results: In the 72-hour incubation group, cell viability in the group that received 5 J/cm² energy was significantly lower than that in the groups receiving 1 J/cm², 2 J/cm², and 4 J/cm² irradiation. The variables of time (P=0.001) and energy level (P=0.024) had significant effects on the cell viability of the samples. In the 24-hour incubation groups, no significant difference in cell viability was observed.

Conclusion: The diode 808 nm Low-level laser irradiation (LLLI) at doses of 5 J/cm² and less did not show a significant increase in the proliferation of chondrocytes (regardless of incubation time). However, the best survival rate of chondrocytes was observed in the group of 4 J/cm² with 72-hour incubation.

Introduction: Photoaging that is accompanied by gene expression alteration is known as early aging of the skin due to overexposure to natural and/or artificial ultraviolet radiation (UVR). The assessment of gene expression alteration in human primary neonatal dermal fibroblasts depending on recovery time after exposure to solar simulated ultraviolet radiation (ssUVR) is the main aim of this bioinformatic study.
Methods: Data are extracted from Gene Expression Omnibus (GEO). The pre-evaluation is done via the GEO2R program. The Significant differentially expressed genes (DEGs) were assessed via protein-protein interaction (PPI) network analysis, and the central genes were identified. The central genes were enriched via gene ontology assessment.
Results: Among 224 significant DEGs, 20 central genes including TOP2A, MKI67, BRCA1, HELLS, MAD2L1, ANLN, KIF11, MSH2, KRAS, NCAPG, RFC3, PLK4, WDHD1, BLM, CDKN3, KIF15, SMARCA5, and ATAD2 as hub genes and TOP2A, MKI67, BRCA1, ANLN, KRAS, PLK4, SMARCA5, MMP2, and TLR4 as bottleneck genes were determined. Eight central genes were associated with 16 biological terms.
Conclusion: In conclusion, significant differences appeared between gene expression conditions of the cells after 1-day and 5-day recovery. Molecular events include the repair and continuation of photodamages. It is possible to introduce drug targets to prevent the progress of induced damages.

Introduction: This study aimed to compare the effects of high-intensity laser therapy (HILT) and low-level laser therapy (LLLT) on the disability and architecture of the quadriceps in patients with knee osteoarthritis (OA).
Methods: Ninety-eight patients with knee OA (KOA) were selected by convenience sampling and then divided into three groups: control, LLLT and HILT. Disability was determined using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Quadriceps structures including thickness, fascicle length and pennate angle of the vastus lateralis (VL) and thickness, volume and fiber angle of vastus medialis obliquus (VMO) muscles were assessed using ultrasonography. All evaluations were performed before interventions, immediately after interventions, and one month later. Between-group data were analyzed with two-way ANOVA and paired-samples t-test.
Results: The within-group comparisons of WOMAC scores before, after and at a one-month follow-up showed significant differences between the groups (P<0.001). The VMO thickness revealed significant increases after the treatment in both HILT (P<0.001) and LLLT (P=00.03) groups. The between-group comparison revealed a significantly lower score of WOMAC in the HILT group compared to the other groups after a one-month follow-up (P=00.03). VMO thickness showed a significant increase in the HILT group after the treatment (P=0.002). The VL structures and VMO fiber angle and volume did not exhibit significant changes in within-group and between-group comparisons (P>00.05).
Conclusion: Both HILT and LLLT may improve functional ability and VMO thickness in patients with knee osteoarthritis. After a one-month follow-up, functional ability was greater in the HILT group.

Introduction: Vitiligo poses a significant challenge, particularly in treatment-resistant areas such as acral regions. This study aimed to evaluate the effectiveness and safety of combining fractional CO2 laser and microneedling with conventional therapies for non-segmental vitiligo in resistant areas.
Methods: A randomized clinical trial with a paired design was conducted on 84 individuals with non-segmental vitiligo and treatment-resistant lesions. Participants in two separate groups received various combinations of interventions, including narrowband ultraviolet B (NB-UVB) and topical steroid (Clobetasol ointment) as conventional treatments, with fractional CO2 laser or microneedling as add-ons for four symmetrical treatment-resistant lesions. The treatment duration was 16 weeks, followed by observation until six months post-intervention for each patient, and it focused on assessing the percentage of repigmentation, safety, patient satisfaction, and potential adverse effects.
Results: The results of the study revealed a significant difference in average efficacy, with treatments involving fractional CO2 laser and microneedling compared with other interventions without them showing a higher percentage of repigmentation. No notable distinction in repigmentation patterns was observed, except for slightly higher marginal repigmentation with microneedling. Side effects, including pain, burning sensation, and erythema, were more frequent, with no significant difference between the groups. Itching and crusting had a substantial difference in the two groups. Patient satisfaction levels were comparable, with the first group slightly more than the second.
Conclusion: In conclusion, combining NB-UVB and topical steroid therapies with the fractional CO2 laser or microneedling seems to be effective for vitiligo treatment in resistant areas. Attention to variations in patients’ characteristics and specific body locations is necessary when applying these modalities. This study provides valuable insights into novel approaches to managing vitiligo and highlights the potential benefits of these innovative treatments in combination with conventional therapy.

Introduction: Fiber-reinforced composite posts (FRCP) have become popular due to their multiple advantages in teeth with extensive crown destruction. Proper disinfection is essential for the successful bonding of these posts. Commonly used solutions for cleaning and disinfecting the root canals adversely affect the bond strength (BS). Photodynamic therapy is an alternative method for irrigating the root canal and disinfecting the post space. This study was designed to evaluate the impact of photodynamic therapy on the BS of fiber posts to root canal dentin.
Methods: Human maxillary canines were recruited for this study. The tooth crowns were removed at the cervical line and endodontically treated. After fiber post spaces were prepared, the teeth were assigned to five groups based on the light-sensitive material: deionized water, indocyanine green and 810-nm laser, methylene blue and 660-nm laser, toluidine blue and 635-nm laser, curcumin and LED. The posts were cemented after photodynamic therapy. Cervical, middle, and apical samples were prepared by transverse sectioning. Push-out bond strength (PBS) values were measured in a universal testing machine. Finally, the data underwent statistical analyses with ANOVA and Howell-Games tests.
Results: One-way ANOVA revealed no significant differences between the groups (P<0.001). The Games-Howell test showed that curcumin (7.23±3.75) and the control group (5.92±4.04) had a similar BS (P>0.005). The BS was lower in the methylene blue (3.34±2.15), indocyanine green (2.59±3.16), and toluidine blue (2.45±1.73) groups than in the control group (P<0.005).
Conclusion: Unlike other light-sensitive materials, curcumin did not adversely affect the BS.

Introduction: The adhesion ability of mesenchymal stem cells can significantly affect their viability and is considered a prerequisite for cell therapy. The current study sought to evaluate the effect of fibroblast growth factor 2 (FGF2) and low-level laser therapy (LLLT), either individually or in conjunction, on the adhesion and proliferation of periodontal ligament stem cells (PDLSCs) when applied on the first day of cell seeding.
Methods: The experimental groups of this study comprised a control group and different combinations of adjunctive FGF2 (50 ng/mL) and LLLT with an 808 nm diode laser in one (LLLT1) or two sessions (LLLT-2) of irradiation. The proliferation and adhesion of cells were evaluated by using the methylthiazolyl tetrazolium (MTT) assay and 4′,6-diamidino-2-phenylindole (DAPI) staining. All experiments were done in triplicates on the first, third, and fifth days after cell seeding. Two-way ANOVA and post hoc Tukey tests were used to analyze the data of the MTT assay. P<0.05 was considered statistically significant.
Results: One-day post-culture, only significant differences were found between the control group and the FGF2 (P=0.04) and FGF2+LLLT-2 application (P=0.04) groups. After three days post-cell culture, only a significantly higher proliferation rate was found in the control group than in the FGF2 group (P=0.01). After five days, the control group and LLLT-2 groups showed significantly higher amounts of proliferation compared to the other groups (P<0.05). DAPI staining qualitatively confirmed the results of the MTT assay.
Conclusion: The LLLT can be applied to PDLSCs on the day of seeding without causing a notable decrease in their viability and adhesion. Conversely, the administration of FGF2 should be restricted on the seeding day and postponed to subsequent days as it may have adverse effects on their adhesion and proliferation.

Introduction: This study assessed the effect of low-level laser therapy (LLLT) on the osseointegration of immediately loaded implants with a connective tissue graft (CTG).
Methods: This clinical trial was conducted on patients with buccal bone dehiscence requiring dental implants. A CTG was harvested from the palate and placed in the labial side by considering the 2 mm distance between the implant thread and bone. Autogenous bone was harvested from the tuberosity, mixed with the allograft, and implanted at the site. After sufficient torquing of the implant, a customized abutment was fabricated and placed. The patients were randomly assigned to two groups (n=5) of intervention and control. The patients in the intervention group received LLLT with a 940 nm gallium-aluminum-arsenide laser while those in the control group received placebo irradiation. The primary implant stability was measured before the delivery of customized abutment while the secondary implant stability was measured after 12 weeks by Osstell® and reported as the implant stability quotient (ISQ).
Results: No significant difference was found in secondary ISQ between the laser and control groups (P>0.05). In the intervention group, an important difference was found between the primary and secondary ISQ in the buccolingual dimension (P<0.05) but not in the mesiodistal dimension (P>0.05). The two groups had no significant difference in gingival thickness or vertical bone gain (P>0.05). All implants were successful with no complications.
Conclusion: LLLT had a significant positive efficacy for the enhancement of secondary stability of implants in the buccolingual dimension. CTG showed optimal efficacy for the treatment of buccal bone dehiscence.

Introduction: Photobiomodulation with low-level laser treatment can enhance bone formation by stimulating the cell division of osteoblasts and increasing the amount of protein deposition, thus encouraging the formation of new bone. This study aimed to evaluate the effects of photobiomodulation with a low-level laser on proliferation and gene expression related to calcium signaling in human osteoblasts.
Methods: Osteoblastic cell lines of the hFOB1.19 lineage, human osteoblasts, were grown and assigned into two groups, control (C; n=78 cultured wells) and photobiomodulation (L; n=78 cultured wells) with n=6 per day of the experimental period. Cells were cultured (immature at 34 ºC), and after maturation at 37 ºC, group L cells were exposed to laser irradiation with a low-level laser device (gallium and aluminum arsenide), at a wavelength of 808 nm, a power output of 200 mW, and a power density of 200 mW/cm2. The energy delivered to the cells was 37 J/cm2, with a beam area of 0.02 mm2 and an exposure time of 5 seconds. This treatment was applied daily for 13 days. Following this, the number of cells was counted, and RNA was isolated, measured, and then converted into cDNA for further quantification using a comparative Ct method with real-time polymerase chain reaction. The results were then subjected to statistical analysis through a Mann-Whitney test, with a significance level of P<0.05.
Results: The cell count in the L group (37.25x10±4±22.02) was statistically higher compared to the control group (22.75x10±4±7.660) with a P value of 0.0259. The values of 2- ΔΔCt for S100A6, plasma membrane calcium ATPase (PMCA), and calmodulin genes indicated hyperexpression on the thirteenth day, while the osteocalcin gene showed hypo-expression.
Conclusion: The study suggests that the photobiomodulation mechanism with a low-level laser may regulate gene expression in human osteoblasts in a dose-dependent and cumulative manner.

Introduction: One of the clinical problems following orthodontic treatment is white spot lesions around orthodontic brackets due to enamel demineralization. Confronting enamel demineralization during fixed treatments has long been a challenge for orthodontists. The aim of this in vitro study was to evaluate the effect of CO2 laser and Titanium Tetra-fluoride (TiF4) application on the prevention of enamel demineralization around orthodontic brackets.
Methods: Eighty permanent premolars were selected and bonded with brackets. They were randomly divided into four groups (n=20): topical titanium tetra-fluoride gel 4% (TiF4), CO2 laser (10.6 μm wavelength for 10 seconds, peak power=291 W), fluoride+laser (F+L), and control (C). All specimens were demineralized for 10 days in a 0.2 M acetate buffer solution. The mean lesion depths were determined by using polarized light microscopy.
Results: The mean depth of lesion was the highest in the C group and then decreased in the TiF4, CO2
laser, and F+L groups, respectively. The difference between all groups was significant (P<0.05), except for the CO2 laser and F+L groups.
Conclusion: The lowest amount of demineralization around the orthodontic brackets was observed in the L+F group, followed by the CO2 laser, TiF4, and control groups, respectively

Introduction: The retina is a light-sensitive tissue, and intensive light exposure leads to lightinduced retinal damage. It is pointed out that photoreceptor damage is responsible for the decrease in retina function. The aim of this study was to detect the main genes and biological terms which are involved in retinal response to intensive light exposure.
Methods: The effect of intensive light on the mouse retina function was searched in the Gene Expression Omnibus (GEO) database. The data of GSE22818 were assessed by the GEO2R program. The significant differentially expressed genes (DEGs) were determined and evaluated via directed protein-protein interaction (PPI) network analysis. The critical significant DEGs were enriched via gene ontology analysis to find the related biological processes, molecular function, and biochemical pathways.
Results: Data analysis indicates that the high intensity of light induces gene expression alteration in the retina. 105 significant DEGs were identified as the main responsive genes to light damage in the retina. STAT3, JUN, IL6ST, SOCS3, ATF3, JUNB, FOSL1, CCL2, ICAM1, FGF2, AGT, MYC, LIF, CISH, and EGR1 were introduced as the critical affected genes. STAT3, JUN, IL6ST, SOCS3, and ATF3 and “Positive regulation of the receptor signaling pathway via JAK-STAT” were highlighted as the key elements of molecular events.
Conclusion: It can be concluded that regulation of the key DEGs and the dependent biological terms can effectively provide tools to prevent the development of light-induced retinal damage.

Introduction: Heat stress is one of the environmental causes of damage to the testis, whose effects are less known before puberty. The aim of the present study was to investigate the impact of photobiomodulation (PBM) on the testis of prepubertal mice subjected to hyperthermia.
Methods: Twenty-four three-week-old prepubertal male mice were allocated to the following groups: I) control, II) scrotal hyperthermia (Hyp), and III) Hyp+PBM (n=8/each group). In order to induce hyperthermia, the scrotum was placed in water at 43 °C for 20 minutes every other day for a total duration of 10 days. In the Hyp+PBM group, after hyperthermia induction, the testis of the mice was subjected to laser irradiation at a wavelength of 890 nm (0.03 J/cm2 for 30 seconds)
for 35 days. After the mice were sacrificed, the testis and epididymis were removed for testing.
Results: Compared with those of the Hyp group, the sperm parameters of the laser irradiation group improved notably. In addition, histological examinations revealed that the final number of testis cells and the volume of tissue in the Hyp+PBM group were dramatically greater than those in the Hyp group. The analysis of molecular data revealed an increase in the expression of mitotic genes and testosterone levels and a decrease in the formation of reactive oxygen species (ROS) and the expression of the apoptotic gene in the testis subjected to PBM.
Conclusion: Based on the present findings, laser therapy can reduce complications caused by scrotal hyperthermia during prepuberty and ameliorate spermatogenesis during puberty.

Introduction: Psoriasis is a common autoimmune skin disease associated with genetically influenced chronic inflammation accompanied by remitting and deteriorating scaly skin. T-cell targeted biologics, IL-17 inhibitors, IL 12/IL-23 inhibitors, TNF-α inhibitors, PDE4 inhibitors, and ultraviolet (UV) radiation are applied to treat psoriasis. Efficacy evaluation of narrow-band UVB (NB-UVB) radiation was the aim of this study.
Methods: Data were extracted from Gene Expression Omnibus (GEO) and were pre-evaluated via the GEO2R program. The significant differentially expressed genes (DEGs) were included in the protein-protein interaction (PPI) network analysis. The hubs, bottlenecks, and hub-bottleneck DEGs were introduced as central genes. Activation, inhibition, and expression relationship between central genes were assessed to explore the critical individuals.
Results: Among 513 analyzed significant DEGs, 22 hub-bottleneck genes were identified. Further analysis revealed that FN1, STAT3, HIF1A, IL1B, P4HB, SOD2, MMP2, and STAT1 were the crucial genes in psoriasis samples targeted by NB-UVB radiation.
Conclusion: In conclusion, NB-UVB radiation as treatment targets critical genes in peri-lesion skin tissue biopsy of psoriasis patients via a complicated mechanism. This therapeutic method downregulates STAT3, HIF1A, IL1B, and P4HB to treat psoriasis but downregulates STAT1 and SOD2 and upregulates MMP2 and FN1 to develop disease.

Introduction: The treatment of chronic testicular pain is a complex condition that will be encountered by most practicing clinicians. In this study, the influence of low-level laser irradiation of the red and infrared spectral range for treating chronic testicular pain was evaluated and compared.
Methods: In this double-blind, placebo-controlled randomized clinical trial study, 60 patients were randomly divided into three groups of 20: (1) low-level laser group with red (650 nm, 50 mW), (2) low-level laser group with infrared (820 nm, 100 mW) and (3) laser placebo group. The treatment protocol consisted of 15 minutes, three times a week, for only 12 sessions. Then the patients were evaluated for pain and sexual satisfaction during the follow-up.
Results: There was a significant reduction in the pain score in the two groups of the low-level laser group with red (650 nm, 50 mW) and the low-level laser group with Infrared (820 nm, 100 mW) spectra compared with the control, at 6 and 12 weeks after the treatment (P<0.05). Also, the level of sexual satisfaction in the two groups of low-power laser with red and infrared spectra showed a significant improvement (P<0.05).
Conclusion: Low-level laser therapy is a safe, non-invasive, and useful method for treating patients with chronic testicular pain. Therefore, red (650 nm, 50 mW) and Infrared (820 nm, 100 mW) spectra low-level laser therapies improve testicular pain and sexual satisfaction.

Introduction: This study was carried out to assess and compare the efficacies of transcutaneous electrical nerve stimulation (TENS) and low-level laser therapy (LLLT) applied to sciatic Valleix points to reduce sciatica in patients with chronic lumbar radiculopathy.
Methods: The study population consisted of 164 patients with chronic radicular pain caused by LDH. The remaining 75 patients were studied in three groups. TENS and hotpack were applied to the lower back region of all patients. In addition, group 1 (n=24), group 2 (n=25), and group 3 (n=26) received LLLT (4 J/cm2 for each point), TENS, and sham LLLT, respectively, on sciatic Valleix points five days a week, for three weeks (15 sessions). Outcomes were assessed at the beginning of the treatment, after completion of 3 weeks of treatment, and after three months (follow-up).
Results: Post-treatment assessments indicated that all parameters investigated within the scope of the study improved in all three groups, except for the VAS leg pain (VASLP) score in group 3. Post-treatment VASLP and DN4 scores of group 1 were significantly superior to those of group 2 (P˂0.001). Follow-up assessments revealed an improvement only in the VASLP score and in group 1. The VASLP, DN-4, and ODI scores of groups 1 and 2 were significantly superior to those of group 3. There was no significant difference between the groups in the PSQI score and lumbar ROM value.
Conclusion: LLLT and TENS were effective in treating the sciatic nerve associated with lumbar disk herniation with radiculopathy. LLLT was found to be more effective than TENS in reducing leg and neuropathic pains. Follow-up assessments revealed that the only lasting effect of the treatments, which continued into the third month, was the improvement in leg pain.

Introduction: Apical periodontitis is one of the common dental diseases. Microorganisms are the main reasons for these lesions; irrigations are used to remove them, but because of limited penetration, the rinsing agents may not always kill the microorganisms. Laser irradiation is effective in canal disinfection. The goal of this study was to compare the effect of calcium hydroxide (Ca(OH)2) and diode laser on the improvement of apical periodontitis following root canal retreatment (RCR).

Methods: Twenty-four teeth of 19 patients with periapical lesions which needed RCR were divided into two groups (Ca(OH)2 and Ca(OH)2+laser irradiation [LI]). In the first session, after gutta-percha removal, cleaning, and shaping, Ca(OH)2 was used for 10 days. In the second
session, in the Ca(OH)2+LI group, the irradiation utilizing a diode laser (using non-initiated 200- µm fiber, continuous wave (CW), power output of 1W) was done. The periapical radiographic healing was assessed before the retreatment and after 3-month and 6-month follow-ups by periapical index (PAI) Qrstavik. The quantitative data were analyzed (P<0.05).

Results: The initial periapical lesion score was 3.75 and 3.88 in the Ca(OH)2 and Ca(OH)2+LI
groups, respectively. In the Ca(OH)2 and Ca(OH)2+LI groups, 3 months after the RCR, the average periapical lesion score was 2.94 and 3.05, respectively. In the Ca(OH)2 and CA(OH)2+LI groups, 6 months after the RCR, the average periapical lesion score was 1.80 and 1.75, respectively. No significant differences were found at the 3 and 6 months between the experimental groups.

Conclusion: The diode laser can reduce the periapical lesion, but there was no significant difference between CA(OH)2+LI and Ca(OH)2 at 3-month and 6-month follow-ups.

Introduction: Photodynamic therapy (PDT) is a photochemical treatment that involves the use of light and photosensitizer. This method is applied as a therapeutic approach against several types of cancer. The main aim of this study is to compare the efficacy of PDT with that of cisplatin (a well-known chemotherapy agent) through protein-protein interaction (PPI) network analysis.
Methods: Gene expression profiles of human melanoma A375 cells from the Gene Expression Omnibus (GEO) were selected for analysis via directed PPI network analysis. The significant differentially expressed genes (DEGs) were identified and assessed based on co-expression interactions. The critical DEGs were introduced by considering out-degree and in-degree values.
Results: Two directed PPI networks for upregulated and downregulated DEGs were constructed. TP53 was identified as a critical upregulated gene in response to cisplatin in comparison with PDT. EGFR, PPARG, MMP9, PTGS2, FOXO1, and RUNX2 were highlighted as the crucial downregulated genes due to the effect of cisplatin on the gene expression of the treated cells.
Conclusion: Cisplatin directly targets key cellular functions such as cell growth, differentiation, migration, and invasion. It seems that the combination of cisplatin and PDT is a suitable method for treating cancers because cisplatin targets the key genes responsible for cancer development, while PDT intensifies the effect of cisplatin and reduces its side effects.

Introduction: This study explored the synergistic effects of low-level laser therapy (LLLT) and adipose-derived stem cells (ADSCs) on cranial bone regeneration in rats, addressing the limitations of autogenous grafts and advancing bone tissue engineering with innovative photobiomodulation (PBM) applications.
Methods: Sixty Wistar rats were allocated to 5 separate groups randomly; (1) natural bovine bone mineral (NBBM); (2) NBBM+LLLT; (3) NBBM+allogenic ADSCs; (4) NBBM+allogenic ADSCs+LLLT; (5) Only defects. 8-mm calvarial defects were made in each rat in the surgical procedure. A diode laser was applied with the following parameters (continuous mode, power of 100mW, wavelength of 808nm, and 4 J/cm2 energy density) immediately after the procedure and every other day. Bone samples were obtained and assessed histomorphometrically and histologically after staining with hematoxylin and eosin (H&E).
Results: Different volumes of bony material were observed in two weeks; 2.94%±1.00 in group 1, 5.1%±1.92 in group 2, 7.11%±2.82 in group 3, 7.34%±2.31 in group 4, and 2.01%±0.83 in group 5 (P<0.05). On the other hand, foreign body residuals were up by 23% in the groups with scaffolding by the end of 2 weeks. Four weeks of observation led to 6.74 %±1.95, 13.24%±1.98, 15.76%±1.19, 15.92%±3.4, and 3.11%±1.00 bone formation in groups 1 to 5, respectively (P<0.05). Generally, the difference between groups 2-4 was not statistically significant based on different types of bone and the extent of inflammation.
Conclusion: Bearing in mind the limitations of our research, it was demonstrated that ADSCs in combination with PBM have promising effects on bone tissue regeneration in sizeable bony defects. Furthermore, this study also showed that PBM usage improved the newly regenerated bone quality.

Introduction: Polycystic ovary syndrome (PCOS) is a complex condition that can have various symptoms and complications, one of which is infertility. Dysregulation of miRNA has been associated with the pathogenesis of numerous illnesses such as PCOS. In this study, we evaluated the effect of photobiomodulation therapy (PBMT) and exosome therapy (EXO) on the regulation of miRNA and nucleus acetylation in a PCOS oocyte.
Methods: In this research, 36 oocytes were divided into three groups: control, EXO, and PBM (Wavelength of 640 nm). Subsequently, in-vitro maturation (IVM) was evaluated. Real-time PCR was used to evaluate miRNA-21,16,19,24,30,106,155 and GAPDH. Afterward, oocyte glutathione (GSH) and nucleus acetylation were measured by H4K12.
Results: The expression of the miR-16, miRNA-19, miRNA-24, miRNA-106 and miRNA-155 genes in the EXO and PBMT groups was significantly down-regulated in comparison to the control group, but the expression of miRNA-21 and miR-30 significantly increased in the EXO and PBMT groups in comparison to the control group. The EXO and PBMT significantly increased GSH and nucleus acetylation (P<0.0001).
Conclusion: The results of this study showed that the use of EXO and PBMT can improve GSH and nucleus acetylation in the PCOS oocyte and also change the expression of miRNAs.

Introduction: Gingival depigmentation with the help of lasers is known as an effective technique. The aim of this study was to compare the efficiency of 980nm diode and CO2 lasers in the treatment of gingival hyperpigmentation.
Methods: In this study, 14 individuals with the age range of 19 to 47 years were selected. One quadrant was randomly treated with a CO2 laser (10600 nm, non-contact, super pulse mode), and the opposite quadrant was treated with a diode laser (980 nm, continuous wave [CW], 1.5 W). The area of the pigmented region, Dummett oral pigmentation index (DOPI), and the number of changes in the RGB parameter (red, green, blue) and ΔE* in clinical photographs before, one, and three months after the treatment were calculated by ImageJ and Photoshop software. Pain and discomfort were assessed one hour, one day, and one week later by the visual analog scale. In addition, after 3 months, the cosmetic results achieved for the different therapeutic approaches were evaluated by patients and professional evaluators. 
Results: The results of this study showed that the duration of CO2 laser treatment was statistically and significantly shorter than the time of 980-diode laser treatment (P<0.05). There were no statistically significant differences in the pigmented lesion area (P>0.05), RGB parameter (P>0.05), DOPI index (P>0.05), and ΔE parameter (P>0.05) in one month and three months after treatment follow-ups between the two types of lasers. There was no statistically significant difference in patient satisfaction (P>0.05) and professional evaluation (P>0.05) between the two groups of lasers. Post-treatment pain scores were not statistically significant between the two groups.
Conclusion: Both 980-nm diode laser and 10600-nm CO2 are effective in the treatment of gingival depigmentation while CO2 laser radiation with super pulse mode is faster in terms of operating time. While working with the diode laser is more controllable.

Introduction: Numerous strategies have been investigated for addressing recurrent implantation failure (RIF) and enhancing endometrial receptivity, yet agreement on the optimal intervention remains elusive. Our investigation endeavors to assess the effect of low-level laser therapy (LLLT) on pregnancy outcomes in individuals who have undergone a minimum of three unsuccessful embryo transfer cycles (ET).
Methods: In our randomized single-blinded clinical trial, we enrolled thirty females with a medical history of RIF who were eligible for frozen-thawed embryo transfer (FET). Through a random allocation sequence, the participants were divided into two groups. The LLLT was performed one cycle before blastocyst transfer in 15 cases using a New Age BIOLASER device (New Age Co., Italy) with a 900-milliwatt power output and an 850-nm wavelength. The irradiation sessions were conducted transabdominal on the hypogastric area. The considered outcomes were biochemical pregnancy, identified by a positive blood pregnancy test, and clinical pregnancy, confirmed through visualization of the gestational sac using ultrasonography.
Results: The mean age of the subjects was 34.17 years, and they had undergone three to seven previous embryo transfers. There was no significant difference in basic characteristics between the group undergoing laser treatment and the control group. However, the laser-treated group exhibited elevated rates of both biochemical and clinical pregnancies compared to the control group (46.7% vs. 33.3%; P==0.710 and 33.3% vs. 20.0%; P=0.682 respectively).
Conclusion: To our knowledge, this study represents the first single-blinded randomized clinical trial to assess the effectiveness of LLLT pretreatment in individuals with RIF. The findings propose that LLLT may potentially enhance biochemical and clinical pregnancy rates among RIF patients

Introduction: Anal fissures (AFs) are a prevalent pathology. Although internal lateral sphincterotomy is still the gold-standard surgery for treating chronic AFs. This study describes an alternative and minimally invasive technique for treating AFs using photobiomodulation and a high-power diode laser-fissure treatment (LFT) and highlights initial results pertaining to pain.
Methods: This retrospective study focused on 38 patients treated with LFT on an outpatient basis at three different hospitals in different states of Brazil (Santa Catarina, Paraná, and São Paulo). The objective was to evaluate the effects of LFT treatment on AF patient pain following the procedure. The Friedman test was used to identify the effects of LFT treatment over time (D0, D7, D15, D30, and D60) on postoperative pain intensity using the visual analog scale (VAS). Complications and incontinence rates were also analyzed.
Results: Roughly two-thirds of the patients (66%; n=25) were male. The median age of the cohort was 49. Constipation was described by 32% of the patients, 13% were smokers, and 21% had recently used opioids. In 92% of the cases, the AF was localized posteriorly. Skin tags were present in 27% of the cases, and 26% had recently undergone a previous orificial surgery. A significant reduction in pain was observed over time in the intensity of postoperative pain measured by the VAS. Prior to surgery (D0), the patients’ mean VAS score was 4.1; it progressively decreased to 0.1 on the 60th postoperative day (P<0.05). There was no significant change in fecal continence at the end of the 60-day follow-up period. Minor complications occurred in 7.9% of the patients (2.6% hemorrhoidal thrombosis, 2.6% skin tag, and 2.6% “failure”).
Conclusion: Our results suggest that treating AFs with laser therapy results in a significant reduction in pain intensity over time without interfering with anal continence.

Introduction: This study aimed to assess the effect of repeated irradiations of 660 nm photobiomodulation therapy (PBMT) after photodynamic therapy (PDT) with curcumin on the viability of human gingival fibroblasts (HGFs).
Methods: In this in vitro, experimental study, HGFs were cultured and assigned to five groups: One control group with no intervention and four experimental groups of PDT with curcumin, PBMT (660 nm laser irradiation) immediately after PDT, PBMT immediately and 24 hours after PDT and PBMT immediately and 24 hours and 48 hours after PDT. Cell viability was assessed after 1, 4, and 7 days using the methyl thiazolyl tetrazolium (MTT) assay. Data were analyzed by one-way ANOVA.
Results: On day 1, the control group had no significant difference with one-time (P=1.00), two-time (P=1.00), and three-time (P=0.88) laser irradiation groups. On day 4, the difference between the control and one-time (P<0.001), two-time (P<0.001) and three-time (P=0.02) laser irradiation groups was statistically significant, suggesting more cell viability in test groups. On day 7, the three-time laser irradiation group showed significant cell viability compared to the other two test groups but not with the control group (P=0.98).
Conclusion: PBMT with 660 nm laser irradiation after PDT with curcumin would increase the viability of HGFs by increasing the frequency of irradiation.

Introduction: Heat distribution and resulting thermal damage pattern following the light absorption in tissue, can be used for treatment optimization. Besides rejuvenating effects, CO2 fractional-induced microtunnels have recently become a tool for drug delivery. To minimize, the unwanted thermal damage in this latter use, we simulated the heat distribution and thermal damage patterns of CO2 fractional lasers for different spot sizes, pulse durations, and powers to optimize the laser procedure.

Methods: COMSOL software was used for the simulations. The skin was modeled as three homogenous layers of epidermis/dermis/hypodermis. Opto-thermal coefficients of the components and the radiant parameters of the laser (CO2, 10600 nm- Deka) were defined.

Results: Our results show that power of 10w with different time pulses creates a better microtunnel in the tissue while preventing unwanted injuries. At a power higher than 15 watts and 5 pulses, the tissue will be damaged inconsiderably. Fractional laser creates heat only at the desired point of the treatment, and this heat is absorbed through the tissue, and microtunnels in it form the tissue. Also, 10w power with a low time width does not have a good effect on the tissue, but with an increase in the pulse width, it causes less damage to the surroundings. With a power higher than 15w, fractional laser irradiation creates wider microtunnels which might damage the tissue due to the adjacent microtunnels.

Conclusions: Due to the absorbed laser light in tissue and the creation of the heat, skin damage as microtunnels is caused. The greater the distance between the laser irradiation, the better the microtunnels will be created. Also, COMSOL seems to be promising software for preclinical investigations and optimizing laser treatment plans.

Introduction: Photothermal therapy (PTT) by using a near-infrared (NIR) laser, as a successful treatment of cancer, has attracted extensive attention of researchers. Its advantages as a noninvasive and suitable method have been confirmed. Discovery of the NIR laser molecular mechanism at the cellular level via system biology assessment to identify the crucial targeted genes is the aim of this study.
Methods: RNA-seq series of six samples were retrieved from Gene Expression Omnibus (GEO) and pre-evaluated by the GEO2R program for more analysis. The significant differentially expressed genes (DEGs) were determined and studied via gene expression analysis, proteinprotein interaction (PPI) network assessment, action map evaluation, and gene ontology enrichment.
Results: HSPA5, DDIT3, TRIB3, PTGS2, HMOX1, ASNS, GDF15, SLC7A11, and SQSTM1 were identified as central genes. Comparing the central genes and the determined crucial genes via gene expression analysis, actin map results, and gene ontology enrichment led to the introduction of HSPA5, DDIT3, PTGS2, HMOX1, and GDF15 as critical genes in response to the NIR laser.
Conclusion: The results indicated that the principle biological process “Endoplasmic reticulum unfolded protein response” and HSPA5, DDIT3, PTGS2, HMOX1, and GDF15 are the crucial
targets of the NIR laser. The results also showed that the NIR laser induces stress conditions in the irradiated cells.

Introduction: Breast cancer ranks among the most prevalent malignancies, and its prompt diagnosis significantly amplifies the prospects of successful treatment. Approximately one in seven women will experience a breast cancer diagnosis in their lifetime. Stromal cells and their secreted factors exert various effects on tumor growth, impacting proliferation, invasion, and metastasis. Research has emphasized the significant impact of proteins secreted by adipose tissue on breast cancer proliferation, surpassing the influence of factors released by other cell types. Yet, the specific transcription factors and cofactors involved in adipokine expression in the tumor microenvironment remain enigmatic.
Methods: In this study, adipocyte cells were cultured and exposed to 980 nm and 650 nm Photobiomodulation. The MDA-MD-231 cells (triple negative cancer cell line) were cultured with a conditioned medium from laser-treated cells. The real-time assay was employed to analyze the gene expression level changes involved in apoptosis.
Results: Results showed that the irradiated conditioned medium at 980 nm and 650 nm caused a reduction in cell viability of cancer cells. Conversely, the conditioned medium from the irradiated cells triggered an increase in the expression of Caspase 3, Caspase 9, and BAX2 genes, alongside a decrease in BCL2 gene expression.
Conclusion: The findings highlighted the potential of the laser-treated conditioned medium to induce apoptosis pathways in cancer cells, demonstrating a promising avenue for further research in utilizing low-level laser therapy in breast cancer treatment.

Introduction: Many surgical procedures in soft tissue are performed using diode lasers. This study aimed to assess the temperature rise and pain following the use of 810 and 980 nm diode lasers for second-stage dental implant surgery.
Methods: This clinical trial was conducted on 24 osseointegrated dental implants that were randomly divided into two groups of 810 nm and 980 nm diode lasers. The temperature rise in each group was measured right after uncovering by the laser and 15 minutes later by a thermocouple, compared with the baseline temperature of gingival tissue. The level of pain was also measured at 24 hours postoperatively by using a visual analog scale. Data were analyzed by ANOVA, Tukey’s test, and t test (alpha=0.05).
Results: Within-group comparisons by ANOVA showed a significant difference in tissue temperature between the three-time points in both groups (P<0.0001). Pairwise comparisons by Tukey’s test showed that the temperature at baseline (P<0.0001) and 15 seconds after uncovering was significantly lower than that immediately after uncovering in both groups (P<0.0001). The mean tissue temperature and the mean pain score in the 980 nm laser group were significantly higher than the corresponding values in the 810 nm laser group (P<0.05).
Conclusion: According to the results, temperature rise in the use of the 980 nm laser was higher than the 810 nm laser. The use of 810 nm diode laser was associated with lower temperature rise and significantly lower pain score after 24 hours.

Introduction: The basis of successful root canal therapy is the reduction of microorganisms. This in vitro study aimed to compare the antibacterial effect of three different irrigation methods with two laser wavelengths on Enterococcus faecalis biofilm.
Methods: Ninety-five single-canal teeth were prepared, sterilized, and divided randomly into a negative control, a positive control, and five test groups. They were inoculated with the standard strain of E. faecalis. The test groups were conventional irrigation (group 1), Passive ultrasonic irrigation (group 2), Gentle file finisher brush (group 3), 810 nm diode laser (group 4), and 980 nm diode laser (group 5). Microbial sampling, cultivation, and colony counting were done. Data were analyzed with the Kruskal-Wallis test and a negative binomial regression model.
Results: There was a significant difference in the colony count between the groups (P<0.001). the 810 nm diode had the highest and the conventional irrigation group had the lowest reduction in the microbial load. Passive ultrasonic, 980 nm diode laser, and Gentle file finisher brush groups were also ranked respectively from the highest to the lowest in terms of decreasing effect on the number of colonies.
Conclusion: The 810 nm diode laser and conventional irrigation were respectively the most and the least effective methods for reducing the number of E. faecalis colonies.

Introduction: The management of chronic groin and scrotal content pain (orchialgia) is a complex condition after varicocelectomy that is encountered by most practicing clinicians. The aim of this study was to evaluate the effectiveness of low-level laser therapy (LLLT) in orchialgia after varicocelectomy surgery.
Methods: This study was performed as a double-blind, placebo-controlled randomized clinical trial in which sixty patients with orchialgia after varicocelectomy were randomly divided into three groups of 20 as follows: (1) low-level laser group with red (650 nm, 50 mW), (2) low-level laser group with infrared (IR) (820 nm, 100 mW), and (3) laser placebo group. The treatment protocol consisted of 15 minutes, three times a week, for only 12 sessions. Then, the patients were evaluated for pain and sexual satisfaction during the 12-week follow-up.
Results: The pain score in the two groups of low-level laser with red light and IR spectra showed a significant relief (P<0.05) 6 and 12 weeks after starting the treatment, In addition, a significant increase was observed in the level of sexual satisfaction in the red and infrared spectra LLLT groups (P<0.05).
Conclusion: We concluded that the use of LLLT with red light (650 nm, 50 mW)/IR (820 nm, 100 mW) spectra with a power of 6-25 J/cm²/day in 15 minutes, three times a week, for 12 sessions can significantly reduce pain and increase sexual satisfaction in these patients.

Introduction: Photodynamic therapy(PDT)is a minimally invasive technique increasingly used in dentistry for its antimicrobial properties. This research aimed to evaluate the influence of photodynamic therapy (PDT) on the viability of dental pulp stem cells (DPSCs).
Methods: In this laboratory-based, experimental study, DPSCs were cultured in Dulbecco’s modified Eagle’s medium and maintained at 37 °C. The cells were separated into five groups: Toluidine blue (TBO) at concentration of 0.1 mg/mL and 0.5 mg/mL, as well as methylene blue (MB) at concentrations of 0.01 mg/mL and 0.05 mg/mL were added to the wells in groups 1 to 4. The fifth group served as the control group. After 5 minutes of incubation, the experimental groups were irradiated with Fotosan® light-emitting diode (LED) for one minute. Cell viability was assessed after 8, 24, 48, and 72 hours using the methyl thiazolyl tetrazolium (MTT) assay.
Results: Time (P<0.000), photosensitizer type/concentration (P<0.0001), and their interaction effect (P<0.000) on cell viability were all significant. Viability in both MB groups was considerably higher than that in the control group at 8 hours (P<0.001). At 24 hours, no significant difference was observed between the experimental groups and the control (P>0.05). At 48 and 72 hours, cell viability in the TBO groups was markedly lower compared to the control group (P<0.01).
Conclusion: PDT with MB at the tested concentrations had no adverse effect on DPSCs even in the long- term (48 and 72 hours).

Introduction: Recently, various methods such as lasers and different solutions have been investigated to eliminate microorganisms in the root canal. This investigation was aimed at comparing the bactericidal effect on Enterococcus faecalis between a diode laser with a wavelength of 940 nm and a mixture of a tetracycline isomer, an acid, and a detergent (MTAD).
Methods: Forty single-rooted human lower premolar teeth were prepared for inoculation with E. faecalis and incubated for a period of 3 weeks. The 40 samples were randomly divided into 4 groups: the 940 nm diode laser group with irradiation through a 200 µm optical fiber with parameters of (1 W/CW,4 cycles, 20s interval); the MTAD group irrigated with 5 mL for 5 minutes; also, a positive group with 3% NaOCl and a negative group with 0.9% saline solution, both irrigated with 5 mL for 5 minutes. For statistical analysis, the Mann-Whitney U and Wilcoxon tests were used.
Results: The 3% NaOCl positive control group had greater bacterial reduction after treatment (99.99%) compared to the 940nm diode laser (98.96%) and MTAD (99.34%) groups. Statistically, we found a significant difference between all groups regarding the reduction in the colony count (P<0.05).
Conclusion: It was found that there was a significant difference in the percentage of reduction for the bacterial colonies between all the groups evaluated, with the greatest antibacterial effectiveness observed with 3% sodium hypochlorite.

Introduction: One of the common problems among dental patients is tooth hypersensitivity. There are various treatments for hypersensitivity, such as gels, solutions, toothpaste, and laser treatments. This report examined the effect of three treatments, namely 810 nm wavelength diode laser, Gluma gel, and Sensodyne Repair and Protect toothpaste, on tooth hypersensitivity.
Methods: This experimental survey selected 40 premolars free of caries, fractures, restorations, root canal therapy, or wear. The enamel of the midline in the cervical part of the buccal surface was removed by a bur (the area was 2*2 mm and the depth was 2 mm), and the samples were then prepared and divided into four groups. Sensodyne Repair and Protect toothpaste, Gluma gel, and an 810 nm diode laser with 0.5 W power were applied to three groups of teeth. The samples were analyzed using a field emission scanning electron microscope (FE-SEM). The data from the occluded dentinal tubules, partially occluded tubules, and open tubules were analyzed by using the Tamhane test.
Results: The amount of occluded dentinal tubules was 83.2±9% in the laser group, 74.4±11.62% in the Gluma group, 67.1±18% in the Sensodyne group, and 15.03±3.39% in the control group. The difference between the treatment groups and the control group was meaningful (P<0.05). However, the difference between the Gluma group, the Sensodyne group, and the 810 nm laser group was not significant (P>0.05).
Conclusion: The three treatments (810 nm diode laser, Gluma, and Sensodyne) were all effective in occluding dentinal tubules compared to the control group. However, there was no significant difference between these three treatment methods (P>0.05).

Introduction: Nowadays, antimicrobial photodynamic therapy (aPDT) has been introduced as one of the minimally invasive methods for disinfection of the surfaces of dental implants. Being derived from seaweed, Chlorella has been used as a photosensitizer in this study. This study aimed to investigate the impacts of aPDT with Chlorella on the rate of reduction of Streptococcus salivarius in vitro.
Methods: The minimum inhibitory concentration of Chlorella, the sublethal exposure to 660 nm diode laser irradiation, and the minimum sublethal dose of aPDT utilizing Chlorella against S. salivarius were determined. Finally, the CFU/mL value of each plate was calculated. Then, Tukey HSD and one-way ANOVA tests were utilized for comparison the number of colonies after the interventions.
Results: A concentration of 250 µg/mL of Chlorella at an irradiation time of 3 minutes, was
identified as a sublethal dose of aPDT for the reduction of S. salivarius. In contrast, the application of aPDT utilizing a 660 nm diode laser for 4 minutes in combination with Chlorella at a final concentration of 500 µg/mL, demonstrated significantly greater efficacy in reducing S. salivarius compared to the other experimental groups (P<0.001).
Conclusion: Chlorella 500 µg/mL mediated aPDT (660 nm, 4 minutes) has a significant effect on reducing S. salivarius count.

Introduction: Photoacoustic imaging (PAI) uses nonionizing radiation for tumor features and thus can be used as an alternative method for medical features without inducing biological effects. The study aimed to characterize a PAI system utilizing a 650-nm diode laser to detect pathological conditions (benign and malignant tumors) in human uterine tissue, including healthy tissue. The benign tumor tissue used is a leiomyoma, which is a benign tumor that occurs in the middle layer of the uterine (myometrium). Meanwhile, the malignant tumor tissue used is a type of endometrial carcinoma, which is a malignant tumor that occurs in the inner layer of the uterine (endometrium).
Methods: The human uterine tissue was obtained from the hysterectomy procedure conducted to determine the histopathological diagnosis. The PAI system uses a condenser microphone as the acoustic signal detector and a diode laser as the radiation source.
Results: The characterization results of the PAI based on a diode laser with a wavelength of 650 nm and power of 250 mW showed an optimal performance for human uterine tissue in a laser modulation frequency of 16500 Hz and a duty cycle of 50%. Obtained photoacoustic images could differentiate between healthy uterine, leiomyoma, and endometrial carcinoma tissues, as indicated by the intensity level values in each tissue type. Healthy uterine, leiomyoma and endometrial carcinoma tissues had intensity values of 11.87, 26.84, and 37.26 a.u, respectively. A One-way ANOVA test with Bonferroni post hoc analysis revealed a significant difference in the acoustic intensity level between the groups (P<0.05).
Conclusion: The resulting intensity levels indicate a direct correlation with the nature of uterine tumors. The poorer the differentiation, the higher the resulting intensity

Introduction: Studies on head and neck cancer (HNC) patients undergoing radiotherapy have revealed increased numbers of Candida spp., leading to oral candidiasis and oral mucositis. The effects of laser therapy on Candida spp. have been studied with varied results. This study aimed to investigate the effect of low-level laser therapy (LLLT) on C. albicans colonies isolated from HNC patients undergoing radiotherapy.
Methods: This study included a treated group, wherein 11 C. albicans isolates were obtained from the saliva of HNC patients undergoing radiotherapy at a dose exceeding 30 Gy. The control groups consisted of an untreated negative control and a positive control treated with nystatin. The treatment groups were subjected to LLLT in continuous mode for 50 seconds at a wavelength of 976 nm, 0.1 W at a dose of 5 J/cm2 for Laser 1 (L1) group and 0.2 W at a dose of 10 J/cm2 for Laser 2 (L2) group. The tests were conducted using C. albicans inoculum equivalent to a 0.5-McFarland suspension on 96-well plates. All test group inoculums were then cultured on Sabouraud dextrose agar (SDA), and the colony count was assessed at 104 CFU/mL.
Results: LLLT at 5 and 10 J/ cm2 reduced C. albicans colonies by 7.01% and 10.94%, respectively, but the reductions were not statistically significant (P>0.05). Nystatin eliminated all the colonies.
Conclusion: LLLT shows potential for reducing C. albicans colonies in HNC patients undergoing radiotherapy. However, further studies with varied parameters and methods are necessary.

Introduction: Laser therapy employs a concentrated and slender light beam to eliminate or eradicate cancerous cells and pre-cancerous abnormalities. The specific wavelength of 808 nm light is preferentially absorbed by tumor cells compared to healthy cells. This study aimed to assess the combined therapeutic impact of laser and gold, given that gold exhibits photothermal properties when exposed to laser radiation.
Methods: In this in vitro study, two cell lines, namely healthy HuGu cells (human gingival fibroblast cells) and head and neck cancer cells (HN-5), were obtained from the Pasteur Institute. The effect of the laser diode with a density of 3 J/cm2 and wavelength of 808 nm on the proliferation and the survival rate of oral squamous cell carcinoma (HN-5) and human gingival fibroblast (HUGU) was assessed in 60seconds. MTT assay, DAPI test, and trypan blue staining were used to determine the growth and proliferation of HN-5 and HUGU cell lines.
Results: Findings showed that the laser diode along with gold decreased the rate of proliferation and survival cells in HN-5 compared to healthy cells. The changes in the cell population treated with gold and laser diode 808 were insignificant.
Conclusion: Findings reveal that using a low-power laser can effectively inhibit the growth of oral cancer cells. It seems that photothermal therapy is a novel approach to oral cancer therapy.

Introduction: The purpose of this research was to test the impact of seeding a hydrogel chitosan scaffold (HCS) with human adipose-derived stem cells (hADSCs) under the influence of photobiomodulation (PBM) on the remodeling step of the wound repairing process in mice.
Methods: Thirty mice were randomly assigned to five groups (n=6 per group ): The control group (group 1) consisted of mice without any intervention. In group 2, an HCS was implanted into the wound. In group 3, a combination of HCS+hADSC was inserted into the wound. In group 4, an HCS was inserted into the wound and PBM was applied. In group 5, a combination of HCS+hADSCs was inserted into the wound, followed by PBM treatment.
Results: Improvements in the injury closing rate (WCR) and microbial flora were observed in all groups. However, the highest WCRs were observed in groups 5, 4, 3, and 2 (all P values were 0.000). Groups 3-5 showed increased wound strength compared to groups 1 and 2, with group 2 demonstrating better results than group 1 (P values ranged from 0.000 to 0.013). Although groups s 3-5 showed increases in certain stereological elements compared to group s 1 and 2, group 2 exhibited superior results in comparison with group 1 (P values ranged from 0.000 to 0.049).
Conclusion: The joined use of HCS+hADSCs+PBM significantly accelerated the wound healing process during the maturation phase in healthy mice. This approach demonstrated superior wound healing compared to the use of HCS alone, hADSCs+HCS, or PBM+HCS. The findings suggest an additive effect when HCS+hADSCs+PBM are combined.

Introduction: The purpose of this study is to achieve a significant increase in the proliferative activity of mesenchymal stem cells (MSCs) of the bone marrow (BM) at early passages after laser exposure to a suspension of these cells and to estimate the effect of light and heat components of laser radiation on the proliferation of BM MSCs.
Methods: The studies were performed on rats with BM MSCs. MSC suspension was placed into the wells and heated by using laser radiation (980 nm wavelength) or a water bath at 70 °C providing similar temperature dynamics. The studies were carried out in 3 comparison groups: (1) control suspension of MSCs, which was not subjected to heating in a water bath or laser exposure; (2) MSC suspension, which was heated in a water bath; and (3) suspension of MSCs, which was subjected to laser exposure. The exposure times for the 2nd and 3rd experimental groups were 10- 50 seconds.
Results: Under optimal parameters of laser action on the suspension of BM MSCs, a six-fold increase in the number of BM MSCs colonies was registered compared to the control. The role of the light and heat components of laser exposure to MSCs was determined by comparable heating of a suspension of BM MSCs in a water bath, at which only a twofold increase in the number of colonies was maximally obtained.
Conclusion: The increase in the MSC proliferation activity occurs due to their ThermoPhotobiomodulation. The result obtained is important for practical use in cell transplantation in the treatment of traumatic injuries of bone, cartilage, and tendon tissues when a rapid and multiple increase in the initial number of autologous BM MSCs is required.

Introduction: This in vitro study was conducted to assess the phototoxic effects of curcumin, nanocurcumin, 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. Nanocurcumin, at the selected concentration, exhibited lower efficacy in killing S. mutans compared to Curcumin or erythrosine.

Introduction: This study aimed to assess the photobiomodulation effects of blue and red lasers on the proliferation and osteogenic differentiation of periodontal ligament mesenchymal stem cells (PDLMSCs).
Methods: PDLMSCs were cultured and tested in 4 groups. The first two groups were exposed to 445 nm diode laser irradiation (200 mW, 6 and 12 J/cm2), and the third group was exposed to
660 nm diode laser irradiation (50 mW, 4 J/cm2). The fourth group was also considered as the
control group without irradiation. Cell viability/proliferation was assessed by MTT assay. RUNX2, alkaline phosphatase (ALP), collagen type 1 (col1), and osteocalcin (OCN) were evaluated by RTPCR, and Alizarin red was used to evaluate the colonization. The data were analyzed by means of one-way analysis of variance.
Results: The results of our study showed that cell survival/proliferation in the second group was significantly lower than that in the control group on days 1 and 7 (P<0.05). RT-PCR showed a significant increase in osteogenic genes in all three laser groups compared to the control group (P<0.05). All groups showed a significant increase in calcium content compared to the control group (P<0.05). ALP activity also confirmed the osteoblastic differentiation of cells in laser groups.
Conclusion: 445 nm and 660 nm lasers with the studied parameters showed positive effects on the proliferation and osteoblastic differentiation of PDLMSCs.

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 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 22 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.

Introduction: In men, several factors cause infertility, among which we can mention damage to sperm due to high temperature. So far, various treatments have been proposed for it, but they have not been highly effective. The current study aimed to evaluate the effect of exosome therapy (EXO) and photobiomodulation therapy (PBMT) on spermatogenesis arrest in male mice after scrotum hyperthermia.
Methods: In this experimental study, the animals were divided into four groups: control, scrotal hyperthermia, scrotal hyperthermia+EXO (100 μL/d) (mice were treated for 30 days), scrotal hyperthermia+PBMT (laser of 0.03 J/cm2 for 30 seconds/for 30 days). Hyperthermia was induced
by exposure to the temperature of 43 °C for 20 minutes every day 5 times. After 6 weeks, the animals were sacrificed.
Results: The treated groups showed a significant increase in sperm parameters compared to the hyperthermic groups. Moreover, these favorable effects were observed in relation to the volume of testicular tissue, the number of germ cells, Leydig cells, and Sertoli cells, and the level of testosterone. Research on antioxidants showed a significant reduction in oxidized glutathione (GSSG) and reactive oxygen species (ROS) in the treatment groups in comparison to the hyperthermia group (P<0.001). Also, there has been a significant increase in the amount of hydrogen peroxide enzyme observed in the hyperthermia group as opposed to the treatment group (P<0.001).
Conclusion: These findings show that EXO and PBMT can improve spermatogenesis caused by hyperthermia, reduce ROS and GSSG, and increase glutathione (GSH) and sperm quality.

Introduction: The preference for endovascular techniques in treating varicose veins, particularly in the great saphenous vein (GSV), has increased due to their minimally invasive nature and reduced complications. Post-operative care, especially involving compression therapy, remains crucial to improve outcomes, prevent varicose vein recurrence, and enhance overall recovery. This study aimed to evaluate the efficacy of eccentric compression therapy compared to alternative post-operative care methods following endovenous laser treatment (EVLT) for GSV insufficiency.
Methods: This prospective randomized clinical trial encompassed 88 EVLT procedures for GSV insufficiency. The participants were divided into two groups, each receiving different postoperative compression methods, and were evaluated over a specified period. The primary outcome was the pain scale after EVLT; meanwhile, the secondary outcome measured in the present study was the rate of GSV occlusion after EVLT.
Results: Both groups underwent all EVLT procedures successfully without any complications. At the one-month duplex ultrasound (DUS) follow-up, the sapheno-femoral junction occlusion rates were 97% (43 out of 44) for group A (eccentric compression plus gradual compression stocking) and 95% (42 out of 44) for group B (only gradual compression stocking). Ecchymosis was observed in only 12 patients across both groups, accounting for an overall occurrence of 13.6%. Group A patients reported significantly lower analgesic usage (10%) compared to group B (18%), although this difference did not reach statistical significance. Analysis of postoperative pain data utilizing the visual analog scale (VAS) showed a median value of 5.5 in group B patients, which decreased to 3.1 with the application of eccentric compression. Moreover, there was less ecchymosis in group A observed by one week.
Conclusion: This study contributes to the ongoing discourse on the efficacy of postoperative compression in varicose vein treatment. It underscores the necessity for more comprehensive, well-designed studies to yield clearer conclusions and provide better guidance for postprocedure care.

Introduction: Dentin hypersensitivity (DH) is a prevalent unpleasant condition that might affect quality of life. Laser therapy is one of the non-invasive treatments for dentin hypersensitivity. The aim of this umbrella review was to assess the effect of lasers on the treatment of dentin hypersensitivity by analyzing the previously published systematic reviews and meta-analyses.
Methods: Electronic databases (PubMed, Embase, Scopus, Cochrane, and ISI) were searched to identify relevant systematic reviews and meta-analyses based on the keyword search strategy. Two independent reviewers carried out the selection of studies, extraction of data, and assessment of methodological quality. The actual overlap of primary studies was measured through the visual tool known as the citation matrix and three indices of % overlaps, covered area (CA), and corrected covered area (CCA). The reviews were appraised for methodological quality through A Measurement Tool to Assess Systematic Reviews (AMSTAR)-2, and the risk of bias was evaluated using the Risk of Bias in Systematic Reviews (ROBIS) tool.
Results: Following the elimination of duplicates, a total of 2,768 articles were found, and of them, 9 systematic reviews met the inclusion criteria. Six of them included a meta-analysis as well. The actual overlap of primary studies was low. The AMSTAR 2 tool classified one systematic review as high quality, three as moderate quality, three as low quality, and the remaining two as critically low quality. The results of the included reviews generally showed that all types of lasers reduced dentin hypersensitivity compared to placebo/no treatment.
Conclusion: Lasers are effective in treating dentin hypersensitivity.

Introduction: Diabetes is associated with several debilitating complications, including the development of diabetic foot ulcers (DFUs), which can have serious consequences. This study emphasizes a multidisciplinary approach, providing a thorough overview of DFU pathogenesis and available treatments.
Methods: An extensive literature review, covering studies published between 2000 and 2023, was conducted to gather data on DFU pathophysiology and treatments, including wound dressings, photobiomodulation, off-loading devices, adjunct medicines, and stem cell therapy.
Results: DFUs are complicated due to infection, ischemia, and neuropathy. Sufficient wound dressings maintain a moist environment, promoting autolytic debridement and facilitating the healing process. Through cellular mechanisms, photobiomodulation therapy (PBM) was observed to expedite the healing process. Additionally, off-loading devices were invented to reduce ulcer pressure and promote healing. Adjunct therapies such as negative pressure wound therapy and hyperbaric oxygen therapy were identified as valuable tools for enhancing healing outcomes. Furthermore, autologous and allogeneic stem cell treatments exhibited the potential for promoting tissue regeneration and expediting the healing process.
Conclusion: The complex pathophysiology of DFUs necessitates a multimodal treatment approach. Essential components include PBM, wound dressings, off-loading devices, adjunct treatments, and stem cell therapy.

Introduction: The relapse of rotated teeth is a significant concern in orthodontics, and circumferential supracrestal fiberotomy (CSF) presents a potential solution. Traditionally, CSF is performed using a surgical blade; however, employing a laser may reduce complications. This study aimed to systematically review the literature comparing laser-assisted CSF with conventional methods in orthodontic patients.
Methods: A comprehensive search was conducted across the PubMed, Scopus, Web of Science, and Cochrane Library databases using a specific search strategy up to June 16, 2024. Data extraction was done in accordance with the defined inclusion and exclusion criteria.
Results: Initially, a total of 293 articles were identified through the search process, and ultimately, four were selected for analysis based on specific inclusion and exclusion criteria. The studies involved various types of lasers including diode (810 to 940 nm), Er:YAG, and Er,Cr:YSGG lasers, and examined the effects of low-level laser therapy (LLLT) in conjunction with surgical interventions. Regarding relapse rates, two studies reported that both laser and surgical blade techniques demonstrated comparable efficacy, while adjunctive LLLT was effective in reducing relapse. In the other two studies, the use of laser therapy was found to be effective in decreasing relapse rates compared to the control group. Pain assessment results were inconclusive; one study reported reduced pain in the laser group, while another found no significant difference in pain levels between the laser and blade techniques. Furthermore, no significant differences were observed in periodontal pocket depth or gingival recession between the two methods.
Conclusion: Within the limitations of the current systematic review, our findings indicate that there is no significant difference in relapse rates between laser and blade CSF procedures. Furthermore, our results suggest that the incorporation of photobiomodulation at higher doses is correlated with a reduction in relapse rates following fiberotomy procedures.

Introduction: High-intensity laser therapy (HILT) and low-level laser therapy (LLLT) combined with exercise therapy (ET) have emerged as effective treatment options for musculoskeletal pain. However, there have remained uncertainties regarding the magnitude of their effects in reducing pain and improving function in patients with knee osteoarthritis. Hence, we performed a systematic review and network meta-analysis of available evidence in the literature to answer this query.
Methods: A literature search was carried out in Embase, PubMed, and Scopus databases without any language restrictions from 1 January 1990 to 31 December 2023. We examined randomized controlled trial (RCT) studies that investigated the efficiency of HILT or LLLT plus knee osteoarthritis ET in pain and functional improvement of the knee. We performed a network meta-analysis and provided the standardized mean difference (SMD) with a 95% confidence interval (CI) by pooling the continuous data on the visual analogue scale (VAS) pain score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score using a random-effects model.
Results: In total, 11 eligible RCTs were included. Our analysis revealed significant improvements in the VAS pain and WOMAC function scores on weeks 4 and 8 after interventions in groups treated with LLLT+ET and HILT+ET compared with placebo+ET. Moreover, HILT+ET showed a greater reduction in the VAS pain score (SMD=-1.41; 95% CI: -2.05 to -0.76) and improvement in the WOMAC function score (SMD=-2.20; 95% CI: -3.21 to -1.19) than LLLT+ET in week 8.
Conclusion: Based on our findings, both HILT+ET and LLLT+ET treatments effectively reduced pain and improved function, but HILT+ET showed a more significant improvement in both outcomes compared to LLLT+ET.

Introduction: The treatment of endocrine problems like thyroid disease, diabetes mellitus (DM), and polycystic ovary syndrome (PCOS) faces significant challenges so medical professionals worldwide are trying to find a new therapeutic approach. However, along with common treatments which include medications, hormone replacement therapy, and surgery; there is a growing interest in alternative therapies like laser therapy, which offers a non-invasive and unique technique for treating endocrine disorders alone or in combination with traditional methods. The main goal of this review was to do a systematic review of the role of the laser and Microwave in the treatment of endocrine disorders.
Methods: In the present systematic review, the most important databases, including PubMed, Scopus, and Google Scholar were searched for studies examining the effect of lasers on the treatment of endocrine problems by using appropriate keywords and specific strategies from 1995 to 2023. All the studies that were not about lasers and endocrine were excluded.
Results: Based on 51 reviewed studies, lasers and radiofrequency ablation such as RFA are effective in the treatment of thyroid diseases, hyperparathyroidism, pancreatic disorders, and sexual dysfunctions. Laser-induced interstitial thermal therapy (LITT) and microwave ablation (MWA) are genuine minimally invasive methods for the treatment of benign nodules, adenomas, and tumor ablation including pancreatic carcinomas and adrenal tumors. Intravenous laser blood irradiation (ILBI) which uses red, UV, and blue light could be effective in treating various metabolic disorders, such as DM.
Conclusion: Laser as a cutting-edge and minimally invasive approach could treat various
endocrine disorders. It has great potential to treat and regulate hormonal imbalances, decrease
inflammation, and relieve symptoms of various ailments, such as endocrine disorders.

Introduction: Endodontic treatment of teeth with periapical lesions presents more clinical difficulty. Various lasers in several methods are used in endodontics, and most of them are utilized as an adjunctive protocol in order to reduce the bacterial load of the root canal system. Improved disinfection plays a crucial role in enhanced and accelerated healing of periapical lesions. This review aims to summarize studies assessing the effect of lasers on periapical lesion healing.
Methods: PubMed/MEDLINE, Scopus, Embase, and Web of Science (ISI) online databases were searched, with no publication year or status restriction, for relevant articles on April 2023. Clinical studies evaluating the effect of laser application on the periapical lesion of patients using radiographic assessment were considered eligible for inclusion.
Results: Eight studies were included after carefully screening the obtained articles, first by their title and abstract and then by their full texts. Diode (4), Er, Cr: YSGG (3), and Nd: YAG (1) lasers were used with output powers that varied from 0.75 to 2 watts. Photodynamic therapy was employed in two studies, and in other studies, the root canal system was directly irradiated. Irradiation of the root canal system was adjunctive to standard preparation in all studies. The healing of the teeth treated with lasers was not inferior to those conventionally treated. In all of the included studies, laser application outperformed the standard cleaning and shaping protocol; however, this improved or faster healing was not statistically significant in most studies.
Conclusion: Lasers might expedite and improve the healing process of periapical lesions. Since lasers enhance the quality of cleaning of the root canal system, it is hard to point out the exact mechanism of it. Further investigations are needed to realize the effectiveness of this treatment modality and to discover the underlying biological concepts.

Introduction: Developing regenerative endodontic treatment (RET) is an exciting approach to managing immature permanent teeth with pulp necrosis. RET is usually performed in two clinical steps: disinfection (first step) and tissue engineering (second step). Recently, laser therapy has entered the field of RET. This study aimed to provide an overview of the literature that employed laser therapy for root regeneration.
Methods: A comprehensive search was performed on four databases, including PubMed, Web of Science, Scopus, and Google Scholar. The searched keywords were laser, regenerative endodontics, immature permanent teeth, and dental pulp necrosis, and related English-published articles were included up to October 2023.
Results: Thirteen studies utilized a laser for RET. In the first step of RET, both high-power and low level lasers (through photodynamic therapy [PDT]) may be applied for canal disinfection. In contrast, regenerative procedures in the second step of RET are just accelerated by low-power lasers (biostimulation). The literature does not support the benefit of laser-assisted irrigation in improving the clinical success of RET. There is some evidence that laser-assisted disinfection with a diode laser may provide comparable results to triple antibiotic paste in reducing bacterial counts in root canals while providing slightly better clinical and radiographic outcomes. PDT may be an effective and suitable adjunct to conventional disinfection methods in immature, necrotic teeth.
Conclusion: Low-power lasers may be beneficial tools for improving the results of regenerative endodontics through chemical disinfection in the first step (PDT) or by biostimulation in the second step of RET.

Introduction: Trastuzumab is now increasingly being used as a potent HER2 inhibitor in treating breast cancer, while acneiform rashes sometimes arise as skin-related side effects in patients undergoing treatment with HER2 inhibitors, and their specificity as drug-induced eruptions makes their management quite challenging. Pulsed dye laser (PDL) therapy has been utilized to treat a wide variety of vascular lesions, achieving excellent outcomes.
Case Report: A 595 nm PDL was used to treat a 38-year-old woman suffering from an acneiform rash induced by trastuzumab as neoadjuvant therapy for breast cancer. One-half of the face received PDL treatment, while the other half served as the control.
Conclusion: After just one PDL treatment, the skin lesion demonstrated a remarkable improvement, with a significant reduction in erythematous papules and inflammatory pustules, as well as an improvement in skin thickening. PDL therapy might offer an effective alternative for managing acneiform rashes induced by trastuzumab.

Introduction: Diabetic patients frequently experience a serious complication known as impaired wound healing, which increases the likelihood of foot infection and limb amputation. Investigators have been looking for novel methods to treat diabetic foot ulcers (DFUs) recently.
Case Report: A 75-year-old woman with type one diabetes mellitus (DM) has been accepted. There was a sizable (40 cm2 full-thickness cutaneous wound) in the plantar part of her right foot (Wagner Ulcer Grade Classification System: grade 3) which had not been treated by the usual treatment for DFUs. In this present case, we used amniotic fluid gel (AF gel) and photobiomodulation therapy (PBMT) (400 mW/cm2 ; 810 nm, once a week for 16 weeks) to treat
and speed up the healing of a harsh DFU. The size of the ulcer area significantly decreased as combination therapy progressed, and within 16 weeks, the wound was healed and the pain was reduced.
Conclusion: This revealed contextual analysis demonstrated the useful effect of the mix of PBMT and AF gel on a serious DFU. To confirm the findings, we recommend conducting additional clinical trials in a clinical setting. In addition, it is recommended that additional research using preclinical models uncover the mechanism of action of the combination therapy.

Introduction: Odontogenic extraoral sinus tracts are rare conditions that can be misdiagnosed as skin lesions and lead to unnecessary treatments. They are caused by dental infections spreading through bone and draining externally. Conservative nonsurgical endodontic treatment should be pursued first. However, conventional instrumentation and irrigation techniques cannot fully decontaminate root canal systems. New disinfection techniques, including ultrasonic activation of irrigation, photodynamic therapy (PDT), and lasers, have been developed as adjunctive techniques. Photobiomodulation (PBM) (also known as low-level laser therapy) has also demonstrated beneficial effects on tissue healing.
Case Presentation: This report presents a case of an extraoral sinus tract associated with a necrotic mandibular molar that was treated successfully with nonsurgical endodontic therapy using ultrasonically-activated PDT, PBM, and high-intensity laser therapy (HILT). Six- and 12-month follow-ups showed resolution of the sinus tract and healing of the apical lesion radiographically. The extraoral lesion had diminished significantly.
Conclusion: Combining nonsurgical endodontic treatment with PDT with ultrasonic activation, PBM, and HILT allowed successful management of an odontogenic extraoral sinus tract without surgical intervention. Using PDT combined with ultrasonic activation enhanced disinfection while PBM and HILT improved wound healing. This report demonstrates a conservative approach to treating these lesions.

Introduction: Facial partial unilateral lentiginosis (PUL) is an infrequent skin pigmentation disorder characterized by multiple lentigines. Despite the availability of various treatment modalities, there is no standard treatment for PUL. This study reports a successful treatment of facial PUL in a female patient using a novel 532-nm Nd:YAG fractional picosecond laser (FPL)
Case Report: The patient underwent four treatment sessions at four-week intervals. The treatments
were administered using a 9 mm high coverage handpiece microlens array (MLA), with a fluence of 0.2–0.4 J/cm², a frequency of 2 Hz for 2-3 passes, and approximately 10% overlap. The treatment was well-tolerated by the patient, with significant improvement in pigmentation and no significant side effects observed. The outcomes confirmed the efficacy of the 532-nm Nd: YAG FPL in treating facial PUL.
Conclusion: The 532-nm Nd: YAG FPL appears to be an effective and well-tolerated treatment for facial PUL, offering significant improvement in pigmentation without notable side effects.

International Seminar of Lasers and Biomedical Photonics, LBMP 2023

18-20 October 2023, Tehran, Iran

Cooperated organization:

Laser Application in Medical Sciences Research Center

Medical Laser Research Center, Yara Institute, ACECR

Co-operators:

Amirkabir University of Technology

Royan Institute, ACECR

YARA Institute, ACECR

Sharif University of Technology

Laser and Plasma Research Institute, SBU

Shahid Beheshti University of Medical Sciences

Radiation Sciences Research Center, AJA University of Medical Sciences