Photobiomodulation Photomedicine and Laser Surgery

Photobiomodulation as a Potential Adjuvant Therapy to Improve Cochlear Implant Efficiency
Chang SY and Lee MY
Photobiomodulation (PBM) is a noninvasive therapeutic modality with widespread applications for modulating various biological processes. Although the exact mechanisms of action remain uncertain, PBM promotes homeostasis through diverse pathways, including reducing inflammation and enhancing tissue recovery. Hearing loss is irreversible in mammals due to the limited regenerative capacity of cochlear hair cells. Cochlear implants offer a solution by electrically stimulating the auditory nerve, bypassing damaged hair cells in individuals with severe hearing loss. However, postoperative inflammatory responses and cochlear nerve fiber damage can compromise implant efficacy. We investigated current strategies to minimize secondary cochlear damage after cochlear implantation and evaluated the potential of PBM as an adjuvant therapeutic approach. The auditory cell protective effects of PBM could significantly enhance the performance of EAS devices in individuals with residual hearing. Further, postoperative CI is accompanied by an inflammatory response characterized by the upregulation of specific cytokines. Considering the neuroregenerative potential of PBM, its application as a neuroprotective strategy warrants further validation.
The Effects of Photobiomodulation Therapy in Cubital Tunnel Syndrome, Clinical Trial
Yağcı G, Kasapoğlu Aksoy M, Aykurt Karlıbel İ and Seferoğlu M
We aimed to evaluate the effects of laser therapy together with rest splint and exercise on muscle strength, function, activities of daily living, and pain in individuals suffering from cubital tunnel syndrome (CuTS) by comparing it with placebo treatment. This prospective, single-blind, and randomized controlled study was conducted with 64 patients with CuTS in total. They were divided into two groups by randomization: Group 1 ( = 32) was provided with low-energy laser therapy + splint + exercise, and Group 2 ( = 32) was provided with low-energy sham laser therapy + splint + exercise. Patients in both groups received resting splints and nerve release exercises. Pretreatment and posttreatment (3rd week, 3rd month) evaluations were made with the Visual Analog Scale (VAS), the Quick Disability of Arm, Shoulder, and Hand Questionnaire, hand grip strength, fingertip grip strength, the Patient-Rated Ulnar Nerve Evaluation Scale (PRUNES), and Short Form-12. An electrophysiological evaluation was performed at baseline and at the 3rd month. We observed significant improvements in both groups regarding pain, function, muscle strength, health profile, and quality of life in the early posttreatment (3rd week) stage and at the 3rd-month follow-up. When both groups were compared, a significant difference was determined between the VAS-Rest, VAS-Movement, PRUNES-Pain, PRUNES-Function, and PRUNES-Total parameters in the posttreatment (3rd week follow-ups), as well as PRUNES-Pain scores in the post-treatment (3rd month) stage, of the groups in favor of those in Group 1 ( < 0.05). The findings of our study have shown that in the treatment of CuTS, laser treatment is superior to placebo in the short term, but they have equivalent effects in the medium term. Further studies with large patient populations are needed to provide more diverse information about the therapeutic effectiveness of low-intensity laser therapy.
The Effect of Photobiomodulation on Bone Mineral Density, Serum Vitamin D, and Bone Formation Markers in Individuals with Complete Spinal Cord Injuries with Osteoporosis
Mohammadzadeh E, Amiri AH, Fekrazad R, Leitgeb RA, Mayr W and Ezzati K
A quasi-experimental study utilized a matched-pair design, administering photobiomodulation at four-sites on one side of the body and assigning control to the other side at corresponding sites. This study aimed to assess photobiomodulation treatment effects on bone mineral density (BMD) measurement using dual-energy X-ray-absorptiometry in individuals with complete spinal cord injury (C.SCI) and osteoporosis. Eight patients received treatment at four-sites: forearm-mid-distal (MID), proximal-femur, distal-femur, and proximal-tibia, totaling 32 sites. Using an 830 nm gallium-aluminum-arsenide semiconductor laser irradiation was administered three times weekly for 8 weeks. Different doses (energy density) were determined depending on bone depth from skin surface, as assessed by sonography and adjusted through irradiation time to be 8, 10, and 12 J/cm for depths <1 cm, between 1 and 1.5 cm, and >1.5 cm, respectively, using 200 mW power to deliver the optimal isodose of laser at each depth of bone within each therapeutic site. BMD was measured at baseline, week 8 of treatment, and week 15 of follow-up. Serum 25-(OH)-vitamin D and bone formation markers including osteocalcin and bone-alkaline-phosphatase (B-ALP) were also assessed at baseline and week 8 of treatment. Significant increases in BMD were noted in proximal-femur and forearm-MID at both week 8 and week 15. Serum 25-(OH)-vitamin D levels significantly increased after treatment. However, no notable changes were observed in distal-femur and proximal-tibia BMD or in osteocalcin and B-ALP levels. Photobiomodulation (830 nm) laser demonstrated efficacy in improving BMD at proximal-femur and forearm-MID in individuals with C.SCI. Moreover, the observed positive influence on vitamin D levels suggests a potential photobiomodulation role, warranting further investigation.
Modulatory Effects of 830 nm on Diabetic Wounded Fibroblast Cells: An In Vitro Study on Inflammatory Cytokines
Mgwenya TN, Abrahamse H and Houreld NN
After skin damage, a complicated set of processes occur for epidermal and dermal wound healing. This process is hindered under diabetic conditions, resulting in nonhealing diabetic ulcers. In diabetes there is an increase in inflammation and proinflammatory cytokines. Modulating cells using photobiomodulation (PBM) may have an effect on inflammation and cell viability, which are crucial for the healing of wounds. This study explored the impact of PBM in the near-infrared spectrum (830 nm; 5 J/cm) on inflammation in diabetic wound healing. Five cell models, namely normal, wounded, diabetic, diabetic wounded, and wounded with d-galactose were used. Cell morphology and migration rate were assessed, while cellular response measures included viability (Trypan blue and adenosine triphosphate), apoptosis (annexin-V/PI), proinflammatory cytokines interleukin-6, tumor necrosis factor-alpha (TNF-α), and cyclooxygenase-2, nuclear translocation of nuclear factor kappa B (NF-κB), and gene expression of advanced glycation end product receptor (AGER). PBM resulted in increased levels of TNF-α, supported by activation of NF-κB. PBM stimulated translocation of NF-κB and upregulation of AGER. PBM modulates diabetic wound healing in vitro at 830 nm through stimulated NF-κB signaling activated by TNF-α.
Effects of Laser Acupuncture on Metabolic Functions of Sedentary People: A Double-Blind Randomized Clinical Trial
Martins Filho HMA, Mangueira MAMM, Nóbrega LGD, Gama Filho OP, Neto OP, Mangueira NM and Zângaro RA
Laser acupuncture regulates energy flow and restores body fluid metabolism. To evaluate the effects of the laser acupuncture protocol (LAP) on hepatic and renal metabolism in sedentary people. Longitudinal, double-blind, and randomized clinical trial with 29 participants, adults, both sexes, sedentary, without pre-existing metabolic diseases, subdivided into control and laser groups. Based on the STandards for Reporting Interventions in Clinical Trials of Acupuncture 2010 guidelines, 10 laser applications (660 nm ±10 nm wavelength, 100 mW power. The irradiation tip has a diameter of 5 mm, which corresponds to an area of 0.19 cm, totaling a power density of 0.52 W/cm and considering the irradiation time of 90 s, the energy density applied was 47.3 J/cm) were performed on the acupoints of metabolic functions (LR3, SP6, ST36, and LI4) and blood samples were collected for fasting glycemia, lipid profile (HDL, LDL, total cholesterol, and triglycerides), liver function (AST/GOT and ALT/GPT), and renal function (serum creatinine and urea). A repeated measures analysis of variance (ANOVA) with Bonferroni corrected post hoc comparisons was applied to compare statistical differences between groups and times, adopting < 0.05 as the null hypothesis. The laser stimulated changes in serum lipid profile values and renal and hepatic functions. There was a significant ( = 0.014) reduction in LDL ("bad" cholesterol) from 105.75 ± 32.83 pre- to 84.32 ± 18.38 mg/dL postintervention, associated with cardioprotective function. Positive significant ( = 0.035) impacts were also observed in the reduction of creatinine (0.86 ± 0.12 mg/dL to 0.75 ± 0.12 mg/dL) and the enzyme AST/GOT (33.73 ± 12.95 U/L to 20.80 ± 4.99 U/L, = 0.002). LAP applied to basal metabolism acupoints promoted positive metabolic changes in the lipid profile (LDL), and in main markers of the liver (AST/GOT) and kidney (creatinine) functions, contributing to risk control of cardiovascular diseases.
Photobiomodulation and Physical Exercise Modulate of Cell Survival Proteins in the Skeletal Muscle of Rats with Heart Failure and Diabetes Mellitus
Bahr AC, Scherer NB, de Gregório E, Kieling L, de Castro AL, Araujo ASDR, Türck P and Dal Lago P
Heart failure (HF) and type 2 diabetes mellitus (DM2) are global health problems that often lead to muscle atrophy. These conditions are associated with increased autophagy and apoptosis in the muscle cells, resulting in decreased muscle mass. Physical exercise associated with photobiomodulation (PBM) seems promising to attenuate the skeletal muscle changes caused by HF and DM2, due to its direct effects on mitochondria, which may result in an increase in antioxidant capacity. To verify the influence of physical exercise and the association with PBM on autophagy, apoptosis, and cell survival signaling pathways in myocytes from rats with HF and DM2. Male rats were assigned to one of four groups: control (CT), HF+DM (disease model), exercise+HF+DM (EX+HF+DM), and EX+HF+DM+PBM (EX+HF+DM+PBM). To induce DM2, we administered streptozotocin (STZ) (0.25 mL/kg, intraperitoneally). HF was induced by coronary ligation. One week post-induction, an 8-week aerobic exercise and PBM protocol was initiated. Western blot analysis was used to measure the expression of apoptosis-related proteins and autophagy. The EX+HF+DM+PBM group showed a substantial increase in Nrf2, -AKT, and LC3-I levels compared to the HF+DM group. These findings suggest that physical exercise combined with PBM can upregulate proteins that promote myocyte survival in rats with HF and DM2.
Analysis of the Ultrasensitive C-Reactive Protein and Homocysteine Biomarkers after Photobiomodulation Therapy in Hormone Blocker-Treated Mastectomized Women: A Randomized, Blind, and Controlled Clinical Study
Pacheco JA, Fernanda Molena K and Veiga EV
The pharmacological treatment of cancer can lead to undesirable hemodynamic adverse effects. Laser therapy may promote hemodynamic balance in these patients. This study aimed to analyze the values of the biomarkers ultrasensitive C-reactive protein (PCR_us) and Homocysteine (HCy) after the use of intravascular laser irradiation of blood (ILIB) in mastectomized patients using hormonal blockers Tamoxifen and Aromatase Inhibitors. This was an experimental, placebo-controlled, randomized clinical trial with experimental (G1) and control (G2) groups. In G1, patients were irradiated with ILIB using a red laser at 660 nm on the carotid artery, while G2 received a placebo treatment. Blood collection for HCy and us-CRP biomarker evaluation was conducted monthly for 4 months. Statistical analysis was performed using R Studio 4.4.2 and JAMOVI, with a significance level of 5%. A total of 21 patients participated in the study, with 12 in G1 and 9 in G2. There were no differences in age, systolic, diastolic blood pressure, and heart rate between the groups. The initial and final mean PCR_us levels for G1 were 6.8 and 3.8 mg/dL, and for HCy were 14.2 and 12.1 µmol/L, respectively. While for G2 initial and final mean PCR_us levels were 9.40 and 7.60 mg/dL, and for HCy were 14.33 and 16.69 µmol/L. There was no statistical difference for PCR_us. However, a significant difference between the groups ( < 0.05) for HCy in the 3rd and 4th months. During ILIB Therapy, there was a reduction in HCy, which may favor the improvement of cardiovascular function in these patients undergoing anticancer therapies.
Underexplored Areas of Photobiomodulation in Oral Oncology: An Expert Analysis
Gueiros LA, Gobbo M, Santos-Silva AR, Merigo E, Miranda-Silva W, Fregnani ER, Ottaviani G, Kauark-Fontes E, Bensadoun RJ and Arany P
This study aimed to review the current body of literature on underexplored areas of photobiomodulation (PBM) for preventing and/or treating oral adverse events. Recent studies suggest that PBM may offer potential benefits in managing cancer-related toxicities other than oral mucositis. Nevertheless, further research to establish conclusive evidence is still missing. A panel of specialists conducted a narrative review to evaluate the evidence on PBM therapy for oral mucositis, xerostomia, dysgeusia, dysphagia, and trismus/fibrosis. Each topic was reviewed by two specialists who discussed treatment rationale, summarized current evidence, evaluated risk/benefit ratio, and identified future research directions. The current evidence suggests promising outcomes in nonroutine uses of PBM for xerostomia, dysgeusia, odynophagia, oral mucositis (extraoral PBM and the pediatric population), and trismus/fibrosis. However, the primary studies are often small and may have biases that require further evaluation, particularly regarding treatment safety. Despite the overall positive impression of PBM therapy for oral adverse events of cancer treatment, robust evidence from large multicentered studies is necessary to support its widespread clinical use.
Photobiomodulation Literature Watch December 2023
Carroll JD
Comparative Study of Photobiomodulation Effects on Alveolar Socket Hard Tissue Healing in Rats: Application of 980 nm Versus 810 nm Lasers
Fan B, Shao B, Lv S, Liu X, Sui J, Bai C, Zhang W, Xiao S and Jiao XH
This study aimed to explore the differential effects of photobiomodulation (PBM) via 980 nm and 810 nm lasers on the hard tissue healing of rat alveolar sockets, with a focus on a comparative analysis of hard tissue regeneration and osteogenic gene expression. This study aimed to explore the effects of PBM using 980 nm and 810 nm lasers on hard tissue healing of rat alveolar sockets, focusing on hard tissue regeneration and osteogenic gene expression. Thirty-six male Wistar rats (5 weeks old) had both right and left maxillary first molars extracted. Post extraction, the right alveolar sockets received PBM treatment with either 980 nm (0.3 W, 18 J/cm) or 810 nm (0.1 W, 6 J/cm) lasers for seven days, whereas the left sockets served as controls. Rats were euthanized on days 3, 7, 14, and 28 for histopathological, immunohistochemical, micro computed tomography (micro-CT), and quantitative polymerase chain reactionanalyses. On day 3, early granulation tissue, neovascularization, and inflammatory cell aggregates were observed in all groups. By day 7, active osteoclasts and osteoblasts were noted, with a significant increase in CD31-positive cells in the 980 nm group ( < 0.05). Day 14 showed new bone formation, and by day 28, increased cancellous bone and collagen content were present in all groups, with no significant differences between them ( > 0.05). Gene expression analysis revealed higher BMP-2 and Runx-2 levels in laser-treated groups on day 14 ( < 0.05), with the 980 nm group having higher BMP-2 levels than the 810 nm group ( < 0.05). Bone sialoprotein expression was higher in laser-treated groups on days 14 and 28 ( < 0.05), and osteocalcin expression was highest in the 980 nm group on both days ( < 0.05). Micro-CT analysis showed no significant differences among groups in bone mineral density, bone surface (BS)/bone volume (BV), or bone volume (BV)/TV (total volume) indices. PBM with 980 nm and 810 nm lasers promotes early-stage hard tissue healing in extraction sockets, with the 980 nm laser more effectively enhancing osteogenic gene expression, suggesting its potential as an adjunctive therapy in dental and oral surgery.
The Biofilm Removal and Bactericidal Effect of an 810-nm High-Power Laser on an Orthodontic Bracket Surface: An In Vitro Study
Yang H and Yang K
The present study aimed to analyze the biofilm removal and bactericidal effect of laser treatment alone and laser combined with ultrasonic scaling on orthodontic brackets. It also assessed whether the use of a laser can improve the efficiency of biofilm removal and bactericidal effect compared with traditional ultrasonic instrumentation. () can lead to white spots and dental caries. Orthodontic brackets make teeth cleaning more difficult, and biofilms or bacteria on the surface of brackets worsen the oral environment, which may cause some oral diseases. Laser can be used for biofilm removal and killing bacteria on the surface of an object through thermal, photochemical, and pressure effects, which is widely used in the treatment of oral diseases. A total of 600 mandibular incisor brackets were collected for this study. Among these, 320 unused brackets were used for the crystal violet assay ( = 160) and for live/dead bacterial staining ( = 160). Another 280 brackets, obtained from patients who had undergone therapy for over two years, were used for the mature multispecies biofilms removal assay ( = 120) and multispecies bacterial live/dead bacterial staining ( = 160). Ultrasonic scaling, laser, and laser combined with ultrasonic scaling were applied to the labial surface of brackets covered by biofilm or mature multispecies biofilms. Specifically, we used the following three methods: ultrasonic scaling for 10 sec without laser; 810-nm laser (Doctor Smile, Italy, LA5D0 001.1) with 0.3-mm spot size at total 21.2 kJ/cm for 10 sec; and 810-nm laser at total 10.6 kJ/cm for 5 sec, followed by ultrasonic scaling for 5 sec. The 810-nm diode laser removed biofilms with a power of 1.5 W and a power density of 2.12 kW/cm. The biofilm was examined using crystal violet assay, and scanning electron microscopy (SEM) was used for mature multispecies biofilms to evaluate the effect of the three methods on biofilm removal. Live/dead bacterial staining was used to examine the bactericidal effect on remaining biofilms by confocal laser scanning microscopy (CLSM). For biofilm, the optical density (OD) value and live/dead bacterial ratio in the laser and the laser combined with ultrasonic scaling groups were significantly lower than those in the ultrasonic scaling group ( < 0.05); moreover, the OD value and the live/dead bacterial ratio in laser treatment combined with ultrasonic scaling and laser treatment alone showed no significant difference ( > 0.05). For mature multispecies biofilms, the percentage of biofilm coverage after treatment was higher in the laser group than in the ultrasonic scaling group ( < 0.05) and lower in the laser combined with ultrasonic scaling group than in the ultrasonic scaling group ( < 0.05), and live/dead bacterial staining showed that laser treatment alone killed the most bacteria, followed by laser treatment combined with ultrasonic scaling, while ultrasonic scaling alone seldom killed bacteria. Laser treatment alone has a better bactericidal effect and can also remove more biofilm than ultrasonic scaling alone, but it fails to remove more mature multispecies biofilms. Laser treatment combined with ultrasonic scaling can remove more biofilm and mature multispecies biofilms than ultrasonic scaling alone and also has a better bactericidal effect than ultrasonic scaling alone on a bracket surface.
Efficacy of Laser Acupuncture on Neurophysiological Parameters of Median Nerve and Hand Function in Postpartum Women: A Randomized Controlled Clinical Trial
Botla AM, Lasheen YR, Mohamed SS, Alwhaibi RM, Zakaria HM, Ragab WM and El-Shafei MA
This study was conducted to ascertain the efficacy of photo acupuncture (PA) on the neurophysiological parameters of the median nerve and hand function in postnatal women. Carpal tunnel syndrome (CTS) has been documented in up to 62% of pregnant females. PA, a noninvasive treatment that utilizes photo therapy on acupoints, could aid in the management of CTS. Thirty-six postpartum women diagnosed with CTS depending on their medical history, physical examination, and electrodiagnostic study were distributed into two equal-sized groups at random. The PA group ( = 18) received PA for 12 min on the following acupuncture points: PC4, PC6, PC7, PC8, HT2, HT3, HT7, LI10, LI11, LI4, LU9, and LU10. The treatment was given 3 times weekly for four weeks; in addition, night splints were worn. Women in the control group ( = 18) just wore night splints. Before and after the 12-session treatment, each woman was assessed using an electrodiagnostic test to measure the motor distal latency (MDL), sensory distal latency (SDL), motor conduction velocity (MCV), sensory conduction velocity (SCV), pinch dynamometer for assessing pinch strength, and the Brief Michigan Hand Questionnaire (BMHQ) for assessing hand function. A statistically significant improvement was observed in both groups after therapy regarding SDL, SCV, MDL, MCV, pinch strength, and BMHQ ( < 0.05) in favor of the PA group. Adding PA to a night splint should be suggested as an effective conservative therapy for CTS in postpartum women.
Green Synthesis of Au-Doped Tin Oxide Nanoparticles Using Extract with Potential Applications in Photodynamic Therapy
Karimi M, Sadeghi E, Zahedifar M, Mirzaei H, Nejati M and Hamblin MR
The green synthesis of Tin(IV) oxide (SnO): Gold (Au) nanoparticles (NPs) using medicinal plant extract was investigated, and the NPs were characterized and tested as photosensitizers to produce reactive oxygen species (ROS). The cytotoxic effect on C26 cells was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) technique. The results showed their toxicity in a dose-dependent manner. The green synthesis of SnO:Au NPs was achieved for the first time using an extract of medicinal plant as a reducing and stabilizing agent. The produced NPs were examined for their application in photodynamic therapy (PDT) for cancer. Methylene blue and anthracene were used to confirm that the photosensitizer could produce ROS when excited with UVA radiation. The anticancer activity of SnO:Au was investigated in vitro using the C26 cell line and an MTT assay, showing that PDT with SnO:Au NPs could inhibit cancer cell proliferation. The significant afterglow of the SnO:Au NPs could cause the generation of ROS to continue several minutes after switching off the light source.
Effects of Local Anesthetics on Tissue Penetration Using Diode Lasers in Intraoral Tissues
Romanos G, Wu J, Roibu EG, Zhang Y and Delgado-Ruiz R
The purpose of this study was to demonstrate heat transfer within oral soft tissues using different lasers under the effect of local anesthetics (LA). Bovine tongue slices were placed in between two glass slides and at a distance from a thermographic camera. In total, 2-cm-long 240 incisions were made along the surface of the tissue parallel to glass slides and the camera capture field. Incisions were performed using 445-nm and infrared (IR) lasers (970 nm and 980 nm on a continuous wave at 2 W) with 320 µm-initiated (concentrated energy at the tip provided by a blue articulated paper and laser irradiation) and noninitiated (defused energy) fiber (30-sec irradiation period). LA was injected into the specimens before irradiation. The temperature changes in °C (ΔT) and vertical and lateral heat transfer (in mm) were recorded at 10-sec intervals for 30 sec, using thermographic images. The amount of lateral and vertical heat transfer was measured. A repeated analysis of variance statistical comparison test was used to analyze differences between the lateral (width) and the vertical (height) heat transfer for initiated and noninitiated lasers and different lasers. The maximum ΔT in °C utilizing initiated tips of 970, 980, or 445 nm were 11.82 ± 3.46, 7.66 ± 3.24, and 18.94 ± 7.01 and using noninitiated tips were 8.27 ± 1.69, 8.87 ± 2.40, and 12.31 ± 8.65, respectively. Heat transfers (height/width) for initiated were 40.65 ± 10.40/90.65 ± 10.77 mm, 41.50 ± 11.83/83.95 ± 11.20 mm, and 33.70 ± 9.10/95.10 ± 11.17 mm and for noninitiated lasers were 52.95 ± 6.89/96.10 ± 11.17 mm, 47.75 ± 7.41/93.75 ± 14.96 mm, and 31.35 ± 11.40/75.20 ± 19.68 mm, respectively. A statistically significant difference was found between all lasers ( < 0.05) for initiated and noninitiated lasers (except for 970/980 nm for noninitiated lasers). Lower penetration depth ( < 0.05) at 445-nm diode and greater lateral heat spreading ( < 0.05) were identified under LA especially utilizing noninitiated tips without significant difference in IR lasers. LA might negatively influence soft tissues creating scattering when noninitiated tips are used and IR diode laser technology.
The Effects of Photobiomodulation Therapy on Tensile-Cultured Cementoblasts Cells
Kao CY, Ho CT, Huang TH and Kao CT
Studies show that photobiomodulation therapy (PBMT) boosts cellular ATP production and cell growth and reduces inflammation. Additionally, mechanical tension affects gene expression, impacting cellular functions like proliferation and migration. We investigated the impact of PBMT on OCCM-30 cementoblast cells under tensile stress, focusing on cell survival, differentiation, and inflammatory responses, particularly relating to orthodontic tooth movement and root resorption. Cultured OCCM-30 cells under negative pressure received PBMT with a 10.6 μm wavelength in continuous mode at 1.0 W power for 3, 5, or 10 sec, corresponding to energy densities of 3, 5, or 10 J/cm. We assessed cell viability with the Presto Blue assay and inflammatory markers Interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) through western blots at 1, 12, 24 h, and 7 days post-irradiation. PBMT improved cell viability over time while maintaining levels of inflammatory markers. alkaline phosphatase levels dropped initially but increased after 7 days, suggesting enhanced cementoblast differentiation. IL-6 levels rose gradually, with 3J and 5J treatments showing significantly higher levels than the control. iNOS levels spiked within the first 24 h, then declined by day 7. COX-2 levels consistently rose, with the 5J treatment showing greater increases. PBMT appears to support cementoblast survival and differentiation while managing inflammation, potentially aiding root repair during orthodontic treatments and reducing inflammatory root resorption.
NIR Laser Irradiation Promotes Osteogenic Differentiation of PDLSCs Through the Activation of TRPV1 Channels and Subsequent Calcium Signaling
Zeng JH, Ma B, Shen XQ and Geng YM
Near-infrared (NIR) irradiation has shown potential to stimulate osteogenic differentiation, but the mechanisms are not fully understood. The study is to investigate the effects of NIR laser irradiation on osteoblastic differentiation. Human periodontal ligament stem cells (hPDLSCs) were cultured in osteogenic medium and exposed to 810 nm NIR laser at 0.5 J/cm every 48 h. The transient receptor potential vanilloid (TRPV1) channel inhibitor capsazepine (CPZ) was used to evaluate the role of calcium influx. Osteogenic differentiation was assessed by proliferation (CCK-8), alkaline phosphatase (ALP) activity, mineralization (Alizarin Red), and expression of bone markers by PCR and Western blot over 2 weeks. Intracellular calcium was measured by Fluo-4M dye and flow cytometry. Results showed that NIR irradiation enhanced hPDLSC proliferation, ALP activity, mineralization, and bone marker expression, indicating increased osteogenic differentiation. These effects were inhibited by CPZ. NIR induced a transient rise in intracellular calcium peaking at 3 min, which was blocked by CPZ. In conclusion, this study demonstrates that NIR laser irradiation promotes osteogenic differentiation of PDLSCs through the activation of TRPV1 channels and subsequent calcium signaling. Further research is warranted to optimize the treatment parameters and elucidate the detailed signaling pathways involved, paving the way for the clinical application of NIR therapy in the treatment of bone disorders and periodontal disease.
Comparative Investigation of Photobiomodulation in Diabetes-Impaired Alveolar Bone Healing: A Histomorphometrical and Molecular Study
Dalirsani Z, Davaji M, Salari Sedigh H, Hosseinian S, Ranjbar E, Yaqoubi A, Moghaddam KM and Shafieian R
Diabetes mellitus is increasing worldwide. Photobiomodulation (PBM) is proposed as a therapeutic method in various medical concerns. This study aimed to compare the effects of PBM at the wavelengths of 660, 808, or 660 + 808 nm on alveolar bone healing in diabetic rats. Bilateral maxillary first molars were extracted from diabetic Wistar rats ( = 36). Right-sided sockets were treated by an In-Ga-Al-P laser at 660 nm (7.2 J/cm, 24 s; DM660), Ga-Al-As laser at 808 nm (7 J/cm, 14 s; DM808), or a combination of these two sets (DM-dual) ( = 12). Left sides served as controls. On days 7 or 14, specimens were assigned for histomorphometric or real-time PCR analysis of runt-related transcription factor 2, osteocalcin, collagen I, and vascular endothelial growth factor expression. Irradiated sockets of groups DM-808 and DM-dual showed a significant increase in bone tissue and blood vessel establishment as compared to DM-660. Further, group DM-dual exhibited the least amount of fibrotic tissue as compared to the other groups. Within our study limits, the present experiment suggested PBM at 808 nm, alone or combined with 660 nm irradiation, could promote alveolar bone healing, along with minimal fibrosis induction, in diabetic rats.
The Effects of Photodynamic Therapy with Low-Level Diode Laser Compared with Doxorubicin on HT-29 Colorectal Adenocarcinoma Cells Viability
Zafari J, Omidi Sarajar B, Assar N, Moshaii A, Jafarzadeh E and Javani Jouni F
Colorectal adenocarcinoma is considered one of the major causes of cancer-related lethality among other type of malignancies. Given the several limitations and adverse outcomes of conventional therapeutic regimens against colorectal cancer, the focus of many investigations has been attributed to the introduction of a novel combined regimen with harmless agents. The purpose of the present study was to investigate the effect of combined doxorubicin (DOX) treatment and photodynamic therapy (PDT) on colorectal adenocarcinoma cells. HT-29 cells were exposed to different concentrations of DOX, low-level (630 nm) diode laser, and methylene blue (MB) as a photosensitizer substrate separately and a combination of them. The cytotoxic effect of the DOX, laser, MB, and their combination and the IC50 value for each treatment group were calculated by 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT). The malondialdehyde (MDA) content as a biomarker of the lipid peroxidation process and liberated lactate dehydrogenase (LDH) enzyme into supernatant was determined. The results of our study evidenced that a combination of photodynamic light (laser plus MB) and DOX caused a significant reduction in the percentage of HT-29 viable cells compared with control and other treatment groups. In addition, this mentioned combination led to a considerable decrease in IC50 of DOX. Increased cell membrane lipid peroxidation and cell destruction processes in the combination therapy group were proven through significant elevation of MDA content and LDH activity in the medium, respectively. The findings of the present study suggested that DOX combined with PDT had a better therapeutic impact on HT-29 colorectal adenocarcinoma cells. Hence, the simultaneous application of PDT along with antineoplastic drugs improves the chemosensitivity of cancerous cells via the disruption of their membrane and triggering death processes that lead to the decrease of chemotherapeutic agents required doses and undesirable effects.
Photobiomodulation in Burn Wounds: A Systematic Review and Meta-Analysis of Clinical and Preclinical Studies
Pradal LA, de Freitas E, Azevedo MRB, Costa R and Bertolini GRF
This systematic review and meta-analysis main goal was to evaluate the efficacy of photobiomodulation as burn wounds treatment. Systematic review of literature available in databases such as PubMed, Web of Science, Embase, Latin American and Caribbean Health Sciences Literature (LILACS), and The Cumulative Index to Nursing and Allied Health Literature (CINAHL) and gray literature in Google Scholar, Livivi, and Open Gray. SYRCLE's RoB tool was applied to determine methodological quality and risk of bias, and meta-analysis was performed using the software Review Manager. Fifty-one studies, gathering more than three thousand animals were included in this systematic review, and four studies were selected to the meta-analysis due to their suitability. The results indicated that photobiomodulation was not effective to improve, statistical significantly, wound retraction (SMD = -0.22; 95% CI = -4.19, 3.75; = 0.91; = 92%) or collagen deposition (SMD = -0.02; 95% CI = -2.17, 2.13; = 0.99; = 78%). This meta-analysis suggests that photobiomodulation, applied in burn wounds, accordingly to the protocols presented by the selected studies, was not effective over analyzed outcomes. However, this conclusion could be further discussed and verified in more homogeneous animal models and human clinical trials.
Modified Hybrid Hydroxyapatite-Silver Nanoparticles Activated via a Blue Light Source in Various Concentrations in Two-Step Self-Etch Adhesive to Caries-Affected Primary Dentin
Bin Abbooud AlQhtani FA, Abdullah Kamran M, Sainudeen S, Albalawi M, Hani Murad M, Kamal Abdelrahim R, Gaafar SS, Ayman Alkhateeb F and Niazi FH
To evaluate hydroxyapatite-silver (HA-Ag) hybrid nanoparticles (NPs), as an antibacterial agent when integrated in self-etch (SE) adhesive. Blue light activated HA-Ag hybrid NP incorporation on mechanical properties, degree of conversion (DC), and microtensile bond strength (μTBS). Eighty primary molar teeth have carious lesions reaching the dentin but not involving the pulp. The infected dentin was removed and carious-affected dentin (CAD) was preserved. Forty samples were inoculated with . All primary teeth ( = 80) were allocated into four groups based on the incorporation of HA-Ag hybrid NPs in different concentrations (0%, 1%, 5%, and 10%). Group 1: 0% HA-Ag hybrid NPs + Clearfil SE bond primer, group 2: 1% HA-Ag hybrid NPs + Clearfil SE bond primer, group 3: 5 wt% HA-Ag NPs + Clearfil SE bond primer, and group 4: 10 wt% HA-Ag NPs + Clearfil SE bond primer. The survival rate assessment of was conducted on 40 inoculated samples. On the remaining primary teeth ( = 40), Clearfil SE bonding agent was applied uniformly via a blue light source. The composite buildup was performed on the samples and μTBS and failure analysis assessed. Fourier transform infrared spectroscopy was performed to assess DC. Survival rates of and μTBS among the tested groups were compared using ANOVA and Tukey post hoc analysis. 10 wt % HA-Ag NPs + Clearfil SE bond primer exhibited the highest level of antibacterial efficacy (0.14 ± 0.02 CFU/mL) against . The highest μTBS (18.38 ± 0.78 MPa) at the composite/CAD interface was in group 2 (1 wt % HA-Ag NPs + Clearfil SE bond primer + Clearfil SE bonding agent + activation with a blue light source). The highest DC was observed in the control group with Clearfil SE bond primer + Clearfil SE bonding agent + activation with a blue light source. 1 wt% HA-Ag hybrid NPs showed enhanced antibacterial effectiveness, DC, and bond strength of the SE adhesive to the primary CAD.
High-Precision Implant Cavity Fabrication Using Femtosecond Lasers
Chen W, Yuan F, Zhang Z, Yan L, Li X and Shi X
This study aims to enhance the precision of implant cavity preparation, addressing a notable challenge in the current state of the field by utilizing femtosecond lasers. The application of femtosecond lasers in implant cavity preparation heralds a noninvasive and efficient technique, characterized by diminished thermal damage and high biocompatibility. Despite these promising attributes, the realization of precise cavity preparation remains a significant challenge in the contemporary domain. Our research group devised a specialized femtosecond laser microsurgery robotic system tailored for sophisticated implant cavity preparation. This system facilitated the meticulous analysis of sheep shank bone samples, enabling precise three-dimensional cutting. The analysis included an extensive examination of ablation effects, using a laser scanning microscope and VK Analyzer software. This investigation spanned the phases of laser flux calibration and experimental validation, offering a critical evaluation of the automated preparation process. The study delineated that at the focus position of our custom-made oral clinical femtosecond laser microsurgery robotic system, the laser spot diameter is 75.69 μm, and ascertained the ablation threshold for sheep shank cortical bone to be 1.47 J/cm. Utilizing low laser flux with minimal ablation craters overlap compromised the sidewall precision of the implant cavity, whereas employing high laser flux with extensive ablation craters overlap resulted in an enlarged ablation angle. At a laser energy setting of 2.2362 J/cm and a 50% ablation crater overlap, an implant cavity was successfully crafted featuring a top diameter of 4.41 mm, a bottom diameter of 3.98 mm, and a depth of 3 mm, devoid of any adverse thermal effects such as cracking or carbonization. The oral clinical femtosecond laser microsurgery robotic system can achieve automated and precise implant cavity preparation. This advancement promotes the broader application of femtosecond lasers in the field of orthopedics.