Diode Laser Irradiation Research Articles

Investigating the Effect of Incident Intensity on Single-junction GaAs PV Cells Conversion Efficiency at Different Temperatures

Abstract Laser Power Transmission (LPT) is emerging as a highly promising method for wireless energy transfer, particularly for extending the operational endurance of small unmanned aerial vehicles (UAVs) and supporting the construction of space-based solar power stations. This study investigated the optimal operational parameters of single-junction gallium arsenide
(GaAs) photovoltaic (PV) cells under laser diode (LD) irradiation to enhance the efficiency of
LPT systems. A detailed theoretical analysis was conducted to examine the effects of incident light intensity and spot size on the photoelectric conversion efficiency of GaAs PV cells across different temperature ranges. Experimental results demonstrated that the optimal efficiency of the photovoltaic cell is associated with a rise in incident intensity from 0.35
W/cm² to 0.65 W/cm² as the temperature decreases from 55°C to 5°C, that higher incident intensities are required for optimal efficiency when PV cells operate at lower temperatures, and the 2cm photovoltaic cell can attain a conversion efficiency exceeding 50% only when exposed to a 2cm incident light spot, that high efficiency in photovoltaic cells is attainable solely when the size of the incident light spot is as closely matched to the cell's size as possible. Additionally, this study provides an in-depth discussion of factors limiting photoelectric conversion efficiency and the underlying mechanisms at various temperature conditions.

The effect of diode laser on the shear bond strength of one step self adhesive systems to human dentin: An in vitro study

Adhesives are integral to modern restorative dentistry for enhanced functional and esthetic outcomes. The use of lasers for improved bonding is on the rise and there is a need to understand the effect of lasers on adhesives. The study aims to evaluate the effect of diode laser irradiation on one-step self-etch adhesive before their polymerization on the shear bond strength between resin cement and dentin. Thirty extracted human teeth were collected and the buccal surface was grounded till dentin was exposed. A window of 3mm x 3mm was made on all the specimens that served as test sites and were randomly allocated to three groups (n = 10); Group 1: G-Premio bond without laser irradiation followed by photopolymerization; Group 2: G-Premio bond with laser irradiation without photopolymerization, and Group 3: G-Premio bond with laser irradiation followed by photopolymerization. The Shear Bond Strength (SBS) was determined using a Universal Testing Machine. One-way ANOVA followed by post hoc Tukey test was used with a level of significance at P ≤ 0.05. SBS was significantly highest among Group 3 followed by Group 1 and the least SBS was found in Group 2 (P < 0.001). A post hoc test revealed significant differences between all three groups (P < 0.001). G-Premio bond irradiated with a diode laser followed by photo-polymerization exhibited the highest SBS.

Effect of diode laser (980 nm) on IL-8 expression in failed endodontic cases: Randomised control trial.

This clinical study assessed the effectiveness of diode laser-980 nm as adjuvant in retreatment of failed endodontic cases with chronic periapical lesions on basis of IL-8 expression and postoperative pain when compared to placebo. For 28 patients, the pre-instrumentation periapical samples (S1) were gathered, following retreatment. After chemo-mechanical preparation, post-instrumentation samples (S2) were collected. Patients were allocated to diode laser (DL) or placebo (PL) groups. After which post-irradiation samples (S3) were gathered. Patients recorded their pain on NRS scale at 6, 12, 24 and 7 days. After 1 week, samples (S4) were collected. An ELISA kit was used to measure an amount of IL-8. DL group showed significantly lower IL-8 levels at S4 (p < 0.001) and postoperative pain at 6 h (p = 0.003) compared to PL. Intracanal diode laser irradiation is a beneficial adjunct to endodontics, in retreatment cases regarding reducing postoperative pain and lowering the level of IL-8 expression.

Reduction of Streptococcus salivarius by Chlorella-Mediated Antimicrobial Photodynamic Therapy.

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.

Effect of photobiomodulation and corticopuncture methods on tooth displacement and gene expression: animal study.

The aim of this study was to evaluate the expression levels of vascular endothelial growth factor (VEGF), Peroxiredoxin 1 (PRX1), glucose transporter 1 (GLUT1) and type I collagen (COL1) and the rate of tooth movement comparing 3 accelerated tooth movement (ATM) methods: Corticopuncture (CP), photobiomodulation (PBM) and the combined technique (CP + PBM) on days 1, 3, 7 and 14. Orthodontic tooth movement was induced in 24 male Wistar rats. CP procedure included three perforations: two in the palate and one mesial to the molars. GaAlAs diode laser irradiation was performed on days 0, 2, 4 and 6, totaling 4 irradiations. 14 days (810nm, 100 mW, 15s). Gingival tissue was collected from the cervical area of both first molars and qPCR was performed to isolate and quantify mRNA levels. All ATM groups showed increased tooth displacement compared to control after 14 days (20% for PBM; 40% for CP and 60% for CP + PBM). PBM showed higher VEGF expression on days 1,3 and 7 followed by CP and CP + PBM. PRX1 levels increased on days 1 and 3 in PBM and CP + PBM. GLUT1 increased on day 3 in all groups. No difference was found on levels of VEGF, PRX1 and GLUT1 among the groups on day 14, except for COL1 which increased significantly in PBM group. All ATM methods showed higher expression of all of VEGF, PRX1, GLUT1, COL1 than control group. PBM and CP + PBM groups had more expression related to angiogenesis, glucose uptake, oxidative stress and collagen synthesis.

The efficacy of infrared diode laser in enhancing the regenerative potential of human periodontal ligament stem cells (hPDLSCs)

BackgroundThe present study aimed to investigate the effects of infrared diode laser irradiation on the proliferation and differentiation capacity of periodontal ligament stem cells (hPDLSCs), which are optimal cell sources for periodontal regeneration.MethodshPDLSCs were isolated and characterized by flow cytometric analysis of mesenchymal stem cell markers, and their trilineage differentiation capacity was tested. hPDLSCs were then cultured and irradiated with infrared diode laser (970 nm) at a power of 200 mW and a fluence of 4 J/cm2 for 3 s. MTT assay was performed to assess cellular proliferation. Cell cycle analysis was performed, and the impact of infrared diode laser irradiation on the stemness and osteogenic differentiation potential of hPDLSCs was evaluated via RT‒PCR.ResultsInfrared diode laser application enhanced the stemness, viability, proliferation, and differentiation of PDLSCs. Stem cell markers (OCT4, SOX2, and NANOG) were significantly upregulated in hPDLSCs exposed to laser irradiation. There was significant overexpression of RUNX2, ALP, OPN, and OCN on day 14 after laser application.ConclusionsThese findings provide valuable insights into the specific applications of infrared diode lasers to effectively regenerate periodontal tissues. The results can aid in the development of precise clinical protocols aimed at enhancing osseointegration and promoting tissue regeneration. Ultimately, the combination of infrared diode laser with hPDLSCs is promising for stimulating periodontal regeneration.

Metallic-based phthalocyanine nanoemulsions for photodynamic purging of ovarian tissue in leukemia patients

For cancer patients with a high risk of ovarian tissue metastasis, ovarian autotransplantation is not advised due to the potential spread of malignant cells. Ex vivo purging of ovarian fragments may offer a more suitable alternative for fertility restoration. Eradicating malignant cells should be done selectively without affecting follicles or ovarian stromal cells (SCs). As a clinically licensed method, photodynamic therapy (PDT) is a minimally invasive treatment to destroy cancer cells. This study evaluates the effectiveness of nanoemulsions (NE) containing two phthalocyanine photosensitizers; aluminum (III) phthalocyanine (AlPc) and zinc (II) phthalocyanine (ZnPc) in eliminating cancer cells. Human leukemic malignant (HL-60) and ovarian stromal cells (SCs) were treated with AlPc/ZnPc loaded NEs with or without diode laser irradiation. HL-60 leukemia cells in 2D culture were eliminated by treatment with 10 nM AlPc-NE or 0.1 µM ZnPc-NE, while no toxicity was observed in SCs. In 3D culture models, although the cells showed more resistance to the NEs as a result of limited oxygen and photosensitizer penetration, the treatment remained selective for cancer cells. These approaches have the potential to eliminate malignant cells from ovarian tissue fragments.

Diode Laser Irradiation Effects on Physical Properties of Titanium Dioxide Nano Fillers Doped Polyvinyl Alcohol Films

Study effect of diode laser (wavelength 650 nm) irradiation for different irradiant times (0.25, 0.5, 1.00, 3.00, and 4.00 hrs) on the physical properties of titanium dioxide (TiO2) possess particle size of 15.7 nm doped polyvinyl alcohol (PVA) films were experimentally investigated. The solution casting process has been utilized to create as-prepared TiO2/PVA nanocomposite films. Ultraviolet-Visible (UV-Vis) spectroscopy investigates the samples' optical characteristics by analyzing optical absorption spectra in a wavelength range of (200 - 900 nm) at room temperature (RT) of 300 K. The PVA matrix could be used to describe the influence. All optical constants produced artificially through laser radiation, like absorption, refraction index, extinction coefficient and complex dielectric constants, have decreased with increasing radiation times. On the contrary of optical energy gap they increased with increasing radiation times, according to the study's findings. TiO2 Nanoparticles (NPs) additions significantly impacted the PVA host's optical characteristics. When FTIR-spectrum regarding the TiO2/PVA nanocomposite films was examined in various ratios of irradiation times, the peak positions or bonds did not change; instead, they became smaller or larger as the irradiation time increased.

Comparison of the antimicrobial reduction effect of photodynamic inactivation with the addition of chlorophyll and curcumin photosensitizer in Aggregatibacter actinomycetemcomitans and Enterococcus faecalis

Background Aggregatibacter actinomycetemcomitans and Enterococcus faecalis are pathogenic bacteria of the oral cavity that cause various diseases such as periodontitis and endodontics. These bacteria are easily resistant to antibiotics. Photodynamic inactivation (PDI) is a method of inactivating microorganisms that utilizes light to activate a photosensitizer agent (PS) that produces reactive oxygen species causing cell lysis. Methods This study used the PDI method with a 405 nm diode laser at various energy density with the addition PS curcumin or chlorophyll Alfalfa, as much as 1.6 mg/ml on A. actinomycetemcomitans and E. faecalis bacteria. Results The study on E. faecalis bacteria showed that the energy density diode laser irradiation of 1.59 J/cm² gave the percentage of E. faecalis bacteria death 36.7% without PS, 69.30% with the addition of chlorophyll Medicago sativa L and 89.42% with the addition of curcumin. Meanwhile, the bacteria A. actinomycetemcomitans showed that the energy density diode laser irradiation of 1.59 J/cm² gave the percentage of bacterial death 35.81% without PS, 64.39% with the addition of chlorophyll Medicago sativa L and 89.82% with the addition of curcumin. PS was critical to the success of the PDI. Conclusions The addition of PS curcumin increased the effectiveness of reducing bacteria E. faecalis and A. actinomycetemcomitans compared to chlorophyll Medicago sativa L.

Biocompatibility and enamel remineralization potential of titanium-doped phosphate glasses with/without diode laser irradiation

This study investigates the biocompatibility and enamel remineralization potential of titanium-doped phosphate glasses (TDPG), third-generation materials with promising applications in dentistry. The biocompatibility of TDPG paste and its components (TDPG powder and polyacrylic acid liquid) was assessed using human gingival fibroblast cells (hGF) and human dental pulp stem cells (hDPSC). Cell attachment and viability were examined at 1, 3, and 7 days, and the results were compared with Nupro® Prophy paste and Teethmate, commonly used desensitizers, and positive control cells grown in normal tissue culture medium. Furthermore, the remineralization potential of these glasses with or without the use of diode laser irradiation on white spot lesions in enamel was explored at 12- and 21-days using Raman Spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). The remineralization potential of TDPG was compared with Nupro® Prophy paste and Teethmate. Furthermore, both sound and demineralized enamel were also used as other controls.Results indicated that cells exposed to TDPG extracts displayed similar morphology and viability to positive control cells. While all tested pastes did not show remineralizing action after 12 days, Nupro® Prophy and Teethmate exhibited such action after 21 days. However, laser application enhanced remineralization potential for all pastes at both time points, with TDPG showing comparable results to Nupro® Prophy paste and significantly higher potential than Teethmate when used with laser at 21 days.In summary, this study reveals the biocompatibility and enhanced remineralization potential of TDPG when combined with diode laser irradiation. These findings signify innovative strides in dental materials and treatment modalities, offering new possibilities for advanced dental applications.

Photothermal Effect of 970 nm Diode Laser Irradiation on Enterococcus faecalis Biofilms in Single-Rooted Teeth Ex Vivo.

Objective: The aim of this study was to evaluate the photothermal effect of a 970 nm diode laser on Enterococcus faecalis biofilms. Methods: 72 extracted human single-rooted teeth were prepared, sterilized, and inoculated with Enterococcus faecalis to establish a two-week-old biofilm. The specimens were divided into six groups (n = 12): Group 1 (G1)-negative control (PBS-no laser), Group 2 (G2)-positive control (1% NaOCl rinse-no laser), Group 3 (G3)-a 970 nm laser in 1.5 W pulse mode, Group 4 (G4)-a 970 nm laser in 2 W pulse mode, Group 5 (G5)-a 970 nm laser in 1.5 W continuous mode, Group 6 (G6)-a 970 nm laser in 2 W continuous mode. Bacterial viability was evaluated using the LIVE/DEAD BacLight kit and analyzed by flow cytometry (FCM). Temperature changes on the root surface during irradiation were analyzed using a K-type thermocouple. Data were statistically analyzed using one-way ANOVA and Tukey's multiple comparison test (α = 0.05). Results: Bacterial viability was significantly reduced after laser irradiation in continuous mode using 1.5 W (21% of live bacteria) and 2 W (14% of live bacteria). When the pulsed mode was applied, the reduction in bacterial viability was less, with a mean survival of 53% (1.5 PF, whereas 29% of bacteria survived after 2 W irradiation). Conclusions: The 970 nm diode laser at 2 W continuous mode effectively reduced the viability of E. faecalis biofilms in root canals without causing unacceptable temperature rises at the root surface.

The impact of 980nm diode laser irradiation on the proliferation of mesenchymal stem cells derived from the umbilical cord's

Various cell types can have their growth accelerated by using low-intensity laser radiation. The study is intended to look at the impacts of laser radiation at low energy intensity on the ability of mesenchymal stem cells (MSCs) generated from umbilical cords to proliferate as well as survive in low-nutrient conditions. The study applied two different energy densities, 2.5 j/cm2 and 5 j/cm2, using a 980 nm diode laser radiation. This allowed for the observation of the effects of these specific elements on the behavior of the cells in a controlled environment at various concentrations of fetal bovine (7.5 %, 10 %, 12.5 %, and 15 %). The cells were grown in a medium lacking in nutrients and were enriched with varying quantities of serum from fetal bovines. The MTT test was used to evaluate the mitochondrial activity of the cell. Following 72 hours, it was shown that cells treated with 2.5 j/cm2 and 10 % fetal bovine serum had significantly higher MTT test activity than cells treated with 5 j/cm2.The results of this study show that even in the presence of dietary deficiencies, low-intensity laser radiation therapy can stimulate the growth of mesenchymal stem cells isolated from umbilical cords.

The elicitation effects of diode and He-Ne laser irradiations on the alleviation of nutrient-deficiency induced damage in anthocyanin-producing red-fleshed apple cell suspension

Purpose We explored the elicitation role of the laser irradiations on the alleviation of nutrient-deficiency induced damage in anthocyanin-producing red-fleshed apple cell suspension in continuous production of anthocyanin. Methods Anthocyanin-producing red-fleshed apple cells were irradiated by 4 intensity levels of red He-Ne (RHNL) and blue diode (BDL) lasers for 20 min. Results Nutrient deficiency indicated negative effect on total soluble proteins (TSP), superoxidase dismutase (SOD) activity, and total phenolics content (TPC) while it displayed a positive effect on malondialdehyde (MDA), total flavonoids content (TFC), O2 -, H2O2 - , and lipoxygenase (LOX) and polyphenol oxidase (PPO) activities in light controls, illustrating oxidative stress. The laser irradiations on suspension cells indicated variable effects on measured parameters and were time of growth-, levels of intensity-, and laser type-dependent. Likewise, the elicitation effects of lasers relied on a critical threshold among ROS generation and antioxidative system which determines the fate of cells against oxidative stress. The same trend was displayed by RHNL at 6.46 mWcm−2 intensity and BDL at 13.73 mWcm−2. These intensities resulted in a significant increase in SOD, APX, POD, and CAT activities and TSP, TPC, TFC, proline, and glycine betaine accumulation, while induced decrease in LOX, and PPO activities and MDA, and ROS generation, alleviating cellular injury from prolonged nutrient deficiency by diminishing lipid peroxidation and oxidative damages of cell membrane. Conclusion Results suggested that lasers application on mitigating nutrient deficiency stress relied on establishing a suitable balance between ROS generation and antioxidative system, which enables the nutrient-starved anthocyanin-producing cells to continuously produce anthocyanin.

The Effect of Cold Plasma and Low-Level Laser Therapy on Oral Fibroblast Proliferation

Background: Wound healing is a complex physiological process involving multiple phases and cellular mechanisms that restore damaged tissue. The oral cavity presents unique challenges for wound healing due to the presence of microorganisms and the impact of various diseases and treatments. Recent advancements, including low-level laser therapy (LLLT) and cold plasma, offer promising approaches to enhance wound healing by promoting cell proliferation and reducing inflammation. This study aimed to investigate the effects of cold plasma and low-level 980nm laser on the growth of oral fibroblasts and compare their respective impacts on wound healing. Methods: Human gingival fibroblasts were divided into nine study groups, including a control group. Two groups were exposed to low-level 980nm diode laser irradiation for 15 and 30 seconds, while six groups received cold plasma irradiation with helium gas at flow rates of 1.85, 2.78 and 5.56 cm3/s for the same durations. Fibroblast proliferation was evaluated on days 1, 3, and 5 after treatment using the MTT assay. Results: The results showed that on the 5th day after irradiation, 30 seconds of 980 nm laser irradiation significantly increased fibroblast proliferation compared to the other groups. In contrast, 15 seconds of plasma irradiation at a flow rate of 1.85 cm3/s had the least effect on promoting fibroblast proliferation. On the 1st day after radiation, plasma irradiation at flow rates of 2.78 and 5.56 cm3/s exhibited a greater impact on fibroblast proliferation compared to the other five test groups. Conclusion: The 980nm diode laser demonstrated a greater capacity to enhance the proliferation of oral fibroblasts compared to cold plasma using helium gas.

Surface and Mineral Changes of Primary Enamel after Laser Diode Irradiation and Application of Remineralization Agents: A Comparative In Vitro Study.

The purpose of this study is to evaluate the remineralization potential of primary teeth enamel after being exposed to different laser diode therapies. Ninety-six vestibular primary teeth enamel samples were divided into eight groups (n = 12) with varying treatments: control (G1), CPP-ACP-fluoride varnish (G2), diode lasers at 980 nm (G3), 808 nm (G4), 450 nm (G5), 980 nm + CPP-ACP-fluoride varnish (G6), 808 nm + CPP-ACP-fluoride varnish (G7), and 450 nm + CPP-ACP-fluoride varnish (G8). Each sample was assessed using a DIAGNOdent® (KaVo Dental, Biberach, Germany), at baseline, post-treatment, and post-pH cycle remineralization. SEM imaging was performed before and after treatment and following the pH cycle. The results indicated that the 980 nm and 808 nm diode lasers, both alone and in combination with CPP-ACP-fluoride varnish, either maintained or increased the calcium (Ca) weight percentage (Wt%) in the enamel. The 980 nm diode laser combined with CPP-ACP-fluoride varnish (G6) showed a significant increase in Ca Wt%, suggesting a strong remineralization effect. Similarly, the 808 nm diode laser alone (G4) also promoted a substantial increase in Ca Wt%. In contrast, the 450 nm diode laser, whether applied alone or in combination with CPP-ACP-fluoride varnish, resulted in a lower Ca Wt% and an increase in phosphorus (P) Wt%. Most groups, except for the CPP-ACP-fluoride varnish alone (G2), demonstrated an increase in P Wt%, indicating a complex interaction between laser therapy and enamel remineralization. The combined use of laser therapy with CPP-ACP-fluoride varnish significantly enhanced the remineralization of temporary teeth enamel. The 980 nm diode laser + CPP-ACP-fluoride varnish showed the most pronounced improvement in remineralization, while the 808 nm diode laser alone also effectively increased calcium solubility. These findings suggest that higher-wavelength diode lasers, particularly when combined with remineralizing agents, can effectively enhance the mineral content of primary teeth and promote enamel remineralization.

Near-infrared laser diode mitigates Aβ1–42-induced neurodegeneration in cortical neurons

Alzheimer's disease, a prevalent neurodegenerative condition primarily affecting older adults, remains incurable. Its principle pathological hallmark is the accelerated accumulation of amyloid β (Aβ) protein. This study investigates the potential of photobiomodulation using near infrared light to counteract Aβ1–42-induced synaptic degeneration and neurotoxicity. We focused on the effect of 808 nm near-infrared laser diode (LD) on Aβ1–42 cytotoxicity in primary cultured cortical neurons. We assessed cell survival using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, observing substantial benefits from LD irradiation with a power of 10 mW and a dose of 30 J. Cells exposed to Aβ1–42 exhibited morphological changes indicative of synaptic damage and a significant decrease in the number of postsynaptic density protein-95 (PSD-95) contacts, which were significantly improved with near-infrared LD therapy. Furthermore, this therapy reduced Aβ and phosphorylated tau (P-tau) protein accumulation. Additionally, near-infrared LD irradiation substantially lessened the Aβ1–42–induced rise in glial fibrillary acid protein (GFAP) and ionized calcium-binding adaptor molecule 1 (IBA1) in astrocytes and microglia. Remarkably, near-infrared LD irradiation effectively inhibited phosphorylation of key proteins involved in Aβ1–42-induced necroptosis, namely Receptor-interacting protein kinase-3 (RIP3) and Mixed Lineage Kinase domain-Like protein (MLKL). Our findings suggest that near-infrared LD treatment significantly reduces neurodegeneration by reducing glial overactivation and neuronal necroptosis triggered by Aβ1–42. Thus, near-infrared LD treatment emerges as a promising approach for slowing or treating Alzheimer's disease, offering new avenues in its management.

Protecting celtuce (Lactuca sativa L. var. augustana) slices against storage-induced oxidative stress and discoloration by using diode laser exposure

Diode laser irradiation is a novel approach applied to preserve the quality of fresh commodities and minimise oxidative processes, including browning in fresh-cut products. The objective of this study was to investigate the efficacy of diode laser treatment in enhancing the quality of celtuce slices during refrigerated storage at 4 °C. The celtuce slices were subjected to a 660 or 450 nm diode laser for 5 min and then stored for 10 d. Both laser treatments hindered the progression of weight loss and firmness increase in the celtuce slices. The use of a 450 nm diode laser effectively prevented the development of browning and preserved the surface colour by inhibiting the increase in a* and overall colour difference values, as compared to other treatments, during storage for 10 d. The diode laser treatment suppressed the increase in oxidative stress by lowering the levels of MDA, H2O2, and O-2 while retaining a high level of DPPH scavenging activity, AsA, and antioxdant enzyme activities, including SOD, CAT, APX, and GR, in comparison to the untreated slices. The treatment enhanced chlorophylls content due to the up-regulation of LsHEMA1 gene and down-regulation of LsNYC1 gene. The treatment also inhibited factors involving enzymatic browning reaction by suppressing PAL activity, total phenols content, PPO activity and LsPPO gene expression. These suggest that the blue diode laser exposure at 450 nm for 5 min is an effective approach hindering oxidative stress and discoloration of celtuce slices during storage.

Influence of diode laser irradiation on microtensile bond strength of etch-and-rinse adhesive to dentin using two different etchants: An in vitro study

Aim: The aim of this study was to evaluate the influence of 970 nm diode laser (DL) irradiation on the microtensile bond strength (µTBS) of etch-and-rinse adhesive (ERA) to dentin using phosphoric acid (PA) or alpha-hydroxy glycolic acid (GA) as etchants. Materials and Methods: A total of 32 human third molars were selected and assigned randomly among two different groups and four subgroups based on etching protocols and DL irradiation: PA, PA-DL, GA, and GA-DL. After tooth preparation and subsequent incremental composite build-up, the samples were stored in distilled water for 24 h at 37°C. µTBS values were obtained using the universal testing machine. The failure modes observed in dentin were categorized as adhesive, cohesive within dentin/resin, or mixed. Statistical Analysis: The data were analyzed using one-way analysis of variance, followed by Tukey’s post hoc test (P ≤ 0.001). Results: GA showed better or similar bond strength values to PA. Furthermore, irradiation of DL increased the µTBS to dentin when both PA or GA are used as etchants. Conclusion: GA can be used as an alternative etchant to PA. DL irradiation stands as a promising approach for elevating the performance of ERA adhesive systems to dentin.

Effect of SDF Application versus Diode Laser Irradiation on Incipient Carious Lesion’s Progression in Primary Molars: A Randomize Clinical Trial

Effect of SDF Application versus Diode Laser Irradiation on Incipient Carious Lesion’s Progression in Primary Molars: A Randomize Clinical Trial

Efficacy of photobiomodulation following L-PRF application for recovery of mental nerve neurosensory disturbances caused by genioplasty: A randomized triple-blind clinical trial

The present study assessed the efficacy of photobiomodulation (PBM) following leukocyte-platelet rich fibrin (L-PRF) application for recovery of mental nerve neurosensory disturbances (NSDs) caused by genioplasty. This randomized triple-blind split-mouth clinical trial was conducted on 20 female patients (40 quadrants) requiring genioplasty. In each patient, one random side of the mandible served as the intervention (laser), and the other side as the control group. After genioplasty and L-PRF application, the intervention side underwent GaAIAs diode laser irradiation (880 nm, 500 mW, 15 J/cm2, 0.5 cm2 spot size, continuous-wave). Each point was laser irradiated for 15 s. Unilateral extraoral PBM was performed at 1, 3, 7, 14, 21, and 28 days, postoperatively. Laser in off mode (sham laser) was used for the control side. A visual analog scale (VAS) was used for general sensitivity, and 2-point discrimination, directional discrimination, pain discrimination, and thermal discrimination tests were used to assess the neurosensory recovery at 2 days, 2 weeks, 4 weeks, and 2 months, postoperatively. Statistical analyses were performed using two-way repeated measures ANOVA, Bonferroni test, and generalized estimating equation (alpha = 0.05). Time had a significant effect on improvement of all sensory variables (P < 0.05). Neurosensory recovery was significantly better in the intervention than the control group at all time points according to the two-point discrimination test (P = 0.0135) and brush test (P = 0.025) results. The interaction effect of time and intervention was not significant on any dependent variable (P > 0.05). Application of L-PRF + PBM resulted in significantly greater sensorineural recovery according to the two-point discrimination and brush test results.