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The purpose of this research was to investigate the effect of toluidine blue (TB) mediated photodynamic therapy (PDT) on the inhibition of lipopolysaccharide (LPS)-induced inflammation in rat gingival fibroblasts through in vitro experiments. Rat gingival fibroblasts were divided into five groups: (1) control, (2) LPS treatment, (3) laser treatment, (4) TB treatment (1.0 µg/mL), and (5) PDT treatment (TB plus laser irradiation at 320 mW/cm2 for 240 s). After 24 h, cell growth activity was measured using MTT assay. The levels of receptor activator for nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) in the cell culture supernatant were measured using enzyme-linked immunosorbent assay (ELISA). Nuclear proteins were extracted and the phosphorylation levels of phosphorylated nuclear factor-κB/p65 (p-p65) and phosphorylated inhibitor of nuclear factor-κB (p-IκBα) were determined using Western Blot. MTT results showed no significant difference in cell viability between the groups (P > 0.05). After LPS induction, OPG expression decreased, RANKL expression increased, and the OPG/RANKL ratio decreased, which was different from the control group (P < 0.05). After PDT treatment, OPG expression increased, RANKL expression decreased (P < 0.05), and the OPG/RANKL ratio increased (P < 0.05). Compared to the control group, there was no significant difference in OPG and RANKL expression or the OPG/RANKL ratio (P > 0.05). The activation of NF-κB was closely related to the phosphorylation levels of p-p65 and p-IκBα. LPS significantly up-regulated p-p65 and p-IκBα expression (P < 0.05), while PDT treatment decreased their phosphorylation levels (P < 0.05). TB-PDT treatment can inhibit NF-κB signaling pathway activation, decrease RANKL and OPG expression, and reduce the OPG/RANKL ratio, thereby reducing inflammation and playing a role in periodontitis treatment. [ABSTRACT FROM AUTHOR]

Background: This study aimed to examine the efficacy of methylene blue (MB) and toluidine blue O (TBO) photodynamic therapy (PDT) as adjuncts to root surface debridement (RSD). Methods: This split-mouth, randomized, controlled clinical trial included eighteen patients, and a total of 332 sites (control = 102, MB = 124 and TBO = 106) were examined. Two sessions of PDT were completed at baseline and two weeks after RSD. Clinical parameters of bleeding on probing (BOP), plaque index (PI), probing pocket depth (PPD), and clinical attachment level (CAL) were measured pre- and post-treatment. Results: PPD and BOP reductions in sites treated by RSD with adjunctive photosensitizers (MB and TBO) were significantly higher than in control sites. RSD with MB showed higher efficacy in improving moderately deep pockets (OR 3.350), while adjunctive TBO showed better results in treating deeper pockets (OR 4.643). Conclusions: Results suggested that adjunctive use of MB and TBO to RSD could significantly improve periodontal pocket closure and reduce signs of inflammation. In addition, TBO seems to be more efficient in treating deep periodontal pockets than MB, which is more effective in resolving shallower pockets. [ABSTRACT FROM AUTHOR]

Background: Chronic hyperplastic candidiasis (CHC) is a chronic oral mucosal infection caused by Candida, which has potential for malignant transformation. Diagnosing CHC can be challenging due to its various manifestations. In addition, fungal treatments often prove to be ineffective, highlighting the urgent need for a new safe and efficient treatment approach. Given the potential of CHC to transform into malignancy, it is crucial to emphasize dynamic monitoring and follow-up after treatment. Objective: We attempted to investigate the effect of semiconductor laser pretreatment combined with 5-amino-levulinic acid (5-ALA) photodynamic therapy (PDT) for CHC. Methods: We presented the successful treatment of CHC with mild dysplasia in a 30-year-old man using semiconductor laser and 5-ALA PDT after antifungal therapy proved ineffective. Toluidine blue staining, autofluorescence imaging, and DNA image cytometry were combined to dynamically monitor the progress of the disease. Results: We have obtained positive outcomes with the use of laser combined with PDT treatment. The patients experienced only mild adverse reactions after the treatment, and there was no indication of recurrence or malignant transformation during the subsequent follow-up period, as observed through various auxiliary examinations. Conclusions: This case report suggests that semiconductor laser surgery combined with PDT could be a promising treatment option for patients with CHC who do not respond to antifungal therapy. In addition, the use of combined noninvasive examinations might provide a more accurate assessment of malignant transformation in patients with CHC. [ABSTRACT FROM AUTHOR]

Introduction: Photodynamic Therapy has been an important ally in tissue repair, with positive effects in the treatment of wounds and infections. Objective: To analyze the effects of the Healing Acceleration Methodology (MAC®) using propolis and toluidine blue on lower limb ulcers. Methods: Single-center, experimental, randomized and controlled study. Carried out between April 2021 and May 2022 at the outpatient clinic of the school clinic in a Brazilian capital. Patients were randomly assigned in a 1:1 ratio to receive photodynamic therapy (experimental group) or conventional dressing alone (control group). Patients over 18 years of age diagnosed with lower limb ulcers were included. Ten patients comprised the experimental group and 10 the control group. Patients were seen three times a week and monitored for two months. The primary outcome was the assessment of healing progress and the secondary outcome was the microscopic analysis of wound smears for the presence of cells and microorganisms. Results: In the experimental group, two wounds did not heal completely while in the control group, none of the 10 wounds healed completely during the 60-day follow-up. In the experimental group, 90% of patients did not have bacteria and fungi at the end of 30 days versus 40% in the control group. Conclusion: The present study showed that photodynamic therapy is a potential effective treatment in the healing process of lower limb ulcers. This can impact cost reduction and quality of life. Larger, well-designed studies are needed to corroborate the findings of the present study. [ABSTRACT FROM AUTHOR]

The efficiency of antimicrobial photodynamic therapy (PDT) might be improved by using multiple wavelengths. This study investigates the sensitivity of implant-adherent biofilms of Staphylococcus aureus, Escherichia coli, and Candida albicans to indocyanine green (ICG)-808 nm diode laser, toluidine blue O (TBO)-635 nm diode laser, and hydrogen peroxide (HP)-980 nm diode laser and their combination when irradiated with dual-wavelength laser irradiation (simultaneously 980–635 nm or 980–808 nm). After an incubation period of 72 h, the infected implants were randomly divided into seven different treatment modalities: Control, HP, HP-PDT, TBO-PDT, HP-TBO-PDT, ICG-PDT, and HP-ICG-PDT. After the treatments, the colony-forming units (CFUs)/mL and reactive oxygen species (ROS) generation were determined. All evaluated disinfection methods were significantly effective against the three investigated bacteria compared to the control. The combined treatment of HP-ICG-PDT or HP-TBO-PDT had the greatest antibacterial effect compared to each treatment alone. There were statistical differences between HP-ICG-PDT and ICG-PDT or HP-TBO-PDT and TBO-PDT for all three bacteria studied. PDT with simultaneous dual-wavelength laser irradiation is an efficient strategy to improve the therapeutic effect of PDT. [ABSTRACT FROM AUTHOR]

In this article, the synthesis of a new hybrid compound, candidate as photothermal agent, is proposed, based on TDPP (3,6‐di(thiophene‐2‐yl)‐2,5‐dihydropyrrolo[3,4‐c]pyrrole‐1,4‐dione) and toluidine blue. Electronic structure calculations at the DFT, TD‐DFT and CCSD level of theories were performed to obtain ground and excited states molecular structures, photophysical properties and absorption spectrum of the hybrid and the starting compounds. Additionally, ADMET calculations were performed to predict the pharmacokinetic, metabolic and toxicity properties of the proposed compound. The results showed that the proposed compound is a strong candidate for photothermal agent since (1) it absorbs close to the near‐infrared region, (2) it has low fluorescence and intersystem crossing rate constants, (3) it has accessible conical intersection with low energy barrier, (4) the compound shows lower toxicity than the well know compound toluidine blue, which is used in photodynamic therapy, (5) the compound does not show carcinogenic potential, and (6) it obeys the Lipinski's rule of five, used as a reference for the design of new pharmaceuticals. [ABSTRACT FROM AUTHOR]

To evaluate the effect of the photodynamic therapy (PDT) using with different photosensitizers on the bond strength of BioRoot RCS (BR) to radicular dentin by comparing with AH Plus (AH). The shaped root canals of 80 human mandibular premolars were divided into four groups based on the final disinfection protocol: NaOCl/EDTA, PDT with methylene Blue (MB), PDT with curcumin (CUR) and PDT with toluidine blue O (TBO) (n = 20). Each group was randomly divided into two subgroups (n = 10), according to the endodontic sealer used for obturation (n = 10). The test of push‐out bond strength (PBS) was performed using an universal test machine. The data were analysed using ANOVA, Tukey post‐hoc, and independent sample t‐test (α = 0.05). MB‐BR group showed the highest PBS at the cervical level (p < 0.05). The selection of the photosensitizer in PDT influenced adhesion of root canal sealers to radicular dentin. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the efficacy of photodynamic therapy (PDT) using tolonium chloride and a 635 nm diode laser as an adjunct to non-surgical periodontitis treatment, specifically scaling and root planing (SRP) alone. A total of 32 patients with a pocket probing depth > 5 mm were included in the study. Among them, 16 patients underwent SRP alone (control group), and the remaining 16 patients received SRP along with PDT (study group). The PDT procedure utilized a 635 nm diode laser (Smart M, Lasotronix, Poland) and tolonium chloride. Clinical periodontal parameters, such as the plaque index (PI), bleeding on probing (BOP), gingival recession (GR), probing pocket depth (PPD), and clinical attachment loss (CAL), were assessed before treatment (T0) and at 3 months after treatment (T3). At T3, both groups demonstrated a significant reduction in the PI, BOP, PD, and CAL compared to T0. The SRP + PDT group displayed a significant reduction in PPD (3.79 mm ± 0.35) compared to the SRP alone group (4.85 mm ± 0.42) at T3. Furthermore, the SRP + PDT group exhibited a significant reduction in CAL (5.01 ± 0.81) compared to the SRP group (5.99 ± 1.08) at T3. Within the study's limitations, it was concluded that PDT, with tolonium chloride and a 635 nm diode laser, significantly contributed to the non-surgical treatment of periodontitis. [ABSTRACT FROM AUTHOR]

Background: Despite intensive research, the ideal protocol applied to maximize the overall benefits of antimicrobial photodynamic therapy (aPDT) remains unexplored. Evidence exists that following aPDT, the diffused light beyond the photosensitizer can exert a secondary therapeutic effect known as photobiomodulation (PBM), which stimulates the healing of the surrounding tissues. Therefore, the aim of this study was to examine the attenuation properties of five different photosensitizers activated by their corresponding laser wavelengths. Methods: The illumination of various concentrations of chosen photosensitizers, curcumin, methylene blue, toluidine blue, indocyanine green and a methylene blue derivative, irradiated by their respective laser wavelengths (445 nm, 635 nm, 660 nm and 808 nm) was explored via a spectrophotometric analysis. The onward transmitted light intensities for each combination of a photosensitizer and laser wavelength were assessed. The attenuation percentages observed were statistically evaluated using an analysis-of-variance (ANOVA) model. A Tukey's post hoc test was performed to determine the significance of differences between individual group mean values. Results: With the exception of toluidine blue illuminated by an 808 nm laser, which showed the lowest intensity loss, all the other photosensitizers presented an attenuation range of 63% to 99%. Conclusions: At appropriate concentrations, all the examined photosensitizers may allow the passage of sufficient wavelength-dependent light transmission. Calculated fluences are proposed to achieve secondary, beneficial PBM effects. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) provides an effective therapeutic option for different types of cancer in addition to surgery, radiation, and chemotherapy. The treatment outcome of PDT is largely determined by both the light and dark toxicity of photosensitizers (PSs), which can be technically improved with the assistance of a drug delivery system, especially the nanocarriers. Toluidine blue (TB) is a representative PS that demonstrates high PDT efficacy; however, its application is largely limited by the associated dark toxicity. Inspired by TB’s noncovalent binding with nucleic acids, in this study, we demonstrated that DNA nanogel (NG) could serve as an effective TB delivery vehicle to facilitate anticancer PDT. The DNA/TB NG was constructed by the simple self-assembly between TB and short DNA segments using cisplatin as a crosslinker. Compared with TB alone, DNA/TB NG displayed a controlled TB-releasing behavior, effective cellular uptake, and phototoxicity while reducing the dark toxicity in breast cancer cells MCF-7. This DNA/TB NG represented a promising strategy to improve TB-mediated PDT for cancer treatments.

Streptococcus mutans (S. mutans) and Candida albicans (C. albicans) are prominent microbes associated with rapid and aggressive caries. In the present study, we investigated the antimicrobial efficacy, cytotoxicity, and mechanism of toluidine blue O (TBO)-mediated antimicrobial photodynamic therapy (aPDT) and potassium iodide (KI). The dependence of KI concentration, TBO concentration and light dose on the antimicrobial effect of aPDT plus KI was determined. The cytotoxicity of TBO-mediated aPDT plus KI was analyzed by cell counting kit-8 (CCK-8) assay. A singlet oxygen (1O2) probe test, time-resolved 1O2 detection, and a 1O2 quencher experiment were performed to evaluate the role of 1O2 during aPDT plus KI. The generation of iodine and hydrogen peroxide (H2O2) were analyzed by an iodine starch test and Amplex red assay. The anti-biofilm effect of TBO-mediated aPDT plus KI was also evaluated by counting forming unit (CFU) assay. KI could potentiate TBO-mediated aPDT against S. mutans and C. albicans in planktonic and biofilm states, which was safe for human dental pulp cells. 1O2 measurement showed that KI could quench 1O2 signals, implicating that 1O2 may act as a principal mediator to oxidize excess iodide ions to form iodine and H2O2. KI could highly potentiate TBO-mediated aPDT in eradicating S. mutans and C. albicans due to the synergistic effect of molecular iodine and H2O2. [ABSTRACT FROM AUTHOR]

Antimicrobial photodynamic therapy (a-PDT) in combination with scaling root planing (SRP) is more effective at improving periodontal status than SRP alone. However, the effectiveness of a-PDT in combination with irrigation for patients undergoing periodontal maintenance has not been clarified. This study evaluated the efficacy and safety of a-PDT in the maintenance phase. Patients who had multiple sites with bleeding on probing (BOP) and periodontal probing depth (PPD) of 4–6 mm in the maintenance phase were treated with a split-mouth design. These sites were randomly assigned to one of two groups: the a-PDT group and the irrigation group. In the a-PDT group, the periodontal pockets were treated with light-sensitive toluidine blue and a light irradiator. In the irrigation group, the periodontal pockets were simply irrigated using an ultrasonic scaler. After 7 days, the safety and efficacy of a-PDT were assessed. The mean PPD of the a-PDT group had reduced from 4.50 mm to 4.13 mm, whereas negligible change was observed in the irrigation group. BOP significantly improved from 100% to 33% in the PDT group, whereas it hardly changed in the irrigation group. No adverse events were observed in any patients. a-PDT may be useful as a noninvasive treatment in the maintenance phase, especially in patients with relatively deep periodontal pocket. [ABSTRACT FROM AUTHOR]

Background: Photodynamic therapy is a two‐step procedure, involving the use of photosensitizing agents followed by selective illumination of the target lesion with visible light. Photodynamic therapy has been described recently as a promising strategy for treatment of leishmaniasis. This study aims to evaluate the in vitro phototoxic, morphological, and apoptotic effect of methylene blue, toluidine blue, chloro‐aluminum phthalocyanine, and pheophorbide a‐mediated photodynamic therapy on the viability of Leishmania tropica promastigotes. Methods: Parasites were treated with methylene blue, toluidine blue, chloro‐aluminum phthalocyanine, and pheophorbide a or/and methylene blue, toluidine blue, chloro‐aluminum phthalocyanine, and pheophorbide a‐mediated photodynamic therapy, and cell proliferation, morphological changes, and apoptosis were evaluated by XTT, giemsa staining, DAPI staining, and DNA fragmentation, respectively. Results: Parasite viability was significantly different in between the groups treated with methylene blue, toluidine blue, and pheophorbide a, with or without irradiation. chloro‐aluminum phthalocyanine treatment did not lead to any alterations in cell viability in Leishmania tropica promastigotes with or without irradiation. DAPI staining results indicated that apoptotic bodies and nucleus fragmentation started to be visible in methylene blue, chloro‐aluminum phthalocyanine, and pheophorbide a‐mediated photodynamic therapy groups. DNA ladder pattern which is used to define apoptosis was observed in irradiated methylene blue, chloro‐aluminum phthalocyanine, and pheophorbide a groups. Conclusions: The results revealed that apoptosis‐induced cell death was observed in Leishmania tropica promastigotes after the application of photosensitizers in combination with light irradiation. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the effect of dyes used in photodynamic therapy (PDT) on color changes of resin-based composites (RBCs). Methods: A total of 120 composite discs were made of microfilled, nanohybrid, and nanoceramic RBCs, and the CIE Lab system was used to assess initial colors with a spectrophotometer. Photosensitizers were used in accordance with the experimental design, as follows: MB (methylene blue), TB (toluidine blue), ICG (indocyanine green), and control (no dye). The samples were irradiated with a 940-nm diode laser. After irradiation, the photosensitizers were removed with distilled water (ΔE1) and sodium hypochlorite (ΔE2), and final colors were measured. Data were analyzed by the three-way ANOVA and Bonferroni tests (a = 0.05). Results: There was no statistically significant difference between the ICG and control groups; however, the TB and MB groups exhibited the strongest staining. The nanohybrid RBC exhibited the greatest color change, and there were no significant differences between the microhybrid and nanoceramic RBCs. After NaOCl irrigation, ΔE2 values decreased to clinically acceptable values (ΔE2 < 3.3). Conclusion: The intensity of staining of the RBCs differed according to the type of photosensitizer used and the content of the composite resin. The irrigant NaOCl was effective in removing discoloration. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is an effective method for bacterial infection control in root canals of teeth with a broad-spectrum antibacterial activity. However, its application in root canal treatment is limited due to its inefficiency under hypoxic conditions and dentin staining. Triton X-100 (TX) shows great potential in enhancing the efficiency of antimicrobial agents through improving bacterial membrane permeability. The present study employed a combination of toluidine blue O (TB)-mediated PDT with TX to target the Enterococcus faecalis (E. faecalis), a bacterium with strong resistance to various antibacterial agents and mostly detected in infected root canals. PDT combined with TX showed enhanced antibacterial efficiency against both planktonic cells and biofilms of E. faecalis. At the same time, TX enhanced the antibacterial effect in dentinal tubules and reduced the incubation time. Mechanism studies revealed that TX improved reactive oxygen species (ROS) production through increasing the proportion of TB monomers. Additionally, increased membrane permeability and wettability were also observed. The findings demonstrated the PDT combined with TX could be used as a highly effective method for the root canal disinfection of teeth. [Display omitted] • Triton X-100 (TX) enhanced the antibacterial effect of photodynamic therapy. • TX enhanced the degradation of extracellular polymer substances of E. faecalis biofilms. • TX increased the wettability of photosensitizer and permeability of E. faecalis cells. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study is to evaluate the influence of the antimicrobial photodynamic therapy with phycocyanin and toluidine blue on the bond strength of resin composite to the sound dentin. Materials and methods: The samples include 120 tooth blocks taken from 60 human extracted sound third molar teeth. They were randomly divided into 12 groups and disinfected with two different photosensitizers (Phycocyanin and Toluidine blue) activated by 635 nm diode laser for aPDT procedure. Then two different protocols (total-etch and self-etch) of universal adhesive system (G-Premio BOND, GC Dental Products CORP. Japan) were applied. The samples then filled with resin composite (Gradia® Direct, GC Dental Products CORP. Japan). After 10000 cycles of thermocycling, all samples were subjected to the micro shear bond strength (μSBS) test using a universal testing machine (1 mm/min). The data were analyzed with One Way ANOVA. Results: The effect of aPDT using both photosensitizers (phycocyanin and toluidine blue O) on the bonding strength to dentin was not significant (P>0.05). However, the bonding strength of total etch groups was reduced significantly (P<0.05) after aPDT using both photosensitizers. Phycocyanin self-etch group showed the greatest bonding strength (19.48 ± 3.89 MPa) in comparison to other aPDT groups. No significant reduction after thermocycling in dentin bond strength was observed in all groups (P>0.05), with exception of control total etch groups, which showed significant difference (P<0.05). Conclusion: aPDT using toluidine blue O and phycocyanin has no adverse effect on bonding to sound dentin when using universal adhesive in self-etch protocol. Clinical relevance: Phycocyanin is more recommended to be used in aPDT in comparison to toluidine blue as a natural photosensitizer. [ABSTRACT FROM AUTHOR]

Introduction: This in-vitro study comprises Antimicrobial and Confocal Microscopic analysis of the efficacy of Triple Antibiotic and Toluidine Blue (TBO) loaded chitosan nanoparticles (chnp) activated with photodynamic therapy (PDT) against Enterococcus faecalis (Ef). Methodology: 105 single-rooted extracted teeth were decoronated, cleaned and shaped, and incubated with Ef. The roots were randomly divided into three groups: Group I-Control, Group II-Triple Antibiotic Paste (TAP), Group III: Triple antibiotic-loaded chitosan nanoparticles (tachnp), and Group IV: Tachnp and TBO loaded chnp activated with PDT. Ten specimens from all the groups were subjected to antimicrobial analysis and five specimens were observed under the confocal microscope after 24 h and 7 days. Group IV was additionally analyzed after 24 h and 7 days of laser activation. Results: Group IV C showed the least colony-forming units followed by Group IVB, Group IIIB, Group IVA, and Group IIIA. Group II showed more colony-forming units. On intergroup comparison of mean colony count in control and experimental groups at 24 h and 7 days using one-way ANOVA F test was highly significant P < 0.001. The confocal microscopic images of IV C showed the increased intensity of fluorescent red indicating dead bacteria. Conclusion: Within the limitations of this study, TAP loaded chitosan nanoparticles activated with PDT showed a significant reduction in colony count. [ABSTRACT FROM AUTHOR]

Introduction: Photodynamic therapy (PDT) is now a widely used treatment modality in many fields of dentistry, including endodontics. The most common application of PDT in endodontics is to disinfect root canals. The purpose of this study was to present the experience of using PDT in root canal disinfection of three patients. Case Presentation: Three patients referred to the Endodontics Department of Shahid Beheshti University of Medical Sciences were treated using 0.1 mg/mL Toluidine Blue (FotoSan® agent; CMS Dental, Denmark) irradiated with a light-emitting diode (LED) lamp (FotoSan®; CMS Dental, Denmark) with a mean wavelength of 630 nm and a mean power density of 3 W/cm2 over two 30-second periods. Conclusion: PDT using LED lighting can be used in conjunction with conventional root canal treatment (RCT) to achieve great results. [ABSTRACT FROM AUTHOR]

The aim of this study was to use microscopic and molecular techniques to evaluate the effects of a single session of antimicrobial photodynamic therapy (aPDT) on the alveolar repair process after tooth extraction in rats. The study sample included 84 rats divided into four groups, as follows: a) Control - untreated socket; b) Laser - socket treated using photobiomodulation; c) TBO - socket treated with topic application of the photosensitizer agent, toluidine blue O (TBO); and d) aPDT - socket treated with TBO and laser irradiation. An additional rat was used for thermal mapping during socket irradiation. The animals were euthanatized at 6, 15, and 28 days after unilateral extraction of the upper incisor. Quantitative and qualitative analyses of the connective and bone tissues, blood clot, blood vessel, and inflammatory infiltrate were performed, and real-time polymerase chain reaction was used to study the expression of genes (collagen type I, osteocalcin, alkaline phosphatase [ALP], runt-related transcription factor 2 [RUNX2], and vascular endothelial growth factor [VEGF]) involved in the bone healing process. No statistically significant differences in microscopic and molecular outcomes were observed between the groups (p > 0.05). A positive correlation was seen to exist between blood clot and VEGF (p = 0.000), and a negative correlation was observed between bone tissue and ALP (p = 0.028) and blood vessel and VEGF (p = 0.018). A single session of aPDT in the dental extraction site did not influence the alveolar repair process in rats. [ABSTRACT FROM AUTHOR]

Diabetic foot infection caused by multidrug-resistant bacteria, is becoming serious problem. Moreover, polymicrobial biofilms contribute significantly to the persistent infections. In the present study, we investigated the effectiveness of novel toluidine blue conjugated chitosan coated gold–silver core–shell nanoparticles (TBO–chit–Au–AgNPs) mediated photodynamic therapy and demonstrate their use as a nontoxic antibacterial therapy to combat diabetic foot ulcer (DFU) caused by multi-drug resistant strains both in monomicrobial and polymicrobial state of infection. In vitro efficacy of TBO–chit–Au–AgNPs mediated photodynamic therapy (PDT) against polymicrobial biofilms was determined using standard plate count method and compared with that of monomicrobial biofilms of each species. Different anti-biofilm assays and microscopic studies were performed to check the efficacy of TBO–chit–Au–AgNPs mediated PDT, displayed significant decrease in the formation of biofilm. Finally, its therapeutic potential was validated in vivo type-2DFU. Cytokines level was found reduced, using nano-phototheranostic approach, indicating infection control. Expression profile of growth factors confirmed both the pathogenesis and healing of DFU. Hence, we conclude that TBO–chit–Au–AgNPs mediated PDT is a promising anti-bacterial therapeutic approach which leads to a synergistic healing of DFU caused by MDR bacterial strains. [ABSTRACT FROM AUTHOR]

Research is aimed at studying the antimicrobial efficacy of photodynamic therapy in treatment patients with pulpitis and periodontitis. Light-emitting-diode lamp «Fotosan» with wavelength 625-635nm was used as light source. Toluidine blue was used as photosensitizer. 73 specimens of root canal content before and after PDT were tested. The current study results prove the antimicrobial efficacy of PDT in endodontic treatment.

Current research is aimed at long term results evaluation of the photodynamic therapy efficacy in treatment patients with periodontitis. Light-emitting-diode lamp «Fotosan» with wavelength 625-635 nm was used as light source. Toluidine blue was used as photosensitizer. This article presents results of the photodynamic therapy treatment patients with periodontitis in 6, 12 and 24 months. The current study results show PDT efficacy in endodontic treatment.

Photodynamic therapy (PDT) provides a potential therapeutic approach for killing malignant cell/solid tumors, but currently approved photosensitizers (PSs) are generally excited by visible light, limiting the penetration depth in tissues. It is necessary to develop a near-infrared (NIR) responsive photodynamic platform, providing maximum tissue penetration. Here, we present a gold nanopeanut platform exhibiting dual functions of NIR PDT and two-photon luminescence imaging. The nanopeanut with a size less than 100 nm exhibits two distinct NIR surface plasmon absorption bands at approximately 1110 and 1300 nm. To perform PDT, we conjugated commercial toluidine blue O (TBO) PS on the surface of the nanopeanuts. With spectral overlap, the 1230-nm femtosecond Cr: forsterite laser can excite the surface plasmons of nanopeanuts, transfer energy to TBO, and generate singlet oxygen to kill cells. Moreover, the plasmon resonance-enhanced two-photon luminescence of nanopeanuts can be used to map their delivery in vivo. These results demonstrate that the PS-conjugated gold nanopeanut is an effective theranostic system for NIR PDT. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the effects of antimicrobial photodynamic therapy (aPDT) with indocyanine green (ICG) and toluidine blue (TB) on protease activity (matrix-bound cathepsin K and matrix metalloproteinase (MMP) and dentin bond strength. Caries-free human third molars were assigned to five groups: 1—control group, 2—application of ICG with activation using an 810 nm diode (aPDT), 3—application of ICG, 4—application of TB with activation using a 660 nm diode (aPDT), and 5—application of TB. For the enzymatic investigation, dentin beams were incubated for either 3 days or 3 weeks. Aliquots of the incubation media were analyzed by ELISA for CTX (C-terminal cross-linked telopeptide of type I Collagen) and ICTP (cross-linked carboxy-terminal telopeptide of type I collagen). For microtensile bond strength testing (μTBS), composite resins were layered onto the tooth surface; the samples were then subjected to μTBS. Kruskall–Wallis and Mann–Whitney U tests were applied for statistical analysis of CTX and ICTP, one way-ANOVA and Tukey's test were applied for statistical analysis of μTBS. Pretreating the dentin matrices with aPDT decreased the endogenous protease activity. ICG with laser activation resulted in the highest μTBS. Therefore, aPDT should be considered as a treatment method because it can reduce MMP-mediated dentin degradation and increase the μTBS. Inhibiting endogenous protease activity improves the stability of the dentin–adhesive bond and the durability of the bond strength. [ABSTRACT FROM AUTHOR]

The article discusses the influence of photodynamic therapy on bacterial attachment. Topics include infectious diseases of the oral cavity generated by bacteria and fungi remain one of the major problems confronting clinical dentistry; and Dental biofilm can cause bacterial infection around dental implants leading to the risk of implant failure due to the loss of the supporting bone.

Lactobacillus acidophilus (L. acidophilus) is one of the etiological agents for dental caries and dominant in the deep carious lesion. L. acidophilus has also been identified in persistent root canal infection and also related to the failure of endodontic treatment. Photodynamic therapy is a therapeutic process involving the combination of a nontoxic photosensitizer and a light source. The excited photosensitizer reacts with reactive oxygen species (ROS), which induce injury and death of the microorganism. This study aimed to prove the effect of irradiation time of photodynamic therapy to the number of L. acidophilus. Fortytwo Eppendorf tubes were treated with 0.5 ml L. acidophilus distributed into seven groups. Group 1 as the control group received no treatment. Groups 2, 3, 4, 5, 6 and 7 were treated with a combination of 0.5 ml toluidine blue O (TBO) as a photosensitizer and 630 nm photoactivated (Fotosan®) exposure time for 10, 20, 30, 40, 50 and 60 sec. Then, all were stored in an incubator of 37°C for 48 h. Later, the colony-forming unit (CFU) was counted for each group. There were significant differences in the number of L. acidophilus in CFU of the various irradiation times. The longer the photodynamic therapy irradiation was, the lesser the number of live L. acidophilus became. At 50 sec and 60 sec irradiation, none of the L. acidophilus was found alive. [ABSTRACT FROM AUTHOR]

Skin damage is accompanied by bacterial infection of the wound. Different materials are used for accelerate tissue regeneration and minimize bacterial contamination. Also it is prevent the penetration of bacteria to damaged tissues. After the emergence of antibiotic-resistant strains of microorganisms began the search for alternative means of their inactivation. Photosensitizers are used for this purpose. Their maxima of optical absorbance are in the red and infrared regions. Theuse of such substances provides powerful bactericidal effects, but with low toxicity to surrounding tissues. The aim of the investigation is to determine the effectiveness of combining hydrogels with toluidine blue and irradiation by light of 600 nm to inhibit the in vitro of Staphylococcus aureus growth. Equilibrium is not formed after incubation of hydrogels with toluidine blue after 3 h in aqueous solution. During this time, 57 and 43 % of the photosensitizer is desorbed from the hydrogels PAA and D-PAA, respectively. Process rate depends on the type of polymer. Desorption of TB from D-PAA is 30% faster. Irradiation of the suspension of S. aureus by light of 600 nm reduced the CFU amount by 25 % at a dose more than 4 J/ml. Short incubation (20 min) of the PAA and D-PAA hydrogels in the bacterial suspension and light irradiation (600 nm), the amount of CFU are reduced by 33% and 15 %, respectively. Increasing the incubation time of PAA does not increase the bactericidal effect.Exposure of 80 min D-PAA with TB in a suspension of S. aureus, followed by light irradiation provides inactivation of 50 % CFU. Thus, the D-PAA system with toluidine blue in combination with 600 nm light can be used to inactivate S. aureus. Keywords: bacteria photoinactivation, toluidine blue, polyacrylamide, dextran-polyacrylamide, photodynamic therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dual charge metallo-catanionic vesicles were optimized for aPDT against E. coli. • Efficiency of Toluidine blue and Rose Bengal was evaluated using visible light. • 1O 2 generation enhanced for oppositely charged photosensitizer/ vesicle combination. • metallo-catanionic vesicles favoured uptake of PS into bacterial cells. • Non-invasive method to fight acquired infections. The rising incidence of hospital-acquired infections and the increasing antibiotic resistance in bacteria are among the foremost challenges in the field of public health. Antibacterial Photodynamic Therapy (aPDT) has emerged as a promising alternative method for eradicating bacterial biofilms. Nonetheless, the limited ability of photosensitizers (PS) to penetrate bacterial cell walls and bacterial biofilms reduces their effectiveness in combating microbial activity. To address these limitations, we suggest formulations that incorporate common dyes such as Rose Bengal (RB) and Toluidine Blue (TB) as photosensitizers within vesicles. The self-assembled structures are formed from an aqueous mixture of two oppositely charged surfactants, creating metallo-catanionic vesicles. The innovative aspect here lies in the inclusion of a double-chain copper based metallosurfactant (bishexadecyltrimethyl ammonium copper tetrachloride (CuC II)) as a cationic component with anionic sodium dodecyl sulphate (SDS). The formation, stability and aggregation behaviour of the synthesized metallo-catanionic vesicles were estimated in the presence of cationic and anionic photosensitizers i.e. TB and RB, respectively. The confocal fluorescence microscopy confirmed the PS encapsulation into selected fractions SDS:CuC II (30:70) and (70:30). Further, in-situ singlet oxygen quantification was done using chemical trapping method which supports enhanced singlet oxygen quantum yields in the presence of metallo-catanionic vesicles. PS-loaded metallo-catanionic vesicles were further used in antimicrobial Photodynamic Therapy against Gram-negative bacteria Escherichia coli (E. coli). A tremendous decrease in bacterial growth was observed after applying a dose of PS (TB and RB) loaded metallo-catanionic vesicles in the presence of laser light irradiation. The colony forming unit (CFU) value decreases from 5.84 × 106 CFU/mL to nil with metallo-catanionic vesicles (SDS:CuC II) encapsulated with both TB and RB PS (light dose 40 mins). Hence, our current research demonstrates that these dual-charge metallo-catanionic vesicles can serve as effective delivery vehicles for photosensitizers in photodynamic therapy to combat bacterial infections. Furthermore, these vesicles have potential applications in the field of photomedicine. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of toluidine blue-mediated photodynamic therapy (TB-PDT) on the periodontitis-induced bone resorption in periodontitis in rats. Periodontal disease was induced by cotton ligature around the right second maxillary molar in 64 rats. After 4 weeks, the rats were randomly divided into four groups: sterile saline solution (control group); laser therapy (laser group); TB (100 μg/mL); TB plus laser (0.15 W/cm2) irradiation every other day for 240 s (PDT group). All rats were euthanized at 15 days postoperatively. Eight gingival tissue samples were collected from each group. The expressions of receptor activator of nuclear factor kappa-Β ligand (RANKL) and osteoprotegerin (OPG) in gingival tissue samples were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The maxillae from the rest of the rats were taken for histological examination. In the PDT group, the analysis revealed less bone loss than in the control treatment (P < 0.05). No significant difference was found among the control group, TB group, and laser group (P > 0.05). Significantly higher and lower expressions of RANKL and OPG were revealed in the PDT group than that in control group, respectively (P < 0.01). When compared with the control group, the expression of RANKL was significantly reduced by 40.0% in periodontitis in rats treated with TB-PDT for 15 days (P < 0.01). The expression of OPG was increased in the PDT group with TB-PDT for 15 days, when compared with the control group (P < 0.05). TB-PDT treatment significantly reverses the abnormal expression of RANKL and OPG in periodontitis in rats. [ABSTRACT FROM AUTHOR]

Aim: To compare Enterococcus faecalis reduction after antimicrobial photodynamic therapy (aPDT) used with methylene blue, toluidine blue, tannin, and curcumin as photosensitizers, an adjunct to endodontic chemomechanical preparation (CMP) in root canals of human teeth. Methods: A total of 120 single-rooted teeth were divided into 6 groups (n = 20): G1-CMP and 2.5% sodium hypochlorite (NaOCl); G2- CMP and saline solution; G3- CMP, 2.5% NaOCl, and aPDT with 0.005% methylene blue; G4- CMP, 2.5% NaOCl, and aPDT with 0.005% toluidine blue; G5- CMP, 2.5% NaOCl, and aPDT with 0.005% tannin; and G6- CMP, 2.5% NaOCl, and aPDT with 0.005% curcumin. A portable semiconductor laser was used (660 nm, 100 mW, 1.8 J, 180s) in groups 1, 2, 3, 4, 5, and a blue LED light-curing (420-480 nm, 1200 mV/cm2) in G6. For all groups, a 5 min pre-irradiation time was applied. Samples were collected before (initial collection), immediately after (intermediate collection) and 7 days after CMP (final collection) for colony-forming unit (CFU) counting. The Kruskal-Wallis test and analysis of variance (ANOVA) were performed (p < 0.05; 95% confidence interval). Results: In between-group comparisons, there was no significant difference observed in the number of CFUs at the initial (p < 0.001) and final collections (p < 0.001) for G2 and G3. In within-group comparisons, the number of CFUs showed a decreasing trend in G4 (p = 0.007) and G5 (p = 0.001). Conclusion: Photosensitizers promoted E. faecalis reduction, with better results for tannin and curcumin. Alternative photosensitizers should be the focus of further studies. [ABSTRACT FROM AUTHOR]

Introduction: Antimicrobial photodynamic therapy (aPDT) as a supplement to the conventional root canal preparation has shown promising results. Previous studies have adopted various combinations of light sources and photosensitizers, which makes it difficult to compare the disinfection efficacy of different PDT protocols. The aim of the present study was to compare the efficacy of three photosensitizers (toluidine blue, methylene blue, and curcumin) in PDT using LED against Enterococcus faecalis in root canal disinfection. Methods: Root canals of 54 single-rooted extracted teeth were prepared using the ProTaper Gold rotary system and were incubated with E. faecalis for three weeks. They were then randomly divided into five experimental groups and a control group: (1) Irrigation with 2.5% NaOCl for 30 seconds, (2) NaOCl irrigation followed by TB-PDT, (3) NaOCl irrigation followed by MB-PDT, (4) NaOCL irrigation followed by curcumin-PDT, (5) Curcumin solvent (1% ethanol+1% BSA), (6) Control (irrigation with normal saline). Sampling was done by collecting dentin shavings from the root canals, and colony-forming units were determined for each treatment group. The data were analyzed by Kruskal-Wallis and Mann-Whitney U tests. The significance level was set at P=0.05. Results: In all treatment groups, the mean values of colony forming unit (CFU) decreased by 99% compared to the control group. The lowest mean values of CFU were observed in groups 2 and 4, followed groups 3, 1, and 5 respectively. The mean CFU count in group 2 was significantly lower than that of group 1 (P value=0.011), while there were no significant differences among groups 1, 3, and 4 (P value >0.05). Conclusion: The adjunction of toluidine blue-mediated PDT by means of a light-emitting diode to NaOCl irrigation increased its antibacterial efficacy against E. faecalis and could be an effective complementary method in root canal disinfection. [ABSTRACT FROM AUTHOR]

Introduction: Photodynamic therapy (PDT) is a therapy involving light and a photosensitising chemical substance, used in conjunction with molecular oxygen in order to elicit cell death (photo-toxicity) and thus ability to kill microbial cells, including bacteria, fungi and viruses. Photodynamic therapy is an alternative method of biofilm disruption and it is considered a new way of microorganism inactivation. It is also an additional procedure to reduce the infection rate in patients, caused by the increasing antimicrobials resistance of bacteria. The aim of this literature review was to evaluate the specific effects and the antibacterial effectiveness of photodynamic therapy using different types of photosensitizers (Erythrosine, Rose Bengal, Toluidine blue, Methylene blue, Ozone, Riboflavin, Curcumin, Chlorhexidine, SAPYR) and a visible light of a specific wavelength for each photosensitizer and to reveal the applications of PDT in periodontics, endodontics, prosthodontics and dental caries. Methods: A research of literature was performed in an attempt to find all the articles published on this topic in the last 10 years. The articles was searched by using a certain combination of different keywords (photodynamic therapy ) and (diode laser ) and (teeth) in PubMed database. Results: A total number of 83 articles were found. After applying inclusion and exclusion criteria, 35 articles were taken into consideration for our study and among them 4 were a manuscript, 3 was a review of literature, 1 was an in vivo evaluation and 27 were in vitro studies. Conclusion: Considering that none of the disinfection methods can completely remove the biofilm, PDT is a therapeutic tool complementary to conventional disinfection, with great applicability in dentistry. PDT showed significantly efficacy in reduction of biofilms. Exposure to light in the presence of a photosensitizing chemical substance helps in the reduction of microbes and the protocols could be recommended for clinical usage, but only together with 'classic ' disinfection. [ABSTRACT FROM AUTHOR]

Introduction: Periodontitis is a chronic inflammatory disease of periodontal tissues, which can lead to tooth loss and significant sub-gingival tissue deformities anaerobic pathogenic bacteria, where Porphyromonas gingivalis play a vital role in the pathogenesis of chronic periodontitis. Antimicrobial photodynamic therapy (aPDT) is proposed as an alternative treatment approach due to bacterial resistance. Objectives: The objective of this study was to prepare and characterize the photodynamic effect of toluidine blue (TB)-loaded PLGA nanoparticles, in combination with a red light on the periodontal microorganism P. gingivalis. Material and methods: The present study include the following methods: 1) preparations, characterization, and optimization of TB-loaded surface PLGA nanoparticles, and 2) bacterial photodestruction mediated by cationic or anionic TB-loaded nanoparticles in vitro. Results: Particle size and zeta potential of cationic TB-loaded PLGA nanoparticles were 24.0 nm and +44.0 mV, respectively. TB loading and release show in sufficient concentrations in killing P. gingivalis. Nano-photodynamic therapy with TB-loaded PLGA nanoparticles inhibited 8 log10 the growth of bacteria at concentrations of 6.25-12.5 µg/ml. The minimal bactericidal concentration of TB for 8 log10 CFU reduction (0.5 McFarland) was 12.5 µg/ml. Conclusions: Nano-photodynamic therapy with cationic TB-loaded PLGA red light is useful in killing P. gingivalis than anionic TB-loaded PLGA. It gives future directions and promising results in clinical trials. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the antimicrobial effect of photodynamic therapy (PDT) with the use of Toluidine Blue (TB) on extracted teeth infected with biofilms of Enterococcus faecalis. Fifty-four extracted teeth with single-roots and single canals were mechanically shaped, autoclaved, and contaminated with E. faecalis. They were randomly divided into six groups: two groups were negative and positive control groups, two groups were subjected to mechanical instrumentation and PDT with different pre-irradiation times and irradiation times, and two groups were subjected to chemo-mechanical endodontic treatment and PDT with different pre-irradiation times and irradiation times. In PDT groups, after the application of TB, the canals were irradiated with a diode laser of wavelength 635 nm, with a fiber diameter of 200 μm and 100 mW of power in continuous mode. The bacterial load was evaluated using a BioTimer Assay protocol. The greatest reduction of bacterial load was observed in groups of combined PDT with chemo-mechanical treatment. The reductions of bacterial load in groups of combined PDT with chemo-mechanical treatment, and in the positive control group, were significant (p < 0.01) when compared to that of the negative control group. Photodynamic therapy as an adjunctive modality may improve the disinfection capacity of conventional endodontic treatment against E. faecalis. [ABSTRACT FROM AUTHOR]

Chagas disease is endemic in Latin America and increasingly found in non-endemic countries. Its treatment is limited due to the variable efficacy and several side effects of benznidazole. Photodynamic antimicrobial chemotherapy (PACT) may be an attractive approach for treating Chagas disease. Here, the trypanocidal activity of PACT was investigated in vitro using phenothiazine derivatives. The cytotoxicity of both, methylene blue (MB) and toluidine blue (TBO), was determined on macrophages cultures using AlamarBlue method. The trypanocidal activity of the two photosensitizers was initially evaluated by determining their IC50 values against trypomastigote forms. After this, the trypanocidal effect was evaluated in cultures of infected macrophages using an automatized image analysis protocol. All experiments were performed in the dark and in the clear phase (after a photodynamic exposure). The compounds showed no cytotoxicity in both phases at the tested concentrations. The IC50 values for the sole use of MB and TBO were 2.6 and 1.2 μM, respectively. The photoactivation of the compounds using a fixed energy density (J/cm2) caused a reduction of the IC50 values to 1.0 and 0.9 μM, respectively. It was found that, on infected macrophage, the use of TBO significantly reduced the number of infected cells and parasitic load, and this effect was increased in the presence of light. The results of the present study are indicative that PACT may be considered as both selective and effective therapeutic intervention for treating Chagas disease. [ABSTRACT FROM AUTHOR]

Antimicrobial photodynamic therapy (aPDT) has been recommended for clinical application. Its antibacterial effect on bacteria remained in dentinal tubule was seldom investigated. Here, we evaluated the antibacterial effects of aPDT on Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus) in planktonic lifestyle, biofilm and carious dentine. Mono‐species biofilms or dentinal caries formed on human dentine slices or slabs. Bacterial suspension, biofilms and dentine caries were treated with 0.1 mg mL−1 toluidine Blue O followed by irradiation with a light emission diode (λ − 635 ± 10 nm; 500 mW; 31.5 J cm−2; 60 s) and 0.12% chlorhexidine (CHX), respectively. Residual bacteria were determined by microbial culture analysis and scanning electron microscopy (SEM). One‐way analysis of variance (ANOVA) was performed to detect the significance of the variables. Both treatments significantly reduced the number of L. acidophilus in planktonic state, biofilm and carious dentine (P < 0.05). For S. mutans, CHX was only bactericidal against suspension (P < 0.05), while aPDT was effective on both suspension and biofilm (P < 0.05) while not for dentin caries (P > 0.05). Under the experimental conditions assessed, aPDT could be an alternative disinfection method for superficial layer of caries cavity. Its disinfection on bacteria in dentinal tubule of deep layer was deficient. [ABSTRACT FROM AUTHOR]

• ALA-PDT is a minimally invasive and effective treatment for actinic cheilitis. • Autofluorescence imaging and toluidine blue are alternative noninvasive modalities to visualize lesions and decide the treatment area. • Aneuploidy with DNA image cytometry has monitoring and predictive values in follow-up of actinic cheilitis. • Non-invasive auxiliary tests assisted ALA-PDT is attractive and well-tolerated and may have synergistic effects against actinic cheilitis. Actinic cheilitis (AC) is recognized as the most common precursor lesion of squamous cell carcinoma (SCC) of the lip, with a higher risk of invasiveness and metastasis. Early accurate diagnosis and appropriate therapy are essential to prevent carcinogenesis and progression of AC. Topical 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT), a non-surgical and minimally invasive modality, has been proposed as an effective treatment for oral potentially malignant diseases (OPMDs) and oral cancers. Herein, we report a 64-year-old female patient with AC on the lower lip who received 3 sessions of ALA-PDT with an interval of 1 week. Multiple noninvasive auxiliary tests including autofluorescence imaging, toluidine blue staining, and aneuploidy with DNA image cytometry (DNA-ICM) using brushing from screening through diagnosis, treatment, and follow-up. The patient successfully showed a complete response with no adverse effects and no evidence of recurrence at the 20-month follow-up. Noninvasive auxiliary tests assisted PDT is attractive and well-tolerated and may have synergistic effects against AC. [ABSTRACT FROM AUTHOR]

Objective: In this study, the effect of photodynamic therapy with topical corticosteroid in oral lichen planus patients was compared. Material and Methods: In this randomized, double‐blind clinical trial, eight patients with bilateral oral OLP lesions were recruited. Toluidine blue was applied on the lesions of both sides; a 660‐nm diode laser InGaAlP was irradiated for 10 min (power: 25 mW, fluence: 19.23 J/cm2, probe cross section: 0.78 cm2) for three sessions. In the control side of the oral mucosa, only sham laser was used. Follow‐up sessions were held on weeks 3 and 7. In week 3, oral paste triamcinolone acetonide 0.1% was prescribed. Response rates were assessed clinically by VAS, Thongprasom sign scoring, clinical severity index, efficacy indices, and the amount of reduction in the size of the lesions. The Mann–Whitney test was used to evaluate the treatment outcomes. Results: In spite of the control side, all scores improved significantly between sessions 0 and 4 for the intervention side. The differences between the changes in almost all scores between sessions 0 and 4 in both the intervention and control sides were significantly considerable (p value <.05). Conclusion: Photodynamic therapy can be used as an alternative therapy alongside standard methods or as a new modality for refractory OLP. [ABSTRACT FROM AUTHOR]

Antibiotics and photodynamic therapy (PDT) are widely employed in curing acne. However, antibiotics as an effective treatment would lead to bacterial resistance and severe side effects. In this study, we aimed to develop a novel TBO hydrogel, which could prolong the retention time of photosensitizer (TBO) at the lesion site and improve therapeutic effect. In vitro antibacterial experiments (against Staphylococcus aureus and Escherichia coli), the response surface methodology was used to optimize the formulation of TBO hydrogel. The results indicated that the optimal formulation was 0.5% (v/v) carbomer, 0.01 mg/mL TBO, 0.5% (v/v) ethanol concentration, 0.5% (v/v) Tween 80, the mass ratio of NaOH to carbomer of 0.4 (w/w). The TBO hydrogel formulation showed the strong antibacterial activity for Propionibacterium acnes. The stability, pH, and antibacterial activity of TBO hydrogel did not significantly change under 4 °C, 25 °C, and 40 °C during 6-week storage. Furthermore, TBO combined with carbomer hydrogel showed the 51.28% (4 h) and 69.80% (24 h) release. In summary, the hydrogel TBO might be a vital therapeutic strategy to promote the PDT applied in the topical therapy of acne. [ABSTRACT FROM AUTHOR]

• The prevalence of peri-implant diseases is increasing. • Antimicrobial photodynamic therapy(aPDT) suggested as an efficient modality for decontamination of implant surface. • aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs. Antimicrobial Photodynamic therapy (aPDT) is a novel modality suggested for treatment of peri-implantitis. This study aimed to assess the effect of aPDT with toluidine blue (TBO) and indocyanine green (ICG) and 635 nm and 808 nm diode laser on Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) biofilm formed on Laser-Lok titanium discs. Eighty sterile Laser-Lok titanium discs were inoculated with A. actinomycetemcomitans to form biofilm and were randomly divided into 8 groups (n = 10) of control, chlorhexidine (CHX), TBO, ICG, 635 nm diode laser with 220 mW power, 808 nm diode laser with 250 mW power, 100 μg/mL TBO+635 nm diode laser and ICG+808 nm diode laser. Number of colony forming units (CFUs) on the surface of each disc was counted after the intervention. Data were analyzed using the Kruskal-Wallis test. Significant differences were noted in colony count among the eight groups after the intervention (P = 0.001). Pairwise comparisons with adjusted P value test showed that aPDT with TBO+635 nm laser and ICG+808 nm laser caused significant reduction of bacterial biofilm compared to the control group (P = 0.0001). TBO alone caused significant reduction of biofilm compared to the control group (P = 0.004). No other significant differences were noted (P > 0.05). Within the limitations of this study, the results showed that aPDT is a potential modality for decontamination of implant surface and reduction of A. actinomycetemcomitans biofilm in vitro. In this study, aPDT with TBO+635 nm diode laser and ICG+808 nm diode laser decreased the bacterial load on titanium discs. [ABSTRACT FROM AUTHOR]

Background: Photodynamic therapy (PDT) can be used for the management of peri‐implantitis. This study aimed to explore the efficacy and safety of PDT for peri‐implantitis in Chinese Han patients. Methods: This was a single‐centre, open‐label, randomized controlled trial of participants with peri‐implantitis treated at the Beijing Chao‐Yang Hospital, randomized 1:1 to PDT or no PDT. PDT was performed using toluidine blue (10 mg/mL; 3 min) and a 635‐nm laser (750 mW; 10 s/implant side; minimum of 60 mW/cm2). The primary outcome was the decline in periodontal probing depth (PD) at 6 months. The secondary outcomes were peri‐implant plaque index (PLI), sulcular bleeding index (SBI), and clinical attachment loss (CAL). Results: PD after treatment was smaller in the PDT group (n = 66) than in controls (n = 65) (all P < 0.001 vs. baseline). At 1 month, compared with controls, the PD in the PDT group was larger, while at 3‐ and 6‐month, the PDs were smaller (all P < 0.001). CAL, PLI and SBI in the PDT group was better (P < 0.05 vs. controls). Conclusion: PDT combined with mechanical debridement significantly improves PD, PLI and SBI in participants with peri‐implantitis. Importantly, PDT achieved a better CAL than mechanical debridement and cleaning. [ABSTRACT FROM AUTHOR]

Background: To compare the therapeutic effect of photodynamic therapy (PDT) with Toluidine blue O hydrogel versus systemic antibiotic (SA) in treating periodontitis on rats.Methods: Thirty-two Wistar rats were divided into four groups and treated differently: Negative control (NC) group, normal rats; positive control (PC) group, rats with periodontitis; SA group, rats with periodontitis treated with systemic antibiotic; PDT group, rats with periodontitis treated with PDT. After treatment, gingival sulcus bacterial load was measured by counting the colony forming units per milliliter (CFU mL-1 ). The tooth and periodontal tissues were histologically processed to analyze histological and immunohistochemical profile. Gingival samples were obtained to quantify interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels.Results: Gingival sulcus bacteria load is significantly lower in PDT group compared with the SA group. The histological analysis showed that some extremely effective repair signs of periodontal tissue were presented in PDT group, such as no periodontal pocket, no bone resorption, few inflammatory cells, massive fibroblasts and collagen fibers. Several effective repair signs of periodontal tissue were also observed in SA group, such as shallow periodontal pocket, small amount of inflammatory cells, substantial fibroblasts and collagen fibers. There were lower cyclooxygenase-2, matrix metalloproteinase -8 (MMP-8) and RANK immunolabeling, higher osteoprotegerin immunolabeling in PDT group compared with SA group. The IL-1β and TNF-α levels in PDT group were lower than those in NC group, but higher than those in SA group.Conclusion: PDT was effective to treat experimental periodontitis and was superior to systemic metronidazole as a treatment for periodontitis. [ABSTRACT FROM AUTHOR]

The aim of the study is to test the application of different laser wavelengths, with and without different photosensitizing dyes on different types of cultures. Laser irradiation was realized on Streptococcus mutans in both solid and liquid culture media in continuous mode at three different fluences (10, 20, and 30 J/cm²) with a red diode (650 nm) with toluidine blue dye, a blue-violet diode (405 nm) with curcumin dye, and a green diode (532 nm) with erythrosine dye. Without a photosensitizer, no growth inhibition was obtained with the red diode at any fluence value. Inhibition rates of 40.7% and 40.2% were obtained with the blue diode and green diode. The blue diode laser used with curcumin obtained results in terms of growth inhibition up to 99.26% at a fluence of 30 J/cm². The red diode laser used with toluidine blue obtained results in terms of growth inhibition up to 100% at fluences of 20 and 30 J/cm². The KTP (potassium-titanyl-phosphate) laser used with erythrosine was able to determine a complete growth inhibition (100%) at the different fluence values. The combination of a laser and its proper color may dramatically change the results in terms of bactericidal effect. It will be interesting to confirm these data by further in vivo studies. [ABSTRACT FROM AUTHOR]

Antibacterial photodynamic therapy (A-PDT) has been shown to kill oral bacteria in the planktonic culture, dental plaque, and biofilm. This study sought to assess the antimicrobial effect of A-PDT with toluidine blue O (TBO) and diode laser on salivary mutans streptococci in 5-6-year-olds with severe early childhood caries (SECC). This case-control study was conducted on 56 children with SECC divided into four groups, namely 0.1 mg/mL TBO, diode laser (633 nm, 20 mW, 6 J/cm2), combination of the two, and no intervention control group. A-PDT was performed on days 1 and 3. Salivary samples were collected before and after A-PDT on days 1 and 3, and 1 and 2 weeks after the second intervention (day 3). Samples were cultured on mitis salivarius agar, and after incubation, the colonies were counted. Data were subjected to repeated measures ANOVA, ANCOVA, and paired comparisons with least square difference and Tukey's test. Bacterial count significantly decreased on days 1 and 3, and 1 and 2 weeks after the second intervention. Bacterial count also decreased following the use of TBO and laser separately, but these reductions were not significant (P > 0.05). Within the limitations of this study, antimicrobial efficacy of TBO + laser was higher than that of diode laser or TBO alone. Durability of treatment increased with double-dose therapy. This modality may be used to decrease the colony count of salivary mutans streptococci in children with SECC. [ABSTRACT FROM AUTHOR]

As an important part of China’s sustainable development strategy, wood’s quality is mainly destroyed by wood decay.White-rot fungus is the most serious damage to wood cell wall in various wood rot fungi. In this paper, the inhibition of white-rot fungi was studied by using low toxicity and low pollution toluidine blue( TB) mediated photodynamic therapy to inhibit pathogenic bacteria, improve wood utilization. When the different concentrations( 0. 01, 0. 02, 0. 05 mg/m L) of TB were applied to white-rot fungi by the Oxford Cup method, no bacteriostatic effect was observed. However, when TB was excited by low-power 630 nm laser, it was found that the three groups of photosensitizer TB inhibited white-rot fungi, and the inhibition rates with TB concentration were 69.67%, 91. 21%, and 99. 44%, respectively. The experimental results show that toluidine blue-mediated photodynamic therapy has a good antibacterial effect on white-rot fungi, and the concentration of photosensitizer is positively correlated with its antibacterial effect, which reflects the good anti-corrosion effect of wood. [ABSTRACT FROM AUTHOR]