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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]

The aim of this study was to evaluate the influence of IR (λ850 ± 10 nm) and violet (λ405 ± 10 nm) LED phototherapy on total mast cells counts and its ability to influence mast cell degranulation. For this, 27 Wistar rats were used and were randomly distributed into three groups: control, IR LED, and violet LED. When indicated, irradiation done and they were sacrificed, had their tongue removed immediately, 20-min, 45-min, and 2-h after irradiation. Samples were processed to wax, cut, and stained with Toluidine Blue. Intact and degranulated mast cells were counted under light microscopy, and statistical analysis was carried out. In the superficial connective tissue and muscular tissues, violet LED light caused a significant increase in both total number and degranulated mast cells when compared to the control group immediately after irradiation. The degranulation indexes were higher in the groups irradiated with Violet light, both in superficial connective tissue and muscular tissues in relation to the timing. Irradiation with IR LED caused immediate increase in the total number and degranulated of mast cells when compared to the control group only in the superficial connective tissue. In all times observed, the highest total amount of mast cells was seen immediately after irradiation, except in the muscular tissue, which presented the highest amount after 20-min. It was concluded that IR and violet LED light were able to increase the number of mast cells and inducing degranulation in oral mucosa. However, considering that violet LED light can be harmful in periodontal disease, it seems that the use of IR LED light could be the best option in Dentistry. [ABSTRACT FROM AUTHOR]

Periodontitis is an infectious disease characterized by the destruction of supporting tissues. Antimicrobial photodynamic therapy (aPDT) has been proposed as an improved method for eliminating microorganisms. Its efficiency depends on the correct use of physical and chemical parameters. Thus, these parameters and their relations were evaluated in this study with the purpose of establishing lethal conditions for combating bacterial agents. Diode lasers and light-emitting diodes (LEDs) were characterized to evaluate the absorption profile and resonance of methylene blue (MB) and toluidine blue O (TBO). The relations between light energy density and photosensitizer absorption were determined. Two methodologies were used to evaluate the effects of aPDT against Aggregatibacter actinomycetemcomitans. LED light exhibited a broad emission spectrum with a peak light wavelength of 637 nm and 99% purity. The resonance intensity of MB was higher with diode laser irradiation, and TBO showed higher resonance intensity with LED irradiation. There was no difference in the absorption profile of photosensitizers using diode lasers or LEDs, and variations in power density did not result in an increasing or decrease in light absorption. A. actinomycetemcomitans was susceptible to photodynamic processes. Emission spectra and peak light wavelengths of light sources combined with the absorption profiles of photosensitizers were the main parameters involved in determining the efficiency of photodynamic effects. Power density did not alter the light absorption of photosensitizers. The association between adequate irradiation characteristics and photosensitizer absorption results in complete inactivation of A. actinomycetemcomitans. In addition, the bactericidal effect was not altered by an increase in energy densities. [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]

This study aimed to investigate the anti-inflammatory effects of different dosage of low-level laser therapy (LLLT) in an experimental model of temporomandibular joint (TMJ) arthritis. One hundred male Wistar rats were used and divided into the following groups: CG, control group; AG, animals group with left TMJ arthritis induced by intra-articular injection of Complete Freund's adjuvant - CFA; LG5, LG10 and LG20 - animals with arthritis and treated with LLLT at doses 5, 10, and 20 J/cm2, respectively. Morphological analysis was performed by TMJ histological sections stained with hematoxylin-eosin (HE), picrosirius (PSR), and toluidine blue (TB), as well as histomorphometric evaluation of cartilage, articular disc, and masticatory muscles. The amount of feed consumed within 3 weeks was evaluated, and biochemical analysis of TMJ tissues included measurement of sulfated glycosaminoglycans (GAGs), matrix metalloproteinases (MMPs) 2 and 9 zymography, and ELISA for cytokines IL-6, TNF-α, and IL-1β. Only the 20 J/cm2 dose promoted higher feed intake compared to AG. On the other hand, all LLLT doses promoted better organization of articular disc collagen fibers, greater number of proteoglycans in articular cartilage, increased area and diameter of left lateral pterygoid fibers, reduced latent and active MMP 9 and 2 activity, and lower IL-1β concentration compared to AG. Considering the study limitations, it was observed that LLLT treatments were effective in protecting and tissue cleansing joint structures, accelerating tissue repair, especially at lower doses. [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]

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]

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]

Among non-albicans Candida species, the opportunistic pathogen Candida krusei emerges because of the high mortality related to infections produced by this yeast. The Candida krusei is an opportunistic pathogen presenting an intrinsic resistance to fluconazol. In spite of the reduced number of infections produced by C. krusei, its occurrence is increasing in some groups of patients submitted to the use of fluconazol for prophylaxis. Photodynamic antimicrobial chemotherapy (PACT) is a potential antimicrobial therapy that combines visible light and a nontoxic dye, known as a photosensitizer, producing reactive oxygen species (ROS) that can kill the treated cells. The objective of this study was to investigate the effects of PACT, using toluidine blue, as a photosensitizer on both growth and biofilm formation by Candida krusei. In this work, we studied the effect of the PACT, using TB on both cell growth and biofilm formation by C. krusei. PACT was performed using a light source with output power of 0.068 W and peak wavelength of 630 nm, resulting in a fluence of 20, 30, or 40 J/cm2. In addition, ROS production was determined after PACT. The number of samples used in this study varied from 6 to 8. Statistical differences were evaluated by analysis of variance (ANOVA) and post hoc comparison with Tukey-Kramer test. PACT inhibited both growth and biofilm formation by C. krusei. It was also observed that PACT stimulated ROS production. Comparing to cells not irradiated, irradiation was able to increase ROS production in 11.43, 6.27, and 4.37 times, in the presence of TB 0.01, 0.02, and 0.05 mg/mL, respectively. These results suggest that the inhibition observed in the cell growth after PACT could be related to the ROS production, promoting cellular damage. Taken together, these results demonstrated the ability of PACT reducing both cell growth and biofilm formation by C. krusei. [ABSTRACT FROM AUTHOR]

Porphyromonas gingivalis is a significant root canal pathogen capable of causing endodontic infections, which during their treatment may receive sub-lethal doses of photo-activated disinfection (sPAD). As sPAD can influence microbial virulence, this study was designed to evaluate the effect of sPAD on gene expression level of arginine A-specific cysteine proteinase (rgpA), as one of the underlying virulence factors involved in the development of endodontic infection via P. gingivalis strains. To find out the sPAD against 16 clinical isolates of PAD-resistant P. gingivalis that were isolated in vivo, we used toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) as the photosensitizers, which were excited with specific wavelength of light in vitro. Quantitative real-time PCR (qRT-PCR) was then applied to monitor gene expression of rgpA in P. gingivalis isolates to characterize its virulence agent and understand the effect of sPAD on its pathogenicity. Maximal sPAD that could not decrease the count of P. gingivalis isolates were 6.25, 15.6, and 25 μg/mL at fluencies of 171.87, 15.6, and 93.75 J/cm2 for TBO, ICG, and MB, respectively. ICG-sPAD could suppress the rgpA gene expression about 14-fold, while MB and TBO-mediated sPAD could cause the attenuation of rgpA expression about 4.9- and 11.6-fold, respectively. ICG-sPAD with the maximum ability to reduce rgpA gene expression compared with other photosensitizers can be an appropriate candidate for the treatment of endodontic infections. [ABSTRACT FROM AUTHOR]

Photodynamic inactivation (PDI) has been used to inactivate microorganisms through the use of photosensitizers and visible light. On the one hand, near-infrared treatment (NIRT) has also bactericidal and dispersal effects on biofilms. In addition, dispersal biological tools such as enzymes have also been employed in antibiotic combination treatments. The aim of this work was to use alternative approaches to increase the PDI efficacy, employing combination therapies aimed at the partial disruption of the biofilms, thus potentially increasing photosensitizer or oxygen penetration and interaction with bacteria. To that end, we applied toluidine blue (TB)-PDI treatment to Staphylococcus aureus biofilms previously treated with NIRT or enzymes and investigated the outcome of the combined therapies. TB employed at 0.5 mM induced per se 2-log drop in S. aureus RN6390 biofilm viability. Each NIRT (980-nm laser) and PDI (635-nm laser) treatment induced a further reduction of 1-log of viable counts. The combination of successive 980- and 635-nm laser treatments on TB-treated biofilms induced additive effects, leading to a 4.5-log viable count decrease. Proteinase K treatment applied to S. aureus of the Newman strain induced an additive effect on PDI mortality, leading to an overall 4-log decrease in S. aureus viability. Confocal scanning laser microscopy after biofilm staining with a fluorescent viability test and scanning electron microscopy observations were correlated with colony counts. The NIRT dose employed (227 J/cm2) led to an increase from 21 to 47 °C in the buffer temperature of the biofilm system, and this NIRT dose also induced 100% keratinocyte death. Further work is needed to establish conditions under which biofilm dispersal occurs at lower NIRT doses. [ABSTRACT FROM AUTHOR]

The antifungal drug therapy often employed to treat paracoccidiodomycosis (PCM), an important neglected fungal systemic infection, leads to offensive adverse effects, besides being very long-lasting. In addition, PCM compromises the oral health of patients by leading to oral lesions that are very painful and disabling. In that way, photodynamic therapy (PDT) arises as a new promising adjuvant treatment for inactivating Paracoccidioides brasiliensis (Pb), the responsible fungus for PCM, and also for helping the patients to deal with such debilitating oral lesions. PDT has been linked to an improved microbial killing, also presenting the advantage of not inducing immediate microbial resistance such as drugs. For the present study, we investigated the generation of reactive oxygen species (ROS) by using the fluorescent probes hydroxyphenyl fluorescein (HPF) and aminophenyl fluorescein (APF) after toluidine blue (TBO-37.5 mg/L)-mediated PDT (660 nm, 40 mW, and 0.04 cm2 spot area) and the action of TBO-PDT upon Pb cultures grown for 7 or 15 days in semisolid Fava Netto's culture medium; we also targeted oral PCM manifestations by reporting the first clinical cases (three patients) to receive topic PDT for such purpose. We were able to show a significant generation of hydroxyl radicals and hypochlorite after TBO-PDT with doses around 90 J/cm2; such ROS generation was particularly useful to attack and inactivate Pb colonies at 7 and 15 days. All three patients reported herein related an immediate relief when it came to pain, mouth opening, and also the ability to chew and swallow. As extracted from our clinical results, which are in fact based on in vitro outcomes, TBO-PDT is a very safe, inexpensive, and promising therapy for the oral manifestations of PCM. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of a low-level laser therapy in combination with toluidine blue on polysaccharides and biofilm of Streptococcus mutans. S. mutans biofilms were formed on acrylic resin blocks. These biofilms were exposed eight times/day to 10 % sucrose, and two times/day, they were subjected to one of the following treatments: G1, 0.9 % NaCl as a negative control; G2, 0.12 % chlorhexidine digluconate (CHX) as a positive antibacterial control; and G3 and G4 antimicrobial photodynamic therapy (aPDT) combined with toluidine blue using dosages of 320 and 640 J/cm(2), respectively. The experiment was performed in triplicate. The biofilm formed on each block was collected for determination of the viable bacteria and concentration of insoluble extracellular polysaccharides (IEPS) and intracellular polysaccharides (IPS). CHX and aPDT treatments were able to inhibit bacterial growth in comparison with negative control (p < 0.05). The aPDT treatment reduced the number of viable bacteria formed in the S. mutans biofilm, in a dose-dependent manner (p < 0.05). The concentration of IEPS and IPS in the biofilms formed in presence of aPDT did not differ each other or in comparison to CHX (p > 0.05). The results suggest that low-level laser therapy presents effects on biofilm bacteria viability and in polysaccharides concentration. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the antifungal effects of light-activated disinfection (LAD) in comparison with contemporary root canal irrigation solutions: sodium hypochlorite and 2 % chlorhexidine gluconate and a new wound antiseptic, octenidine hydrochloride. Seventy extracted teeth having single root canals were contaminated with Candida albicans for 14 days. The samples were divided into five experimental ( n = 10) and two control (positive and negative) groups ( n = 10): (1) LAD with toluidine blue O, (2) octenidine hydrochloride (OCT), (3) 2.5 % sodium hypochlorite (2.5 % NaOCl), (4) 5.25 % sodium hypochlorite (5.25 % NaOCl) and (5) 2 % chlorhexidine. Five millilitres of each test solution was applied for 3 min, and irradiation time used for LAD was 30 s. After treatment, the dentin chips were collected from inner canal walls into vials containing phosphate buffered saline, vortexed, serially diluted, seeded on Tryptic Soy Agar plates and incubated (37 °C, 48 h). The number of colony-forming units was then counted. Differences between LAD group and positive control group were statistically significant ( P < 0.05). All Candida cells were totally eliminated in root canals irrigated with OCT, 2.5 % NaOCl, 5.25 % NaOCl and 2 % chlorhexidine groups (CFU = 0). Within the limitations of this ex vivo study, LAD had minimal antimicrobial effect on C. albicans when used 30 s, and further modifications in LAD protocol are required to improve its antifungal capability. A new wound antiseptic, octenidine hydrochloride, demonstrated better potential than LAD in elimination of Candida albicans cells and may be a promising alternative to NaOCl and chlorhexidine solutions in future. [ABSTRACT FROM AUTHOR]

Photodynamic antimicrobial chemotherapy (PACT) is an antimicrobial approach that uses photosensitizers (PS) in combination with light sources at specific wavelengths aiming the production of reactive oxygen species. The long illumination time necessary to active PS is a challenge in PACT. Thus, this study investigated the antimicrobial effect of a novel single source of light-emitting diode (LED) light that covers the entire spectrum of visible light beyond interchangeable probes at high power intensity. Blue and red LED probes were used into different exposure times to active different concentrations of curcumin (C) and toluidine blue (T) on planktonic suspensions of Streptococcus mutans UA 159 ( S. mutans). S. mutans were standardized and submitted to (1) PACT treatment at three concentrations of C and T exposure at three radiant exposures of a blue LED (BL) (C+BL+) and a red LED (RL) (T+RL+), (2) C (C+BL−) or T alone (T+RL−), (3) both LED lights (C−BL+ and T−RL+), and (4) neither PS nor LED illumination (control group: C−BL− and T−RL−). Aliquots of the suspensions were diluted and cultured on blood agar plates. The number of colony-forming units was calculated after 48 h. The groups submitted to PACT presented a lethal photokilling rate to all PS concentrations at tested dosimetries. The comparison to control group when PS and LED lights used alone demonstrated no decrease in the number of viable bacterial counts. The novel LED device in combination with curcumin and toluidine blue promoted an effective photoinactivation of S. mutans suspensions at ultrashort light illumination times. [ABSTRACT FROM AUTHOR]

The opportunistic fungal Candida albicans is able to produce both superficial and systemic infections in immunocompromised patients. Photodynamic antimicrobial chemotherapy (PACT) is a process that combines visible light and a photosensitizer, producing reactive oxygen species (ROS) that can kill the treated cells and has been presented as a potential antimicrobial therapy. In this work, we study the effects of PACT, using toluidine blue (TB) as a photosensitizer drug, on ROS production and cell damage and the ability of C. albicans to form biofilm. A significant decrease was observed in the cell growth after PACT in a TB concentration-dependent manner. This effect was dependent on the incubation time after PACT. In addition, an increase in both the ROS production and cell permeability, after PACT, in a TB concentration-dependent manner was observed. PACT, using 0.1 mg/ml TB was able to reduce biofilm formation in 30, 50, and 62 %, in cells submitted to incubation times of 1, 2, and 3 h, respectively. These results suggested that PACT, using TB, is able to decrease both growth and biofilm formation by C. albicans, possibly by a mechanism evolving both ROS production and the increase in the cell permeability. [ABSTRACT FROM AUTHOR]

Shorter times and lower energies of application of light sources are desirable to use photodynamic antimicrobial chemotherapy (PACT) to the clinical control of candidiasis, especially among babies and children. Light energies ranging from 39.5 to 100 J/cm were previously applied to kill Candida albicans by PACT. The present study evaluated the efficacy of a combination of 0.05 mg/mL toluidine blue O (TBO) and a short time of application (60 s) and a low density of light energy (18 J/cm) of a red light-emitting diode (LED) in killing C. albicans planktonic cells. Standard suspensions of C. albicans were randomly assigned for four treatment groups: control (L−P−), LED alone (L+P−), TBO alone (L−P+), and PACT (L+P+). After treatments, serial dilutions of suspensions were prepared and streaked on Sabouraud dextrose agar to determine colony-forming units of C. albicans per milliliter (CFU/mL). The results were analyzed by ANOVA and Tukey's post-hoc test ( P < 0.05). PACT significantly reduced CFUs of C. albicans in comparison to other three treatments. Our results demonstrated a fungicidal effect of PACT mediated by a shorter time of application of LED on C. albicans planktonic cells. Further in vivo studies are needed to elucidate the efficacy of PACT to treat human fungal infections. [ABSTRACT FROM AUTHOR]

In the last decades, the tendon injuries have increased substantially. Previous results suggested that low-level laser treatment (LLLT) promotes synthesis of extracellular matrix and improves the functional properties of the tendon. The aim of this study was to evaluate the effects of different protocols of LLLT on partially tenotomized tendons. Adult male rats were divided into the following: G1-intact, G2-injured, G3-injured + LLLT (4 J/cm continuous), G4-injured + LLLT (4 J/cm at 20 Hz). G2, G3, and G4 were euthanized 8 days after injury. G5-injured, G6-injured + LLLT (4 J/cm continuous), and G7-injured + LLL (4 J/cm at 20 Hz until the seventh day and 2 kHz from 8 to 14 days). G5, G6, and G7 were euthanized on the 15th day. Glycosaminoglycan (GAG) level was quantified by dimethylmethylene blue method and analyzed on agarose gel. Toluidine blue (TB) stain was used to observe metachromasy. CatWalk system was used to evaluate gait recovery. Collagen organization was analyzed by polarization microscopy. The GAG level increased in all transected groups, except G5. In G6 and G7, there was a significant increase in GAG in relation to G5. In G3 and G4, the presence of dermatan sulfate band was more prominent than G2. TB stains showed intense metachromasy in the treated groups. Birefringence analysis showed improvement in collagen organization in G7. The gait was significantly improved in G7. In conclusion, pulsed LLLT leads to increased organization of collagen bundles and improved gait recovery. [ABSTRACT FROM AUTHOR]

This study was to evaluate specific effects of photodynamic therapy (energy density 15.8 J/cm(2), 26.3 J/cm(2) and 39.5 J/cm(2)) using methylene blue, toluidine blue and malachite green as photosensitizers and low-power laser irradiation on the viability of Candida albicans. Suspensions of C. albicans containing 10(6) cells/ml were standardized in a spectrophotometer. For each dye, 120 assays, divided into four groups according to the following experimental conditions, were carried out: laser irradiation in the presence of the photosensitizer; laser irradiation only; treatment with the photosensitizer only; no exposure to laser light or photosensitizer. Next, serial dilutions were prepared and seeded onto Sabouraud dextrose agar for the determination of the number of colony-forming units per milliliter (CFU/ml). The results were subjected to analysis of variance and the Tukey test (P < 0.05). Photodynamic therapy using the photosensitizers tested was effective in reducing the number of C. albicans.. The number of CFU/ml was reduced by between 0.54 log(10) and 3.07 log(10) and depended on the laser energy density used. Toluidine blue, methylene blue and malachite green were effective photosensitizers in antimicrobial photodynamic therapy against C. albicans, as was low-power laser irradiation alone. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the concentration of mast cells (MCs) in the healing process of incisions. Thirty rats were submitted to six linear incisions each, performed in the dorsal skin by carbon dioxide (CO(2)) and diode lasers, electrocautery and conventional scalpel. The animals were euthanized at intervals of 0 h, 24 h, 48 h, 72 h, 7 days and 14 days after the incisions had been made. Histological sections were obtained and stained with toluidine blue for identification of MCs, which were manually counted by conventional microscopy in 20 microscopic fields in the border of the incision, near the granulation tissue, or in the area of new collagen formation, depending on intervals. The concentration of MCs was significantly higher in the wounds made by scalpel than in those made by other techniques at 48 h and 72 h. After 72 h the number of MCs was also significantly higher after electrocautery than after incisions made by 4 W CO(2) laser. On days 7 and 14, there was no significant difference in the MC count among the different types of incisions. In summary, the MC concentration varied after different surgical incisions at early phases of wound healing. At the end of the healing process, however, there were similar MC concentrations around the incisions, suggesting that, in standard incisions in the surgical techniques studied, the wound healing process ultimately occurred in a similar pattern. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate photodynamic therapy in deciduous teeth with necrotic pulp by means of fully quantifying viable bacteria, before and after instrumentation and after the use of photodynamic therapy. Radicular canal cultures were conducted (n = 10): the first one was performed right after access and location of the radicular canal; the second was performed after the conclusion of chemical-mechanical instrumentation, and the last one after photodynamic therapy. The photodynamic therapy was performed with 4 J/cm energy low-intensity diode together with toluidine blue. The results (log(10)) were submitted to a descriptive analysis and Wilcoxon test. The percentage of reduction was submitted to the Mann-Whitney test. The instrumentation resulted in a reduction of 82.59% of viable bacteria, and, after photodynamic therapy, the microbial reduction observed was 98.37% (P = 0.0126). Photodynamic therapy is recommended as adjunct therapy for microbial reduction in deciduous teeth with necrotic pulp. [ABSTRACT FROM AUTHOR]

Our previous in vitro study has shown that toluidine blue (TB)-mediated lethal photosensitization of periodontal pathogens (PPs) from periodontal patients is possible. The purpose of this study was to investigate whether TB-mediated photosensitization exerted damaging effects on periodontal tissues in mice. Twenty-four mice were randomly divided into four groups; the experimental photodynamic therapy (PDT) group was treated with 1 mg/ml TB and light irradiation (60 J/cm(2), 635 nm, 337 s). Those in control groups were subjected to 140 J/cm(2) laser irradiation alone or to 2.5 mg/ml TB alone or received neither TB nor light exposure. All the mice were killed 72 h after they had been subjected to PDT, and periodontal tissue samples were taken for histological examination. During the 72 h observation period, no mice showed any distress. No necrotic or inflammatory changes were found in the gingiva, dentin, dental pulp or alveolar bone of the mice in any of the groups in this study. The results suggest that TB-mediated PDT is a safe antimicrobial approach for the treatment of periodontopathy without damaging effects to adjacent normal tissues. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effect of toluidine blue (TB)-mediated photodynamic inactivation of periodontal pathogens (PP) from periodontopathic patients. Photodynamic therapy (PDT) was carried out using TB and 635 nm laser light irradiation. The bactericidal effect was evaluated, and important PDT parameters including light intensity, energy dose, and TB concentration were determined. Our findings suggest that TB-mediated lethal photosensitization of PP in vivo is possible. However, to obtain ideal bactericidal effect, higher doses of light and photosensitizer should be required in treatment in vivo than their planktonic counterparts. The best therapeutic effect was observed in treatment by 1 mg/ml TB combined with 12 J/cm2 at 159 mW/cm2 light irradiation. Moreover, because of the considerable interindividual differences of bacterial populations, TB-mediated PDT might not be equally effective among periodontopathic patients, and further studies on improvement of this therapeutic modality is needed. [ABSTRACT FROM AUTHOR]

Suspensions of Candida albicans in saliva, serum, broth or saline were treated with toluidine blue O or methylene blue and exposed to light from a helium/neon orgallium aluminium arsenide laser, respectively, for 120 s and survivors enumerated. Experiments were also carried out in broth at a pH ranging from 4.0 to 7.0. Appreciable kills (>10 cfu ml) of the yeast were obtained regardless of the nature of the suspending fluid. Lethal photosensitization of the yeast was also possible at a pH as low as 4.0 Only short-term (3 min) incubatin of the photosensitizer with the yeast was necessary to render it susceptible to killing by laser light. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine whether bacteria in subgingival plaque samples from patients with chronic periodontitis could be sensitized to killing by low-power laser light in the presence of blood. Toluidine blue O (45 μg ml) was added to the plaque samples which were then exposed to light from a 7.3 mW HeNe laser for 30 or 120 s in the presence and absence of 10% horse blood. Viable counts of various groups and species of bacteria were determined before and after irradiation. A substantial bactericidal effect was obtained after irradiation for 30s regardless of whether or not blood was present. However, in most cases irradiation in the absence of blood resulted in greater decreases in the viable counts of aerobes, anaerobes, streptococci and blackpigmented anaerobes. When the samples were irradiated for 120s, 10% blood had little effect on the kills attained and elimination of periodontopathogenic species (black-pigmented anaerobes and Fusobacterium nucleatum) was achieved both in the presence and absence of blood. [ABSTRACT FROM AUTHOR]

Solutions of various photosensitizers were added to suspensions of the dental plaqueforming organism, Streptococcus sanguis. These were then exposed to light from a 7.3 mW Helium/Neon (He/Ne) laser for various time periods and the numbers of surviving cells determined by viable counting. Toluidine blue O, haematoporphyrin ester, thionin and methylene blue enabled substantial kills of the organism after irradiation times as short as 10 s which corresponds to an energy dose of 73 mJ. However, haematoporphyrin ester and, to a lesser extent, methylene blue were toxic to the organism in the absence of He/Ne light. Aluminium disulphonated phthalocyanine and crystal violet were ineffective as photosensitizers under the experimental conditions employed. The killing of sensitized S. sanguis by light from a low-power laser suggests the possibility of a new approach to the control of dental plaque bacteria. [ABSTRACT FROM AUTHOR]