[show abstract][hide abstract] ABSTRACT: Antimicrobial photodynamic therapy (APDT) may become a useful clinical tool to treat microbial infections, and methylene blue (MB) is a well-known photosensitizer constantly employed in APDT studies, and although MB presents good efficiency in antimicrobial studies, some of the MB photochemical characteristics still have to be evaluated in terms of APDT. This work aimed to evaluate the role of MB solvent's ionic strength regarding dimerization, photochemistry, and photodynamic antimicrobial efficiency. Microbiological survival fraction assays on Escherichia coli were employed to verify the solution's influence on MB antimicrobial activity. MB was evaluated in deionized water and 0.9% saline solution through optical absorption spectroscopy; the solutions were also analysed via dissolved oxygen availability and reactive oxygen species (ROS) production. Our results show that bacterial reduction was increased in deionized water. Also we demonstrated that saline solution presents less oxygen availability than water, the dimer/monomer ratio for MB in saline is smaller than in water and MB presented a higher production of ROS in water than in 0.9% saline. Together, our results indicate the importance of the ionic strength in the photodynamic effectiveness and point out that this variable must be taken into account to design antimicrobial studies and to evaluate similar studies that might present conflicting results.
Photochemical and Photobiological Sciences 02/2014; · 2.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: Low-level laser therapy (LLLT) has been widely applied in pain relief in several clinical situations, including temporomandibular disorders (TMD). However, the effects of LED therapy on TMD has not been investigated. This study aims to evaluate the effects of red and infrared LEDs on: (1) tissue temperature in ex vivo and (2) pain relief and mandibular range of motion in patients with TMD. Thirty patients between 18 and 40 years old were included and randomly assigned to three groups. The two experimental groups were: the red LED (630 ± 10 nm) group and the infrared LED (850 ± 10 nm) group. The irradiation parameters were 150 mW, 300 mW/cm(2), 18 J/cm(2), and 9 J/point. The positive control group received an infrared laser (780 nm) with 70 mW, 1.7 W/cm(2), 105 J/cm(2), and 4.2 J/point. LED and laser therapies were applied bilaterally to the face for 60 s/point. Five points were irradiated: three points around the temporomandibular joint (TMJ), one point for the temporalis, and one near the masseter. Eight sessions of phototherapy were performed, twice a week for 4 weeks. Pain induced by palpating the masseter muscle and mandibular range of motion (maximum oral aperture) were measured at baseline, immediately after treatment, 7 days after treatment, and 30 days after treatment. There was an increase in tissue temperature during both the red and the infrared LED irradiation in ex vivo. There was a significant reduction of pain and increase of the maximum oral aperture for all groups (p ≥ 0.05). There was no significant difference in pain scores and maximum oral aperture between groups at baseline or any periods after treatment (p ≥ 0.05). The current study showed that red and infrared LED therapy can be useful in improving outcomes related to pain relief and orofacial function for TMD patients. We conclude that LED devices constitute an attractive alternative for LLLT.
Lasers in Medical Science 10/2013; · 2.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: Abstract Objective: The aim of this study was to test photodynamic therapy (PDT) as an alternative approach to biofilm disruption on dental hard tissue, We evaluated the effect of methylene blue and a 660 nm diode laser on the viability and architecture of Gram-positive and Gram-negative bacterial biofilms. Materials and methods: Ten human teeth were inoculated with bioluminescent Pseudomonas aeruginosa or Enterococcus faecalis to form 3 day biofilms in prepared root canals. Bioluminescence imaging was used to serially quantify and evaluate the bacterial viability, and scanning electron microscopic (SEM) imaging was used to assess architecture and morphology of bacterial biofilm before and after PDT employing methylene blue and 40 mW, 660 nm diode laser light delivered into the root canal via a 300 μm fiber for 240 sec, resulting in a total energy of 9.6 J. The data were statistically analyzed with analysis of variance (ANOVA) followed by Tukey test. Results: The bacterial reduction showed a dose dependence; as the light energy increased, the bioluminescence decreased in both planktonic suspension and in biofilms. The SEM analysis showed a significant reduction of biofilm on the surface. PDT promoted disruption of the biofilm and the number of adherent bacteria was reduced. Conclusions: The photodynamic effect seems to disrupt the biofilm by acting both on bacterial cells and on the extracellular matrix.
Photomedicine and laser surgery 07/2013; · 1.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Antimicrobial photodynamic therapy (aPDT) has been used to combat local infections, and it consists of the combination of a photosensitizer, a light source, and reactive oxygen species (ROS) to kill microbial cells. In this study, we evaluated the effectiveness of aPDT in the treatment of candidiasis in HIV-infected patients.
Twenty-one patients were divided into three groups. Control group (CG) was treated with the conventional medication for candidiasis (fluconazole 100 mg/day during 14 days). Laser group (LG) was subjected to low-level laser therapy (LLLT), wavelength 660 nm, power of 30 mW, and fluence of 7.5 J/cm(2), in contact with mucosa during 10 sec on the affected point. An aPDT group (aPDTG) was treated with aPDT, that is, combination of a low-power laser and methylene blue 450 μg/mL. Pre-irradiation time was 1 min. Parameters of irradiation were the same ones as for the LG, and patients were single irradiated. Patients were clinically evaluated and culture analysis was performed before, immediately after, and 7, 15, and 30 days after the treatment. Results: Our results showed that fluconazole was effective; however, it did not prevent the return of the candidiasis in short-term. LLLT per se did not show any reduction on Candida spp. aPDT eradicated 100% of the colonies of this fungus and the patients did not show recurrence of candidiasis up to 30 days after the irradiation.
These findings suggest that aPDT is a potential approach to oral candidiasis treatment in HIV-infected patients.
Photomedicine and laser surgery 06/2012; 30(8):429-32. · 1.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Low-level laser therapy (LLLT) promotes biomodulation of wound healing and literature reports that light delivery during the inflammation could play a different role compared with latter phases of the healing process. The objective of this study was to investigate whether single dose of a red laser (λ = 660 nm) is different from fractionated delivery protocol in full thickness burns. Two lesions were inflicted on the back of 36 rats. In the fractionated dose group (FG), the lesions were irradiated with 1 J/cm² on days 1, 3, 8, and 10 post-wounding. In the single dose group (SG), the lesions were irradiated with 4 J/cm² on day 1, immediately after injury. Control lesions (CG) received no light and were left to heal spontaneously. Blood flow was measured on days 1, 3, 8, 10, 15, and 21 using laser Doppler flowmetry. Animals were killed on days 3, 8, 10, 15, and 21. Skin specimens were obtained and routinely processed for hematoxylin and eosin. The specimens were evaluated according to differential leukocyte counting and angiogenesis. Statistical analysis was performed, and significance was accepted at p < 0.05. Irradiated groups showed a peak of new vessels on day 15 while, for CG, the peak was on day 21. On day 21, FG exhibited a significantly greater number of cumulative neutrophils while SG showed a higher number of mononuclear cells. Our results confirm that both protocols used accelerate angiogenesis and stimulate leukocyte chemotaxis on burn treatment. In addition, this work suggests that a single-dose LLLT accelerates the inflammatory phase of skin repair.
Lasers in Medical Science 05/2012; · 2.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: Pseudomonas aeruginosa is considered one of the most important pathogens that represent life-threatening risk in nosocomial environments, mainly in patients with severe burns. Antimicrobial photodynamic therapy (aPDT) has been effective to kill bacteria. The purpose of this study was to develop a burn wound and bloodstream infection model and verify aPDT effects on it. In vitro, we tested two wavelengths (blue and red LEDs) on a clinical isolate of P. aeruginosa strain with resistance to multiple antibiotics using HB:La(+3) as photosensitizer. Verapamil(®) associated to aPDT was also studied. In vivo, P. aeruginosa-infected burned mice were submitted to aPDT. Bacterial counting was performed on local infection and bloodstream. Survival time of animals was also monitored. In this study, aPDT was effective to reduce P. aeruginosa in vitro. In addition, Verapamil(®) assay showed that HB:La(+3) is not recognized by ATP-binding cassete (ABC) efflux pump mechanism. In the in vivo study, aPDT was able to reduce bacterial load in burn wounds, delay bacteremia and keep the bacterial levels in blood 2-3 logs lower compared with an untreated group. Mice survival was increased on 24 h. Thus, this result suggests that aPDT may also be a novel prophylactic treatment in the care of burned patients.
Photochemistry and Photobiology 03/2012; 88(3):590-5. · 2.29 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study analyzed the necessity of use of an optical fiber/diffusor when performing antimicrobial photodynamic therapy (PDT) associated with endodontic therapy. Fifty freshly extracted human single-rooted teeth were used. Conventional endodontic treatment was performed using a sequence of ProTaper (Dentsply Maillefer Instruments), the teeth were sterilized, and the canals were contaminated with Enterococcus faecalis 3 days' biofilm. The samples were divided into five groups: group 1-ten roots irradiated with a laser tip (area of 0.04 cm(2)), group 2-ten roots irradiated with a smaller laser tip (area of 0.028 cm(2)), and group 3-ten teeth with the crown, irradiate with the laser tip with 0.04 cm(2) of area. The forth group (G4) followed the same methodology as group 3, but the irradiation was performed with smaller tip (area of 0.028 cm(2)) and G5 ten teeth with crown were irradiated using a 200-mm-diameter fiber/diffusor coupled to diode laser. Microbiological samples were taken after accessing the canal, after endodontic therapy, and after PDT. Groups 1 and 2 showed a reduction of two logs (99%), groups 3 and 4 of one log (85% and 97%, respectively), and group 5 of four logs (99.99%). Results suggest that the use of PDT added to endodontic treatment in roots canals infected with E. faecalis with the optical fiber/diffusor is better than when the laser light is used directed at the access of cavity.
Lasers in Medical Science 03/2012; · 2.40 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study describes the use of methylene blue (MB) plus light (photodynamic inactivation, PDI) in the presence of hydrogen peroxide (H(2)O(2)) to kill Staphylococcus aureus, Escherichia coli, and Candida albicans. When H(2)O(2) was added to MB plus light there was an increased antimicrobial effect, which could be due to a change in the type of ROS generated or increased microbial uptake of MB. To clarify the mechanism, the production of ROS was investigated in the presence and absence of H(2)O(2). It was observed that ROS production was almost inhibited by the presence of H(2)O(2) when cells were not present. In addition, experiments using different sequence combinations of MB and H(2)O(2) were performed and MB optical properties inside the cell were analyzed. Spectroscopy experiments suggested that the amount of MB was higher inside the cells when H(2)O(2) was used before or simultaneously with PDI, and ROS formation inside C. albicans cells confirmed that ROS production is higher in the presence of H(2)O(2). Moreover enzymatic reduction of MB by E. coli during photosensitizer uptake to the photochemically inactive leucoMB could be reversed by the oxidative effects of hydrogen peroxide, increasing ROS formation inside the microorganism. Therefore, the combination of a photosensitizer such as MB and H(2)O(2) is an interesting approach to improve PDI efficiency.
Photochemical and Photobiological Sciences 12/2010; 10(4):483-90. · 2.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study reports the antimicrobial effect of photodynamic therapy (PDT) combined with endodontic treatment in patients with necrotic pulp infected with microflora resistant to a previous antibiotic therapy.
Thirty anterior teeth from 21 patients with periapical lesions that had been treated with conventional endodontic treatment and antibiotic therapy were selected. Microbiological samples were taken (1) after accessing the root canal, (2) after endodontic therapy, and (3) after PDT.
All the patients had at least 1 microorganism resistant to antibiotics. PDT used polyethylenimine chlorin(e6) as a photosensitizer and a diode laser as a light source (P = 40 mW, t = 4 minutes, E = 9.6 J). Endodontic therapy alone produced a significant reduction in numbers of microbial species but only 3 teeth were free of bacteria, whereas the combination of endodontic therapy with PDT eliminated all drug-resistant species and all teeth were bacteria-free.
The use of PDT added to conventional endodontic treatment leads to a further major reduction of microbial load. PDT is an efficient treatment to kill multi-drug resistant microorganisms.
Journal of endodontics 09/2010; 36(9):1463-6. · 2.95 Impact Factor
[show abstract][hide abstract] ABSTRACT: Photodynamic antimicrobial therapy (PAT) may become a useful clinical tool to treat microbial infections, overcoming microbial resistance that is a major problem nowadays. The aim of our work was to verify the damage caused by photosensitization over a Escherichia col) via atomic force microscopy (AFM), looking for structural changes that might occur in cells after PAT. Cells culture were grown until a stationary phase to reach a concentration of approximately 108 cells/mL allowing the production of extracellular slime in a biofilm-like structure. The cells including the extracellular matrix were put in a slide and its structure was observed using AFM; subsequently a water solution of methylene blue at 60muM was applied over the cells and a pre-irradiation time of 3 minutes was waited and followed by illumination with a diode laser (lambda=660nm, power 40mW, 3min, fluence 180J/cm2, beam diameter 0.04cm2). The same cells were observed and the images stored. A second set of experiments was performed with a smaller number of cells/area and without extracellular slime, using the parameters abovementioned. The results showed alterations on cellular scaffold markedly dependent on the number of cells and the presence of extracellular slime. The slime is targeted by the photosensitizer, and after irradiation a destruction of the matrix was observed; when fewer cells were evaluated the destruction is much more evident. The images suggested rupture of the cellular membrane and cellular fragments were observed. Our findings indicate that AFM seems is a useful tool to investigate parameters linked with photodestruction of microorganisms.
[show abstract][hide abstract] ABSTRACT: Recent progress in identification of oral microorganisms has shown that the oropharynx can be a site of origin for dissemination of pathogenic organisms to distant body sites, such as the lungs.
To compare the oropharyngeal microbiological profile, duration of mechanical ventilation, and length of stay in the intensive care unit of children receiving mechanical ventilation who had pharmacological or nonpharmacological oral care.
A randomized and controlled study was performed in a pediatric intensive unit in São Paulo, Brazil. A total of 56 children were randomly assigned to an experimental group (n=27, 48%) that received oral care with use of 0.12% chlorhexidine digluconate or a control group (n=29, 52%) that received oral care without an antiseptic. Oropharyngeal secretions were collected and cultured on days 0, 2, and 4, and at discharge.
The 2 groups had similar demographic characteristics, preexisting underlying diseases, and pharmacological, nutritional, and ventilatory support. Gram-negative bacteria were the predominant pathogens: Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enter-obacter species. The 2 groups did not differ significantly in the colonization of normal (P= .72) or pathogenic (P= .62) flora, in the duration of mechanical ventilation (P= .67), or in length of stay in the intensive care (P= .22).
Use of chlorhexidine combined with nonpharmacological oral care did not decrease the colonization profile, duration of mechanical ventilation, or length of stay in critically ill children receiving mechanical ventilation.
American Journal of Critical Care 08/2009; 18(4):319-28; quiz 329. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to investigate the effects of laser phototherapy as preventive and therapeutic regime on induced-oral mucositis in hamsters.
The animals were divided into four groups: preventive cryotherapy, preventive laser, therapeutic laser and therapeutic control group. Mucositis was induced in hamsters by intraperitoneal injection of 5-fluorouracil (5-FU) and superficial scratching. All preventive treatment was performed on the right cheek pouch mucosa. The left pouch mucosa was used for a spontaneous development of mucositis and did not receive any preventive therapy. Laser parameters were: lambda=660nm, P= 30mW, D=1.2J/cm(2), Deltat=40s, spot size 3mm(2), I=1W/cm(2). Cryotherapy was done positioning ice packs in the hamster mucosa 5min before 5-FU infusion and 10min afterward. To study the healing of mucositis, the left pouch mucosa of each of the hamsters in the TLG received laser irradiation on the injured area. Irradiation parameters were kept the same as abovementioned. The control hamsters in the TCG did not receive any treatment. The mucositis degree and the animal's body mass were evaluated. An assessment of blood vessels was made based on immunohistochemical staining.
The CG animals lost 15.16% of theirs initial body mass while the LG animals lost 8.97% during the first 5 days. The laser treated animals had a better clinical outcome with a faster healing, and more granulation tissue. The quantity of blood vessels at both LG and CG were higher than in healthy mucosa. Regarding the therapeutic analysis, the severity of the mucositis in the TLG was always lower than TCG. TLG presented higher organization of the granulation tissue, parallel collagen fibrils, and increased angiogenesis.
The results suggest that laser phototherapy had a positive effect in reducing mucositis severity, and a more pronounced effect in treating established mucositis.
Journal of Photochemistry and Photobiology B Biology 10/2008; 94(1):25-31. · 3.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study analyzed the antimicrobial effect of photodynamic therapy (PDT) in association with endodontic treatment. Twenty patients were selected. Microbiological samples were taken after accessing the canal, endodontic therapy, and PDT. At the end of the first session, the root canal was filled with Ca(OH)(2), and after 1 week, a second session of the therapies was performed. Endodontic therapy gave a mean reduction of 1.08 log. The combination with PDT significantly enhanced the reduction (1.83 log, p = 0.00002). The second endodontic session gave a similar diminution to the first (1.14 log), and the second PDT was significantly more effective than the first (p = 0.002). The second total reduction was significantly higher than the second endodontic therapy (p = 0.0000005). The total first + second reduction (3.19 log) was significantly different from the first combination (p = 0.00006). Results suggest that the use of PDT added to endodontic treatment leads to an enhanced decrease of bacterial load and may be an appropriate approach for the treatment of oral infections.
Journal of Endodontics 03/2008; 34(2):138-42. · 2.93 Impact Factor
[show abstract][hide abstract] ABSTRACT: Severe burns cause extensive damage and are complicated by loss of body fluids, injury in the cutaneous vasculature and delayed wound healing. Low-intensity laser therapy (LILT) has been studied as an alternative method to accelerate wound healing. This study was carried out to evaluate LILT effects (lambda= 660 nm) in rat burned skin with two different dose regimens. Thirty-six male adult Wistar rats with two burns created on their back using steam water were divided into 3 groups. In the fractioned dose laser group (FG), the lesions were irradiated with 1J/cm2 on days 1, 3, 8 and 10; in the single dose laser group (SG), the lesions were irradiated with 4J/cm2 on day 1. On control group (CG), lesions were not irradiated. Three animals per group were sacrificed on days 1, 3, 8, 10, 15 and 21 post-wounding and skin specimens were collected and processed to histomorphometry. At days 1, 3 and 8, statistical significant differences were not observed among groups. On the 10th day, mean values of the number of blood vessels for FG was significantly higher than CG. Irradiated groups showed a peak of new blood vessels formation at day 15 while for CG the peak was at day 21. The number of vessels in CG was significantly higher than FG and SG at day 21. These findings suggest that LILT may accelerate angiogenesis compared to control group, however, no significant differences were observed between laser groups with fractioned or single dose during all experiment.
[show abstract][hide abstract] ABSTRACT: Photodymanic antimicrobial therapy (PAT) has been proposed to treat oral infections and the phenothiazinic compound Methylene Blue (MB) has been considered as a suitable photosensitizer for this application. MB is a known methachromatic compound and the dimerization process may lead to different photochemical reactions, into the oral cavity, where the complete isolation of the saliva may not be possible. The aim of this study is to monitor the dimerization process of MB in the presence of human saliva through absorption spectroscopy. Absorption spectra of 30muM MB solutions in water and in human saliva were recorded in the wavelengths ranging from lambda=400nm to lambda=700nm. The spectra were recorded immediately after mixture and 1 min, and 5 minutes after blending. The results were evaluated by spectral analyses and through the calculus of the dimer/monomer ratio. The results demonstrated that immediately after mixture a hypochromic effect characterized by the diminishing on the total absorption in the visible range of the spectrum (lambda= 400nm - 700nm) is observed, but the aggregation process is not detectable. After 1 minute the ratio between dimer and monomer absorption increase and this increase became higher upon increasing the contact time. The results indicate that the addition of saliva into the mixture leads to and hypochromic effect follow by the dye aggregation. Aggregation is probably an important variable to be analyzed when choosing the pre-irradiation time in oral cavity application, because it may lead to different photochemical routes.
[show abstract][hide abstract] ABSTRACT: This study compares the antimicrobial effect of photodynamic therapy (PDT) combined to endodontic treatment with conventional endodontic treatment alone in patients with necrotic pulp and has a 6-month radiographic follow up comparing the healing of periapical lesions. Fifteen patients with periapical lesion and requiring root canal treatment were selected. Microbiological samples were taken after accessing the root canal, conventional manual endodontic therapy (group 1 n=5) and after accessing the canal, endodontic therapy and PDT (group 2 n=10). All the root canals were filled with a calcium hydroxide paste for 1 week. Radiographs were taken after obturation and following 6 months. Endodontic therapy alone presented an 87% reduction in microorganisms while the combination with PDT had a 95% reduction. Radiographic follow up showed 32% higher reduction in the lesion area in PDT group. Results suggest that the use of PDT added to conventional endodontic treatment leads to a further major reduction of microbial load. PDT is an efficient alternative to chemical antimicrobial agents. It is a non-cumulative local treatment, which may be an appropriate approach for the treatment of infections in the oral cavity.
[show abstract][hide abstract] ABSTRACT: Studies on the influence of low-power red laser on the repair of dental structures are very scarce. This study investigated the effects of the laser therapy on the ultrastructure of the dentine-pulp interface after conservative class I cavity preparation.
Two female volunteers with 8 premolars indicated for extraction for orthodontic reasons were recruited. Class I cavities were prepared and the teeth were randomly divided into two groups. The first group received treatment with a GaA1As laser, lambda=660nm, power of 30mW and energy dose of 2J/cm(2), directly and perpendicularly into the cavity in a single visit. After the irradiation, the cavities were filled with composite resin. The second group received the same treatment, except by the laser therapy.
Twenty-eight days post-preparation, the teeth were extracted and processed for transmission electron microscopy analysis. Two sound teeth, without cavity preparation, were also studied. The irradiated group presented odontoblast process in higher contact with the extracellular matrix and the collagen fibrils appeared more aggregated and organised than those of control group. These results were also observed in the healthy teeth.
These findings suggest that laser irradiation accelerates the recovery of the dental structures involved in the cavity preparation at the predentine region.
Archives of Oral Biology 10/2007; 52(9):899-903. · 1.55 Impact Factor