997 resultados para photodynamic inactivation (PDI)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Introduction: Photodynamic antimicrobial chemotherapy studies regarding dental caries have been present more frequently in the literature. However, photodynamic antimicrobial chemotherapy depends on the adjustment of variables such as the type of light source and, photosensitisers target microorganism; this makes it difficult to draw meaningful comparisons. The purpose of this paper was to provide a critical review related to this coadjuvant approach in the prevention and treatment of dental caries. Materials and Methods: A database search was made via Medline/PubMed (keywords: photodynamic therapy and dental caries) and 33 articles were found. Results: Twelve articles were included after using the filter tool, being excluded reviews and manuscripts reporting works not related to the studied area. Conclusion: The manuscripts showed that photodynamic therapy presents optimal results against dental caries, even though better understanding of photodynamic antimicrobial chemotherapy and its components are necessary before the clinical application of this alternative modality in the dental practice.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Aim: The aim of this study was investigate the effect of photodynamic therapy (PDT) using curcumin (C) as a photosensitizing agent irradiated with an LED (L) in the blue wavelength as a light source on a standard and clinical isolate of Streptococcus mutans (S. mutans) in a planktonic suspension model. Materials and methods: Suspensions of both strains were divided into 4 groups as follows: absence of C and L (control group: C–L–), with C and without L (C group: C+L–), absence of C with L (L group: C–L+) and presence of C and L (PDT group: C+L+). Three different concentrations of curcumin (0.75 mg/ml, 1.5 mg/ml and 3 mg/ml) and three light fluences of studied light source (24, 48 and 72 J cm–2) were tested. Aliquots of each studied group was plated in BHI agar and submitted to colony forming units counting (CFU/ml) and the data transformed into logarithmical scale. Results: A high photoinactivation rate of more than 70% was verified to standard S. mutans strain submitted to PDT whereas the clinical isolate showed a lower sensitivity to all the associations of curcumin and LED. A slight bacterial reduction was verified to C+L– and C–L+, demonstrating no toxic effects to the isolated application of light and photosensitizer to both S. mutans strains tested. Conclusion: Photodynamic therapy using a combination of curcumin and blue LED presented a substantial antimicrobial effect on S. mutans standard strain in a planktonic suspension model with a less pronounced effect on its clinical isolate counterparts due to resistance to this alternative approach. Clinical significance: Alternative antimicrobial approaches, as photodynamic therapy, should be encouraged due to optimal results against cariogenic bacteria aiming to prevent or treat dental caries.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of the study was to evaluate the photodynamic therapy (PDT) effect on root canals contaminated with Enterococcus faecalis using a light emitting diode (LED) light and a curcumin solution (CUR) as photosensitizer (PS). Eighty root canals from uniradicular human teeth were prepared with Protaper Universal rotary system and contaminated with E. faecalis for 21 days. They were divided as: GIa-PDT (CUR, pre-irradiation for 5 + 5 min of irradiation); GIb-PDT (CUR, pre-irradiation for 5 + 10 min of irradiation); GIIa-(CUR, pre-irradiation for 5 + 5 min without irradiation); GIIb-(CUR pre-irradiation for 5 + 10 min of irradiation); GIIIa-(physiological solution and irradiation for 5 min); and GIIIb-(physiological solution and irradiation for 10 min); positive and negative control groups. Collections from root canals were made at time intervals of 21 days after contamination, immediately after treatment, and 7 days after treatment, and submitted to colony forming units per milliter (CFU mL-1) counts. The data were submitted to ANOVA and Tukey multiple comparison tests, at a level of significance of 5 %. In the immediate post-treatment collection, group GIa showed greater bacterial reduction in comparison with GIIa, GIIb, GIIIa, GIIIb, and positive control (P < 0.05). At 7 days post-treatment, GIa showed significant bacterial reduction only in comparison with GIIIa (P < 0.05). Curcumin as sensitizer was effective by 5 min LED irradiation but not by 10 min irradiation PDT using LED light, and curcumin as PS was not effective in eliminating E. faecalis. No difference was observed for periods of irradiation.
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Water disinfection usually requires expensive chemicals or equipment. Chlorination is a common disinfection method, although it is not able to inactivate all pathogens. High concentrations of residual chlorine also cause an unpleasant taste and smell in drinking water. As an alternative, photocatalysis and photoelectrochemical treatment has a high disinfection potential in drinking water by using solid catalysts, such as titanium dioxide. Highly reactive hydroxyl radical generated during the process serves as the main oxidant, capable of inactivating a wide range of microorganisms. In this study, we proposed a novel comparison between Gram-positive and gram-negative microorganisms. An immobilized TiO2 film promoted higher efficiency in water disinfection processes. The treatment effectively inactivated Escherichia coli and Staphylococcus aureus bacterial microorganisms in a shorter period than other alternative methods.
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Background: The management of aggressive periodontitis (AgP) represents a challenge for clinicians because there are no standardized protocols for an efficient control of the disease. This randomized controlled clinical trial evaluated the effects of repeated applications of antimicrobial photodynamic therapy (aPDT) adjunctive to scaling and root planing (SRP) in patients with AgP. Methods: Using a split-mouth design, 20 patients with generalized AgP were treated with aPDT + SRP (test group) or SRP only (control group). aPDT was applied at four periods. All patients were monitored for 90 days. Clinical, microbiologic, and immunologic parameters were statistically analyzed. Results: In deep periodontal pocket analysis (probing depth [PD] >= 7 mm at baseline), the test group presented a decrease in PD and a clinical attachment gain significantly higher than the control group at 90 days (P < 0.05). The test group also demonstrated significantly less periodontal pathogens of red and orange complexes and a lower interleukin-1 beta/interleukin-10 ratio than the control group (P < 0.05). Conclusion: The application of four sessions of aPDT, adjunctive to SRP, promotes additional clinical, microbiologic, and immunologic benefits in the treatment of deep periodontal pockets in single-rooted teeth in patients with AgP.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Background The aim of this study was to compare antimicrobial photodynamic therapy (aPDT) as an adjunctive treatment to scaling and root planing (SRP) for induced periodontitis in nicotine-modified rats. Material & Methods A total of 240 rats were evenly divided into two groups: C – saline solution treatment; N – nicotine treatment. Periodontal disease was induced in both groups at the first mandibular molar. After 7 days, the ligature was removed. All animals were submitted to SRP and were divided according to the following treatments: SRP – irrigation with saline solution; Toluidine Blue-O (TBO) – irrigation with phenothiazinium dye (100 μg/ml); LLLT – laser irradiation (660 nm; 0.03 W; 4 J); and aPDT – TBO and laser irradiation. Ten animals in each group/treatment were euthanized at 7, 15 and 30 days. The histometric and immunohistochemical values were statistically analysed. Results Intragroup analysis demonstrated that in both groups the aPDT treatment resulted in lower bone loss (BL) when compared to SRP in all experimental periods. Intergroup analysis demonstrated that aPDT treatment resulted in lower BL in Group N than in Group C treated with SRP in all experimental periods. Conclusion Antimicrobial photodynamic therapy was an effective adjunctive treatment to SRP for induced periodontitis in nicotine-modified rats.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The photodynamic properties of eight hydrophobic monocationic methyl and ruthenium polypyridine complex derivatives of free-base and zinc(II) meso-triphenyl-monopyridylporphyrin series were evaluated and compared using HeLa cells as model. The cream-like polymeric nanocapsule formulations of marine atelocollagen/xanthan gum, prepared by the coacervation method, exhibited high phototoxicity but negligible cytotoxicity in the dark. Interestingly, the formulations of a given series presented similar photodynamic activities but the methylated free-base derivatives were significantly more phototoxic than the respective ruthenated photosensitizers, reflecting the higher photoinduced singlet oxygen quantum yields of those monocationic porphyrin dyes.