Antimicrobial Effects of Photodynamic Therapy on Patients With Necrotic Pulps and Periapical Lesion

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. (J Endod 2007;xx:xxx)


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Antimicrobial Photodynamic Therapy Combined With Conventional Endodontic Treatment to Eliminate Root Canal Biofilm Infection

Background and Objective: To compare the effectiveness of antimicrobial photodynamic therapy (PDT), standard
endodontic treatment and the combined treatment to eliminate bacterial biofilms present in infected root canals. Study Design/Materials and Methods: Ten singlerooted freshly extracted human teeth were inoculated with stable bioluminescent Gram-negative bacteria, Proteus mirabilis and Pseudomonas aeruginosa to form 3-day biofilms in prepared root canals. Bioluminescence imaging was used to serially quantify bacterial burdens. PDT employed a conjugate between polyethylenimine and chlorin(e6) as the photosensitizer (PS) and 660-nm diode laser light delivered into the root canal via a 200-m fiber, and this was compared and combined with standard endodontic treatment using mechanical debridement and antiseptic irrigation.

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Comparative study among three different phototherapy protocols to treat chemotherapy-induced oral mucositis in hamsters

In this study, clinical, biochemical and histological analysis were used to compare different phototherapies, including LED, low and high-power laser (HPL) for the treatment of chemotherapy (CT)-induced oral mucositis (OM). One-hundred-fifty hamsters were divided into five groups: C: control; CH: CT/OM induction; L: CT/OM induction and treatment with LED (635 nm, 1.2 J), HL: CT/ OM induction and treatment with HPL (808 nm, 10 J), LL: CT/OM induction and treatment with low-level laser therapy (LLLT) (660 nm, 1.2 J). OM was induced by scratches performed on check pouch mucosa after two injections of 5-Fluorouracil. The experiment lasted 10 days and OM was analyzed by specific clinical scales on days 5, 7 and 10. The animals were euthanized and the cheek pouch mucosa removed for biochemical (TNF-α concentration) and histological (light microscopy) analysis. After statistical analysis, the authors’ results showed LED and LLLT therapies were efficient treatments for OM, decreasing TNF-α concentration on day 7 (p < 0.05) and completely healing the mucosa on day 10. HPL showed no interference in final healing of OM. According to the methodology used and the results obtained in the present study, LLLT and LED therapies were the best choices to decrease the severity of OM, accelerating tissue repair and decreasing the inflammatory process.

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Uso da LEDTERAPIA na Mucosite Oral: Avanços na Prevenção e Tratamento.

De acordo com o Instituto Nacional do Câncer (INCA), estima-se para o Brasil no biênio 2018-2019, a ocorrência de 600 mil novos casos de câncer. Os principais tratamentos para esta condição consistem em Cirurgia, Quimioterapia e Radioterapia, que podem ser de forma combinada ou não.
O tratamento antineoplásico promove uma série de efeitos colaterais, pois não existe uma seletividade apenas pelas células neoplásicas. Esses efeitos adversos diminuem muito a qualidade de vida dos pacientes.
Neste contexto, a Mucosite Oral (MO) representa uma reação adversa nos protocolos de Radioterapia (RT) e Quimioterapia (QT) na Oncologia, representando a maior complicação nos pacientes que fazem RT em neoplasias na região da cabeça e pescoço, e em associação com a QT pode ser um sério problema dose-limitante, tendo muitas vezes que se realizar a interrupção do tratamento de base, em virtude do surgimento e agravamento de tais lesões e consequentemente sobrevida do paciente. A ruptura da integridade da mucosa resulta nesta condição, produto dos efeitos citotóxicos da terapia oncológica.

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Photodiagnosis and Photodynamic Therapy

Abstract
Background: Photobiomodulation (PBM) therapy is a rapidly growing approach to stimulate healing, reduce pain, increase athletic performance, and improve general wellness. Objective: Applying PBM therapy over the site of a tumor has been considered to be a contraindication. However, since another growing use of PBM therapy is to mitigate the side effects of cancer therapy, this short review seeks to critically examine the evidence of whether PBM therapy is beneficial or harmful in cancer patients. Materials and methods: PubMed and Google Scholar were searched. Results: Although there are a few articles suggesting that PBM therapy can be detrimental in animal models of tumors, there are also many articles that suggest the opposite and that light can directly damage the tumor, can potentiate other cancer therapies, and can stimulate the host immune system. Moreover, there are two clinical trials showing increased survival in cancer patients who received PBM therapy. Conclusions: PBM therapy may have benefits in cancer patients and should be further investigated.

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Tratamento do herpes labial pela terapia fotodinâmica​​

Descrição de Casos – MM Optics

Caso 1

Paciente do gênero feminino, 25 anos, apresentou-se no LELO-FOUSP com queixa de herpes labial na fase de vesícula no lábio superior esquerdo (A) devido a intenso estresse no dia anterior. Foi proposto tratamento por meio da terapia fotodinâmica para a fase de vesícula e laserterapia para a fase de crosta. A Figura 1 mostra os passos utilizados durante o tratamento: drenagem das vesículas com agulha estéril (B), aplicação do corante azul de metileno 0,01% m/V por 5 minutos (C) e irradiação com laser de baixa potência (Twin Flex Laser – MM Optics) pela técnica pontual em contato, modo contínuo, comprimento de onda de 660nm, 120J/cm² de densidade de energia, 40mW de potência, 2min por ponto, 4 pontos na lesão. A paciente retornou após 24h, 72h (D) e 1 semana para a laserterapia objetivando-se aceleração do processo de reparação tecidual (E): Twin Flex Laser, técnica pontual em contato, modo contínuo, comprimento de onda de 660nm, 3,8J/cm² de densidade de energia, 15mW de potência, 10s por ponto, 4 pontos na lesão. Observou-se reparação completa das lesões após 1 semana (F).

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Antimicrobial mechanisms behind photodynamic effect in the presence of hydrogen peroxide

This study describes the use of methylene blue (MB) plus light (photodynamic inactivation, PDI) in the presence of hydrogen peroxide (H2O2) to kill Staphylococcus aureus, Escherichia coli, and Candida albicans. When H2O2 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 H2O2. It was observed that ROS production was almost inhibited by the presence of H2O2 when cells were not present. In addition, experiments using different sequence combinations of MB and H2O2 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 H2O2 was used before or simultaneously with PDI, and ROS formation inside C. albicans cells confirmed that ROS production is higher in the presence of H2O2. 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 H2O2 is an interesting approach to improve PDI efficiency.

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