Photodynamic Therapy with Two Different Photosensitizers as a Supplement to Instrumentation/Irrigation Procedures in Promoting Intracanal Reduction of Enterococcus faecalis

Lima

et al. 2016

Rev. odontol. UNESP

ResumoIntrodução: A PDT antimicrobiana é um eficiente método coadjuvante na desinfecção do sistema de canais radiculares, o que torna importante o estudo sobre a possibilidade de alterações morfológicas e permeabilidade provocadas pelo laser de diodo na estrutura dentinária radicular. Objetivo: A proposta deste estudo foi investigar as alterações morfológicas e percentual de infiltração apical radicular após o uso do laser diodo. Material e método: Quarenta dentes monorradiculares foram instrumentados pelo sistema rotatório Protaper e irrigados com NaOCl 5,25% e EDTA 17%. Depois, foram divididos aleatoriamente em: G1: não receberam PDT (controle); G2: receberam pré-irradiação com fotossensibilizador azul de toluidina e irradiação com laser diodo de AsGaAl. Em seguida, 10 dentes de cada grupo foram analisados por MEV quanto as alterações morfológicas. Os outros 10 dentes foram obturados e corados por Rodamina B para avaliar o percentual de infiltração apical. Resultado: Os resultados mostraram diferença significativa entre G1 e G2 (p<0,001 -qui-quadrado), verificando maior presença de debris em G1 (controle) e maior ocorrência de túbulos dentinários abertos em G2 (PDT). Erosões e cracks foram observadas em ambos os grupos, sem diferença estatística significativa (p>0,001). O percentual de infiltração apical foi significativamente maior em G2 que em G1 (p<0,001 -t student). Conclusão: Concluiu-se que a utilização do laser diodo promoveu a redução de smear layer e abertura dos túbulos dentinários, não influenciando na ocorrência de erosão, cracks e carbonização. O laser aumentou a permeabilidade da dentina apical.Descritores: Fotoquimioterapia; laser; endodontia. AbstractIntroduction: Antimicrobial photodynamic therapy (PDT) is an efficient adjuvant technique to promote disinfection of the root canal system. Therefore, it is important to investigate changes to dentin morphology and permeability induced by the use of diode laser on the root dentin. Objective: The purpose of this study was to investigate morphological changes and the percentage of apical leakage after the use of laser. Material and method: Forty single-rooted teeth were instrumented using rotary system and irrigated. Teeth were randomly divided in two groups: G1 -not exposed to PDT (control), and G2 -pretreated with toluidine blue photosensitizer and irradiated with AsGaAl laser diode. Ten teeth in each group were evaluated by SEM for morphological changes. The other ten teeth were filled and stained with Rhodamine B to evaluate the apical leakage. Result: The results showed significant difference between G1 and G2 (p <0.001 -chi-square), with greater presence of debris in G1 and higher incidence of open dentinal tubules in G2. Erosions and cracks were observed in both groups, with no statistically significant difference (p> 0.001). The apical leakage was significantly higher in G2 than in G1 (p <0.001 -Student's t-test). Conclusion: It was concluded that the use of low-level laser reduced the smear layer and opened the dentinal tubules. Use of laser...

Section: Discussionsupporting

confidence: 90%

“…Use of EDTA at 17% and pH 7.5 aims to promote further penetration of the solution and remove the smear layer, which occludes dentinal tubules that may contain microorganisms and their sub-products 15 .…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the dentin changes in teeth subjected to endodontic treatment and photodynamic therapy

Lima

et al. 2016

Rev. odontol. UNESP

“…Photodynamic therapy (PDT) uses a specific wavelength of light to activate a light compatible nontoxic dye known as a photosensitizer (PS (68)(69)(70)(71)(72). As an example, the application of PDT using methylene blue as a PS against E. faecalis, has been shown to functionally impair the cell wall, damage chromosomal DNA, and degrade membrane proteins (72).…”

Section: Photodynamic Therapymentioning

confidence: 99%

Bioactive Chitosan Nanoparticles and Photodynamic Therapy Inhibit Collagen Degradation In Vitro

Persadmehr

Torneck

Cvitkovitch

et al. 2014

Journal of Endodontics

This study evaluated the ability of photodynamic therapy (PDT), chitosan nanoparticles (CSnp), or their combination, to inhibit bacterial collagenase-mediated degradation of collagen. Rat type 1 fibrillar collagen matrices were untreated or treated with 2.5% glutaraldehyde (GD), 2.5% GD followed by 1% CSnp, 1% CSnp, PDT, or 1% CSnp followed by PDT. Samples, except untreated controls, were exposed to Clostridium histolyticum collagenase. The soluble digestion products were assessed by hydroxyproline assay and the remaining adherent collagen was quantified by picrosirius red (PSR) staining. Collagen treated with CSnp, PDT, or a combination of CSnp and PDT, exhibited less degradation than controls. The abundance of post-treatment residual collagen correlated with the extent of degradation. Fourier transform infrared (FTIR) spectroscopy analysis showed that PDT treatment enhanced collagen cross-linking.Immunoblotting of sedimented CSnp indicated that CSnp and collagenase bound with low affinity. However, CSnp-bound collagenase showed a significant reduction in collagenolytic activity compared with controls.III

“…Based on this context, various studies have been developed to investigate the efficacy of alternative approaches against E. faecalis, including antimicrobial photodynamic therapy (PDT) [16][17][18][20][21][22][23][24][25]. PDT is a therapeutic strategy that involves the combination of a nontoxic photosensitizer (PS) and a harmless visible light source [19].…”

Section: Introductionmentioning

confidence: 99%

“…For this reason, the action of different PSs has been the subject of widespread research, mainly phenothiazine dyes, porphyrins, and phthalocyanines [22]. Currently, the association of methylene blue (MB), with lasers at red wavelengths (600-700 nm), has been widely used for bacterial management in endodontic treatment by PDT [16][17][18][20][21][22][23][24][25]. In the presence of a light source, permeability to MB can vary according to the structural components present on the surface of the microorganisms, reducing their antimicrobial effects.…”

Section: Introductionmentioning

confidence: 99%

Enterococcus faecium and Enterococcus faecalis in endodontic infections: antibiotic resistance profile and susceptibility to photodynamic therapy

et al. 2017

Introduction Enterococcus faecium has become an important microorganism in nosocomial infections with great ability to acquire antibiotic resistance. However, little is known about their presence on the oral cavity. Therefore, our objective was to verify the presence of E. faecium and E. faecalis in endodontic infections and compare their susceptibility to conventional antibiotics and photodynamic therapy. Methods We performed 38 collections from the root canals of different patients. Positive Enterococcus agar samples were submitted to phenotypic and genotypic testing for speciesspecific confirmation. The isolates identified as E. faecium and E. faecalis were tested for susceptibility to antibiotics by the E-test method. After that, the isolates were evaluated for susceptibility to photodynamic therapy (PDT) using methylene blue and gallium arsenide aluminum laser with a wavelength of 660 nm and fluence of 39.5 J/cm 2 (energy of 15 J and time of 428 s).Results Cultures positive for E. faecalis were found in 22 patients (58%). Among these patients, only two had E. faecium in mixed infections with E. faecalis. In the isolates of E. faecalis, 27% were resistant to antibiotics, including tetracycline, ciprofloxacin, and azithromycin. The isolates of E. faecium showed no resistance to the antibiotics tested. Both the isolates of E. faecium and E. faecalis exhibit significant susceptibility to PDT, including the isolates resistant to antibiotics. The reductions achieved by PDT ranged of 2.76 to 4.31 log 10 for E. faecalis strains and of 3.93 to 4.33 log 10 for E. faecium strains. Conclusion E. faecium showed lower prevalence in endodontic infections and higher susceptibility to antibiotics when compared to E. faecalis. In in vitro assays, PDT had a significant antimicrobial activity for both strains.