Browsing by Subject "photodynamic therapy"

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    Antimicrobial photodynamic therapy alone or in combination with antibiotic local administration against biofilms of Fusobacterium nucleatum and Porphyromonas gingivalis
    (Elsevier, 2018-11) Tavares, Livia J.; de Avila, Erica D.; Klein, Marlise I.; Panariello, Beitriz H. D.; Spolidório, Denise M. P.; Pavarina, Ana Cláudia; Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    Antimicrobial photodynamic therapy (aPDT) kills several planktonic pathogens. However, the susceptibility of biofilm-derived anaerobic bacteria to aPDT is poorly characterized. Here, we evaluated the effect of Photodithazine (PDZ)-mediated aPDT on Fusobacterium nucleatum and Porphyromonas gingivalis biofilms. In addition, aPDT was tested with metronidazole (MTZ) to explore the potential antimicrobial effect of the treatment. The minimum inhibitory concentration (MIC) of MTZ was defined for each bacterial species. Single-species biofilms of each species were grown on polystyrene plates under anaerobic conditions for five days. aPDT was performed by applying PDZ at concentrations of 50, 75 and 100 mg/L, followed by exposure to 50 J/cm2 LED light (660 nm) with or without MTZ. aPDT exhibited a significant reduction in bacterial viability at a PDZ concentration of 100 mg/L, with 1.12 log10 and 2.66 log10 reductions for F. nucleatum and P. gingivalis in biofilms, respectively. However, the antimicrobial effect against F. nucleatum was achieved only when aPDT was combined with MTZ at 100× MIC. Regarding P. gingivalis, the combination of PDZ-mediated aPDT at 100 mg/L with MTZ 100× MIC resulted in a 5 log10 reduction in the bacterial population. The potential antimicrobial effects of aPDT in combination with MTZ for both single pathogenic biofilms were confirmed by live/dead staining. These results suggest that localized antibiotic administration may be an adjuvant to aPDT to control F. nucleatum and P. gingivalis biofilms.
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    Curcumin—A Natural Medicament for Root Canal Disinfection: Effects of Irrigation, Drug Release, and Photoactivation
    (Elsevier, 2019-11) Sotomil, Julian M.; Münchow, Eliseu A.; Pankajakshan, Divya; Spolnik, Kenneth J.; Ferreira, Jessica A.; Gregory, Richard L.; Bottino, Marco C.; Prosthodontics, School of Dentistry
    Introduction Curcumin incorporation into polymeric fibers was tested for its antimicrobial properties and potential use in root canal disinfection. Methods Curcumin-modified fibers were processed via electrospinning and tested against a 7-day old established Actinomyces naeslundii (An) biofilm. The medicaments tested were as follows: curcumin-modified fibers at 2.5 and 5.0 mg/mL, curcumin-based irrigant at 2.5 and 5.0 mg/mL, saline solution (negative control), and the following positive controls: 2% chlorhexidine, 1% NaOCl, and triple antibiotic paste (TAP, 1 mg/mL). All medicaments, except for the positive controls, were allocated according to the light exposure protocol: photoactivation with an LED every 30 s for 4 min or without photoactivation. After treatment, the medicaments were removed and 1 mL of saline solution was added; the biofilm was scraped from the well and used to prepare a 1:2000 dilution. Spiral plating was done using anaerobic blood agar plates. After 24 h, colony-forming units (CFU/mL, n=11/group) were counted to determine the antimicrobial effects. Results Data exhibited significant antimicrobial effects on positive control groups, followed by the curcumin irrigants, and lastly, the photoactivated curcumin-modified fibers. There was a significant reduction of viable bacteria in curcumin-based irrigants, which was greater than the TAP-treated group. Curcumin-free fibers, saline, and the non-photoactivated curcumin-modified fibers did not display antimicrobial activity. Conclusions Curcumin seems to be a potential alternative to TAP when controlling infection, but it requires a minimal concentration (2.5 mg/mL) to be effective. Photoactivation of curcumin-based medicaments seems to be essential to obtain greater antibiofilm activity.