| Autor: |
Richard P. Ellen, Howard C. Tenenbaum, Donco Matevski, Guylaine Lépine, Robert A. Weersink, Brian J. Wilson |
| Rok vydání: |
2003 |
| Předmět: |
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| Zdroj: |
Journal of Periodontal Research. 38:428-435 |
| ISSN: |
0022-3484 |
| DOI: |
10.1034/j.1600-0765.2003.00673.x |
| Popis: |
Background: The ability of Helium–Neon (He–Ne) laser irradiation of a photosensitizer to induce localized phototoxic effects that kill periodontal pathogens is well documented and is termed photodynamic therapy (PDT). Objectives: We investigated the potential of a conventional light source (red-filtered Xenon lamp) to activate toluidine blue O (TBO) in vitro and determined in vitro model parameters that may be used in future in vivo trials. Materials and methods: Porphyromonas gingivalis 381 was used as the primary test bacterium. Results: Treatment with a 2.2 J/cm2 light dose and 50 µg/ml TBO concentration resulted in a bacterial kill of 2.43 ± 0.39 logs with the He–Ne laser control and 3.34 ± 0.24 logs with the lamp, a near 10-fold increase (p = 0.028). Increases in light intensity produced significantly higher killing (p = 0.012) that plateaued at 25 mW/cm2. There was a linear relationship between light dose and bacterial killing (r2 = 0.916); as light dose was increased bacterial survival decreased. No such relationship was found for the drug concentrations tested. Addition of serum or blood at 50% v/v to the P. gingivalis suspension prior to irradiation diminished killing from approximately 5 logs to 3 logs at 10 J/cm2. When serum was washed off, killing returned to 5 logs for all species tested except Bacteroides forsythus (3.92 ± 0.68 logs kill). Conclusions: The data indicate that PDT utilizing a conventional light source is at least as effective as laser-induced treatment in vitro. Furthermore, PDT achieves significant bactericidal activity in the presence of serum and blood when used with the set parameters of 10 J/cm2, 100 mW/cm2 and 12.5 µg/ml TBO. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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