Monitoring the effectiveness of photodynamic therapy with periodic renewal of the photosensitizer on intracanal Enterococcus faecalis biofilms

作者：Soares Janir Alves^*; Cunha Santos Soares Suelleng Maria; Santos Cesar Carlos Augusto; Roque de Carvalho Maria Auxiliadora; Brito Junior Manoel; de Sousa Gerdal Roberto; Soares Betania Maria; Farias Luiz de Macedo

来源：Photodiagnosis and Photodynamic Therapy, 2016, 13: 123-127.

DOI：10.1016/j.pdpdt.2016.01.002

• Photodynamic therapy
• Methylene blue
• Enterococcus faecalis
• Chemomechanical preparation
• Endodontic treatment

Background and objective: Photodynamic therapy (PDT) can eliminate microorganisms in a root canal. However, the parameters for disinfection remain undefined. This study assessed the effectiveness of a PDT protocol against intracanal Enterococcus faecalis biofilms.
Materials and methods: Root canals were contaminated with E. faecalis for 21 days. The instrumentation was associated to irrigation with 0.85% saline or an alternate irrigation (Al) with 5.25% NaOCl and 17% EDTA. Complementary treatments included saline/PDT and AI/PDT. Four PDT cycles were performed using a diode laser (660 nm, 40 mW) delivered through a tapered optical fiber. In each cycle, the root canal was filled with 1.56 mu M/mL methylene blue and irradiated for 150 s. Microbiological samples were collected before (51) and after (S2) instrumentation; after PDT (S3); and daily over the course of 14 days (S4-S17). Colony-forming units (CFUs) were counted, positive cultures verified, and data subjected to parametric and proportion's tests.
Results: The highest bacterial load reduction was observed in S2. In regard to S3, Saline/PDT reduced 1.3 log(10) CFU counts (p = 0.000 for S2) and no CFUs were recovered after AI/PDT treatment. All canals were CFU-free on the 14th day for saline/PDT, AI and AI/PDT. Positive cultures were observed in 60% of saline irrigated canals on the 14th day, whereas the saline/PDT, AI and AI/PDT treatments resulted in germ-free canals after 10, 5 and 2 days, respectively.
Conclusion: Our findings suggest immediate and delayed antibacterial effects using the PDT protocol tested. Published by Elsevier B.V.

• 出版日期2016-3