Endodontic Photodynamic Therapy Ex Vivo
Raymond Ng, DDS,*¶ Fiza Singh, DDS,*¶ Despina A. Papamanou, DDS,† Xiaoqing Song, MD, MS,† Chitrang Patel, BS,† Colleen Holewa, BS,† Niraj Patel, BS, MS,† Vanja Klepac-Ceraj, PhD,† Carla R. Fontana, DDS, PhD,† Ralph Kent, ScD,‡ Tom C. Pagonis, DDS, MS,* Philip P. Stashenko, DMD, PhD,§ and Nikolaos S. Soukos, DDS, PhD†
Introduction:
The objective of this study was to eval- uate the antimicrobial effects of photodynamic therapy (PDT) on infected human teeth ex vivo.
Methods:
Fifty-two freshly extracted teeth with pulpal necrosis and associated periradicular radiolucencies were ob- tained from 34 subjects. Twenty-six teeth with 49 canals received chemomechanical debridement (CMD) with 6% NaOCl, and 26 teeth with 52 canals received CMD plus PDT. For PDT, root canal systems were incubated with methylene blue (MB) at concentration of 50 mg/ mL for 5 minutes, followed by exposure to red light at 665 nm with an energy fluence of 30 J/cm2. The contents of root canals were sampled by flushing the canals at baseline and after CMD alone or CMD+PDT and were serially diluted and cultured on blood agar. Survival frac- tions were calculated by counting colony-forming units (CFUs). Partial characterization of root canal species at baseline and after CMD alone or CMD+PDT was per- formed by using DNA probes to a panel of 39 endodontic species in the checkerboard assay.
Results:
The Mantel- Haenszel c2 test for treatment effects demonstrated the better performance of CMD+PDT over CMD (P = .026). CMD+PDT significantly reduced the frequency of posi- tive canals relative to CMD alone (P = .0003). After CMD+PDT, 45 of 52 canals (86.5%) had no CFUs as compared with 24 of 49 canals (49%) treated with CMD (canal flush samples). The CFU reductions were similar when teeth or canals were treated as indepen- dent entities. Post-treatment detection levels for all species were markedly lower for canals treated by CMD+PDT than they were for those treated by CMD alone. Bacterial species within dentinal tubules were de- tected in 17 of 22 (77.3%) and 15 of 29 (51.7%) canals in the CMD and CMD+PDT groups, respectively (P = .034).
Conclusions:
Data indicate that PDT significantly reduces residual bacteria within the root canal system, and that PDT, if further enhanced by technical improve- ments, holds substantial promise as an adjunct to CMD.
Key Words
Endodontic disinfection, ex vivo, methylene blue, photodynamic therapy
(J Endod 2011;37:217–222)
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