Endodontic photodynamic therapy ex vivo.
BACKGROUND
The objective of this study was to evaluate 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 obtained 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 μg/mL for 5 minutes, followed by exposure to red light at 665 nm with an energy fluence of 30 J/cm(2). 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 fractions were calculated by counting colony-forming units (CFUs). Partial characterization of root canal species at baseline and after CMD alone or CMD+PDT was performed by using DNA probes to a panel of 39 endodontic species in the checkerboard assay.


RESULTS
The Mantel-Haenszel χ(2) test for treatment effects demonstrated the better performance of CMD+PDT over CMD (P = .026). CMD+PDT significantly reduced the frequency of positive 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 independent 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 detected 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 improvements, holds substantial promise as an adjunct to CMD.
Division of Endodontics, Harvard School of Dental Medicine, Boston, MA, USA.
Raymond
R
Ng
Fiza
F
Singh
Despina A
DA
Papamanou
Xiaoqing
X
Song
Chitrang
C
Patel
Colleen
C
Holewa
Niraj
N
Patel
Vanja
V
Klepac-Ceraj
Carla R
CR
Fontana
Ralph
R
Kent
Tom C
TC
Pagonis
Philip P
PP
Stashenko
Nikolaos S
NS
Soukos
D001419:Bacteria / Q000528:radiation effects; D016009:Chi-Square Distribution; D003131:Combined Modality Therapy; D003646:Debridement / Q000379:methods; D003786:Dental Pulp Cavity / Q000382:microbiology / Q000528:radiation effects* / Q000601:surgery; D003790:Dental Pulp Necrosis / Q000628:therapy*; D004203:Disinfection / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008751:Methylene Blue / Q000528:radiation effects / Q000627:therapeutic use; D010485:Periapical Periodontitis / Q000628:therapy*; D010778:Photochemotherapy / Q000295:instrumentation / Q000379:methods*; D011838:Radiation-Sensitizing Agents / Q000528:radiation effects / Q000627:therapeutic use; D012390:Root Canal Therapy / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome
D011838:Radiation-Sensitizing Agents; D008751:Methylene Blue
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