Photodynamic inactivation of Enterococcus faecalis in dental root canals in vitro

F Foschi; CR Fontana; K Ruggiero; R Riahi; A Vera; AG Doukas; TC Pagonis; R Kent; PP Stashenko; NS Soukos

doi:10.1002/lsm.20579

Photodynamic inactivation of Enterococcus faecalis in dental root canals in vitro

F Foschi, CR Fontana, K Ruggiero, R Riahi, A Vera, AG Doukas, TC Pagonis, R Kent, PP Stashenko, NS Soukos

Peninsula Dental School

Research output: Contribution to journal › Article › peer-review

Abstract

AbstractBackground and ObjectivesWe previously reported the use of a flexible fiber optic that uniformly distributed light in the root canal space for targeting bacteria after their sensitization with methylene blue (MB). In the present study, we investigated the photodynamic effects of MB on Enterococcus faecalis species in experimentally infected root canals of extracted teeth after their sensitization with a concentration of MB that exhibits reduced dark toxicity.Study Design/Materials and MethodsIn a model of root canal infection, 64 root canal specimens were prepared from extracted, single‐rooted teeth and inoculated with E. faecalis (ATCC 29212). Three days later root canal infection was confirmed by scanning electron microscopy. The root canal systems were then incubated with 6.25 µg/ml MB for 5 minutes followed by exposure to light at 665 nm (60 J/cm2) that was delivered from a diode laser via a fiber optic with a diameter of 500 µm. Following photodynamic therapy (PDT) the canal content was sampled by flushing the root canals, serially diluted and cultured on blood agar. Survival fractions were calculated by counting colony‐forming units. High‐performance liquid chromatography (HPLC) was employed to determine the porphyrins content of E. faecalis.ResultsScanning electron microscopy confirmed the presence of bacteria in the root canal system. PDT achieved 77.5% reduction of E. faecalis viability. MB alone and light alone reduced bacterial viability by 19.5% and 40.5%, respectively. HPLC did not reveal any porphyrin patterns expressed by E. faecalis.ConclusionThe results of this study support the need to determine the optimum MB concentration and light parameters to maximize bacterial killing in root canals. Lasers Surg. Med. 39:782–787, 2007. © 2007 Wiley‐Liss, Inc.

Original language	English
Pages (from-to)	782-787
Number of pages	0
Journal	Lasers in Surgery and Medicine
Volume	39
Issue number	10
DOIs	https://doi.org/10.1002/lsm.20579
Publication status	Published - Dec 2007

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10.1002/lsm.20579

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title = "Photodynamic inactivation of Enterococcus faecalis in dental root canals in vitro",

abstract = "AbstractBackground and ObjectivesWe previously reported the use of a flexible fiber optic that uniformly distributed light in the root canal space for targeting bacteria after their sensitization with methylene blue (MB). In the present study, we investigated the photodynamic effects of MB on Enterococcus faecalis species in experimentally infected root canals of extracted teeth after their sensitization with a concentration of MB that exhibits reduced dark toxicity.Study Design/Materials and MethodsIn a model of root canal infection, 64 root canal specimens were prepared from extracted, single‐rooted teeth and inoculated with E. faecalis (ATCC 29212). Three days later root canal infection was confirmed by scanning electron microscopy. The root canal systems were then incubated with 6.25 µg/ml MB for 5 minutes followed by exposure to light at 665 nm (60 J/cm2) that was delivered from a diode laser via a fiber optic with a diameter of 500 µm. Following photodynamic therapy (PDT) the canal content was sampled by flushing the root canals, serially diluted and cultured on blood agar. Survival fractions were calculated by counting colony‐forming units. High‐performance liquid chromatography (HPLC) was employed to determine the porphyrins content of E. faecalis.ResultsScanning electron microscopy confirmed the presence of bacteria in the root canal system. PDT achieved 77.5% reduction of E. faecalis viability. MB alone and light alone reduced bacterial viability by 19.5% and 40.5%, respectively. HPLC did not reveal any porphyrin patterns expressed by E. faecalis.ConclusionThe results of this study support the need to determine the optimum MB concentration and light parameters to maximize bacterial killing in root canals. Lasers Surg. Med. 39:782–787, 2007. {\textcopyright} 2007 Wiley‐Liss, Inc.",

author = "F Foschi and CR Fontana and K Ruggiero and R Riahi and A Vera and AG Doukas and TC Pagonis and R Kent and PP Stashenko and NS Soukos",

year = "2007",

month = dec,

doi = "10.1002/lsm.20579",

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T1 - Photodynamic inactivation of Enterococcus faecalis in dental root canals in vitro

AU - Foschi, F

AU - Fontana, CR

AU - Ruggiero, K

AU - Riahi, R

AU - Vera, A

AU - Doukas, AG

AU - Pagonis, TC

AU - Kent, R

AU - Stashenko, PP

AU - Soukos, NS

PY - 2007/12

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N2 - AbstractBackground and ObjectivesWe previously reported the use of a flexible fiber optic that uniformly distributed light in the root canal space for targeting bacteria after their sensitization with methylene blue (MB). In the present study, we investigated the photodynamic effects of MB on Enterococcus faecalis species in experimentally infected root canals of extracted teeth after their sensitization with a concentration of MB that exhibits reduced dark toxicity.Study Design/Materials and MethodsIn a model of root canal infection, 64 root canal specimens were prepared from extracted, single‐rooted teeth and inoculated with E. faecalis (ATCC 29212). Three days later root canal infection was confirmed by scanning electron microscopy. The root canal systems were then incubated with 6.25 µg/ml MB for 5 minutes followed by exposure to light at 665 nm (60 J/cm2) that was delivered from a diode laser via a fiber optic with a diameter of 500 µm. Following photodynamic therapy (PDT) the canal content was sampled by flushing the root canals, serially diluted and cultured on blood agar. Survival fractions were calculated by counting colony‐forming units. High‐performance liquid chromatography (HPLC) was employed to determine the porphyrins content of E. faecalis.ResultsScanning electron microscopy confirmed the presence of bacteria in the root canal system. PDT achieved 77.5% reduction of E. faecalis viability. MB alone and light alone reduced bacterial viability by 19.5% and 40.5%, respectively. HPLC did not reveal any porphyrin patterns expressed by E. faecalis.ConclusionThe results of this study support the need to determine the optimum MB concentration and light parameters to maximize bacterial killing in root canals. Lasers Surg. Med. 39:782–787, 2007. © 2007 Wiley‐Liss, Inc.

AB - AbstractBackground and ObjectivesWe previously reported the use of a flexible fiber optic that uniformly distributed light in the root canal space for targeting bacteria after their sensitization with methylene blue (MB). In the present study, we investigated the photodynamic effects of MB on Enterococcus faecalis species in experimentally infected root canals of extracted teeth after their sensitization with a concentration of MB that exhibits reduced dark toxicity.Study Design/Materials and MethodsIn a model of root canal infection, 64 root canal specimens were prepared from extracted, single‐rooted teeth and inoculated with E. faecalis (ATCC 29212). Three days later root canal infection was confirmed by scanning electron microscopy. The root canal systems were then incubated with 6.25 µg/ml MB for 5 minutes followed by exposure to light at 665 nm (60 J/cm2) that was delivered from a diode laser via a fiber optic with a diameter of 500 µm. Following photodynamic therapy (PDT) the canal content was sampled by flushing the root canals, serially diluted and cultured on blood agar. Survival fractions were calculated by counting colony‐forming units. High‐performance liquid chromatography (HPLC) was employed to determine the porphyrins content of E. faecalis.ResultsScanning electron microscopy confirmed the presence of bacteria in the root canal system. PDT achieved 77.5% reduction of E. faecalis viability. MB alone and light alone reduced bacterial viability by 19.5% and 40.5%, respectively. HPLC did not reveal any porphyrin patterns expressed by E. faecalis.ConclusionThe results of this study support the need to determine the optimum MB concentration and light parameters to maximize bacterial killing in root canals. Lasers Surg. Med. 39:782–787, 2007. © 2007 Wiley‐Liss, Inc.

U2 - 10.1002/lsm.20579

DO - 10.1002/lsm.20579

M3 - Article

SN - 0196-8092

VL - 39

SP - 782

EP - 787

JO - Lasers in Surgery and Medicine

JF - Lasers in Surgery and Medicine

IS - 10

ER -

Photodynamic inactivation of Enterococcus faecalis in dental root canals in vitro

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