Eradication of Enterococcus faecalis biofilms by cetrimide and chlorhexidine.
BACKGROUND
Enterococcus faecalis is the most commonly isolated bacteria from root canals of teeth with persistent periapical periodontitis. Its ability to grow as a biofilm impedes the elimination of E. faecalis by using irrigating solutions. The purpose of this study was to assess the efficacy of cetrimide and chlorhexidine (CHX), alone and in association, in combined and alternating form, in eradicating biofilms of E. faecalis.


METHODS
Biofilms grown in the MBEC-high-throughput device for 24 hours were exposed to irrigating solutions for 30 seconds and 1 and 2 minutes. Eradication was defined as 100% kill of biofilm bacteria. The Student t test was used to compare the efficacy of the associations of the 2 irrigants.


RESULTS
Cetrimide eradicated E. faecalis biofilms at concentrations of 0.5%, 0.0312%, and 0.0078% at 30 seconds and 1 and 2 minutes of contact time, respectively. CHX did not eradicate the biofilms at any of the concentrations (4% initial concentration) or times assayed. The association of 0.1% and 0.05% cetrimide with any concentration of CHX, whether in combined or alternating application, effectively eradicated E. faecalis biofilms at all the contact times tested. Eradication was also achieved with 0.02% and 0.01% cetrimide at 2 minutes. Statistical analysis revealed significantly better results with alternating rather than combined use of cetrimide and CHX (P < .05).


CONCLUSIONS
The associated use of cetrimide and CHX provided better results than their applications as single agents against E. faecalis biofilms, and the alternating application was significantly more effective than the combined mode of application.
Arias-Moliz
María Teresa
MT
Department of Microbiology, School of Dentistry, University of Granada, Granada, Spain. mtarias@correo.ugr.es
Ferrer-Luque
Carmen María
CM
González-Rodríguez
María Paloma
MP
Valderrama
Mariano José
MJ
Baca
Pilar
P
D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D002710:Chlorhexidine / Q000008:administration & dosage / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004338:Drug Combinations; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000502:physiology; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000494:pharmacology*
D000891:Anti-Infective Agents, Local; D002593:Cetrimonium Compounds; D004338:Drug Combinations; D012388:Root Canal Irrigants; D002710:Chlorhexidine; D000077286:Cetrimonium