title: Antimicrobial substantivity of alexidine and chlorhexidine in dentin.
abstract: BACKGROUND
  The use of irrigating solutions with long-lived activity helps to avoid failure of endodontic therapy. The aim of the present study was to evaluate and compare the antimicrobial substantivity against Enterococcus faecalis by using as carrier a dentin-volumetric unit exposed to chlorhexidine (CHX) and alexidine (ALX).
  
  
  METHODS
  Standardized dentin blocks of human molars were treated for 1 minute with 0.5% CHX, 2% CHX, 1% ALX, and 2% ALX. They were exposed to E. faecalis in suspension to determine antimicrobial substantivity during a period of 80 days. Results were analyzed by means of Kaplan-Meier survival analysis (P < .05).
  
  
  RESULTS
  ALX obtained the best results, with differences that were significantly different from CHX regardless of the concentration. Although all the samples treated with CHX were contaminated at the end of the study period, a direct relationship was seen between concentration and survival time. There was no statistically significant difference between 2% and 1% ALX.
  
  
  CONCLUSIONS
  The present study shows that 2% and 1% ALX used for 1 minute provide longer antimicrobial substantivity against E. faecalis than CHX when applied to 2% and 0.5%.
authors.affiliation: Department of Stomatology, School of Dentistry, University of Granada, Granada, Spain. Electronic address: rbarrios@ugr.es.
authors.forename: Rocío
authors.initials: R
authors.lastname: Barrios
authors.forename: Carmen María
authors.initials: CM
authors.lastname: Ferrer-Luque
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Arias-Moliz
authors.forename: Matilde
authors.initials: M
authors.lastname: Ruiz-Linares
authors.forename: Manuel
authors.initials: M
authors.lastname: Bravo
authors.forename: Pilar
authors.initials: P
authors.lastname: Baca
mesh_terms: D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000494:pharmacology*; D058491:Bacterial Load / Q000187:drug effects; D001431:Bacteriological Techniques; D001645:Biguanides / Q000008:administration & dosage / Q000494:pharmacology*; D002710:Chlorhexidine / Q000008:administration & dosage / Q000494:pharmacology*; D003804:Dentin / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000254:growth & development; D006801:Humans; D008422:Materials Testing; D050296:Microbial Viability / Q000187:drug effects; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000891:Anti-Infective Agents, Local; D001645:Biguanides; D012388:Root Canal Irrigants; C001570:alexidine; D002710:Chlorhexidine
keywords: Alexidine; Enterococcus faecalis; antimicrobial substantivity; chlorhexidine