title: Microbiological profile resistant to different intracanal medications in primary endodontic infections.
abstract: BACKGROUND
  This clinical study aimed to determine the microbiological profile resistant to different intracanal medications in primary endodontic infections by using both microbiological culture and the checkerboard DNA-DNA hybridization technique.
  
  
  METHODS
  Twenty primarily infected root canals were selected and then instrumented before being randomly divided into 2 groups according to the intracanal medications: calcium hydroxide (Ca[OH]2) or Ca(OH)2 + chlorhexidine (CHX). Samples were collected before and after root canal procedures, which consisted in submitting them to microbiological culture and processing them for checkerboard DNA-DNA hybridization.
  
  
  RESULTS
  No differences were found between the Ca(OH)2 (99.98%) and Ca(OH)2 + CHX groups (99.76%) regarding the median percentage values for the reduction of cultivable bacteria. The most frequently detected species were Capnocytophaga ochracea (70%) and Fusobacterium nucleatum ssp. vincentii (70%) in the initial samples. After instrumentation, the most frequently detected species were E. faecium (60%). After root canal treatments using either Ca(OH)2 or Ca(OH)2 + CHX as intracanal medications, the most frequently detected species were F. nucleatum ssp. vincentii (90%) and Enterococcus faecium (40%), respectively. Both treatments significantly decreased the number of bacterial species compared with the initial sample. However, this reduction was significantly greater in the Ca(OH)2 + CHX group (P < .05). This difference was also observed when evaluating the total bacterial load (P < .05).
  
  
  CONCLUSIONS
  The use of Ca(OH)2 associated with CHX as an intracanal medication showed better results by acting on gram-positive and gram-negative microorganisms although such an action to eradicate enterococci should also be sought.
authors.affiliation: Department of Restorative Dentistry, Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil.
authors.forename: Nadia S
authors.initials: NS
authors.lastname: Ferreira
authors.affiliation: Department of Restorative Dentistry, Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil.
authors.forename: Frederico C
authors.initials: FC
authors.lastname: Martinho
authors.affiliation: Department of Restorative Dentistry, Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil.
authors.forename: Flavia G R
authors.initials: FG
authors.lastname: Cardoso
authors.affiliation: Pelotas School of Dentistry, Federal University of Pelotas, Pelotas, Rio Grande do Sul, Brazil.
authors.forename: Gustavo G
authors.initials: GG
authors.lastname: Nascimento
authors.affiliation: Department of Restorative Dentistry, Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil.
authors.forename: Cláudio A T
authors.initials: CA
authors.lastname: Carvalho
authors.affiliation: Department of Restorative Dentistry, Universidade Estadual Paulista, São José dos Campos, São Paulo, Brazil. Electronic address: marcia@fosjc.unesp.br.
authors.forename: Marcia C
authors.initials: MC
authors.lastname: Valera
mesh_terms: D000293:Adolescent; D000328:Adult; D058491:Bacterial Load; D001431:Bacteriological Techniques; D002126:Calcium Hydroxide / Q000627:therapeutic use*; D002710:Chlorhexidine / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D006801:Humans; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D010485:Periapical Periodontitis / Q000382:microbiology* / Q000628:therapy; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D012388:Root Canal Irrigants; D002126:Calcium Hydroxide; D002710:Chlorhexidine
keywords: Bacteria; checkerboard DNA-DNA hybridization; endodontic infection