title: Short-chain Fatty Acids in Infected Root Canals of Teeth with Apical Periodontitis before and after Treatment.
abstract: BACKGROUND
  Short-chain fatty acids (SCFAs) are bacterial metabolic end products that may function as virulence factors. This study evaluated the occurrence of SCFAs in infected root canals before and after treatment.
  
  
  METHODS
  Samples were taken from root canals of teeth with apical periodontitis before (S1) and after (S2) chemomechanical preparation with either NaOCl or chlorhexidine as the irrigant and then after interappointment medication with calcium hydroxide (S3). High-performance liquid chromatography was used for detection of SCFAs. Selected bacterial taxa that are recognized producers of the target SCFAs were identified by real-time polymerase chain reaction.
  
  
  RESULTS
  Butyric acid was the most common fatty acid in S1, followed by propionic acid. Both molecules were also found in S2 and S3 from both NaOCl and chlorhexidine groups. Lactic acid was not present in detectable levels in S1, but it occurred in 1 postinstrumentation sample and in 9 samples taken after calcium hydroxide medication. Of the target taxa, Fusobacterium nucleatum was the most prevalent in S1 (76%), followed by members of the Actinobacteria phylum (71%), Streptococcus species (59%), and Parvimonas micra (53%). Gram-positive taxa, especially streptococci, were the most prevalent bacteria in S2 and S3. SCFA detection was matched with the respective potential producer species in most cases.
  
  
  CONCLUSIONS
  This first report of SCFAs in infected root canals suggests that these molecules may play a role in the pathogenesis of apical periodontitis. Significance of persistence of SCFAs after treatment and its effects on the long-term outcome await elucidation.
authors: Molecular Microbiology Laboratory, Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: zecpro1982@gmail.com.
authors: José Claudio
authors: JC
authors: Provenzano
authors: Molecular Microbiology Laboratory, Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Isabela N
authors: IN
authors: Rôças
authors: Laboratory of Molecular Microbiology and Proteins, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Luís Fernando D
authors: LF
authors: Tavares
authors: Laboratory of Molecular Microbiology and Proteins, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Bianca Cruz
authors: BC
authors: Neves
authors: Molecular Microbiology Laboratory, Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Rio de Janeiro, Brazil.
authors: José F
authors: JF
authors: Siqueira
mesh_terms: D002126:Calcium Hydroxide / Q000627:therapeutic use; D002710:Chlorhexidine / Q000627:therapeutic use; D005232:Fatty Acids, Volatile / Q000032:analysis*; D006801:Humans; D010485:Periapical Periodontitis / Q000378:metabolism* / Q000382:microbiology / Q000628:therapy*; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D037521:Virulence Factors / Q000032:analysis
chemical_list: D005232:Fatty Acids, Volatile; D012388:Root Canal Irrigants; D037521:Virulence Factors; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide; D002710:Chlorhexidine
keywords: Apical periodontitis; butyric acid; endodontic treatment; lactic acid; propionic acid; root canal infection; short-chain fatty acids