title: In vivo antimicrobial effects of endodontic treatment procedures as assessed by molecular microbiologic techniques.
abstract: BACKGROUND
  This culture-independent molecular microbiology study evaluated the antimicrobial effects of chemomechanical preparation supplemented by intracanal medication during treatment of teeth with apical periodontitis.
  
  
  METHODS
  Samples were taken from 24 necrotic root canals at the baseline (S1), after chemomechanical preparation by using 2.5% NaOCl as the irrigant (S2), and after a 7-day interappointment medication with calcium hydroxide paste in either glycerin (CHG) or camphorated paramonochlorophenol/glycerin (CHPG) (S3). Bacterial, archaeal, and fungal presence was evaluated by polymerase chain reaction (PCR), and bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 28 candidate endodontic pathogens.
  
  
  RESULTS
  All S1 samples were positive for bacteria but negative for both archaea and fungi. Treatment procedures were highly effective in reducing the bacterial levels and number of taxa. Overall, 46% of S2 samples and 62.5% of S3 samples were PCR-negative for bacteria. Specifically, S2 and S3 samples yielded negative PCR results in 50% and 58% of the canals in the CHG group and in 42% and 67% of the canals in the CHPG group, respectively. Except for comparisons with S1 samples, no other statistically significant differences were observed for intragroup and intergroup comparisons involving S2 and S3. Several taxa were still found in S2 and S3 samples, and the most prevalent were Propionibacterium acnes and Streptococcus species.
  
  
  CONCLUSIONS
  Bacterial levels and number of taxa were substantially reduced after chemomechanical preparation and intracanal medication. However, presence of detectable levels of persisting bacteria in many cases indicates that the search for more effective antimicrobial treatment strategies should be stimulated.
authors.affiliation: Department of Endodontics and Molecular Microbiology Laboratory, Estácio de Sá University, Rio de Janeiro, Brazil.
authors.forename: Isabela N
authors.initials: IN
authors.lastname: Rôças
authors.forename: José F
authors.initials: JF
authors.lastname: Siqueira
mesh_terms: D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D001105:Archaea / Q000302:isolation & purification; D001419:Bacteria / Q000145:classification / Q000187:drug effects; D058491:Bacterial Load; D041963:Bacteroidetes / Q000187:drug effects / Q000302:isolation & purification; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002164:Camphor / Q000627:therapeutic use; D002733:Chlorophenols / Q000627:therapeutic use; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003790:Dental Pulp Necrosis / Q000382:microbiology / Q000628:therapy; D004203:Disinfection / Q000379:methods*; D004338:Drug Combinations; D005658:Fungi / Q000302:isolation & purification; D005990:Glycerol / Q000627:therapeutic use; D006801:Humans; D008828:Microbiological Techniques; D009693:Nucleic Acid Hybridization; D010485:Periapical Periodontitis / Q000382:microbiology / Q000628:therapy; D016133:Polymerase Chain Reaction; D017861:Porphyromonas / Q000187:drug effects / Q000302:isolation & purification; D011425:Propionibacterium acnes / Q000187:drug effects / Q000302:isolation & purification; D012388:Root Canal Irrigants / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D012997:Solvents / Q000627:therapeutic use; D013291:Streptococcus / Q000187:drug effects / Q000302:isolation & purification
chemical_list: D000891:Anti-Infective Agents, Local; D002733:Chlorophenols; D004338:Drug Combinations; D012388:Root Canal Irrigants; D012997:Solvents; D002164:Camphor; C029804:camphorated parachlorophenol; D012973:Sodium Hypochlorite; D005990:Glycerol; D002126:Calcium Hydroxide