title: Efficacy of 4 Irrigation Protocols in Killing Bacteria Colonized in Dentinal Tubules Examined by a Novel Confocal Laser Scanning Microscope Analysis.
abstract: BACKGROUND
  The aim of this study was to determine the efficiency of 4 irrigation systems in eliminating bacteria in root canals, particularly in dentinal tubules.
  
  
  METHODS
  Roots of human teeth were prepared to 25/04, autoclaved, and inoculated with Enterococcus faecalis for 3 weeks. Canals were then disinfected by (1) standard needle irrigation, (2) sonically agitating with EndoActivator, (3) XP Endo finisher, or (4) erbium:yttrium aluminum garnet laser (PIPS) (15 roots/group). The bacterial reduction in the canal was determined by MTT assays. For measuring live versus dead bacteria in the dentinal tubules (4 teeth/group), teeth were split open and stained with LIVE/DEAD BackLight. Coronal, middle, and apical thirds of the canal dentin were scanned by using a confocal laser scanning microscope (CLSM) to determine the ratio of dead/total bacteria in the dentinal tubules at various depths.
  
  
  RESULTS
  All 4 irrigation protocols significantly eliminated bacteria in the canal, ranging from 89.6% to 98.2% reduction (P < .001). XP Endo had the greatest bacterial reduction compared with other 3 techniques (P < .05). CLSM analysis showed that XP Endo had the highest level of dead bacteria in the coronal, middle, and apical segments at 50-μm depth. On the other hand, PIPS had the greatest bacterial killing efficiency at the 150-μm depth in all 3 root segments.
  
  
  CONCLUSIONS
  XP Endo appears to be more efficient than other 3 techniques in disinfecting the main canal space and up to 50 μm deep into the dentinal tubules. PIPS appears to be most effective in killing the bacteria deep in the dentinal tubules.
authors.affiliation: Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Adham A
authors.initials: AA
authors.lastname: Azim
authors.affiliation: Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Hacer
authors.initials: H
authors.lastname: Aksel
authors.affiliation: Department of Biostatistics, University at Buffalo School of Public Health and Health Professions, Buffalo, New York.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhuang
authors.affiliation: Department of Biostatistics, University at Buffalo School of Public Health and Health Professions, Buffalo, New York.
authors.forename: Terry
authors.initials: T
authors.lastname: Mashtare
authors.affiliation: Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Jegdish P
authors.initials: JP
authors.lastname: Babu
authors.affiliation: Department of Bioscience Research, College of Dentistry, University of Tennessee Health Science Center, Memphis, Tennessee. Electronic address: gtjhuang@uthsc.edu.
authors.forename: George T-J
authors.initials: GT
authors.lastname: Huang
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D058491:Bacterial Load; D001431:Bacteriological Techniques; D001641:Bicuspid / Q000000981:diagnostic imaging / Q000187:drug effects / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology / Q000648:ultrastructure; D003804:Dentin / Q000000981:diagnostic imaging* / Q000187:drug effects* / Q000382:microbiology* / Q000648:ultrastructure; D004203:Disinfection / Q000379:methods; D004492:Edetic Acid / Q000494:pharmacology; D013293:Enterococcus faecalis / Q000187:drug effects / Q000254:growth & development; D006801:Humans; D053844:Lasers, Solid-State / Q000627:therapeutic use; D008334:Mandible; D008422:Materials Testing; D050296:Microbial Viability / Q000187:drug effects; D018613:Microscopy, Confocal / Q000379:methods*; D008963:Molar / Q000000981:diagnostic imaging / Q000187:drug effects / Q000382:microbiology; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000494:pharmacology*; D018915:Root Canal Preparation / Q000379:methods; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000494:pharmacology; D013010:Sonication / Q000379:methods; D019227:Tooth Apex / Q000000981:diagnostic imaging / Q000187:drug effects / Q000382:microbiology / Q000648:ultrastructure
chemical_list: D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite
keywords: CLSM; EndoActivator; MTT assay; PIPS; XP Endo; dentinal tubules; root canal disinfection