One- versus two-visit endodontic treatment of teeth with apical periodontitis: a histobacteriologic study.
BACKGROUND
This study analyzed the in vivo microbiological status of the root canal systems of mesial roots of mandibular molars with primary apical periodontitis after 1- or 2-visit endodontic treatment.


METHODS
Mesial root canals were instrumented by using either a combination of K3 and LightSpeed instruments (mesiobuccal canals) or the ProTaper system (mesiolingual canals), with 5% NaOCl irrigation. Patency files were used. Smear layer was removed, and a final rinse with 5 mL of 2% chlorhexidine was performed. In the 2-visit group (7 roots, 14 canals), canals were medicated with calcium hydroxide for 1 week and then obturated by using the continuous wave of compaction technique. In the 1-visit group (6 roots, 12 canals), canals were immediately obturated after chemomechanical procedures. Teeth were extracted 1 week after root canal instrumentation and processed for histobacteriologic analysis.


RESULTS
In the 1-visit group, no case was completely free of bacteria; residual bacteria occurred in the main root canal (5 of 6 cases), isthmus (5 of 6), apical ramifications (4 of 6), and dentinal tubules (5 of 6). In the 2-visit group, 2 cases were rendered bacteria-free; residual bacteria were found in the main canal only in 2 cases (none of them with persistent dentinal tubule infection), in the isthmus (4 of 7 cases), and in ramifications (2 of 7). The 2 instrumentation techniques performed similarly. When filling material was observed in ramifications, it was usually intermixed with necrotic tissue, debris, and bacteria.


CONCLUSIONS
The 2-visit protocol by using an interappointment medication with calcium hydroxide resulted in improved microbiological status of the root canal system when compared with the 1-visit protocol. Residual bacteria were more frequent and abundant in ramifications, isthmuses, and dentinal tubules when root canals were treated without an interappointment medication. Apical ramifications and isthmuses were never completely filled. The use of an antibacterial interappointment agent is necessary to maximize bacterial reduction before filling.
Department of Endodontics, University of Tlaxcala, Tlaxcala, Mexico.
Jorge
J
Vera
José F
JF
Siqueira
Domenico
D
Ricucci
Simona
S
Loghin
Nancy
N
Fernández
Belina
B
Flores
Alvaro G
AG
Cruz
D000328:Adult; D000368:Aged; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use; D001419:Bacteria / Q000302:isolation & purification*; D058491:Bacterial Load; D018441:Biofilms; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002710:Chlorhexidine / Q000627:therapeutic use; D003722:Dental Alloys / Q000737:chemistry; D003754:Dental High-Speed Equipment; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003790:Dental Pulp Necrosis / Q000382:microbiology / Q000628:therapy; D003804:Dentin / Q000382:microbiology; D004867:Equipment Design; D005260:Female; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008768:Methylmethacrylates / Q000627:therapeutic use; D008875:Middle Aged; D009532:Nickel / Q000737:chemistry; D010485:Periapical Periodontitis / Q000382:microbiology / Q000628:therapy*; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation; D012390:Root Canal Therapy / Q000379:methods*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000382:microbiology; D015035:Zinc Oxide-Eugenol Cement / Q000627:therapeutic use
D000891:Anti-Infective Agents, Local; D003722:Dental Alloys; D008768:Methylmethacrylates; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D015035:Zinc Oxide-Eugenol Cement; C040654:titanium nickelide; C031667:IRM cement; D009532:Nickel; D006171:Gutta-Percha; D014025:Titanium; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide; D002710:Chlorhexidine