title: Influence of sodium hypochlorite-based irrigants on the susceptibility of intracanal microbiota to biomechanical preparation.
abstract: This study evaluated the microbiological conditions of root canals, using smears and culture from anterior teeth and premolars with necrotic pulps associated with chronic periapical pathologies, before and after biomechanical preparation (BMP). During double-flared instrumentation, 1, 2.5 and 5% sodium hypochlorite (NaOCl)-based irrigants were used in 3 groups: GI (n=39), GII (n=36) and GIII (n=36), respectively. Before BMP, all cultures were positive and the smears showed microbiologically diverse morphotypes, including fusiforms, pleomorphic, rods, cocci and filaments. Quantitatively, 20, 20 and 23 morphotypes were identified in GI, GII and GIII, respectively). After BMP, the percentages of negative cultures in GI, GII and GIII were 74.2%, 86.3% and 93.4% (p>0.05) and the number of morphotypes decreased to 14, 15 and 5, respectively. All teeth with 2 root canals and/or associated fistulas were microbiologically negative after BMP, regardless of irrigant concentration. Gram-negative morphotypes were more susceptible to the action of irrigants. After irrigation with 5% NaOCl, only structural arrangements consisting of Gram-positive cocci and bacilli persisted. Thus, BMP plus 5% NaOCl offered the best antiseptic potential because in the few positive cultures a significant reduction in the number of microbiological morphotypes was also shown (p<0.05).
authors.affiliation: Department of Dentistry, Federal University of Vales do Jequitinhonha e Mucuri, Rua da Glória 187, 39100-00 Diamantina, MG, Brazil. janirsoares@cite11.com.br
authors.forename: Janir Alves
authors.initials: JA
authors.lastname: Soares
authors.forename: Donaldo Rosa
authors.initials: DR
authors.lastname: Pires Júnior
mesh_terms: D000293:Adolescent; D000328:Adult; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000627:therapeutic use*; D001419:Bacteria / Q000145:classification / Q000187:drug effects*; D001696:Biomechanical Phenomena; D002614:Chelating Agents / Q000627:therapeutic use; D003731:Dental Caries / Q000382:microbiology / Q000628:therapy; D003786:Dental Pulp Cavity / Q000382:microbiology*; D003790:Dental Pulp Necrosis / Q000382:microbiology / Q000628:therapy; D004492:Edetic Acid / Q000627:therapeutic use; D006090:Gram-Negative Bacteria / Q000145:classification / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000145:classification / Q000187:drug effects; D006095:Gram-Positive Cocci / Q000187:drug effects; D006801:Humans; D008875:Middle Aged; D016155:Oral Fistula / Q000382:microbiology / Q000628:therapy; D010483:Periapical Diseases / Q000382:microbiology / Q000628:therapy; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000627:therapeutic use*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000891:Anti-Infective Agents, Local; D002614:Chelating Agents; D012388:Root Canal Irrigants; D004492:Edetic Acid; D012973:Sodium Hypochlorite