title: Smear layer influence on the apical seal of four different obturation techniques.
abstract: The purpose of this study was the in vitro evaluation of four techniques for the obturation of the root canal system in the presence or absence of a smear layer. Ninety-six human upper central incisors were instrumented using the pressureless crown-down technique and irrigated with 5.25% NaOCl. The teeth that had the smear layer removed were irrigated with this solution in combination with 17% EDTA. The teeth were obturated with lateral condensation with an accessory or standardized cone as the main cone, with vertical condensation of warm gutta-percha or with thermoplasticized injectable gutta-percha. Apical leakage was assessed by measuring the linear penetration of methylene blue dye with a stereomicroscope. The results showed no significant differences in the degree of leakage with and without the smear layer when the samples were considered as a whole. However, when the groups were assessed separately, teeth in the lateral condensation with an accessory main cone group and teeth in the thermoplasticized group leaked less with a smear layer present. In contrast teeth with lateral condensation and a standardized main cone leaked more with a smear layer present. In the vertical condensation groups there was no difference attributable to the smear layer.
authors.affiliation: Departamento de Odontologia, Pontifícia Universidade Católica de Minas Gerais, Avenida Francisco Deslandes 62, 30310-530-Anchieta, Belo Horizonte, M.G., Brazil.
authors.forename: J A
authors.initials: JA
authors.lastname: Fróes
authors.forename: H G
authors.initials: HG
authors.lastname: Horta
authors.forename: A B
authors.initials: AB
authors.lastname: da Silveira
mesh_terms: D002614:Chelating Agents / Q000627:therapeutic use; D004396:Coloring Agents; D001840:Dental Bonding; D003763:Dental Leakage / Q000175:diagnosis; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003804:Dentin / Q000648:ultrastructure*; D004202:Disinfectants / Q000627:therapeutic use; D004492:Edetic Acid / Q000627:therapeutic use; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D007180:Incisor; D008751:Methylene Blue; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000295:instrumentation / Q000379:methods*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013223:Statistics as Topic
chemical_list: D002614:Chelating Agents; D004396:Coloring Agents; D004202:Disinfectants; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D006171:Gutta-Percha; D004492:Edetic Acid; D012973:Sodium Hypochlorite; D008751:Methylene Blue