title: Thermocompaction decreases long-term push-out bond strength of methacrylate-based sealers.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the immediate and long-term bond strengths to root dentin of Epiphany/Resilon and AH Plus/gutta-percha fillings, after using either lateral condensation or Tagger's hybrid thermomechanical compaction techniques.
  
  
  METHODS
  Eighty human single-rooted teeth were used. The root canals were prepared by means of hand crown-down technique up to a #45 K-file and irrigation with 1% sodium hypochlorite was performed. Samples were randomly divided into eight (n=10) experimental groups divided according to filling material (gutta-percha/AH Plus and Resilon/Epiphany), obturation technique (Lateral compaction and Tagger's hybrid thermomechanical compaction) and storage time (24 h and 6 months). During storage, the samples were kept at 37°C and 100% humidity. After the two experimental periods, each root was sectioned perpendicular to its long axis into three serial slices and push-out tests were carried out using a universal testing machine. Statistical significant differences were set by ANOVA and Tuckey post-hoc (p<0.05).
  
  
  RESULTS
  Using thermocompaction technique, the samples filled with Epiphany/Resilon decreased significantly the bond strength after a 6 months storage-period (p<0.05) and the ones filled with AH Plus/gutta-percha presented a tendency to lower values of the push-out test, although not statistically significant. For both materials, dentin bond strength of the specimens filled by means of lateral condensation remained stable throughout the experimental periods.
  
  
  CONCLUSIONS
  Under the limitations of the current study, it can be concluded that the thermocompaction technique and the storage time can inﬂuence push-out bond strength when used with methacrylate-based sealers.
authors.affiliation: Department of Conservative Dentistry, Federal University of Rio Grande do Sul, UFRGS , Porto Alegre , Brazil.
authors.forename: Carolina Bender
authors.initials: CB
authors.lastname: Hoppe
authors.forename: Roberta Krochenborger
authors.initials: RK
authors.lastname: Scarparo
authors.forename: Daiana Elisabeth
authors.initials: DE
authors.lastname: Böttcher
authors.forename: Vicente Castelo Branco
authors.initials: VC
authors.lastname: Leitune
authors.forename: Fabrício Mezzomo
authors.initials: FM
authors.lastname: Collares
authors.forename: Susana Maria Werner
authors.initials: SM
authors.lastname: Samuel
authors.forename: Fabiana Soares
authors.initials: FS
authors.lastname: Grecca
mesh_terms: D055117:Curing Lights, Dental; D001840:Dental Bonding; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D004853:Epoxy Resins / Q000737:chemistry; D006171:Gutta-Percha / Q000737:chemistry; D006801:Humans; D006813:Humidity; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D011897:Random Allocation; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods*; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors
chemical_list: D004853:Epoxy Resins; D008689:Methacrylates; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; C486893:epiphany sealer; C534916:epoxy resin-based root canal sealer; C486892:resilon sealer; D006171:Gutta-Percha; D012973:Sodium Hypochlorite
keywords: bond strength; endodontics; push-out test; root canal filling materials