title: Dissolution, dislocation and dimensional changes of endodontic sealers after a solubility challenge: a micro-CT approach.
abstract: OBJECTIVE
  To evaluate, using a novel micro-CT approach, the solubility and dimensional changes of an MTA-based sealer inside the root canal system after a solubility challenge. The MTA-based material (MTA Fillapex) was compared to a gold standard epoxy-based endodontic sealer (AH Plus).
  
  
  METHODS
  Ten human mandibular premolars with a single canal were divided randomly into two groups (n = 5) according to the sealer used. The canals were instrumented using the Reciproc System (VDW) with a R40 file and filled with R40 gutta-percha cones and one of the sealers. The filled canals were immediately scanned in a micro-CT, and after that, the teeth were immersed in 20 mL phosphate-buffered saline (PBS) at 37 °C for 7 days, when they were removed and rescanned. Final image stacks were registered against the initial stacks and the numerical difference between the initial and final volume of the filling material was obtained. Calculations were performed to identify dimensional changes of the filling material. All image stacks were 3D rendered to disclose areas of dislocation of the filling material inside or outside the root canal. The Shapiro-Wilk's test revealed that data were normally distributed; thus, the Student's t-test was used to detect statistically significant changes, assuming a 5% α-error.
  
  
  RESULTS
  No significant changes were seen for the percentage volume of material lost after the solubility challenge for both AH Plus and MTA Fillapex groups (1.44% and 1.16%, respectively). A significant difference was, however, found for the volume of filling material which revealed dimensional changes after the solubility test (6.68% for MTA Fillapex and 1.09% for AH Plus). In fact, observation of 3D models disclosed that MTA Fillapex was associated with material extrusion through the foramen in all but one sample. In AH Plus filled samples, no material extrusion was detected.
  
  
  CONCLUSIONS
  Although the solubility of both sealers was similar using this novel micro-CT approach, MTA Fillapex was associated with significant dimensional changes related to material extrusion through the apex after PBS storage compared to AH Plus.
authors.affiliation: Escola de Ciências da Saúde, Universidade do Grande Rio, Rio de Janeiro, Brazil.
authors.forename: E J
authors.initials: EJ
authors.lastname: Silva
authors.affiliation: Corpo de Bombeiros Militar do Estado do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: R
authors.identifier: http://orcid.org/0000-0003-2192-0124
authors.initials: R
authors.lastname: Perez
authors.affiliation: Escola de Ciências da Saúde, Universidade do Grande Rio, Rio de Janeiro, Brazil.
authors.forename: R M
authors.initials: RM
authors.lastname: Valentim
authors.affiliation: Faculdade de Odontologia, Universidade Federal Fluminense, Niteroi, Brazil.
authors.forename: F G
authors.identifier: http://orcid.org/0000-0001-9972-6861
authors.initials: FG
authors.lastname: Belladonna
authors.affiliation: Escola de Ciências da Saúde, Universidade do Grande Rio, Rio de Janeiro, Brazil.
authors.forename: G A
authors.initials: GA
authors.lastname: De-Deus
authors.affiliation: Laboratório de Instrumentação Nuclear, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: I C
authors.initials: IC
authors.lastname: Lima
authors.affiliation: Departamento de Odontopediatria e Ortodontia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: A A
authors.initials: AA
authors.lastname: Neves
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry / Q000627:therapeutic use*; D017610:Calcium Compounds / Q000737:chemistry / Q000627:therapeutic use*; D003786:Dental Pulp Cavity / Q000000981:diagnostic imaging; D004338:Drug Combinations; D004853:Epoxy Resins / Q000737:chemistry / Q000627:therapeutic use*; D006801:Humans; D010087:Oxides / Q000737:chemistry / Q000627:therapeutic use*; D012387:Root Canal Filling Materials / Q000737:chemistry / Q000627:therapeutic use*; D012389:Root Canal Obturation / Q000379:methods*; D017640:Silicates / Q000737:chemistry / Q000627:therapeutic use*; D012995:Solubility; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D004853:Epoxy Resins; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C534916:epoxy resin-based root canal sealer; C086631:mineral trioxide aggregate
keywords: 
  MTA
  ; endodontic sealer; micro-CT; solubility