title: Effect of Resin Cement Porosity on Retention of Glass-Fiber Posts to Root Dentin: An Experimental and Finite Element Analysis.
abstract: The aim of this study was to evaluate the effect of porosity of self-adhesive resin on the stress distribution, post retention and failure mode of fiber post cemented to human root dentin. Ten human central upper incisors with circular root canal were selected. They were sectioned with 15 mm and were endodontically filled. The roots were scanned using micro-CT after post space preparation for root filling remaining evaluation. Fiber posts were cemented using self-adhesive resin cement (Rely X U200, 3M-ESPE). Two 1-mm-thick slices from the cervical, medium and apical thirds were scanned for resin cement bubbles volume measurements and submitted to a push-out test (PBS). Three operators using stereomicroscopy and confocal laser microscopy classified the failure mode. Stress distributions during the push-out test were analyzed using 3D finite element analysis. PBS values (MPa) were submitted to one-way ANOVA and Tukey's post hoc tests and the failure modes using the Kappa coefficient to assess inter-operator agreement. Chi-square test was used to determine significant differences between the methods ( = 0.05). Push-out bond strength was significantly affected by the bubbles presence in all root depth (p<0.05). The stress concentration was higher when the bubbles were present. Adhesive dentin/resin cement interface failure was the most frequent type of failure. Confocal microscopy was better than stereomicroscopy for failure analysis. Bubbles generated during resin cement insertion into the root canal negatively affect the stress distribution and the bond strength. The use of confocal microscopy is recommended for failure analysis.
authors.affiliation: Department of Restorative Dentistry and Dental Materials, BIAOR - Biomechanics Research Group, Dental School, UFU - Universidade Federal de Uberlandia, Uberlandia, MG, Brazil.
authors.forename: Natércia Rezende
authors.initials: NR
authors.lastname: Da Silva
authors.affiliation: Department of Restorative Dentistry and Dental Materials, BIAOR - Biomechanics Research Group, Dental School, UFU - Universidade Federal de Uberlandia, Uberlandia, MG, Brazil.
authors.forename: Grazielle Crystine Rodrigues
authors.initials: GC
authors.lastname: Aguiar
authors.affiliation: Department of Restorative Dentistry and Dental Materials, BIAOR - Biomechanics Research Group, Dental School, UFU - Universidade Federal de Uberlandia, Uberlandia, MG, Brazil.
authors.forename: Monise de Paula
authors.initials: Mde P
authors.lastname: Rodrigues
authors.affiliation: Department of Restorative Dentistry and Dental Materials, BIAOR - Biomechanics Research Group, Dental School, UFU - Universidade Federal de Uberlandia, Uberlandia, MG, Brazil.
authors.forename: Aline Aredes
authors.initials: AA
authors.lastname: Bicalho
authors.affiliation: Department of Oral and Maxillofacial Surgery and Implantology, BIAOR - Biomechanics Research Group, Dental School, UFU - Universidade Federal de Uberlandia, Uberlandia, MG, Brazil.
authors.forename: Priscilla Barbosa Ferreira
authors.initials: PB
authors.lastname: Soares
authors.affiliation: Department of Restorative Dentistry and Dental Materials, BIAOR - Biomechanics Research Group, Dental School, UFU - Universidade Federal de Uberlandia, Uberlandia, MG, Brazil.
authors.forename: Crisnicaw
authors.initials: C
authors.lastname: Veríssimo
authors.affiliation: Department of Restorative Dentistry and Dental Materials, BIAOR - Biomechanics Research Group, Dental School, UFU - Universidade Federal de Uberlandia, Uberlandia, MG, Brazil.
authors.forename: Carlos José
authors.initials: CJ
authors.lastname: Soares
mesh_terms: D003804:Dentin; D020342:Finite Element Analysis; D005898:Glass; D016062:Porosity; D011176:Post and Core Technique; D019279:Resin Cements; D014092:Tooth Root
chemical_list: D019279:Resin Cements