title: Push-out bond strength of circular and oval-shaped fiber posts.
abstract: This study aimed at evaluating the post-root dentin push-out bond strength of circular and oval posts luted in oval-shaped canals with two different resin cements. Twenty extracted premolars with oval-shaped canals were selected, endodontically instrumented and obturated. The teeth were divided into two groups according to the drill used for post-space preparation and to the post shape (Ellipson oval tip + post and MTwoPF + DT Light-Post). Each group was then subdivided into two subgroups according to the cement (Gradia Core and Corecem Automix). The post-dentin bond strength was evaluated with the thin-slice push-out test. The bonded surface area was calculated for each post shape with an appropriate geometric formula in order to express the retentive strength in megapascal. Push-out strength data were analyzed with the Kruskal-Wallis ANOVA. The results showed that neither the drill-post system nor the cement significantly affected the push-out strength. The means (SD) of the push-out bond strengths in the experimental subgroups were the following: 11.79 MPa (4.77) for Gradia Core/Ellipson tip and post, 13.36 MPa (5.16) for Gradia Core/MtwoPF and DT Light-Post, 11.18 MPa (2.58) for Corecem Automix/Ellipson tip and post, and 10.91 MPa (3.89) for Corecem Automix/MtwoPF and DT Light-Post. In conclusion, circular and oval posts achieved similar retentive strengths in oval canals.
authors.affiliation: School of Dental Medicine, Department of Fixed Prosthodontics and Dental Materials, University of Siena, Policlinico Le Scotte, viale Bracci, 53100 Siena, Italy.
authors.forename: Ivanovic
authors.initials: I
authors.lastname: Coniglio
authors.forename: Elisa
authors.initials: E
authors.lastname: Magni
authors.forename: Amerigo
authors.initials: A
authors.lastname: Cantoro
authors.forename: Cecilia
authors.initials: C
authors.lastname: Goracci
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D003786:Dental Pulp Cavity / Q000648:ultrastructure; D003804:Dentin / Q000648:ultrastructure; D006801:Humans; D008422:Materials Testing; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation / Q000379:methods; D055116:Self-Curing of Dental Resins; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D019553:Tooth, Nonvital / Q000473:pathology
chemical_list: D003188:Composite Resins; C470230:Gradia; D019279:Resin Cements