title: Vertical root fracture in upper premolars with endodontic posts: finite element analysis.
abstract: Upper premolars restored with endodontic posts present a high incidence of vertical root fracture (VRF). Two hypotheses were tested: (1) the smaller mesiodistal diameter favors stress concentration in the root and (2) the lack of an effective bonding between root and post increases the risk of VRF. Using finite element analysis, maximum principal stress was analyzed in 3-dimensional intact upper second premolar models. From the intact models, new models were built including endodontic posts of different elastic modulus (E = 37 or E = 200 GPa) with circular or oval cross-section, either bonded or nonbonded to circular or oval cross-section root canals. The first hypothesis was partially confirmed because the conditions involving nonbonded, low-modulus posts showed lower tensile stress for oval canals compared to circular canals. Tensile stress peaks for the nonbonded models were approximately three times higher than for the bonded or intact models, therefore confirming the second hypothesis.
authors.affiliation: Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, Brazil.
authors.forename: Andrea F V
authors.initials: AF
authors.lastname: Santos
authors.forename: Carina B
authors.initials: CB
authors.lastname: Tanaka
authors.forename: Raul G
authors.initials: RG
authors.lastname: Lima
authors.forename: Camila O M
authors.initials: CO
authors.lastname: Espósito
authors.forename: Rafael Y
authors.initials: RY
authors.lastname: Ballester
authors.forename: Roberto R
authors.initials: RR
authors.lastname: Braga
authors.forename: Josete B C
authors.initials: JB
authors.lastname: Meira
mesh_terms: D001641:Bicuspid / Q000293:injuries; D003198:Computer Simulation; D001840:Dental Bonding / Q000009:adverse effects*; D003786:Dental Pulp Cavity / Q000033:anatomy & histology; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D003765:Models, Dental; D011176:Post and Core Technique / Q000009:adverse effects*; D013718:Tensile Strength; D014082:Tooth Fractures / Q000209:etiology*; D014092:Tooth Root / Q000293:injuries*