Biomechanical behavior of teeth without remaining coronal structure restored with different post designs and materials Angélica Maroli a , Kaue Andreas Lotice Hoelcher a , Vagner Flavio Reginato a,b , Aloisio Oro Spazzin a , Ricardo Armini Caldas b , Atais Bacchi a, ⁎ a School of Dentistry, Meridional Faculty – IMED, Passo Fundo, RS, Brazil b Piracicaba Dental School, University of Campinas – FOP/UNICAMP, Piracicaba, SP, Brazil abstract article info Article history: Received 11 December 2016 Received in revised form 13 March 2017 Accepted 14 March 2017 Available online 18 March 2017 The aim of this study was to access the biomechanical behavior of teeth without remaining coronal structure when restored with posts of different materials and configurations. Fifty bovine teeth (n = 10 per group) with standard dimensions were restored as follows: cast post and core (CPC), prefabricated metallic post (PFM), par- allel glass-fiber post (P-FP), conical glass-fiber post (C-FP) or composite core (no post, CC). The survival rate dur- ing thermomechanical challenging (TC), the fracture strength (FS), and failure pattern (FP) were evaluated. Finite element models were realized to evaluate the stress distribution with a 100 N load. All post-containing teeth sur- vived TC, while CC had 30% of failures. CPC and C-FP had the higher fracture strength, but a high number of irrep- arable fractures (60%), such as PFM (70%). Von Mises analysis has shown the maximum stresses into the canal in groups restored with metallic posts, while glass-fiber posts and CC presented the maximum stresses at load con- tact point in the crown. CPC led to higher modified von Mises (mvM) stress in the cervical third of dentin. How- ever, mvM values did not reach the dentin fracture limit for any group. Analysis of maximal contact pressure has shown better stress distribution along with the dentin interface in post-containing groups, especially for CPC. © 2017 Elsevier B.V. All rights reserved. Keywords: Endodontic treated tooth Intracanal post Tooth fracture strength Tooth FEM analysis Prediction of tooth fracture 1. Introduction Intracanal posts are cylindrical or conical structures traditionally made of metal or fiber used into the root canal of endodontically treated teeth. They have been widely used in Dentistry in cases where the tooth remaining coronal structure is not enough to provide adequate support to the restorative material [1]. Cast post and cores were the most used intracanal posts for years. They are confectioned initially as a polymer matrix made by poly (methyl methacrylate) individualized to the tooth structure and posteriorly casted in noble or alterative alloys to be bonded to the tooth structure in a second appointment. However, the need for fastening the clinical procedure led to the development of prefabricated metallic posts. Recently, the use of more esthetic restora- tions such as crowns made of glass ceramics, which are highly translu- cent and because of that, the final color is much dependent on the substrate coloration, claimed for the need of more esthetic alternatives to the metallic posts. Therefore, fiber posts, which are commercially available in white coloration or transparent, have been introduced and are currently used in a large scale. Metallic posts have a much higher elastic modulus (E) than fiber posts. This factor has been pointed as responsible to allow a higher frac- ture strength to the system due to the higher ability to support load con- centration before deformation being indicated in cases where high occlusal loads are present such as bruxer patients and absence of well- distributed occlusion [2–4]. However, it has been suggested that metal- lic posts cause a higher amount of root catastrophic fractures in labora- tory tests by transferring high stress to the tooth structure [3,5,6]. Besides the esthetic advantages of fiber posts, the elastic modulus close to that of dentin might provide better stress distribution along the system even though their fracture strength is considered lower than metallic posts [7]. Variation also exists in regards to the post configurations. Metallic posts can be used as personalized cast post and cores or parallel- prefabricated posts that are relined into the canal with composite resin. Fiber posts were initially introduced in a parallel configuration to be relined with composite resin. More recently, canal-shaped conical fiber posts were introduced having the adaptation provided by a specific reamer to prepare the canal, which has the same post shape and diam- eter. The behavior of teeth reinforced by these different post systems is not elucidated. The absence of remaining coronal structure is one of the conditions that still challenges the post selection. A review has shown that posts behave better when a 1.5 to 2 mm remaining coronal structure is Materials Science and Engineering C 76 (2017) 839–844 ⁎ Corresponding author at: Rua Senador Pinheiro, 304, 99070-220 Passo Fundo, RS, Brazil. E-mail address: atais.bacchi@imed.edu.br (A. Bacchi). http://dx.doi.org/10.1016/j.msec.2017.03.152 0928-4931/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Materials Science and Engineering C journal homepage: www.elsevier.com/locate/msec