Post and core build-ups in crown and bridge abutments: Bio-mechanical advantages and disadvantages

Abstract

Dentists often place post and core buildups on endodontically treated abutments for crown and bridge restorations. This article analyzes the bio-mechanical purposes, advantages and disadvantages of placing a core or a post and core in an endodontically treated tooth and reviews literature on post and core biomechanics. The author assesses the scientific rationale of the claim that the main purpose of a post is to retain a core, or the claim that posts weaken teeth. More likely, the main function of a post is to help prevent the abutment, on which a crown is cemented, from fracturing such that the abutment separates from the tooth root, at a fracture plane that is located approximately and theoretically at the level of the crown (or ferrule) margin. A post essentially improves the ferrule effect that is provided by the partial fixed denture prosthesis. This paper also explores the difference between bio-mechanical failures of crowns caused by lack of retention or excess taper, versus failures due to a sub-optimal ferrule effect in crown and bridge prostheses.

Restoration of Root Filled Teeth; Current Opinions and Techniques

“…Arguably one of the most important factors when considering favorable prognosis of root treated teeth is the presence of a "Ferrule" [47,48]. The presence of at least 1.5-2mm of vertical tooth structure circumferentially has a positive effect on the fracture resistance of RFT [49].…”

One‐step fiber post cementation and core build‐up in endodontically treated tooth: A clinical case report

“…However, teeth restored by such systems may show more frequent oblique/horizontal fractures in the middle third of the root, or vertical root fractures caused by both increased stress concentration in the apical region of the post and a difference in the Young's modulus between dentin and metal . An ideal core and post improves the biomechanical stability of an abutment tooth preventing debonding and root fracture or fracture of the abutment . Therefore, over the last decades, prefabricated glass fiber posts have been used as an alternative for custom metallic posts …”

Gingival tissue reaction to direct adhesive restoration: A preliminary study

“…These dental elements were considered strategic for the oral rehabilitation and needed a pre‐endodontic restorative conservative treatment to allow endodontic treatment (Castellucci, ; Nica et al., ). Selected teeth have then been treated by post‐and‐core technique followed by a complete indirect prosthetic restoration with a dental crown (Mamoun, ; Upadhyaya, Bhargava, Parkash, Chittaranjan, & Kumar, ; Zhang, Peng, Wang, & Li, ). The biologic width (Gargiulo, Wentz, & Orban, ; Hamasni & El Hajj, ) of the chosen teeth was respected, also considering the subgingival part of the defect that corresponded to apical margin of the pre‐endodontic conservative treatment.…”

“…Selected teeth have then been treated by post-and-core technique followed by a complete indirect prosthetic restoration with a dental crown (Mamoun, 2017;Upadhyaya, Bhargava, Parkash, Chittaranjan, & Kumar, 2016;Zhang, Peng, Wang, & Li, 2015).…”