Fracture resistance of teeth restored with post-retained restorations: an overview.

By Al-Omiri MK, Mahmoud AA, Rayyan MR, Abu-Hammad O.

Date: 09/2011
Journal: JOE

Purpose: to critically analyze the concerned topics related to the fracture resistance of teeth restored with dowel retained

restorations.

Materials/Methods:

•A systematic review of PubMed/MEDLINE, Cochrane, and Scopus databases was conducted (from 1960 to 2010). 

•Single or combined key words (fracture resistance, endodontic post and  core , fiber posts, adhesive luting, and endodontically treated teeth) were used to obtain the most possible comprehensive list of articles.

•The references of the relevant obtained sources were checked along with manual search to locate related article on the topic.

•In vivo and ex vivo (laboratory, computer-based finite element, and photoelastic stress analysis studies) investigations related to the topic were included. 

•Retrospective, prospective, descriptive, review, and RCT studies were included. Studies describing post and core systems to restore endodontically treated teeth and their mechanical and physical properties were included.

Most highlighted Results: 

•Many factors influence the fracture resistance of post-restored teeth:

Post length: increased length increases fracture resistance (but not beyond 2/3 of the root)

Post diameter: increased diameter decreases fracture resistance. (ideally should not exceed 1/3 of root width)

Post design: tapered better than parallel sided, fiber glass better than metal.

Post material :  The mechanical properties of materials used for post constructionas well as their biocompatibility may influence the fracture resistance ofrestored teeth. Posts with higher modulus of elasticity like metals are associated with higher failure loads

•Fracture resistance was improved if tooth structure loss was limited, a ferrule was obtained, a post with similar physical properties to natural dentine was used, and adhesive techniques for post luting and coronal restoration were used.

•Resin/fiber posts louted with adhesive with composite cores appear to be the best currently available option in terms of tooth fracture and biomechanical behavior.

Conclusion :

•Unrepairable root fractures have been frequently reported as the most catastrophic mode of failure that was associated with post placement, especially when rigid posts were used 

•lack of long-term controlled clinical trials and the contradictory results of in vitro studies, the optimum post features are not yet clearly determined