Rationale for the suggested use of fibre post segments in composite core build- ups for endodontically treated teeth

The restoration of teeth utilising composites still presents a myriad of clinical challenges for the dental clinician. This is especially true for extensively broken down teeth and as well, those teeth which have been accessed endodontically. Fibre posts such as the quartz Macro-Lock Illusion X-RO post (Recherches Techniques Dentaires—RTD) UniCore Fiber post (Ultradent), and DT Light-Post (RTD) are now the posts of choice for a direct one appointment restoration of the severely compromised endodontically treated tooth. Current research supports the use of an etch and rinse bonding protocol, with a compatible bonding agent, utilising a dual-cured composite cement that can be utilised for the core as well (Cosmecore—Cosmedent; CoreCem—RTD; Zircules—Clinician’s Choice) for best results.1,2 Traditionally, minimally accessed endodontically treated teeth that are not extensively compromised by caries or fracture, have been restored solely with a composite core, without the placement of a post. This decision must be based on the amount of tooth structure left, and if a full coverage restoration is to be placed now or in the future. The width and height of the ferrule remaining is critical to restorative success (Figs. 1a & b),3-6 as well as the number of tooth walls left, post preparation, which significantly affects the long-term restorative outcome (Fig. 2).6-8 In a review of 41 articles published between 1969 and 1999 (the majority from the 90s), Heling states that ‘the literature suggests that the prognosis of root canal-treated teeth can be improved by sealing the canal and minimising the leakage of oral fluids and bacteria into the peri-radicular areas as soon as possible after completion of root canal therapy.’9 A similar review by Saunders et al also concluded that coronal leakage of root canals is a major cause of root canal failure.10 Sritharan states that ‘it has been suggested that apical leakage may not be the most important factor leading to the failure of endodontic treatment—but that coronal leakage is far more likely to be the major determinant of clinical success or failure.’11 Coronal microleakage can occur due to a deficient final restoration (due to resultant microleakage from polymerisation contraction, cement wash out, poor full coverage, flex etc) and resultant secondary caries.12 C L I N I C A L