Numerous options of adhesive build-ups are available today, which dispense with the need for root canal posts and which are preferable because they are less invasive (Creugers et al., 2005). Nevertheless, in clinical situations where there is insufficient coronal hard tissue to support the adhesive build-up, root canal pins/posts still provide the only long-term possibility of retention and stability of the build-up.
From the vast array of commercially available post systems and shapes, the conical, passive posts have received an increased level of attention because of the similarity between their shape and the root’s shape (Morgano and Brackett, 1999).
It has been shown that in combination with appropriate adhesive systems, the retention of conical posts is significantly improved and passive fitting avoids active loading of the canal walls (Boschian Pest et al., 2006; Dietschi et al., 2006).
The ongoing discussion concerning the corrosive characteristics and the biomechanical behavior of root canal posts, as well as the altered optical requirements with regard to the increasing use of metal-free restorations, has led to the introduction and use of posts made of ceramic materials or fiber-reinforced composite resin, alongside traditional metal root canal posts (Arvidson and Wróblewski, 1978).
For root canal posts based on reinforced composite materials, the basic material is an epoxy resin reinforced by carbon or glass fibers. These materials demonstrate mechanical characteristics similar to dentin and can in certain circumstances be relatively easily removed (Lassila, 2004). In vitro investigations have indicated that use of these posts is associated with a less destructive failure mode in comparison to posts made from other materials (Fokkinga, 2004). If these laboratory observations were corroborated by clinical studies, the fact that a fiber-reinforced composite post is relatively easy to remove would allow uncomplicated retreatment of a tooth after post fracture.
So far, posts made of fiber-reinforced composite material exhibit low radiopacity. In addition, the quality of the post can vary considerably depending on the manufacturer (Grandini, 2005).
In general, following the primary treatment (excavation, endodontic therapy), it is prudent to carry out a defect-based preparation of the tooth so that the final restoration can be designed specifically for each tooth. This procedure provides a better estimate of the vertical extent and the thickness of the remaining tooth structure as well as the biological width.
It is generally accepted that the fracture resistance of endodontically treated teeth is significantly affected by the amount of the remaining coronal tooth structure (Creugers et al., 2005; Pereira et al., 2006). The stability of teeth with post-and-core restorations is increased if a dentin collar at least 2-mm wide is prepared apical to the build-up, which is enclosed by the final restoration circumferentially. This preparation, also referred to as the “ferrule” preparation, has a stabilizing effect on the root, and enhances the long-term clinical success of the final restoration (Torbjorner and Fransson, 2004; Pereira et al., 2006).
If the anatomic considerations do not permit this approach, the requirements can be fulfilled by periodontal surgical crown lengthening or orthodontic extrusion, if the root length is sufficient.
Even though endodontically treated teeth have a good clinical long-term prognosis, the possible negative consequences of dental implants should be taken into consideration before such methods involving bone reduction are used in esthetic areas of the mouth (Holm-Pedersen et al., 2007).