Coronal and Corono-Radicular Restorations of Endodontically Treated Teeth 

ABSTRACT

Although the construction of prosthetic crowns supported by metal posts or cast post-and-cores remains the most commonly used technique for restoring devitalized teeth, recent studies have highlighted the limitations of this type of treatment (Dietschi and Bouillaguet, 2011). Endodontic literature shows that the long-term clinical success of non-vital teeth depends on the complete elimination of bacterial infection within the root canal system. While success rates approaching 95% can be achieved in cases of irreversible pulpitis or necrosis without periapical complications, healing rates drop significantly when root infections are associated with radiographically visible periapical lesions (Farzaneh et al., 2004; Friedman, 2008). It is thus acknowledged that the nature and extent of the bacterial infection influence endodontic healing.

It has also been shown that the quality of the coronal restoration significantly affects the success of endodontic treatment: in the presence of poor sealing, failure rates increase, even when the root canal filling appears satisfactory on radiographs (Ray and Trope, 1995). Based on these observations, it is clearly established that conventional restorative techniques—which involve multiple laboratory steps (fabrication of a post-and-core, placement of a temporary crown, fabrication of the final prosthetic crown)—introduce intermediate stages that increase the risk of bacterial reinfection and long-term endodontic complications.

The placement of a prosthetic crown may be indicated to restore the esthetics and function of non-vital teeth with significant coronal loss. Some studies show that cuspal coverage provided by a prosthetic crown offers a better long-term prognosis for devitalized teeth (Salehrabi and Rotstein, 2004). When the indication for a prosthetic crown is established, practitioners typically insert a root post (cast or prefabricated post-and-core) to ensure retention of the final crown. For decades, metal posts of various shapes have been used for this purpose. Contrary to popular belief, the placement of an intra-canal post does not improve the mechanical resistance of the tooth root, but rather contributes to its weakening (Robbins, 2001).

Firstly, it’s important to note that the shape of a metal post only partially matches the anatomical variations found in root canals (Grandini et al., 2005). Consequently, reshaping the canal to fit the post requires additional tissue removal, increasing the risk of root fracture (fig. 14.1). Other studies criticize the invasive nature of such reconstructions and suggest using less invasive techniques based on adhesive restorations (Krejci et al., 2003).

The current trend is toward maximum preservation of residual tooth structure, as this approach positively affects the longevity of dental restorations (Manhart et al., 2004). The aim of this chapter is to present the principles of a modern therapeutic approach based on the concept of minimal invasiveness, aimed at restoring the esthetics and function of non-vital teeth. The physical characteristics of non-vital teeth will also be discussed to support these new treatment options.