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Title: Minimal-invasive restoration of endodontically treated teeth
Other Titles: Minimaal-invasieve restauratie van endodontisch behandelde tanden
Authors: Zicari, Francesca
Issue Date: 3-Oct-2011
Abstract: Restoration of endodontically treated teeth is still considered a challenge. When restoring endodontically treated teeth, the majority of failures appeared to be due to biomechanical or restorative rather than biological reasons. Thanks to the breakthrough of adhesive dentistry, guidelines for restoration of endodontically treated teeth may be revised, in the light of a less invasive approach. The ultimate goal of contemporary adhesive techniques is to preserve as much as possible sound tissue and to use restorative materials with mechanical properties similar to that of dentin in order to reduce the occurrence of severe not-restorable failures and enhance the longevity of the restored tooth.Aim of this study was was to evaluate the in vitro and in vivo efficiency of fiber post-and-core restorations. For this purpose, in vitro research was carried out to evaluate the bonding effectiveness of fiber-posts cemented with adhesive techniques and the bio-mechanical behaviour of endodontically treated teeth. Besides, a randomized controlled clinical trial aimed to compare the durability of alternative adhesive techniques to the cast post-and-core, the so-called “gold-standard”. First, techniques for restoration of endodontically treated teeth were reviewed along with an in-depth discussion on the types and causes of failure. It is clear that several factors may affect bonding into the root canal and the biomechanical behaviour of endodontically treated teeth, and therefore its clinical success.Six different post systems available into the market were analyzed with regard to mechanical properties and structural characteristics. Afterwards, the influence of different adhesive approaches on both the adhesion into the root canal and sealing ability of fiber post bonding was evaluated. Although it is well known that adhesive cementation of fiber post increases post retention and reduces micro-leakage at the interfaces, bonding to root dentin is still a challenge, due to the difficult control of the adhesive procedures and the unfavorable configuration of the root canal. Although etch-and-rinse adhesive systems proved to be the most effective ones when bonding to coronal dentin, their efficacy into the deep root canal appears to be questionable. The more user-friendly and less technique-sensitive self-adhesive cements, that do not require etch and rinse steps, may replace them for fiber post bonding. Nevertheless, in order to achieve a durable bonding at the post-cement-dentin interface, specific combinations of adhesive systems and fiber posts should be carefully evaluated, along with pre-treatments of the substrates.Next we analyzed the biomechanical behavior of endodontically treated teeth restored with adhesive techniques with or without the use of a post. Since failure usually occurs because of cyclic loading during clinical function, fatigue testing still remains, in vitro, the more accurate tool to evaluate biomechanical behavior of post-endodontic restorations. It has been reported that </>avoiding extra-removal of sound tooth structure, at both the root and coronal level, rather than placing a fiber post, can protect endodontically treated teeth against catastrophic failure. In particular, a circumferential ferrule of 2 mm in height led to the highest fatigue-fracture resistance regardless the use of a fiber post. However, when no ferrule can be used, a fiber-post may improve the retention and fatigue resistance of the restoration. Moreover, since bonding appears to be more predictable at the coronal third of the root, adhesively luted posts may not need to be inserted as deep into the root canal as metallic posts conventionally are, thus yielding a less invasive approach. Besides, no influence of the adhesive approach on the fatigue resistance was observed in this study, where the self-etch and the innovative self-adhesive composite cements performed equally well.Finally, in a randomized controlled clinical trial, the cast gold post-and-core and alternative adhesive techniques were compared. Up to 3-years, results were very encouraging, since a few failures occurred and the ensuing overall success/survival rates ranged between the 91.7 and 97.2%. Although longer follow-up times are needed to evaluate which post-and-core system is the most reliable-one for a long term treatment, it could be speculated that preserving the tooth structure may be crucial for the success of the restoration and that the anterior region may be more at risk of failure.
Publication status: published
KU Leuven publication type: TH
Appears in Collections:Prosthetics
Biomaterials - BIOMAT

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