Three-dimensional FEA of Effects of Two Dowel-and-Core Approaches and Effects of Canal Flaring on Stress Distribution in Endodontically Treated Teeth

• Published in: Journal of prosthodontics 2011-02, Vol.20 (2), p.120-129
• Main Authors: Mezzomo, Luis André, Corso, Leandro, Marczak, Rogério José, Rivaldo, Elken Gomes
• Format: Article
• Language: English
• Subjects: Composite Resins; Crowns; Dental Porcelain; Dental Stress Analysis - methods; Dentistry; dowel-and-core technique; Elastic Modulus; endodontic restorations; Finite Element Analysis; finite element method; Glass; Gold Alloys; Humans; Incisor; Maxilla; Models, Biological; multiaxial stress; Post and Core Technique; Root Canal Preparation - methods; Shear Strength; Stress distribution; Tensile Strength; Tooth Preparation, Prosthodontic; Tooth, Nonvital
• ISSN: 1059-941X; 1532-849X
• DOI: 10.1111/j.1532-849X.2010.00669.x

Purpose: The aim of this 3D finite element analysis (FEA) was to assess stress distribution and levels in endodontically treated teeth restored with two dowel‐and‐core systems with differing root canal configurations. Materials and Methods: Four 3D finite element models of a laser‐digitalized maxillary central incisor embedded in alveolar bone were created. Internal morphology data and mechanical properties of the materials were obtained from the literature. Models included a (1) sound tooth (control) versus an endodontically treated maxillary central incisor with a crown ferrule preparation with two restorative approaches of a ceramic crown over a (2) gold alloy dowel‐and‐core or (3) glass‐fiber dowels with composite cores (4) the latter with a flared root canal. A 100 N static load was applied in the center of the palatal surface at a 45° angle, and the stress distribution pattern was analyzed using ANSYS® software. Results: In Model 1 (control), maximum stresses occurred at the coronal third of the buccal (2.32 × 107 Pa) and palatal aspects of dentin. The stress peak value of the model (2.45 × 107 Pa) occurred on the palatal aspect of the enamel at the level of the cementoenamel junction. With the insertion of dowels with thin cement layers (Models 2 and 3), stress concentrations in radicular dentin decreased, while they increased in the dowel/cement/dentin interface. These models exhibited the greatest stress peak values in the incisal margin of the gold alloy core (18.9 × 107 Pa) and in the cement layer (4.7 × 107 Pa). In Model 4, stress peak value was observed in the porcelain crown (4.62 × 107 Pa), and there was no stress concentration inside the cement layer. Conclusions: Within the limits of this study, the results suggest that the use of dowels and cements with mechanical properties similar to those of dentin, and an increased cement layer thickness, results in mechanical behavior similar to the physiological behavior of a sound tooth.