Influence of Cavity Geometry on the Fracture Strength of Dental Restorations: Finite Element Study

Abstract

The main purpose of this work was to analyze the stress distribution in premolars restored with indirect IPS Empress® CAD onlays or inlays. The three-dimensional geometry of a human first premolar was created using modeling software. The tooth fixation system was simulated through box geometry, comprising a cortical bone layer with 2 mm of thickness over a layer of trabecular bone with 15 mm of thickness. The tooth had the following approximated crown dimensions: 10.35 mm buccolingual length; 7.1 mm mesiodistal width; and 7.0 mm cervico-occlusal height. The mesio-occluso-distal (MOD) cavity preparations followed the suggestions available in the literature. The cement geometry was modified to include cohesive zone models (CZM) to perform the adhesive joint’s strength prediction. The loading body was created assuming contact between the food bolus and the tooth surface. Numerical solutions were obtained by performing static analysis and damage analysis using the finite element method. Von Mises stress values generated in the ceramic inlay restoration ranged from 1.39–181.47 MPa, which were on average 4.4% higher than those of the onlay ceramic restoration. The fracture strength of the onlay restoration was about 18% higher than that of the inlay restoration. The onlay design seems to contribute to higher homogenization of the adhesive resin cement strain and higher tooth structure protection.

The Effectiveness of Dental Protection and the Material Arrangement in Custom-Made Mouthguards

“…Some limitations of this study are related to the geometrical and mechanical properties of the maxilla bone and of the teeth. As is well known, maxilla bone has variability in cortical and cancellous mechanical properties [31], and the tooth structure is more complex [32,33] than the one used in the present work. Nevertheless, because this is a comparative study and the realistic mechanical properties of all components will remain in the linear elasticity range, it is expected that these simplification assumptions will affect all models similarly.…”

Biomechanical Performance of Mandibular Molars with Deep Mesio-Occlusal-Distal Cavities Rehabilitated with Horizontal Posts: A 3D Finite Element Analysis

“…Stappert et al [27] drew an inference that only functional cusp coverage could improve fracture resistance as compared to full coverage by ceramics. Thus, there is no consensus on the fracture resistance of restored teeth [8,[17][18][19][20][21][22][23][24]. In the present study, it was observed that there was an exponential increase in deformation and overall stress pattern in a MOD cavity when compared to a sound intact tooth.…”

“…The FEA is one such technique that can analyze the stress distribution of innovation before it is launched commercially or integrated into our day-to-day practice. FEA is a useful computer-based tool that can resolve differential equations by a powerful numeritechnique [9,13,[16][17][18][19][20][21][22][23].…”

“…The complex body is made of multiple elements which join at nodal points called nodes. Thus, when stress has been applied, the deformation that occurs or the concentration of stress under loading conditions is analyzed and the resultant variables are calculated [16][17][18][19][20][21][22]. Since the dental tissues are of different constituents, of varying thickness, shape, and resiliency and more often than not nonhomogenous or symmetrical, thus they have to be simulated and replicated in three dimensions for a validated analysis [16][17][18][19][20][21].…”

“…Thus, when stress has been applied, the deformation that occurs or the concentration of stress under loading conditions is analyzed and the resultant variables are calculated [16][17][18][19][20][21][22]. Since the dental tissues are of different constituents, of varying thickness, shape, and resiliency and more often than not nonhomogenous or symmetrical, thus they have to be simulated and replicated in three dimensions for a validated analysis [16][17][18][19][20][21]. Hence, in this study, based on evidence-based data, the finite model of an intact tooth was generated.…”