Effect of Base and Inlay Restorative Material on the Stress Distribution and Fracture Resistance of Weakened Premolars

Abstract

The purpose of this study was to evaluate the influence of direct base and indirect inlay materials on stress distribution and fracture resistance of endodontically treated premolars with weakened cusps. Forty healthy human premolars were selected; five were left intact as controls (group C+), and the others were subjected to endodontic treatment and removal of buccal and lingual cusp dentin. Five teeth were left as negative controls (group C-). The remaining 30 teeth were divided into two groups according to the direct base material (glass ionomer [GIC] or composite resin [CR]). After base placement, each group was subjected to extensive inlay preparation, and then three subgroups were created (n=5): no inlay restoration (GIC and CR), restored with an indirect composite resin inlay (GIC+IR and CR+IR), and restored with a ceramic inlay (GIC+C and CR+C). Each specimen was loaded until fracture in a universal testing machine. For finite element analysis, the results showed that the removal of tooth structure significantly affected fracture resistance. The lowest values were presented by the negative control group, followed by the restored and based groups (not statistically different from each other) and all lower than the positive control group. In finite element analysis, the stress concentration was lower in the restored tooth compared to the tooth without restoration, whereas in the restored teeth, the stress concentration was similar, regardless of the material used for the base or restoration. It can be concluded that the inlay materials combined with a base showed similar behavior and were not able to regain the strength of intact tooth structure.

Polymerization shrinkage stresses in different restorative techniques for non-carious cervical lesions

“…A previously validated 3D model simulating a maxillary premolar tooth was used [31]. The three-dimensional linear elastic analysis was performed based on anatomical geometric representations of dentine, pulp, enamel, periodontal ligament and alveolar bone (Fig.…”

Finite element analysis on tooth and periodontal stress under simulated occlusal loads

“…In a 3D FEA model of a tooth‐periodontium system with complicated geometry, it is convenient to apply mechanical forces at any regions and in any directions . FEA has provided essential new knowledge for tooth restoration , prosthetic and orthodontic treatment , implant design , tooth fracture and periodontal trauma analysis, as well as the biomechanics of the mandibular system .…”

The Effects of Different Base Materials on the Stress Distribution of the Endodontically Treated Teeth: 3D FEA

“…A lot of studies have been analyzed the biophysical stress and strain in restored teeth and they have shown that restorative procedures can make tooth more vulnerable to fracture and teeth should be strengthened by choosing the appropriate restorative material. [22][23][24] According to the 3D FEA results performed in the current study, the von Mises stress areas were concentrated on the points that oblique forces were applied. Regarding the stress occurred on enamel, high stress areas were concentrated on distobuccal cusp, and cervical area, which was the neighboring area to the cortical bone for both cavity type ( Figure 4).…”