Investigation of distortions around the cervical area of teeth restored with two kinds of crown materials

Abstract

The purpose of this study was to identify crown materials to decrease the stress concentrated at the cervical area of endodontically treated teeth. To this end, 14 extracted human mandibular premolars were divided into two groups for this study: complete cast crowns versus polymer-based crown and bridge material crowns. Both complete cast crowns (MC) and polymer-based crown and bridge material crowns (HC) were cemented with a glycidyl methacrylate-based resin cement (RC) to composite resin cores with glass fiber posts. Static loading was applied and distortion was measured with four pieces of strain gages attached to the marginal area. Findings showed that there was a large difference in distortion between crown and root in MC. On the other hand, distortions at the cervical area of crown and root were similar in HC.

Influence of post and core materials on distortion around 4-unit zirconia bridge margins

“…6-8 (A), (B), (C) and (D)). The results in this study are coincident with these reports 20,43) . The framework and the roots might act as a rigid body, owing to the small difference between the elastic moduli of the restoring materials.…”

“…In the past, studies of stress concentrations in crowns and abutment roots restored by various materials simultaneously under loading have used FEA 26,27) and strain gauge method 20) . However, these studies simulated FPDs and abutment root restoration by various materials has not yet been reported.…”

“…The elastic moduli of resin composite (12 GPa) 29) and glass fiber post (28 GPa) 30) are not close to that of Y-TZP; on the other hand, the modulus of gold alloy (95 GPa) 42) is much closer. Assif et al 43) and Suzuki et al 20) reported that forces were concentrated between a rigid and a less rigid material, especially lateral forces. In this study, the magnitudes of the maximum and minimum principal strain in Group RC were significantly higher than those in Group MC on many surfaces of both frameworks and roots loading at three loading points (p<0.05) (Figs.…”

“…The hypothesis to be tested was that 4-unit zirconia FPD with cast post and core restrain the surface strain compared to with resin composite with glass fiber posts. To evaluate the stress distribution, simulated experimental models using a strain gauge have been employed in various studies [17][18][19][20][21][22] . Compared to other methods such as finite element analysis (FEA) and photoelastic methods, using a strain gauge can detect the magnitude of surface strains more accurately.…”

Photoelastic stress analysis of endodontically treated teeth restored with different post systems: normal and alveolar bone resorption cases

“…Compared with the stress distribution of linear analysis, that of nonlinear analysis may more closely resemble that in endodontically treated teeth in vivo 33,41) . In the other stress-analysis experimental methods, autopolymerizing resin was used instead of the periodontal ligament in the strain gage method 42) , whereas silicone was used in the recent photoelastic and loading test methods 29) . Still, there remained a considerable difference in the periodontal ligament function.…”