### Abstract

The aim of this study was to measure the structural damping constants of premolars after treatment with a cast Co-Cr post-core system or permanent root filling, and to evaluate the stress damping effects of these restored premolars. Both the damping ratio and the natural frequency (NF) of the cast Co-Cr post-core restored premolars and the permanent root-filled premolars were detected by in-vitro NF testing experiments. Unprepared premolars served as the control. The damping constants β of the samples were calculated from the measured damping ratios and natural frequencies. The measured damping constants β of the test premolars were then used for dynamic finite element (FE) analyses. Stress contours and damping effects of stresses in each treated type of premolar were computed and compared using ANSYS. The measured damping constants β were 0.75×10-5 for the unprepared premolars, 0.69×10-5 for the root-filled premolars with coronal restoration, and 0.72×10-5 for the cast Co-Cr post-core restored premolars. The unprepared intact premolars demonstrated the highest stress dissipation effects with a ratio of 29.3 per cent at the middle root opposite to the loading side. However, no stress dissipation effects were found in the premolars that had been restored with the cast Co-Cr post-core system. The FE analysis showed that metallic post treatment attenuated the damping properties of the premolar. The effects of damping on stress concentration were significantly lower in restored premolars than in untreated vital premolars. These findings suggest that future research on post material should take the damping property into consideration. © IMechE 2009.

Original language | English |
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Pages (from-to) | 555-565 |

Number of pages | 11 |

Journal | Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine |

Volume | 223 |

Issue number | 5 |

DOIs | |

Publication status | Published - 2009 |

### Keywords

- Damping ratio
- Finite element
- Premolar
- Stress
- After-treatment
- Damping constants
- Damping effect
- Damping property
- Dissipation effects
- Dynamic finite element
- FE analysis
- In-vitro
- Non-linear finite elements
- Post treatment
- Post-core system
- Post-endodontic restorations
- Stress contours
- Stress damping
- Structural damping
- premolar
- Chromium
- Finite element method
- Natural frequencies
- Restoration
- Stress analysis
- Stress concentration
- Thermoelectricity
- Stresses
- Damping
- article
- biological model
- computer simulation
- dental care
- dental surgery
- finite element analysis
- human
- in vitro study
- instrumentation
- mechanical stress
- methodology
- nonlinear system
- pathophysiology
- premolar tooth
- tooth crown
- vibration
- viscosity
- young modulus
- Bicuspid
- Computer Simulation
- Dental Restoration, Permanent
- Dental Stress Analysis
- Elastic Modulus
- Finite Element Analysis
- Humans
- Models, Biological
- Nonlinear Dynamics
- Post and Core Technique
- Stress, Mechanical
- Vibration
- Viscosity

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## Cite this

Lo, Y-J., Chang, W-J., Lee, S-Y., Chang, K-J., Lin, C-T., & Huang, H-M. (2009). Reductions in the effects of damping on stress concentration in premolars by post-endodontic restorations: A non-linear finite element study.

*Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine*,*223*(5), 555-565. https://doi.org/10.1243/09544119JEIM538