Stress distribution in luting agents with different post and core systems

Siyang Luo, DDS, Daizo Okada, DDS, PhD, Mohammed Bakhit, DDS, Kyoshi Matsukawa, DDS, Chiharu Shin, DDS, PhD, Reiko Ogura, DDS, PhD, and Hiroyuki Miura, DDS, PhD

Fixed Prosthodontics, Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan

Purpose: Collapse of luting agent is one of the main causes of post and restoration detachment, but the stress distribution of luting agent is still unknown. The aim of this study was to analyze the stress distribution in the marginal area of the luting agent.
Materials and Methods: Two types of 3-dimensional root canal treated premolar finite element models were established; one was restored with composite resin core and glass fiber post (GFP), the other was cast post and core (MP). Both models were assumed to be restored with the metal restoration. In each model, two kinds of luting agents, composite resin luting agent (CC) and methyl methacrylate (MMA)-based luting agent (MMA), were applied.
Results: In the same post system, the stress in the CC had a more moderate attenuation amplitude from the restoration side to the dentin side. In contrast, the stress distribution in the MMA was concentrated on the restoration and dentin side, and the middle area suffered relatively little stress.
Conclusion: The stress concentration in the luting agents at the tooth cervical area is lower with an MP than with a GFP, while the stress concentrations in the luting agents at the post apexes are higher with an MP than with a GFP. At the cervical margin, the stress distribution in the CC gradually decreased from the restoration side to the dentin side and showed an even distribution with MMA.
(Asian Pac J Dent 2017; 17: 15-22.)
Key Words: core, nonlinear finite element analysis, post, root fracture, von Mises stress, Young’s modulus