An evaluation of localized debonding between fibre post and root canal wall by finite element simulation

Aim To investigate the effect of localized bonding defects between fibre post and root canal wall on the stress distribution in the radicular dentine. Methodology A tooth restored with a fibre post together with the alveolar bone were axisymmetrically modelled. A total of four models with localized debonding at the post to canal wall interface in different locations were analysed: Model A: perfect bonding layer over the entire interface; Model B: debonding at the cervical 1/3 of the interface; Model C: debonding at the mid 1/3; and Model D: debonding at the apical 1/3. A tooth restored without using a post was also included as the control (Model E). A load of 50 N was applied to the top of the full veneer cast crown at angles of 0, 15, 30, and 45 degrees with the tooth's longitudinal axis. The stress distribution across the fibre post and root dentine was compared. Results Higher stresses were generated in the radicular dentine as a function of the load angle. The differences in the stress distribution were negligible between the four models and virtually the same as that for model E (control). Conclusions In this simulation, localized debonding at the fibre post to root canal wall interface, regardless of its location along the post, had little effect on the stress distribution in the root dentine.