Influence of ceramics Young's modulus in single implant-supported crowns

When cemented, the implant-supported crowns have provided a more uniform stress distribution to the support structures. However, the influence of different metal-free ceramics systems in the stress distribution at the adhesive interface is unclear. Objective: To evaluate, through two-dimensional finite element analysis, the stress distribution at the interface abutment/crown for two ceramics systems for implant-supported crowns (IPS Empress2 and Procera AllCeram). Methods: Two models (M) were built: MA – sagittal view of the maxillary central incisor area restored with IPS Empress2 on zircon abutment; MB: similar to MA, restored with Procera AllCeram. The numerical analysis (Ansys 10.0) was performed under two loading conditions (L): L1 - 50N in the lingual face, in 45^o with the tooth long axis; L2 - 50N perpendicular to the incisal edge. The von Mises equivalent stress (s_vM) and the principal stress (s_max) were obtained. Results: The loading pattern did not influence the peak of the s_vM for the same ceramics system. However, the s_vM were different for individual structures, such as the adhesive interface for the IPS Empress 2. The same behavior was observed for s_max. The L1 showed the highest s_vM and s_max in comparison with the L2. Conclusion: Restorations with lower elastic modulus showed higher stress when placed on abutment with higher elastic modulus. (FAPESP 2006/02336-2)