The influence of the shock-absorbing restorative materials on the stress distributions of short dental implant rehabilitations

OBJECTIVE: Polymer materials with shock-absorbing ability may offer better stress distribution with short dental implants (SDI). The present study aimed to evaluate the effect of abutment and crown materials on the stress distributions in short implant-prosthesis-complex (6 mm) and standard implant-prosthesis-complex (10 mm) using 3D finite element analysis (FEA). MATERIALS AND METHODS: Two FEA models were designed to simulated single implant restoration of mandibular first molar, one each for short implant (6 mm) (Group S) and standard implant (10 mm) (Group C). In each group. two abutment materials were used. Polyetheretherketone (PEEK) and Zirconia (Zr), with two types of crowns, PEEK and Polymer-infiltrated ceramic-network (PICN). A vertical force of 200 N was applied to each central fossa. Stress distribution was evaluated via the von Mises stress analysis. RESULTS: Using the PEEK abutment, the stress was better dispersed with PEEK crowns, as compared to PICN crowns. The stress was concentrated on the platforms of Ti-bases and the head and middle part of abutment screws. In zirconia abutment, the stress was greatly concentrated on the axial angle regions when placed with the PEEK crowns. while the stress was dispersed when placed with PICN crowns. The stress was concentrated on the connector regions of Ti-bases and the middle part of abutment screws. For implants, the stress was concentrated on the neck of the two implants, regardless of crown materials and abutment materials. The PEEK materials were found to be suitable for the hybrid-retained prostheses of SDI. CONCLUSIONS: Our study indicates that the PEEK material is more suitable for the hybrid restorations of SDI. If the Zr abutment is used, the PICN crown would be better. Further, in-vivo clinical trials comparing these materials are needed to strengthen evidence.