Investigation of the cushioning mechanism of a novel dental implant system with composite hydrogel.

Background/purpose: Dental implants can restore both function and aesthetics in edentulous areas. However, the absence of cushioning mechanical behavior in implants may limit their clinical performance and reduce the long-term survival rates. This study aimed to establish an implant cushion mechanism that mimicked the natural periodontal ligament, utilizing the properties of composite hydrogels.

Materials And Methods: In this study, we synthesized two composite hydrogels (HS and HSP groups) using hyaluronic acid (HA) and silk fibroin. We conducted static-constrained compression, creep, and porosity tests to assess the physical properties of these composite hydrogels. Finite element analysis (FEA) was employed to examine the effects of different thicknesses, permeabilities, and compression coefficients on the deformation of the hydrogels. The composite hydrogels were then applied within a novel dental implant, and the displacement performance of the implants, along with stress distribution on the alveolar bone, was evaluated using FEA.

Results: Regarding the mechanical performance of the composite hydrogels, increased permeability led to quicker displacement under compression. Thicker hydrogels with larger compression moduli influenced the biphasic behavior and deformation. The novel dental implants demonstrated biphasic sinking behavior under loading and rapid repositioning during unloading. When evaluating stress distribution on the alveolar bone under oblique loading, the HS and HSP implant groups showed a stress reduction of 10.3 % and 13.6 %, respectively, compared to commercial implant groups.

Conclusion: This study highlights that the biphasic nature of solid and liquid phases is crucial when incorporating a cushioning mechanism into implants to replicate the characteristics of the periodontal ligament.