This study aims to assess clinical bone defects between an implant and jaw bone after dental implantation by examining the mode shape of structures. Different severity of bone defects was evaluated through structure resonant frequencies and their corresponding mode shapes of the implant and jaw bone by using both numerical analysis and experimentation. This study consists of two parts. First, the assumption of two kinds of boundary conditions, bonding and rubbing, was applied to simulate osseointegration in the clinical dentistry and the in-vitro bone defect model, respectively, in finite element analysis. Natural frequencies and their mode shapes of the implant/jaw were computed by the modal analysis. During the harmonic analysis, the response displacements versus frequency of implant in the buccolingual and mesiodistal directions were defined. Secondly, the structural resonant frequencies were measured by a procedure of acoustic excitation and displacement response, and then this result was compared with using the detection of an Osstell mentor.
The simulation results show that the structure local mode corresponding high-frequency resonance can be used to examine bone imperfection remarkably. Limited by extremely tiny response displacement, measuring dynamic range of the capacitive displacement sensor, the acoustic excitation-displacement response measurement can only acquire the structure global mode of the mandible corresponding to low-frequency resonance. Additionally, the Osstell mentor can assess bone defects effectively. Therefore, the above-mentioned simulations and experimental results prove that the local mode is promising to evaluate the defect severity of the dental-implantation osseointegration.