Dental implants press fit phenomena: Biomechanical analysis considering bone inelastic response

Objectives. The paper presents an investigation of the biomechanical effects induced by oral implant insertion because of the press fit action caused by the difference between the major diameter of the implant and that of the drilled hole. The intent is to provide a correlation between bone–implant interaction and heavy stress–strain effects induced in bone tissues. In particular, the analysis allows for the evaluation of the bone mechanical response considering the inelastic range. Materials and methods. Bone material properties are defined, with regard to the elastic phase, according to a procedure that distributes, over the entire volume, the material constants magnitude and orthotropic directions deduced from experimental data. The inelastic phenomena are interpreted by a specific constitutive formulation and parameter identification procedure. The displacement field induced by implant insertion is provided by imposing the geometric configuration of the implant on the assumed drilled surface. Results. Results are reported with regard to the displacement and strain fields caused in the peri-implant region. The range of strains induced in bone confirms that inelastic effects occur and their characterisation is essential for the interpretation of the press fit phenomenon. Significance. The investigation allows for an accurate evaluation of the short term effects induced by press fit phenomenon in bone tissues which can be of particular interest also in consideration of immediate loading techniques in oral surgery.