Effects of elastic modulus of porous implants on success rate of implant surgery - An in vivo study using miniature swine model

Implant therapy is a well-established clinical treatment, and porous implants are reported to be advantageous, which needs to be confirmed in vivo. In this study, we designed and fabricated titanium implants with the same shape but with different porosities (20 %, 30 %, 40 %, and 50 %, respectively), which produce different elastic moduli based on the results of finite element analysis (FEA). These devices were implanted into the mandibular alveolar bone of miniature swine, and their survival rates, osseointegration, and marginal bone loss were evaluated one, three, and six months after implantation. It was demonstrated that the 30 % porosity implants, which had an elastic modulus similar to that of the cortical bone, exhibited the best survival rate (50 %) and the lowest bone resorption height (1.51 +/- 0.33 mm), with almost no inflammation and attachment loss. In vitro analyses indicated that the appropriate pore size is conducive to the extension and cellular communication of cells, which promotes the host cell homing and differentiation functions. Thus, the elastic modulus of the dental implants determines their success rate. Furthermore, the implants with an elastic modulus matching that of the cortical bone of the patient are advantageous in terms of postoperative loading and bone integration.