Effects of abutment-implant combinations with different elastic moduli on osteogenic performance

Many factors affect the success of dental implant surgery, such as surgical trauma, excessive chewing pressure, material performance mismatch, and improper abutment-implant connection. Among these factors, stress shielding caused by the mismatch of elastic modulus of the material is a major problem affecting the biomechanical compatibility of the implant. Also, the elastic modulus of the dental implant directly affects its binding to the surrounding support bone and stress distribution. Presently, most of the abutmentimplant systems on the market use the same material, with TC4 being popular because of its good biocompatibility. However, the elastic modulus of titanium implants is quite different from that of surrounding bone tissue; this difference can cause stress shielding. Additionally, stress concentration may cause implant surgery to fail. The abutment-implant with materials of different elastic modulus directly affect the stability and stress distribution of the bone tissue around the implant; thus, understanding the stress distribution under loading will help to establish a better elastic modulus combination of the dental implant system. In this paper, finite element analysis software was used to calculate the stress distribution of various abutments-implants under different loading conditions. Compared to other experimental abutment-implant systems, the simulation results show that Ti6Al4V abutment-(poly-ether-ether-ketone) (TC4-PEEK) can effectively reduce stress concentration, resulting in uniform stress distribution of surrounding bone tissue whose maximum stress value is 40-60 MPa. The stress level of PEEK implants in different abutment-implant systems is smaller under axial loading condition, whereas the stress level of surrounding bone tissue is larger. In the oblique direction of 45° loading condition, compared to two other abutment-implant systems, the stress level of the TC4-PEEK is lower, and the maximum stress value of the cortical and the cancellous bones in the surrounding bone tissue is 55 and 5 MPa, respectively, and the stress level is the smallest; such conditions contribute to the increase of bone deposition and bone formation, effectively improving the interface stability of the implant.