Implant-retained overdenture has been widely applied as a solution to edentulous ageing; however, a major concern for the denture wearers is bone resorption induced by the prosthetic interaction with soft tissue and bone. Early studies have revealed that the bone resorption is associated with the disturbance to the mucosa blood flow. This study aimed to investigate the contact pressure induced by an implant-retained overdenture, compared to a conventional complete denture without implants, which implies the potential bone resorption for clinical investigation. A three-dimensional finite element model of a full jaw, including mandible bone, mucosa, and denture, was created through a reverse engineering method based on CBCT images, in which the hyperelastic behaviour of mucosa was determined by curve-fitting to the clinical measurement, for a more realistic response. It is found that the location of the bone loss differed between the implant retained and non-implant complete dentures. With the implants, the denture displaced more at posterior ends towards the mucosa bearing area, leading to higher contact pressure accounted for more severe local bone loss.