Purpose: The aim of this work was a simulation of the onset of osseointegration of the transmandibular implant system in the mandible. This was achieved by imposing joint elements at the implant-bone interface. Materials and Methods: The geometric model was derived from the anatomic measurement of several mandibles by tomographic scanning. The spring constants of the joint elements interposed at the implant-bone interface were varied between 1 N/mm and 109 N/mm to represent the conditions leading to osseointegration. Results: Increasing the value of the spring constant at the joint elements gradually increases the effective stress in an increasing volume of crestal cortical bone. Additionally, a larger volume of crestal cortical bone assumes a higher stress value as the simulation proceeds. Conclusion: This work indicates that considerable changes in stress magnitude and distribution occur in the crestal cortical bone margins as osseointegration is simulated, which may be the necessary stimulus for bone remodeling.