De-osseointegration is the loss of a previously achieved osseointegration of a dental implant due to peri-implantitis, occlusal overload, or other factors. Osseointegration takes place when there is direct contact between living bone and a functionally loaded dental implant surface without any interposed soft tissue. Osseointegration creates a secure foundation for the implant and prevents any movement or instability. When de-osseointegration takes place, this foundation is compromised, and implant instability or failure can occur. Peri-implantitis can arise in situations where excess cement is not completely removed following the placement of a cement-retained implant or prosthesis. It has the potential to lead to complications such as de-osseointegration and is one of the greatest disadvantages of a cement-retained implant. Occlusal overload can also cause de-osseointegration and occurs when the chewing force exceeds the capacity of the dental implant, dental interface, or dental componentry. This causes a failure in the overall implant and can reverse the osseointegration process.