For edentulous jaws with low alveolar ridge or edged alveolar ridge, it is difficult to achieve ideal retention with conventional full denture restorations, which can easily fall out and make chewing difficult. In general, two implants in the lower jaw and four implants in the upper jaw can be used to make different forms of implant-supported overdenture. This method is not as comfortable as a full implant-supported fixed denture, but it is less expensive, and in addition to providing good retention, it can also provide some support to the face and lips, relieving facial collapse caused by missing teeth and bone resorption.