Abstract: Objective： To analyze the reasons of the failure after primary implantation. Methods： Implant loos- ening and falling off or swelling and pain in the operative area were the criteria for failure. In this study, a total of 4 patients with implant surgery failure were selected to analyze the causes of failure. Result: The 4 patients failed the primary implantation in the short term due to operational factors, bone burn and un- known reasons. Conclusion： Due to surgical factors, bone burn, implantable instruments are not cleaned and disinfected in place, implantable drill bits are not sharp enough, and intraoperative cooling is not in place, etc. all of which may cause failure of bone union.

Key words: dental implants, failure, bone burn