The following conditions are generally not suitable for dental implants: poor general health or those who cannot tolerate surgery or anesthesia due to systemic diseases; inflammation of the gums, mucous membrane and maxillary sinus in the mouth; osteoporosis and lack of sufficient bone height and width in the area to be implanted; of course, dental implants can be performed after controlling the general health and eliminating local inflammation. Local bone condition is not good, it is also possible to complete dental implantation through maxillary sinus elevation, bone grafting or some other auxiliary methods.