Clinically, local infiltration anesthesia is generally used to inject anesthetic into the local mucosa of the treated tooth. This method of anesthesia generally works well for maxillary teeth as well as mandibular anterior teeth, but for mandibular posterior teeth, especially in males, where the bone is more dense, this is the time to consider mandibular block anesthesia. When playing mandibular block anesthesia, the patient should open his mouth wide, and the occlusal surface of the mandibular teeth should be parallel to the ground. On the buccal side, you can see a triangular buccal fat pad formed by the protrusion of fatty tissue, and its tip is an important mark for injection. Generally, the needle is inserted about 2.5cm, and after about 3-5 minutes, the numbness and swelling of the ipsilateral lower lip corner of the mouth can be felt, and the probe is not painful. Nowadays, the clinical application of STA, or painless injector, is also increasing. In fact, patients who ask where to hit the anesthetic are not really concerned about the location of the hit, but more about the fear of pain, and STA can eliminate this pain to a large extent. For departments where the application of STA is not particularly widespread and patients who are particularly sensitive to pain can also apply a little epi-anesthetic cream to the injection site before the anesthetic is injected, which can relieve pain to a certain extent.