Local anesthetic temporarily stops the nerves from providing feeling to that area of the mouth.
Local anesthesia is used by injecting medication directly into the area the dentist wants to numb. After injecting the area, a dentist can perform a variety of procedures in that area without the patient feeling it. Sometimes a dentist will use a topical anesthetic prior to administering the needle, which will dull the feeling of the needle stick. It is rare for a patient to feel any pain from the prick of the needle at the injection site.
The most common anesthetic is Lidocaine, but there are a few other types of medications that can be used as well. This is the method that all dentists use to do procedures that would be painful otherwise, such as fillings, extractions and root canals.
Local anesthesia will ensure that patients do not feel physical pain, which is the most important thing. However, there are a variety of other factors that disturb patients, such as the sound of the drill, cracking noises and the sensation of pressure. Some patients mistake the feeling of pressure with pain or feel very anxious due to the unpleasant sounds of dental care. For this reason, many patients choose to have other types of sedation in addition to local anesthesia.
In rare cases, when a patient has a severe infection, the nerve is too inflamed to numb. If this is the case, the patient must take antibiotics prior to their procedure.