The ability to anesthetize, or “numb”, areas of the mouth is beneficial to patients during various dental procedures.

In dentistry, “local anesthesia” is a drug that blocks sensations from an area of
the mouth, numbing a small area of tissue.

The original local anesthetic in the 1800’s was cocaine, followed by procaine (better known by the trade name Novocaine), and then by Lidocaine, which is still the main local anesthetic in use today. Five effective and safe Local Anesthetics are used today in dentistry.

Getting “numbed” makes the dental experience far more pleasant. All teeth are supplied by nerves. They normally feel hot, cold, vibration, pressure, sweetness and sometimes pain. Pain messages are carried through the body by electrical signals; this transmission can be blocked by chemicals.

The dental needle is placed close to the nerve (s) supplying the area(s) to be worked on, and Lidocaine is injected into the region. As the nerves are bathed in local anesthetics, their ability to carry messages is interrupted; the area is numb and the dental work can be carried out without pain.

For work in the maxilla (the upper jaw), Local Anesthetics can be placed right next to the teeth. The bone there is fairly porous and the anesthetic can soak into the bone and bathe the nerves.

The mandible (lower jaw) is quite different. The outer layer of bone (cortical bone) is
thick and nonporous. Local anesthetics will not soak into this bone and get to the nerves. To numb most of the lower teeth, we must use a nerve block. The needle is injected toward the back of the mouth, where the main nerve that supplies these teeth, the inferior alveolar nerve, is not encased in cortical bone.

Numbness wears off because the Local Anesthetic is picked up by the bloodstream and
taken away and redistributed. Later, the drug is broken down through chemical processes
in the body (metabolism). Because circulation is greater in the maxilla than in the mandible, the duration of anesthesia is shorter in the upper jaw.

After treatment your mouth is likely to still feel big, swollen, numb. It may also feel like you can’t move your lips, but you can. Numbing affects the sensory nerves as opposed to the motor nerves. In other words, it affects what you feel, but does not prevent you from moving your lips and talking. After the treatment, be careful not to bite your lip or tongue. The soft tissues of the lips and gums stay numb longer than the teeth. Stay away from hot drinks for awhile.

Local anesthesia is one of the most important advancement in modern dentistry as it provides the ability to deliver dental care without pain.