c. Infiltration. The local anesthetic is injected into an area that is to be
surgically treated (see figure 3-1). The anesthetic then spreads to the nerve and
passes through the nerve sheath. When it contacts the nerve fibers, they become
insensitive to pain and other sensations. In dentistry, infiltration is used most often to
anesthetize maxillary teeth for procedures such as restoration and extractions. The
porous alveolar bone in the maxilla permits the anesthetic to spread to the nerves
innervating the teeth.
Figure 3-1. Anesthetic being deposited (infiltration).
Analgesics are agents used to relieve pain. They are classified as narcotic or
non-narcotic and act chiefly to depress the pain systems of the nervous system. The
most common use of analgesics is for the relief of pain following oral surgical
procedures. Often the pain occurs after the patient has left the office and after the
effects of the local anesthetic have worn off. For this reason, the dental officer will
prescribe an analgesic and instruct the patient in its use. Differences in procedures and
variations in patient response to pain require that a wide range of analgesic agents
ranging from mild to potent be available to meet individual patient needs.
3-11. NARCOTIC ANALGESICS
a. Codeine. Codeine is an addictive narcotic derived from opium. Combined
with other drugs such as aspirin or acetaminophen, codeine preparations are effective
in relieving mild to moderate pain in the majority of dental problems. See the appendix
for examples of compounds containing codeine.