Everyone is afraid of going to the dentist. At least everyone was back in the day. Before the use anesthetics dental appointments were synonymous with one thing-pain. This is no surprise given the high density of nerve that makes the mouth a particularly sensitive area. Fortunately, however, medicine has come along way. The study of anesthesiology has made the process a whole lot more comfortable. While the ability to numb patients has made the dental operations much less painful, it has also made the procedures significantly more dangerous. There is a narrow window between a safe and fatal dosage. Understanding the science of dental anesthetics is therefore a critical factor in the safety and success of any procedure.
The Science of Anesthetics
It’s common knowledge that nerves are the body’s sensors responsible for sensations like pain. When a stimulus is detected an electrical signal, known as an action potential is carried up the nerve to the brain. When an anesthetic is present a very important part of the nerve, called the sodium channel, is blocked. When this happens the pain signals can no longer make it to the brain, resulting in the numbness.
In some instances a vasoconstrictor, such as epinephrine, is added to the anesthetic. As the name suggests vasoconstrictors work by constricting the bodies blood vessels. When blood vessels are constricted it takes longer for the body to transport the drug away from the nerve. For this reason chemicals like epinephrine are used to extend the life of the anesthetic.
Types of Anesthetics
Anesthetics come in many varieties. For this reason several subdivisions are used to describe the differences in application and effect. The first major differentiation is whether the drug is a general or local anesthetic. General anesthetics render the patient completely unconscious; local will render a specific area numb. Due to the nature of dental procedures, local anesthetics are far more common.
The next subdivision categorizes the drugs as topical or injected. Typically topicals are used to pre-numb the mouth before the more potent anesthetic is injected. The most common agents used in dental practices today are lidocaine (xylocaine), septocaine, marcaine and mepivicaine. Each of these carries characteristics that range from the length of its life to it’ potential toxicity. Being familiar with these qualities is essential.