Dentists use numbing injections, known as local anesthetics, to ensure patient comfort during procedures. These injections temporarily block nerve signals in a targeted area of the mouth, making treatments like fillings, extractions, or root canals more tolerable. The goal is a pain-free experience while the patient remains awake and aware.
Common Dental Numbing Medications
Dentists primarily use local anesthetics from the “amide” class, including Lidocaine, Articaine, Mepivacaine, and Bupivacaine. Lidocaine is a widely used anesthetic with a rapid onset (2-3 minutes), providing pulpal anesthesia for about 60 minutes and soft tissue numbness lasting 3-5 hours. It is considered a standard for many routine procedures.
Articaine, a newer amide, has a rapid onset of 2-5 minutes and provides pulpal anesthesia for about 60 minutes, with soft tissue numbness lasting 3-5 hours. It is particularly effective for procedures involving bone, such as extractions, due to enhanced tissue diffusion.
Mepivacaine has a rapid onset (2-3 minutes) when a vasoconstrictor is included, providing pulpal anesthesia for about 60 minutes. Without a vasoconstrictor, its duration is shorter, making it suitable for brief procedures.
Bupivacaine is a longer-acting anesthetic, with an onset of 2-10 minutes. It provides prolonged pain relief, lasting 6-8 hours for pulpal anesthesia and up to 12 hours for soft tissue numbness. This extended duration is beneficial for longer surgical procedures or where significant postoperative pain is anticipated. Many anesthetics are combined with a vasoconstrictor, like epinephrine, to prolong their effect and reduce systemic absorption.
How Dental Numbing Works
Local anesthetics temporarily prevent nerve signals from reaching the brain, blocking pain sensation. Nerves transmit signals via electrical impulses, involving the movement of sodium ions into nerve cells through specialized channels. When a local anesthetic is injected, molecules travel to these nerve cells.
The anesthetic works by binding to and blocking sodium channels on the nerve membrane. This stops the influx of sodium ions, necessary for the nerve to generate and transmit an electrical impulse. Pain signals from the treated area cannot travel to the brain, resulting in temporary loss of sensation. This effect is reversible, wearing off as the body metabolizes the drug, allowing normal nerve function to resume.
Choosing the Right Numbing Medication
Dentists consider several factors when selecting numbing medication. The type and expected duration of the dental procedure are primary considerations; longer procedures may need extended-duration anesthetics. Patient medical history, including allergies or heart conditions, plays a significant role. Certain medical conditions or medications may influence the choice of anesthetic or vasoconstrictor use.
For example, mepivacaine without a vasoconstrictor might be preferred for patients with certain cardiovascular conditions or hyperthyroidism to minimize systemic effects. Infection or inflammation in the treatment area can affect anesthetic effectiveness, as acidic environments reduce its ability to numb. Patient response to past anesthetics and preference for numbness duration also contribute to the dentist’s choice.
Your Experience with Dental Numbing
Before the injection, a dentist applies a topical numbing gel to the gum tissue to reduce needle sensation. During the injection, you might feel a slight pinch or pressure, but this is typically minimal due to the topical gel and the dentist’s slow injection technique. Some individuals may experience a brief, mild increase in heart rate, which is a normal reaction to the vasoconstrictor and usually subsides quickly.
As the anesthetic takes effect, typically within 2-10 minutes, you will notice the treated area becoming numb and feeling heavy. This numbness may extend to surrounding areas like the lips, tongue, or cheek, which is a common sensation. After the procedure, the numbness gradually wears off, usually over 1-4 hours, depending on the specific anesthetic and individual metabolism.
As the numbness fades, you might experience a tingling sensation, similar to pins and needles, as feeling returns. It is advisable to avoid eating or chewing until the numbness has completely subsided to prevent accidentally biting your cheek or tongue. Mild and temporary side effects such as slight swelling or minor bruising at the injection site are possible. While rare, if you experience prolonged numbness, severe pain, or any unusual reactions, it is important to contact your dentist.