Dental Nerve Blocks - Indications, Advantages, Types and Contraindications

Introduction:

Dental nerve blocks, or dental anesthesia, are vital for painless and comfortable dental procedures. Dentists are well-trained to give accurate numbing shots, with the most common type being the inferior alveolar nerve block that numbs the lower jaw. Different nerve blocks are used depending on the area to be treated, such as the mental nerve block for the lower lip and chin or the lingual nerve block for the tongue. Dental nerve blocks usually work well, but certain factors like anatomy, infection, drugs, or fear can hinder their effectiveness. Dentists wait a few minutes after the shot to ensure the area is numb and may repeat it if needed.

What Are the Indications for Dental Nerve Blocks?

• Broken jaw bone, teeth, or the bony ridge that holds teeth.

• Tooth decay or cavities.

• Pain in the tooth, often due to decay or infection.

• Inflammation of the tooth's inner part (pulp) causes pain and sensitivity.

• When a tooth's root is blocked or unable to grow properly, causing discomfort and potential problems.

• Painful condition after tooth extraction called dry socket.

• Dental infection with a painful abscess (only if far from the area where the nerve block is given).

• Cuts on the inner lining of the mouth, lower lip, or skin under the chin.

• For certain injuries like cuts on the skin or lip that need careful stitching, a nerve block is preferred over directly injecting numbing medicine into the wound, as it avoids distorting the tissues.

What Are the Advantages of Dental Nerve Blocks?

In the emergency room, doctors can use regional nerve blocks to numb specific areas of the face for various procedures and complaints. These nerve blocks have several advantages:

• Better Numbness: They can provide equally good or even better numbness than other methods.

• Fewer Needle Pokes: Patients do not need multiple injections since these blocks can thoroughly numb the area with just one shot. This is especially helpful for patients who find it challenging to handle multiple needle pokes, leading to a more comfortable and safer procedure.

• Less Pain Medication: These nerve blocks reduce the need for solid painkillers like opioids and other oral pain medications.

What Are the Types of Dental Nerve Blocks and Their Procedure?

Superior Alveolar Nerve Blocks:

1. The dentist will apply a numbing gel to make the needle entry more comfortable.

2. The lip is pulled back, and the needle is inserted gently through the inner cheek at specific locations, which include:

   • The posterior superior alveolar nerve is numbed by inserting a needle behind the second molar's root.

   • The middle superior alveolar nerve is numbed by inserting a needle between the first molar and second premolar.

   • The anterior superior alveolar nerve is numbed by inserting a needle above the canine.

3. one to three milliliter of numbing medicine is injected into the upper jaw area with the bevel (the slanted part of the needle) facing the maxilla (upper jaw).

Inferior Alveolar Nerve Blocks:

1. The dentist applies a numbing gel to make the needle entry more comfortable.

2. The lip/cheek is pulled back, and using the thumb to feel a certain point called the coronoid notch.

3. The syringe is held at an angle as if approaching from the opposite front tooth.

4. The needle is inserted about one to two cemtimeter behind the thumb.

5. 1 to 3 mL of numbing medicine is inserted.

Mental Nerve and Infraorbital Nerve Blocks:

1. These are additional methods for numbing the mouth and oral cavity.

2. The infraorbital block is helpful when combined with a superior alveolar block for patients with significant facial pain related to their dental issues.

3. The mental nerve block only numbs the lips, skin, and cheek area, not the teeth.

4. It is best to use the inferior alveolar nerve block to numb the lower teeth.

Nasopalatine Nerve Blocks:

1. The nasopalatine nerve block numbs the front part of the hard palate and the surrounding soft tissues.

2. The dentist applied the numbing gel, as explained earlier.

3. The needle is inserted just to the side of a small raised area called the incisive papilla, which is about half a centimeter behind the front teeth at the center of the mouth.

4. The needle is pushed about 3-4 mm toward the middle or until it touches the bone.

5. The blood (aspirate) is checked to ensure the needle is not in a blood vessel.

6. A small amount (0.25-0.4 mL) of numbing medicine is injected. It is always avoided to inject more, as it can harm the tissue.

Greater Palatine Nerve Blocks:

1. The greater palatine nerve block numbs the back two-thirds of the hard palate.

2. The dentist applies the numbing gel, as explained earlier.

3. The greater palatine foramen is at the junction of the second and third molars, and the needle is moved 1 cm inward.

4. The needle is inserted next to the greater palatine foramen, keeping it at a 90-degree angle to the curve of the hard palate.

5. Before injecting, blood is aspirated to ensure the needle is not in a blood vessel.

6. A small amount (0.3-0.5 mL) of numbing medicine is inserted. Always is it avoided injecting more, as it can harm the tissue.

What Are the Contraindications of a Dental Nerve Block?

Absolute Contraindications:

• Allergy to the numbing medicine or its delivery method (usually, another type of numbing medicine can be used).

• If the body lacks the necessary landmarks due to previous trauma, it may be challenging to insert the needle correctly.

Relative Contraindications:

• If there is an infection along the path where the needle will be inserted, other forms of sedation or anesthesia may be used instead.

• Patients who are uncooperative due to anxiety, confusion, or any other reason may require procedural sedation, which helps to reduce risks for both the clinician and the patient during the procedure.

• If there is a blood clotting problem, correct it before the procedure.

• Pregnant women should avoid certain treatments in the first trimester if it can be postponed.

• Suppose a patient has a heart condition, such as valve problems, birth defects, or past surgeries. In that case, they require preventive treatment to avoid a condition called endocarditis which helps to protect the heart during dental procedures.

• In some cases, patients may be on medication to prevent blood clots (anticoagulants), which can increase bleeding risk with nerve blocks. However, stopping these medications also increases the risk of dangerous clot formation elsewhere in the body.

What Are the Complications of a Dental Nerve Block?

Possible problems with dental anesthesia:

• Allergic reaction to the numbing medicine.

• Too much numbing medicine causes toxicity and potential issues like seizures or irregular heartbeats.

• Accidentally injecting the numbing medicine into a blood vessel.

• Formation of a painful bruise filled with blood (hematoma) at the injection site.

• Muscle trismus (Medial Pterygoid Trismus) happens due to muscle spasms from the injection, causing small muscle tears.

• Nerve problems lead to numbness or tingling.

• The needle passes through an infected area, potentially spreading the infection.

• Numbing unintended facial nerves due to incorrect needle placement.

• Failure to thoroughly numb the area for the procedure.

• Rare incidents like needle breakage or losing the needle within soft tissues.

• Most of these complications occur when the needle is not accurately placed during anesthesia.

What Should a Person Consider After the Anesthetic Administration?

• After getting a nerve block, the numbed area will remain numb or weak for up to 24 hours.

• For safety, one should be careful not to hurt or bump the numb area since they would not feel pain.

• Putting very hot or cold things should be avoided on the numbed part to prevent burns.

• If a person has a weak leg, they should not walk without assistance.

• Ask the doctor if it's safe to drive or operate machinery.

• If the numbness or weakness disappears after 24 hours, contact the doctor.

• When the block wears off, there might be a significant increase in pain, so one should take prescribed pain medications as directed when more pain is noticed.

Conclusion:

Nerve blocks offer several advantages for patients undergoing surgery. They can reduce the need for additional anesthesia, even allowing some to avoid general anesthesia altogether. After surgery, nerve blocks provide adequate pain relief, enabling patients to move around sooner. By relying less on strong pain medications like morphine, nerve blocks also minimize the associated side effects of nausea, confusion, drowsiness, and constipation. All these benefits combined may contribute to a shorter hospital stay for the patient, promoting a smoother and more comfortable recovery process.