top of page

The mental nerve is a terminal branch of the inferior alveolar nerve.  Exiting the mental foramen at or near the apices of the mandibular premolars, it provides sensory innervation to the buccal soft tissues lying anterior to the foramen and the soft tissues of the lower lip and chin on the side of injection.  The mental nerve block is used primarily for facial/buccal soft tissue procedures.  It has a success rate of about 100% because of the ease of accessibility to the nerve.

The incisive nerve is also a terminal branch of the inferior alveolar nerve.  Originating as a direct continuation of the inferior alveolar nerve at the mental foramen, the incisive nerve travels anteriorly in the incisive canal, providing sensory innervation to those teeth located anterior to the mental foramen.  The premolars, canine, and lateral and central incisors including their facial/buccal soft tissues are anesthetized.  The difference between the mental nerve block and the incisive nerve block is that the incisive nerve block includes bone being anesthetized.  This is achieved by depositing the anesthetic solution just outside the mental foramen (same target area as the mental nerve block) and under pressure, direct the solution into the foramen (extraorally, massage and push deposited solution through the mental foramen).  However, lingual soft tissues are not anesthetized with these blocks.  If lingual soft tissues require anesthesia, local infiltration from the buccal can be accomplished since the buccal soft tissues are already anesthetized and penetration is a traumatic.  

Proper technique for the Mental/Incisive Nerve Blocks:

​

  1. 25 or 27-gauge short needle is recommended

  2. Area of insertion: mucobuccal fold at or just anterior to the mental foramen 

  3. Target area: mental foramen, where the mental nerve as it exits and inside of which the incisive nerve is located (usually located between the apices of the first and second premolars)

  4. Landmarks

    • Mandibular premolars

    • Mucobuccal fold

  5. Orientation of the bevel: toward bone during the injection 

Procedures for the Mental Nerve Block:

​

  1. Correct patient & clinician positioning

    • Right/left mental/incisive, right/left-handed clinician sit comfortably in front of patient so that the syringe may be placed into the mouth below the patient's line of sight

    • Clinician can also sit at 12:00, but the needle and syringe will be in the patient's line of sight (you may ask the patient to close their eyes)

  2. Position the patient supine (recommended) or semisupine

  3. Have the patient partially close.  This permits greater access to the injection site

  4. Locate the mental foramen 

    • The mental foramen usually is found around the apex of the second premolar.  However, it may be found anterior or posterior to this site.

    • Radiographs are important as the mental foramen may be located easily

  5. Prepare tissue at the injection site

    • Dry with gauze or blow air with air/water syringe​

    • Apply topical anesthetic for at least 1 minute

  6. With the mirror or your index finger on your non-dominant hand, pull the lower lip and buccal soft tissues laterally to improve visibility and keep tissues taut to prevent atraumatic penetration 

  7. Orient the syringe with the bevel directed toward bone

  8. Penetrate mucous membrane at the injection site, between the 1st and 2nd premolar directing the syringe toward the mental foramen 

  9. Advance the needle slowly until the foramen is reached​

    • The depth of penetration is about 5-6mm (1/4 the length of short needle)

  10. Aspirate in two planes

  11. If negative, slowly deposit 0.6mL of anesthetic solution (about 1/3 cartridge) over 20 seconds 

    • If tissue at the injection site balloons (becomes swollen during injection), stop depositing solution​ and remove the syringe 

  12. Slowly withdraw needle and safely recap

  13. Wait 2-3 minutes before starting dental procedure​

M E N T A L  /  I N C I S I V E 

Procedures for the Incisive Nerve Block:

​

Steps 1-10 are the same as the Mental Nerve Block

  11.  If negative, slowly deposit 0.6mL of anesthetic solution (about 1/3 cartridge) over 20 seconds​ (tissue at the injection site should balloon, but very slightly

   12.  Slowly withdraw needle and safely recap

   13.  Apply pressure at the injection site for 2 minutes

   14.  Wait 2-3 minutes before starting dental procedure.  Anesthesia of the mental nerve (lower lip, buccal soft tissues) is observed within seconds of the deposition, but anesthesia of the incisive nerve requires additional time.

bottom of page