Infraorbital Nerve Block – Local Anesthesia Technique

Infra Orbital Nerve Block – Block of Anterior and Middle Superior Alveolar Nerves

Inferior alveolar nerve block as the name suggests blocks the Infraorbital nerve block along with some other nerves which is used mainly when working in the Anterior Maxillary region. So let us see in detail about How to give Infra Orbital Nerve Blocks and what are the symptoms and complications seen in Infra Orbital Never Block.

Anatomical Landmarks:

• Infraorbital Ridge
• Infraorbital depression
• Supraorbital notch
• Infraorbital notch
• Anterior teeth
• Pupils of the eyes

Nerves Anesthetized:

• Infraorbital nerve
• Anterior Superior Alveolar nerve
• Middle Superior Alveolar nerve
• Inferior Palpebral Nerve
• Lateral Nasal Nerve
• Superior Labial Nerve

Areas Anesthetized:

• Incisors
• Cuspids
• Bicuspids
• Mesiobuccal root of first molar on the side affected
• Bony Support and Soft tissue
• Upper lip
• Lower eyelid
• Portion of the nose on the same side

Indications:

• Surgical or Operative procedures performed on 5 anterior teeth
• When Anterior and Middle Superior Alveolar nerves are to be anesthetized

Needle Pathway during Insertion:

There are 2 approaches to the Infraorbital nerve block, the most commonly used being Bicuspid approach and Central incisor approach.

1. Bicuspid Approach: Needle is inserted into the mucosa and the areolar tissue using the Maxillary Bicuspid as the guide and the needle should pass beneath and lateral to the external maxillary artery and the anterior facial vein.
2. Central Incisor Approach: Needle is inserted into the mucosa and the areolar tissue using the Maxillary Central Incisor as the guide and it passes beneath the angular head of the Quadratus labii superioris muscle. It proceeds anteriorly to the origin of the caninus muscle and beneath the external maxillary artery and the anterior facial vein.

Approximating structures to the needle:

When the needle is in final position at the orifice of the infraorbital canal, it should be located:

• Beneath the infraorbital head of the quadrates labi superioris muscle
• It should be located above the origin of the caninus muscle

Injection Technique: (How to give infraorbital nerve block)

For an infraorbital block of the right side, the dentist stands on the right side of the chair partially facing the patient. For the left side the operator stands more to the front of the Patient.

Patient should be placed in a comfortable position in the chair such that the maxillary occlusal plane is at a 45 degree angle to the floor.

The infraorbital and supraorbital notches are palpated while the patient is asked to look forward.

Draw an imaginary Straight line through the following landmarks: Mental Foramen, Bicuspid Teeth, Infraorbital foramen and the Pupils of Eyes.

Locate the infra orbital notch with your Thumb finger and after palpating the finger should be moved downwards about 0.5 cm until a shallow depression is felt.

Use the index finger to retract the Lip exposing the muco buccal fold.

Insertion of the needle can be done in 2 directions, the dentist inserts the needle in a line parallel with the supraorbital notch, pupil of the eye, the infraorbital notch and the second bicuspid tooth (if properly aligned)

The needle should be inserted at this location at a sufficient distance (5mm) from the labial plate to pass over the canine fossa.

The Needle after insertion in the desired location should be guided with the help of the thumb which was placed on the infraorbital foramen.

The needle should be guided into position so that it contacts the bone at the entrance to the foramen.

The second needle Approach bisects the crown of the central incisor from the mesioincisal angle to the disto-gingival angle.

The needle is again inserted about 5mm from the mucobuccal fold and guided into position by the thumb marking the location of the infra orbital foramen.

The needle should be guided into the Foramen like shown earlier.

Make sure that the needle does not penetrate more than 3/4^th Inch and use the thumb to prevent the needle from entering the orbital cavity.

Approximately 2 ml of Local anesthetic solution is deposited and Thumb is used to hold the needle in position till the end.

Symptoms of Anesthesia:

1. Objective Symptoms: Instrumentation should be done, use either the Tip of a blunt Probe or Elevator to check for Objective symptoms. The anesthetized tissue and teeth should be pressed and tapped as compared to the un-anesthetized side.
2. Subjective Symptoms: Tingling and numbness of the upper lip, lower eyelid and side of the nose on the side affected will always be present but are not necessarily an indication of good anesthesia.