Posterior Superior Alveolar Nerve Block Overview

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Questions and Answers

What is the primary subjective clinical finding associated with the Posterior Superior Alveolar Nerve Block (PSANB)?

Presence of buccal mucosa sensitivity

Probing test revealing absence of pain

Numbness and tingling in the facial area (correct)

No response from Electrical Pulp Tester

What is a significant advantage of the PSANB technique over traditional techniques?

It provides a higher total volume of anesthetic solution.

It guarantees perfect anesthesia of all molars.

It is an atraumatic technique with minimal pain. (correct)

It involves multiple needle insertions for coverage.

What is the maximum volume of anesthetic solution typically required for a single PSANB injection?

2.5 mL

1.8 mL (correct)

0.9 mL

0.5 mL

Which of the following is a risk associated with the PSANB technique?

Diffuse intraoral hematoma in the buccal region Signup and view all the answers

What limitation does the PSANB technique have regarding the anesthesia of the first molar?

It requires additional injections for complete anesthesia. Signup and view all the answers

What is a primary cause of failure in a Posterior Superior Alveolar Nerve Block technique?

Needle too lateral Signup and view all the answers

What complication may arise from inserting the needle too far posteriorly during a mandibular anesthesia procedure?

Hematoma in buccal tissues Signup and view all the answers

In what percentage of the population is the middle superior alveolar (MSA) nerve present?

30% Signup and view all the answers

Which structure does the anterior superior alveolar nerve NOT supply?

Maxillary molars Signup and view all the answers

What is a critical aspect to consider during the insertion of a needle for the IONB?

Depth of needle penetration Signup and view all the answers

Which terminal branch of the infraorbital nerve controls sensation to the lower eyelid?

Inferior palpebral Signup and view all the answers

What correction can be made if the needle is not inserted high enough during a PSANB?

Redirect the needle superiorly Signup and view all the answers

Which of the following is NOT a concern when performing a mandibular anesthesia?

Excessive bleeding manageable with pressure Signup and view all the answers

What is the primary goal of the Posterior Superior Alveolar Nerve Block (PSANB) technique?

To deposit local anesthetic close to the PSA nerves Signup and view all the answers

Which of the following is NOT an area anesthetized by the PSANB technique?

Dentin of the maxillary incisors Signup and view all the answers

Which of the following is a contraindication for performing a PSANB?

Presence of a hemophiliac condition Signup and view all the answers

Which other names are associated with the Posterior Superior Alveolar Nerve Block (PSANB)?

Zygomatic Block and Tuberosity Block Signup and view all the answers

Which condition is mentioned as an indication for using the PSANB technique?

Previously failed supraperiosteal injection Signup and view all the answers

What is the anatomical location for depositing the anesthetic in PSANB?

Posterosuperior and medial to the maxillary tuberosity Signup and view all the answers

Which of these nerves is mainly anesthetized by the PSANB technique?

Posterior superior alveolar nerve Signup and view all the answers

Which branch of the maxillary nerve is NOT mentioned in the context of PSANB?

Infraorbital nerve Signup and view all the answers

What anatomical landmark is primarily used to locate the infraorbital foramen?

Infraorbital notch Signup and view all the answers

Which direction does the opening of the infraorbital foramen face?

Downward and medially Signup and view all the answers

When performing a nerve block, how should the needle be oriented?

Parallel to the long axis of the ipsilateral maxillary first premolar Signup and view all the answers

What is the recommended depth of needle penetration for an adult during an anterior superior alveolar nerve block?

16 mm Signup and view all the answers

What should be done to properly retract the tissues during the nerve block procedure?

Place the index finger over the foramen and retract the lip with both hands Signup and view all the answers

Which tooth typically provides the shortest and most accurate route for the anterior superior alveolar nerve block?

Maxillary first premolar Signup and view all the answers

What patient sensation is typically reported when palpating the infraorbital foramen?

Mild soreness Signup and view all the answers

How should the needle approach the infraorbital foramen?

From the medial side Signup and view all the answers

What is the maximum recommended volume of local anesthetic to deposit during an Anterior Superior Alveolar Nerve Block?

0.9 ml Signup and view all the answers

What should be done if the needle is palpable during the injection process?

Withdraw and redirect the needle. Signup and view all the answers

How long should finger pressure be maintained over the injection site after administering the local anesthetic?

2 minutes Signup and view all the answers

What specific action should be performed during the second aspiration test?

Rotate the syringe about 45 degrees. Signup and view all the answers

Which of the following is NOT a safety measure for the Anterior Superior Alveolar Nerve Block?

Insert the needle quickly to reduce discomfort. Signup and view all the answers

When should the planned dental procedure commence after administering the local anesthetic?

After 3-5 minutes. Signup and view all the answers

What indicates that the anesthetic solution is correctly deposited during an Anterior Superior Alveolar Nerve Block?

Feeling the solution beneath the finger pad. Signup and view all the answers

Which of these areas is NOT affected by the Anterior Superior Alveolar Nerve Block?

Molar teeth Signup and view all the answers

Study Notes

Posterior Superior Alveolar Nerve Block (PSANB)

Also known as Zygomatic Block or Tuberosity Block
Anesthetizes the PSAN
Anesthetizes the buccal mucoperiosteum over the maxillary molars, buccal and palatal alveolar plates of bone, periodontium of maxillary molars except for the MB root of 1st molar, pulps of maxillary molars except for the MB root of 1st molar, and adjacent lining of the maxillary sinus.
Goal is to deposit local anesthetic near the PSA nerves, located posterosuperior and medial to the maxillary tuberosity.
Indications:
- Treatment involving 2+ maxillary molars
- When supraperiosteal injection is ineffective (e.g. thick zygomatic buttress over the apices of the first molar)
- When supraperiosteal injection is contraindicated (e.g. infection or acute inflammation)
Contraindications:
- Infection at the injection site
- High risk of hemorrhage (e.g. hemophiliac, patients taking drugs that increase bleeding like Coumadin or Plavix)
Clinical Findings:
- Subjective: Tingling and numbness, difficult to determine extent of anesthesia subjectively
- Objective: Absence of pain during probing of facial mucosa of maxillary molars, no response with maximal EPT output (80/80), no response to freezing spray, absence of pain during treatment
Advantages:
- High success rate (>95%)
- Atraumatic technique: little pain due to loose connective tissue target area and no bone contact
- Minimal injections [one injection compared to 3 infiltrations]
- Minimizes LA volume [equivalent volume of anesthetic solution necessary for 3 supraperiosteal injections is 1.8ml]
Disadvantages:
- Risk of diffuse intraoral hematoma in the buccal mandibular region
- Arbitrary technique: no bony landmarks during needle insertion
- Second injection required for anesthesia of the first molar (in approximately 30%)
Causes of Failures & Complications:
- Needle too lateral: Redirect medially
- Needle not high enough: Redirect superiorly
- Needle too far posterior: Withdraw to proper depth
Hematoma in buccal tissues of the mandibular region
- May result from needle insertion too far posteriorly. This can injure the pterygoid plexus of veins or perforate the maxillary artery.
- Use of a short needle and attention to penetration depth is critical.
- Hemorrhage is difficult to stop due to lack of accessible intraoral pressure points. Bleeding continues until extravascular blood pressure equals or exceeds intravascular blood pressure.

Anterior Superior Alveolar Nerve Block (Infraorbital Nerve Block)

MSA nerve is present in only 30% of the population.
The anterior superior alveolar nerve carries the function of the MSA nerve in the majority (70%) of the population, supplying the ipsilateral maxillary anterior teeth, premolars, and the mesiobuccal root of the first molar (ASA).
The anesthetic solution needs to enter the infraorbital canal through the infraorbital foramen for successful IONB.
Anesthetizes:
- Anterior superior alveolar nerve: Pulps of maxillary incisors, canine, premolars, and mesiobuccal root of first molar on the injected side.
- Middle superior alveolar nerve.
- Terminal Branches of Infraorbital Nerve:
  - Inferior palpebral: Lower eyelid
  - Lateral nasal: Lateral aspect of the nose
Locate the Infraorbital Foramen:
- Feel the infraorbital notch.
- Move your finger downward from the notch, applying gentle pressure.
- The bone immediately inferior to the notch is convex (felt as an outward bulge). This represents the lower border of the orbit and the roof of the infraorbital foramen.
- As your finger continues inferiorly, a concavity is felt; this is the infraorbital foramen (this point is on a line with the pupil of the eye when the patient looks straight forward).
- While applying pressure, feel the outlines of the infraorbital foramen at this site. The patient will sense mild soreness when the foramen is palpated as the infraorbital nerve is pressed against bone.
Applied Anatomy:
- The Infraorbital foramen is shaped like a flattened funnel with its opening directed downward and medially.
- The needle must approach the foramen from its medial side.
Intra-Oral Anterior Superior Alveolar Nerve Block:
- Tissue Retraction:
  - Place the bulbous portion of the index finger over the foramen.
  - Ask the patient to partially close their mouth.
  - Insert the thumb of the nondominant hand in the mucobuccal fold.
  - Retract the lip between the index & thumb fingers.
- Point of Needle Insertion:
  - Height of the mucobuccal fold over the first premolar with the bevel facing bone.
  - The needle can be inserted into the height of the mucobuccal fold over any tooth from the second premolar anteriorly to the central incisor, however, the first premolar usually provides the shortest and most accurate route.
- Needle Orientation:
  - Parallel to the long axis of the ipsilateral maxillary first premolar.
- Depth of Needle Penetration:
  - Average penetration depth for an adult is 16mm.
- Safety Measures:
  - Advance the needle slowly until bone is gently contacted.
  - The needle must contact the bone at the roof of the infraorbital foramen to prevent inadvertent over-insertion and possible puncture of the orbit.
  - If the needle is palpable, it is too superficial. Withdraw and redirect toward the target area.
- Aspiration:
  - Perform at least twice before administering the local anesthetic.
  - Rotate the syringe about 45 degrees for the second aspiration test to change orientation of the bevel and exclude the possibility of false negative aspiration.
- Precaution to Prevent Overinsertion:
  - Estimate the proper depth of penetration before injection.
  - Ensure the needle tip contacts the infraorbital rim of bone that forms the superior rim of the infraorbital foramen.
  - Exert finger pressure over the infraorbital foramen.
- Amount of LA Required:
  - Using a 25-gauge long needle, slowly deposit 0.9ml (1/2 cartridge) up to 1.2ml (2/3 cartridge) over 30-40 seconds, respectively.
  - The administrator should feel the deposited anesthetic solution beneath the finger pad on the foramen.
  - Little or no swelling should be visible as the solution is deposited.
- Completion of the Technique:
  - Slowly withdraw the needle from the tissues.
  - Immediately make the needle safe.
  - Maintain direct finger pressure over the injection site for 1-2 minutes to increase diffusion of LA solution into the infraorbital foramen.
  - Wait 3-5 minutes before commencing the planned dental procedure.
- Clinical Findings:
  - Subjective: Tingling and numbness of the ipsilateral lower eyelid, side of the nose, upper lip, teeth & soft tissues along the distribution of the ASA and MSA nerves.
  - Objective:
    - Probing test: Absence of pain during probing of buccal mucosa of maxillary molars.
    - Electrical Pulp Tester: No response with maximal EPT output (80/80).
    - Freezing Spray (e.g., Endo-Ice): No response.
    - Absence of pain during treatment.

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Description

This quiz covers the Posterior Superior Alveolar Nerve Block (PSANB), also known as the Zygomatic or Tuberosity Block. It focuses on the anesthetic targets, indications, and contraindications of the procedure, specifically for maxillary molar treatments. Test your knowledge on the application and implications of PSANB in dental practice.