Posterior Superior Alveolar Nerve Block Techniques

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Questions and Answers

What is the recommended depth of needle insertion for an average adult during the PSANB technique?

10 mm

12 mm

16 mm (correct)

18 mm

What is the appropriate volume of anesthetic solution to be deposited during the PSANB technique?

1.2 mL

0.5 mL

2.0 mL

0.9 mL to 1.8 mL (correct)

Which of the following clinical tests indicates successful anesthesia during the PSANB procedure?

Feeling of tingling and numbness

Presence of pain during probing

Positive response with electrical pulp tester

Absence of pain during probing of facial mucosa (correct)

What is the primary advantage of the PSANB technique regarding patient comfort?

Atraumatic technique with little pain Signup and view all the answers

How long should one wait after administering the PSANB before commencing dental treatment?

3 to 5 minutes Signup and view all the answers

What percentage of the population has the middle superior alveolar (MSA) nerve present?

30% Signup and view all the answers

Which dental structures are primarily supplied by the anterior superior alveolar nerve?

Maxillary incisors, canines, premolars, and the mesiobuccal root of the first molar Signup and view all the answers

What is a major reason the anterior superior alveolar nerve block (ASANB) is less popular compared to the posterior superior alveolar nerve block (PSANB)?

Fear of injury to the patient’s eye Signup and view all the answers

Which of the following is NOT an indication for performing an anterior superior alveolar nerve block?

Presence of extensive mandibular decay Signup and view all the answers

Which terminal branches are anesthetized during an infraorbital nerve block?

Inferior palpebral, lateral nasal, and superior labial Signup and view all the answers

What is the preferred type of injection for discrete treatment areas involving one or two teeth?

Supraperiosteal injection Signup and view all the answers

Which of the following is NOT an advantage of the Anterior Superior Alveolar Nerve Block?

Provides hemostasis in the operative field Signup and view all the answers

What is the most suitable position for the dentist performing the Anterior Superior Alveolar Nerve Block when they are right-handed?

Standing on the right side of the chair Signup and view all the answers

Which step is NOT required when preparing the tissue at the site of injection?

Inject local anesthesia immediately Signup and view all the answers

Which anatomical landmark is crucial for locating the infraorbital foramen when administering the Anterior Superior Alveolar Nerve Block?

Infraorbital notch Signup and view all the answers

What symptom is NOT typically reported as a subjective clinical finding after an Anterior Superior Alveolar Nerve Block?

Prolonged facial swelling Signup and view all the answers

What can result from needle contacting bone inferior to the infraorbital foramen during an ASA nerve block?

Anesthesia of the lower eyelid and lateral side of the nose Signup and view all the answers

What is a complication of the Anterior Superior Alveolar Nerve Block?

Temporary double vision (horizontal diplopia) Signup and view all the answers

Which factor could lead to failure of the Anterior Superior Alveolar Nerve Block?

Needle deviation medial or lateral to the infraorbital foramen Signup and view all the answers

What is the suggested correction if the needle contacts bone prematurely during the ASA nerve block?

Keep the needle in line with the infraorbital foramen Signup and view all the answers

What is the average penetration depth of the needle for an adult of average height?

16 mm Signup and view all the answers

What should occur when the needle contacts the bone during the procedure?

The needle should be withdrawn and redirected. Signup and view all the answers

How many aspiration tests should be performed before administering the local anesthetic?

Two Signup and view all the answers

What action is recommended to prevent over-insertion of the needle?

Exert finger pressure over the infraorbital foramen. Signup and view all the answers

What is the appropriate amount of local anesthetic to deposit using a 25-gauge long needle?

0.5 ml Signup and view all the answers

For the second aspiration test, what should be done to change the orientation of the bevel?

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

What should be done immediately after withdrawing the needle from the tissues?

Make the needle safe. Signup and view all the answers

How long should direct finger pressure be maintained over the injection site?

1 - 2 minutes Signup and view all the answers

Study Notes

Posterior Superior Alveolar Nerve Block (PSANB) Technique

Needle Insertion Depth:
- Average adults: ¾ of short needle length (16 mm)
- Smaller adults and children: ½ of short needle length (10 mm)
Aspiration Test:
- Performed in two perpendicular planes
Anesthetic Solution Deposition:
- 0.9 mL (half-cartridge) to 1.8 mL (full-cartridge) over 30-60 seconds
- Multiple aspirations during injection
Needle Withdrawal:
- Use "single hand scoop technique" for recapping
Treatment Delay:
- Wait 3-5 minutes after injection

Clinical Findings

Subjective:
- Tingling and numbness
Objective:
- Probing: No pain during facial mucosa probing
- Electrical Pulp Tester: No response at maximal output (80/80)
- Freezing Spray: No response
- Absence of pain during treatment

Advantages

High success rate (> 95%)
Atraumatic technique:
- Target area is loose connective tissue
- No bone contact

Clinical Note (Middle Superior Alveolar Nerve)

Present in 30% of the population
In most cases (70%), the Anterior Superior Alveolar Nerve carries the function of the MSA nerve

Anterior Superior Alveolar Nerve Block (ASANB)

Also known as Infraorbital Nerve Block
Nerves Anesthetized:
- Anterior Superior Alveolar Nerve: Maxillary incisors, canine, premolars, and mesiobuccal root of the first molar
- Middle Superior Alveolar nerve
- Terminal Branches of Infraorbital Nerve:
  - Inferior palpebral: Lower eyelid
  - Lateral nasal: Lateral aspect of the nose
  - Superior labial: Upper lip

ASANB: Clinical Note

Less popular than PSANB due to:
- Lack of experience
- Fear of eye injury
Success Rate:
- Highly successful and safe when performed correctly

ASANB: Indications

Procedures involving > 2 maxillary anterior teeth (from incisors to premolars) and overlying buccal tissues
Supraperiosteal injections ineffective due to dense bone
Inflammation or infection (contraindicates supraperiosteal injection)
Cellulitis (may indicate maxillary nerve block instead)

ASANB: Contraindications

Discrete treatment areas (1-2 teeth; supraperiosteal injection preferred)
Localized hemostasis desired

ASANB: Advantages

Minimizes solution volume and needle punctures compared to infiltration
Longer anesthetic effect

ASANB: Positive Aspiration

Negligible (0.7%)

ASANB: Disadvantages

No hemostasis in operative field

ASANB: Armamentaria

Basic:
- Long needle
- Aspirating syringe
- Local anesthetic cartridge ± vasoconstrictor
Auxiliary:
- Topical antiseptic
- Topical anesthetic and applicator
- Hemostat & College Cotton Tweezer

ASANB: Patient Position

Supine or semisupine with neck extended slightly

ASANB: Dentist Position (Right-Handed)

Stand on the right side of the chair
Directly facing the patient

ASANB: Tissue Preparation

Dry with sterile gauze
Apply topical antiseptic (optional)
Apply topical anesthetic (minimum 1 minute)

ASANB: Locating the Infraorbital Foramen

Feel the infraorbital notch
Move finger downward from the notch, applying pressure
Bone inferior to the notch is convex (outward bulge), indicating the inferior border of the orbit and the roof of the infraorbital foramen

ASANB: Needle Penetration Depth

Average adult: 16 mm (half the length of a long needle)

ASANB: Safety Measures

Advance needle slowly until bone contact
Needle must contact the roof of the infraorbital foramen to prevent over-insertion
Needle should not be palpable; if felt, it's too superficial

ASANB: Aspiration

Performed at least twice before injection
Rotate syringe 45 degrees for second aspiration to rule out false negatives

ASANB: Over-Insertion Prevention

Estimate penetration depth before injection
Needle tip contact with infraorbital rim for bone contact
Exert finger pressure over the foramen

ASANB: Intra-Oral Technique

Anesthetic Solution Deposition (using 25-gauge long needle):
- 0.9 mL (1/2 cartridge) to 1.2 mL (2/3 cartridge) over 30-40 seconds
Solution should be felt beneath the finger pad over the foramen
Minimal swelling should be visible during deposition
Completion:
- Slowly withdraw needle
- Recap needle using safe technique
- Maintain finger pressure over injection site (1-2 minutes) to aid solution diffusion
- Wait 3-5 minutes before treatment

ASANB: Clinical Findings

Subjective:
- Tingling and numbness of lower eyelid, side of nose, upper lip, teeth, and soft tissues along ASA and MSA nerve distribution
Objective:
- Probing: No pain during facial mucosa probing of anterior and premolar teeth
- Electrical Pulp Tester: No response at maximal output (80/80)
- Thermal Pulp Test: No response
- Absence of pain during treatment

Causes for ASANB Failure

Needle contacting bone inferior to the foramen:
- Anesthesia of lower eyelid, side of nose, and upper lip may occur with little dental anesthesia
- Correction:
  - Keep needle in line with the foramen
  - Estimate penetration depth before injection
Needle deviation medial or lateral to the foramen:
- Correction:
  - Keep needle oriented towards the foramen during advancement

ASANB: Alternative Techniques

Basic:
- Infiltration technique
- Maxillary nerve block
Supplementary:
- Periodontal ligament injection

ASANB: Complications

Hematoma across the lower eyelid
Temporary double vision (horizontal diplopia)

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Description

This quiz covers essential techniques for the Posterior Superior Alveolar Nerve Block (PSANB), focusing on needle insertion depth, aspiration tests, and anesthetic solution deposition. It also evaluates knowledge of clinical findings and the advantages of the procedure. Test your understanding of this critical dental anesthetic technique.