POSTERIOR SUPERIOR ALVEOLAR NERVE BLOCK
DEFINITION:
- Posterior Superior Alveolar (PSA) nerve branches from V2 prior to entrance into INFRAORBITAL GROOVE.
- PSA then branches further 2 nerves:
i) remain external to bone to provide sensory innervation to buccal gingiva and mucosa surface.
ii) innervate mucous membrane of sinus and continue downwards to Maxillary Molars EXCEPT to mesiobuccal root of 1st Molar.
AREA ANAESTHETIZED:
1. ALVEOLI
2. PERIODONTAL LIGAMENT
3. BUCCAL GINGIVA
4. PULPAL TISSUE OF MOLARS
LANDMARKS:
1. HEIGHT OF MUCCOBUCCAL FOLD
2. 2ND AND 3RD MOLARS/
3. MAXILLARY TUBEROSITY
4. ZYGOMATIC PROCESS OF MAXILLA
POSITIONS:
1. PATIENT’S POSITION:
a.SUPINE / SEMISUPINE
2. OPERATOR’S POSITION:
a. RIGHT – AT 8 O’CLOCK
b. LEFT –AT 10 O’CLOCK
TECHNIQUE:
1. 25/ 27 SHORT NEEDLE (to decrease the risk of hematoma) – mouth is slightly closed and jaw moved lateral slightly.
2. Insert needle at height of MUCCOBUCCAL FOLD between 2nd and 3rd molar / maxillary tuberosity.
3. Angle at 45 degrees superiorly and medially.
4. The needle route is “UP, IN and BACK ” toward PSA Nerve.
5. No resistance should be felt.
6. Insert about 15 - 20 mm.
7. Aspirate then inject IF NEGATIVE.
8. Deposit 0.9 – 1.8 ml of anesthetic solution.
INDICATIONS:
1. When involve 2 or more molars.
2. When Supraperiosteal (local infiltration) is contraindicated or has been ineffective.
CONTRAINDICATION:
When risk of hemorrhage is too great. (supraperiosteal / PDL is recommended)
ADVANTAGES:
1. No pain is experienced when injected properly with no bone contact.
2. High success rate.
3. Minimize the number of injection s and decrease amount of anaesthesia administered.
DISADVANTAGES:
1. Risk of hematoma.
2. Second injection is necessary for treatment of mesiobuccal root.
COMPLICATIONS:
1. HEMATOMA.
- Produced by over insertion of needle into pterygoid plexus of veins. Maxillary artery may also be perforated.
- occurs within minutes.
2. MANDIBULAR ANAESTHESIA.
- V3 is located lateral to PSA Nerve.
- THANK YOU -
