MAXILLARY INJECTION TECHNIQUE

• Field block


  Anesthetic solution is deposited at or above the apex of the tooth to be treated

  
• Nerve block


  Affects a larger area
• Maxillary injection techniques


  • Supraperiosteal (Infiltration)
  • Periodontal Ligament (PDL; Intraligamentary)
  • Intraseptal Injection
  • Intracrestal Injection
  • Intraosseous Injection
  • Posterior Superior Alveolar (PSA)
  • Middle Superior Alveolar (MSA)
  • Anterior Superior Alveolar (ASA)
  • Maxillary (V2, Second Division)
  • Greater (Anterior) Palatine Nerve Block
  • Nasopalatine Nerve Block
  • Anterior Middle Superior Alveolar (AMSA)
  • Palatal Approach ASA (P-ASA)
• Supraperiosteal, PDL, and Intraosseous injections are appropriate for administration in both the maxilla and mandible

  
• PDL, Intraseptal, Intracrestal, and Intraosseous injections are supplemental injections of considerable greater importance of the mandible
• Supraperiosteal injection


  • More commonly (but incorrectly) called local infiltration
  • Multiple supraperiosteal injections necessitate multiple needle penetrations
  • other common names: Local Infiltration o Peraperiosteal Injection
• Nerve anesthetized by supraperiosteal injection

  Large terminal branches of the dental plexus
• Areas anesthetized by supraperiosteal injection


  Pulp and root area of the tooth, buccal periosteum, connective tissue, and mucous membrane
• Indications for supraperiosteal injection


  • Pulpal anesthesia of the maxillary teeth when treatment is limited to one or two teeth
  • Soft tissue anesthesia when indicated for surgical procedures in a circumscribed area

  
• Contraindications for supraperiosteal injection


  • Infection or acute inflammation
  • Dense bone covering the apices of teeth (ex.: the mandible)

  
• Supraperiosteal injection


  • High success rate (>95%)
  • Technically easy injection
  • Usually entire atraumatic
• Disadvantages of supraperiosteal injection


  Not recommended for large areas due to the need for multiple needle insertions and the necessity to administer larger total volumes of local anesthetic
• Positive aspiration for supraperiosteal injection is negligible, but possible (<1%)
• Alternatives to supraperiosteal injection


  • PDL injection
  • Intraosseous injection
  • Regional nerve block
• Supraperiosteal injection technique


  1. Prepare the tissue at the injection site

  2. Orient the needle so the bevel faces bone

  3. Lift the lip, pulling the tissue taut

  4. Hold the syringe parallel to the long axis of the tooth

  5. Insert the needle into the height of the mucobuccal fold over the target tooth

  6. Advance the needle until its bevel is at or above the apical region of the tooth

  7. Aspirate twice, rotating level 90% between aspirations

  8. Slowly inject 0.6 mL over 20 seconds

  9. Slowly withdraw the syringe

  10. Make the needle safe

  11. Wait 3 to 5 minutes before commencing the dental procedure
• In general, wherever possible, the bevel of the needle should be facing toward bone
• Postinjection discomfort is considerably greater with subperiosteal injections than with supraperiosteal injections
• Signs and symptoms of successful supraperiosteal injection


  • Subjective: Feeling of numbness in the area of administration
  • Objective: No response from the tooth with maximal EPT output (80/80), absence of pain during treatment
• Safety features of supraperiosteal injection


  • Minimal risk of intravascular administration
  • Slow injection of anesthetic; aspiration
• Precautions for supraperiosteal injection


  • Supraperiosteal injection is not recommended for larger areas of treatment due to greater number of tissue penetrations and larger volume of solution administered
  • Needle puncture of tissue can lead to permanent or transient damage in vessels (hematoma) and nerves (paresthesia)
• Failures of supraperiosteal anesthesia


  • Needle tip lies below the apex (along the root)
  • Needle tip lies too far from the bone (redirect the needle closer to the periosteum)
• Complications of supraperiosteal injection


  Pain on needle insertion with the needle tip against the periosteum
• Posterior Superior Alveolar (PSA) nerve block


  • Effective for the maxillary third, second, and first molars (first molar in 77% to 100% of patients)
  • Mesiobuccal root of the maxillary first molar is not consistently innervated by the PSA nerve
• Middle Superior Alveolar (MSA) nerve


  Provides sensory innervation to the mesiobuccal root of the maxillary first molar in 28% of specimens examined

  
  

  other common names of PSA: o tuberosity block o zygomatic block

  
• Nerves anesthetized by PSA nerve block


  PSA nerve and branches
• Areas anesthetized by PSA nerve block


  • Pulps of the maxillary third, second, and first molars (entire first molar = 72% success rate)
  • mesiobuccal root of the maxillary first molar not anesthetized = 28% of PSA nerve blocks
  • Buccal periodontium and bone overlying these teeth

  
• Indications for PSA nerve block


  • When treatment involves two or more maxillary molars
  • When supraperioteal injection is contraindicated (ex.: with infection or acute inflammation)
  • When supraperiosteal injection has proved ineffective
• Contraindications for PSA nerve block


  • Risk of hemorrhage is too great (as with a hemophiliac; patients taking drugs that can increase bleeding such as coumadin or clopidogrel in which case a supraperiosteal or PDL injection is recommended)
• Advantages of PSA nerve block


  • Atraumatic
  • High success rate (>95%)
  • Minimum number of necessary injections
  • Minimizes the total volume of local anesthetic solution
• Disadvantages of PSA nerve block


  • Risk of hematoma
  • Technique somewhat arbitrary
  • Second injection necessary (1st molar)
• Positive aspiration rate for PSA nerve block is approximately 3.1%
• Alternatives to PSA nerve block


  • Supraperiosteal or PDL injections for pulpal and root anesthesia
  • Infiltrations for the buccal periodontium and hard tissues
  • Maxillary nerve block
• PSA nerve block technique


  1. Assume the correct position

  2. Prepare the tissues at the height of the mucobuccal fold for penetration

  3. Orient the bevel of the needle toward bone

  4. Partially open the patient's mouth, pulling the mandible to the side of injection

  5. Retract the patient's cheek (for visibility), if possible using a mouth mirror

  6. Pull the tissues at the injection site taut

  7. Insert the needle into the height of the mucobuccal fold over the second molar

  8. Advance the needle slowly in an upward, inward, and backward direction

  9. Slowly advance the needle through soft tissue

  10. Advance the needle to the desired depth

  11. Aspirate in two planes

  12. If both aspirations are negative, slowly deposit 0.9 to 1.8 mL of anesthetic solution over 30-60 seconds

  13. Aspirate several additional times during drug administration

  14. Slowly withdraw the syringe

  15. Make the needle safe

  16. Wait a minimum of 3-5 minutes before commencing the dental procedure

  
• Signs and symptoms of successful PSA nerve block


  • Subjective: Usually none
  • Objective: No response from the tooth with maximal EPT output (80/80), absence of pain during treatment

  
• Safety features of PSA nerve block


  • Slow injection, repeated aspirations
  • No anatomic safety features to prevent over insertion of the needle; therefore, careful observation is necessary
• Precautions for PSA nerve block


  • The depth of needle penetration should be checked: over insertion increases the risk of hematoma; a little shallow might still provide adequate anesthesia
• Failures of PSA nerve block anesthesia


  • Needle too lateral (redirect the needle tip medially)
  • Needle not high enough (redirect the needle tip superiorly)
  • Needle too far posterior (withdraw the needle to the proper depth)
• Wait a minimum of 3-5 minutes before commencing the dental procedure
• Signs and symptoms


  • Subjective: usually none, the patient has difficulty reaching this region to determine the extent of anesthesia
  • Objective: use of a "freezing spray" (ex.: Endo-Ice) or an electric pulp tester (EPT) with no response from the tooth with maximal EPT output (80/80), absence of pain during treatment

  
• Safety features


  • Slow injection, repeated aspirations, no anatomic safety features to prevent over insertion of the needle; therefore, careful observation is necessary