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The interdental infiltration technique is useful in providing osseous and soft tissue anesthesia and hemostasis for different dental procedures in both mandibular and maxillary arches.  The nerves that are anesthetized are the terminal nerve endings at the site of injection and in adjacent soft and hard tissues.  The areas that are anesthetized are the slight alveolar crest, interdental papilla soft tissue, but no pulpal anesthesia.  

Proper technique:

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  1. 27-gauge short needle is recommended

  2. Area of insertion: base of the interdental papilla adjacent to the tooth being treated

  3. Target area: base of the interdental papilla adjacent to the tooth being treated

  4. Landmarks:​​​​​​​​

    • Papillary triangle (about 2mm below the tip, equidistant from adjacent teeth)

  5. Orientation of the bevel: not significant, although recommended toward apex 

Procedures:

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  1. Correct patient & clinician positioning

    • Varies significantly from tooth to tooth

    • Clinician should be comfortable, have adequate visibility of the injection site, and maintain control over the needle

  2. Position the patient supine or semisupine with the head turned to maximize access and visibility

  3. Prepare tissue at the injection site

    • Dry with gauze or blow air with air/water syringe​

    • Apply topical anesthetic for minimum of 1 minute

  4. Stabilize the syringe and orient the needle correctly

    • Front plane: 45 degree to the long axis of the tooth​

    • Sagittal plane: At right angle to the soft tissue

    • Bevel facing the apex of the tooth

  5. Slowly inject a few drops of local anesthetic as the needle enters soft tissue, and advance the needle until contact with bone is made

  6. While applying pressure to the syringe, push the needle slightly deeper (1-2mm) into the interdental papilla

  7. Deposit 0.2-0.4mL of local anesthetic in not less than 20 seconds (the thickness of the rubber plunger is equivalent to 0.2mL​)

  8. Two important items indicate success of the injection:

    • Significant resistance to the deposition of solution​

      • This is especially noticeable when a conventional syringe is used.  Resistance is similar to that felt with nasopalatine and PDL injections

      • Anesthetic solution should not come back into the patient's mouth.  If this occurs, repeat the injection with the needle slightly deeper

    • Blanching of soft tissues adjacent to the injection site (although noted with all local anesthetic solutions, this is more prominent with local anesthetics containing a vasoconstrictor)

  9. Repeat the injections as needed during the surgical procedure

I N T E R D E N T A L   I N F I L T R A T I O N   ( I D ) 

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