Supplemental Injection Techniques in Dentistry

Supplemental Injection Techniques

• This presentation covers various supplemental injection techniques used in dentistry, including PDL, intrapulpal, and comparisons.
• The presenter, Dr. Anuroop Singhai, is from the Oral Surgery division at Batterjee Medical College.

PDL Injection

• Other Names: Peridental (original name) injection, intraligamentary injection
• Nerves Anesthetized: Terminal nerve endings at the injection site and at the apex of the tooth.
• Areas Anesthetized: Bone, soft tissue, apical, and pulpal tissues in the injection area.
• Indications:
  • Pulpal anesthesia for one or two teeth in a quadrant.
  • Treatment of isolated teeth in two mandibular quadrants (to avoid bilateral IANB).
  • Patients needing regional anesthesia for whom residual soft-tissue anesthesia is undesirable.
  • Situations where regional block anesthesia is contraindicated.
  • Aid in diagnosing pulpal discomfort.
  • Adjunctive technique after nerve block if partial anesthesia is present.
• Contraindications:
  • Infection or inflammation at the injection site.
  • Patients who require "numb" sensation for psychological comfort.
• Advantages:
  • No lip, tongue, or other soft tissue anesthesia, enabling treatment in multiple quadrants during the same appointment.
  • Minimal local anesthetic dosage needed (~0.2 mL per root).
  • Faster onset of profound pulpal and soft-tissue anesthesia (30 seconds).
  • Less traumatic than conventional block injections.
  • Well-suited for procedures such as extractions, periodontal and endodontic procedures including children.
• Disadvantages:
  • Difficult needle placement in certain areas (e.g., distal to the second or third molar).
  • Leakage of anesthetic into the mouth causing a bitter taste.
  • Potential breakage of the glass syringe cartridge during overly rapid injection.
  • May need a special syringe in some cases.
  • Potential for focal tissue damage from excessive pressure.
  • Post-injection discomfort may persist for several days.
  • Potential for tooth extrusion if excessive pressure is used.
• Positive Aspiration: Zero percent
• Alternative: Supraperiosteal injection (for maxilla/mandibular incisor region). Infiltration using articaine hydrochloride is highly successful for mandibular molars.
• Technique (for PDL Injection): A 27-gauge needle is recommended. Insertion targeting mesial or distal roots (singular or multiple-rooted). The needle placement is between the root and the interproximal bone, and within the gingival sulcus. Placement involves the following landmarks: roots, periodontal tissues. The angle of the bevel towards the root facilitates the progress into an apical direction.
• Procedure:
  • Proper positioning with sufficient visibility.
  • Correct needle angle (adjusts depending on tooth type).
  • Positioning the patient appropriately.
  • Injecting along the long axis of the root, using a mouth mirror when possible.
  • Needle bevel faces root of the tooth, close to the long axis.
  • Syringe/hand stabilized while keeping contact to face, teeth, lips.
• Dosage: 0.2 mL of local anesthetic solution in up to 20 seconds. The use of a conventional syringe, the rubber stopper's thickness equals 0.2 mL, which can be used as a gauge. With a PDL syringe, each trigger provides 0.2 mL.
• Post Injection: Treatment may start within 30 seconds. In multirooted teeth, repeat the procedure to the other root/s.

Signs and Symptoms

• Subjective: When ischemia of the soft tissue and significant resistance are present, adequate anesthesia is likely.
• Objective: Uses a freezing spray/electric pulp tester (EPT) with maximal output (80/80), no response.

Safety Feature

• Intravascular injection is unlikely.

Precautions

• Maintain needle contact with the tooth to prevent damage to the lingual aspect.
• Inject slowly (minimum 20 seconds for .2 mL).
• Do not inject excessive amounts; .2 mL per root.
• Avoid infected or inflamed tissue.

Failures of Anesthesia

• Periapical infection: Reduced efficacy due to pH and vascular changes.
• Solution not retained: Re-inject at different sites until the 0.2 mL is deposited and retained in tissues.
• Each root should be anaesthetized with ~0.2 mL of solution.

Duration of Expected Anesthesia

• Duration varies, not directly related to the drug.
• Example: Lidocaine with epinephrine (1:100,000) ranges from 5-55 minutes.

Complications

• Needle insertion pain: Maintain the needle against the tooth's structure, use topical anesthesia for inflamed tissues.
• Injection pain: Use a slower injection speed (minimum 20 seconds for .2 mL solution).
• Post-injection pain: Excess volume/multiple penetrations can lead to problems. Address with warm saline rinses and analgesics (resolves in 2-3 days).

Intrapulpal Injection

• Nerves Anesthetized: Terminal nerve endings in the pulp chamber and canals.

• Areas Anesthetized: Tissues within the tooth.

• Indications: Pain control for pulpal extirpation/endodontic treatment if repeated other techniques fail.

• Contraindications: None. May be the only option for some clinical situations.

• Advantages: Lack of lip/tongue anesthesia, minimal anesthetic volume needed, immediate onset of action, few postoperative complications.

• Disadvantages:

  • Brief pain associated with injection.

• Bitter taste if leakage occurs.

• Short duration of action (15-20 minutes).

• Difficulty entering certain root canals (potential need to adjust needle).

• Intense pulp chamber decay presents challenges to achieving profound anesthesia.

• Technique:

  • Insert a 25- or 27-gauge needle into the pulp chamber or root canal as needed.
  • Wedge the needle firmly in the chamber/canal.
  • Deposit ~0.2 to 0.3mL of anesthetic under pressure.

• Positive Aspiration: Zero percent.

• Alternatives: Intraosseous injection, when intrapulpal fails.

• Resistance (back pressure): Crucial for success, should be felt during injection.

• Needle bending: Used to access the pulp chamber to avoid damage to soft surrounding tissues.

• Post-injection Sensitivity: Brief period of pain, but resolves quickly, allows for atraumatic instrumentation.

• Instrumentation: May start ~30 seconds after injection.

Intrapulpal Injection: Signs and Symptoms

• As with other injections, subjective symptoms are typically not present, making objective symptoms (e.g., no response of the pulp to EPT maximal output) useful to determine successful anesthesia.

Safety Features

• Intravascular injection is exceptionally rare.
• Small anesthetic volumes are used.

Precautions

• Avoid injecting anesthetic into infected tissues.
• Gradual/slow injection (minimum 20 seconds for .2- .3 mL).
• Do not inject excessive amounts.

Intrapulpal Injection: Failures of Anesthesia

• Infected/inflamed tissue: Changes in tissue pH negatively affect anesthetic effectiveness.
• Solution not retained: Re-inject into the pulp chamber or root canal, re-administer 0.2 to 0.3 mL of anesthetic, if needed.

Intrapulpal Injection: Complications

• Injection discomfort: Usually brief, mild to intense.
• Discomfort resolves quickly as the injection site anesthetizes.
• Inhalation sedation (N2O/O2) can lessen the sensation.

Duration of Expected Anesthesia

• Duration is variable after intrapulpal anesthetic injection (~15-20 minutes).

Comparison Chart

• Table comparing the three different injection types (PDL, intraseptal, intraosseous, intrapulpal) in terms of injection location, indications, anatomical considerations, advantages, disadvantages, and limitations.