Inferior Alveolar Injection DHYG 149 PAIN CONTROL Local Anesthesia Inferior Alveolar Injection DHYG 149 PAIN CONTROL

Welcome to Dental Analgesia This is a self-paced learning module designed for the student wishing to prepare for or review the inferior alveolar injection technique. The inferior alveolar injection is the most common local anesthesia injection given. It is also a required performance for the Western Regional Examining Board Anesthesia Exam.

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Overview Indications Mandibular anatomy Inferior alveolar injection technique Problems and corrections Lab exercise Basic injection technique

Indications Procedures involving multiple mandibular teeth Procedures requiring lingual anesthesia

Mandibular Anatomy IA nerve and lingual nerve will be anesthetized Evers, p. 76 Coronoid notch Lingual nerve IA nerve Mandibular foramen IA nerve and lingual nerve will be anesthetized Target point is slightly above mandibular foramen Coronoid notch is a guiding landmark

Inferior Alveolar Nerve Evers, p. 71 Mental foramen Mandibular foramen Provides sensory innervation to: Lower teeth on one side Buccal bone from premolars to incisors Soft tissue of lip and chin

Lingual Nerve Provides sensory innervation to: Lingual soft tissue Anterior two-thirds of tongue Mandibular foramen Lingual nerve Evers p. 72

Tissues Anesthetized Molars Premolars Canines Incisors Lingual soft tissue Tongue Buccal soft tissue from mental foramen to midline Evers, p. 87

Pterygomandibular Space The soft tissues in the vicinity of the injection site form a space which should be identified. Target Point Medial pterygoid muscle Evers, p 72

Correct Needle Pathway The barrel of the syringe should be over the opposite premolars. Bone should be contacted prior to depositing anesthetic. Pterygoid raphe Lingual nerve Medial pterygoid muscle Parotid gland IA nerve

Incorrect Needle Pathway The barrel of the syringe is lying over the incisors. This error directs the needle posterior to the target point, possibly resulting in trismus or facial nerve paralysis. Pterygoid raphe Lingual nerve Medial pterygoid muscle Parotid gland IA nerve

Incorrect Needle Pathway The barrel of the syringe is lying over the molars. This error results in premature contact of bone and failure of anesthesia. Pterygoid raphe Lingual nerve Medial pterygoid muscle Parotid gland IA nerve

Intraoral Landmarks The pterygoid raphe and the coronoid notch form an imaginary triangle. It is in approximately the center of this triangle that the needle should inserted. Pterygoid raphe Coronoid notch Evers, p. 80

Insertion Point Insert needle into the depression or imaginary triangle between the pterygoid raphe and the coronoid process 1 centimeter above the mandibular occlusal plane. Evers. P 81

Target Point Advance needle until bone is contacted. Evers p 84

Deposition Aspirate in two planes Deposit at a rate of 1 ml/minute You are ready to deposit the anesthetic. Don’t forget to: Aspirate in two planes Deposit at a rate of 1 ml/minute Deposit 3/4 to 1 full cartridge

Failures of Anesthesia Problem Deposited below mandibular foramen Deposited anterior to mandibular foramen Deposited posterior to mandibular foramen Correction Reinject at height of triangle Bring barrel of syringe mesially over premolars Bring barrel distally over premolars and contact bone Review technique

Lab Exercise Remember: Practice this injection at your next lab. Use 25 gauge needle for this injection Look for intraoral landmarks Visualize mandibular anatomy Apply the basics of all injection techniques

Basic Injection Technique Review patient health history, medications and vitals Determine injection technique based on procedure to be performed Select appropriate anesthetic

Basic Injection Technique continued Prepare syringe use 25, 27, or 30 gauge needle use aspirating syringe Check flow of anesthetic Position patient Dry tissue Apply topical antiseptic (optional)

Basic Injection Technique, continued Apply topical anesthetic Establish fulcrum Stretch tissue Keep syringe out of patient’s sight Insert needle Advance needle Aspirate in two planes 11 12 13 14 15

Basic Injection Technique continued Slowly deposit anesthetic Withdraw syringe Observe patient Record injection and anesthetic in patient’s chart Always communicate with patient throughout entire procedure 16 17 18 19 20

Acknowledgements Hans Evers, Glenn Haegerstam, Introduction to Local Anesthesia, 2nd edition Mediglobe 1990 Margaret Ferenbach, Susan Herring, Illustrated Anatomy of the Head and Neck, W.B. Saunders 1996 Prof. Jill Torres, Oregon Institute of Technology, Department of Dental Hygiene