Techniques of Mandibular Anesthesia PDF

Techniques of Mandibular Anesthesia Dr. Anuroop Singhai Oral Surgery Division Mandibular Nerve  Mandibular Nerve 1 Undivided nerve q Nervus spinosus q Nerve to the medial pterygoid muscle 2 Divided nerve a) Anterior division o Nerve to the lateral pterygoid muscle o Nerve to...

Techniques of Mandibular Anesthesia Dr. Anuroop Singhai Oral Surgery Division Mandibular Nerve  Mandibular Nerve 1 Undivided nerve q Nervus spinosus q Nerve to the medial pterygoid muscle 2 Divided nerve a) Anterior division o Nerve to the lateral pterygoid muscle o Nerve to the masseter muscle o Nerve to the temporal muscle o Buccal nerve b) Posterior division Ø Auriculotemporal nerve Ø Lingual nerve Ø Mylohyoid nerve Ø Inferior alveolar nerve: dental branches Ø Incisive branch: dental branches Ø Mental nerve Inferior Alveolar Nerve Block Other Common Name: Mandibular block Nerves Anesthetized 1. Inferior alveolar nerve 2. Incisive 3. Mental 4. Lingual (commonly)  Inferior Inferior Alveolar Alveolar Nerve Block Nerve block Indications: 1. Procedures on multiple mandibular teeth in one quadrant. 2. When buccal soft-tissue anesthesia (anterior to the first molar) is necessary. 3. When lingual soft-tissue anesthesia is necessary. Contraindications: 1. Infection or acute inflammation in the area of injection (rare). 2. Patients who might bite either the lip or the tongue; for instance, a very young child or a physically or mentally handicapped adult or child.  Inferior Inferior Alveolar Alveolar Nerve Block Nerve block Advantages: One injection provides a wide area of anesthesia (useful for quadrant dentistry). Disadvantages: 1. Wide area of anesthesia (not necessary for localized procedures). 2. Rate of inadequate anesthesia (15% to 20%). 3. Intraoral landmarks not consistently reliable. 4. Positive aspiration (10% to 15%, highest of all intraoral injection techniques). 5. Lingual and lower lip anesthesia, discomfiting to many patients and possibly dangerous for certain individuals. 6. Partial anesthesia possible where a bifid inferior alveolar nerve and bifid mandibular canals are present. Positive Aspiration: 10% to 15% Inferior Alveolar Nerve Block Alternatives: 1. Mental nerve block, for buccal soft-tissue anesthesia anterior to the first molar. 2. Incisive nerve block, for pulpal and buccal soft-tissue anesthesia of teeth anterior to the mental foramen. 3. Supraperiosteal injection, for pulpal anesthesia of the central and lateral incisors, and sometimes the premolars (success rate extremely variable). 4. Gow-Gates mandibular nerve block. 5. Vazirani-Akinosi mandibular nerve block. 6. PDL injection for pulpal anesthesia of any mandibular tooth. 7. Intraosseous (IO) injection for osseous and soft-tissue anesthesia of any mandibular region, but especially molars. 8. Intraseptal injection for osseous and soft-tissue anesthesia of any mandibular region. Inferior Alveolar Nerve Block Technique A 25-gauge long needle is recommended for the adult patient. Area of insertion: mucous membrane on the medial side of the mandibular ramus, at the intersection of two lines: one horizontal, representing the height 244and of injection, PART the III Techniques other vertical,ofrepresenting Regional Anesthesia in Dentistry the anteroposterior plane of injection. Fig. 14.7 Needle insertion is at the point of intersection of horizontal  4 Inferior Alveolar Nerve Block 7 6 5 3 1 2 Target area: inferior alveolar nerve as it passes downward toward the mandibular foramen but before it enters into the foramen. Fig. 14.2 Osseous landmarks for inferior alveolar nerve block. 1, Lingula; 2, distal border of ramus; 3, coronoid notch; 4, coronoid process; 5, sigmoid (mandibular) notch; 6, neck of condyle; 7, head of condyle. Landmarks: a) Coronoid Techniquenotch (greatest concavity on 1. the anterior A long dental borderfor the needle is recommended ofadultthe patient or any pediatric patient where the soft tissue depth at the ramus). injection site is approximately 20 mm. A 25-gauge long needle is preferred; a 27-gauge long is acceptable. b) Pterygomandibular raphe. on the medial (lin- 2. Area of insertion: mucous membrane c) Occlusal gual) sideplane of of the mandibularthe mandibular ramus, at the intersection of two lines—one horizontal, representing the height posterior of needleteeth. insertion, the other vertical, representing the Pterygomandibular raphe anteroposterior plane of injection. 3. Target area: inferior alveolar nerve as it passes downward toward the mandibular foramen but before it enters into the foramen. 4. Landmarks (Figs. 14.2 and 14.3): a. Coronoid notch (greatest concavity on the anterior border of the ramus). b. Pterygomandibular raphe (vertical portion). Fig. 14.3 The posterior border of the mandibular ramus can be Inferior Alveolar Nerve Block Technique: Right Inferior Alveolar Nerve Block Operator position: A right-handed administrator should sit at the 8 o’clock position facing the patient. Positioning the patient: Supine or semisupine. The head should be positioned so that when the mouth is open, body of the mandible is parallel to the floor.  Inferior Alveolar Nerve Block Palpation of Intraoral landmarks: 1) Left index finger or thumb palpates the mucobuccal fold. 2) The finger or thumb is then moved posteriorly until contact is made with the external oblique ridge on the anterior border of the ramus of the mandible. 3) When the finger or thumb contacts the ramus of the mandible, it is moved up and down until the greatest depth of the anterior border of the ramus is identified. This area of depth is called the coronoid notch and is in a direct line with the mandibular sulcus. This places height of the mandibular sulcus. 4) The palpating finger is moved lingually across the retromolar triangle and onto the internal oblique ridge. Inferior Alveolar Nerve Block Technique: Right Inferior Alveolar Nerve Block 5) The finger or thumb, still in line with the coronoid notch and in contact with the internal oblique ridge, is moved to the buccal side, taking with it the buccal sucking pad. 6) When palpating the intraoral landmarks with the thumb, the operator may place the index finger extraorally behind the ramus of the mandible, thus literally holding the mandible between the thumb and index finger. In this manner the anteroposterior width of the ramus may be assessed. Inferior Alveolar Nerve Block Needle insertion: A syringe with a 15/8 inch, 25 – gauge needle is then inserted parallel to the occlusal plane of the mandibular teeth from the opposite side of the mouth, at a level bisecting the finger or thumbnail, penetrating the tissues of the pterygotemporal depression, and entering the pterygomandibular space. During insertion, the patient should be asked to keep mouth wide open. The needle is penetrated into the tissues until gently contacting bone on the internal surface of the ramus of the mandible. The average depth of penetration to bony contact, in the adult, is 20 to 25 mm, approximately two-thirds to three-fourths the length of a long dental needle. Inferior Alveolar Nerve Block Technique: Right Inferior Alveolar Nerve Block Insert the needle. When bone is contacted, withdraw approximately the needle by 1 mm to prevent subperiosteal injection. Aspirate in two planes. If negative, slowly deposit 1.5 mL of anesthetic over a minimum of 60 seconds. (Because of the high incidence of positive aspiration and the natural tendency to deposit solution too rapidly, the sequence of slow injection, reaspiration, slow injection, and reaspiration is strongly recommended.) Slowly withdraw the syringe, and when approximately half its length remains within tissues, reaspirate. If negative, deposit a portion of the remaining solution (0.2 mL) to anesthetize the lingual nerve. In most patients, this deliberate injection for lingual nerve anesthesia is not necessary because local anesthetic from the IANB anesthetizes the lingual nerve. Inferior Alveolar Nerve Block Technique: Left Inferior Alveolar Nerve Block For a left IANB, a right-handed administrator should sit at the 10 o’clock position facing in the same direction as the patient The left arm of the dentist is placed around the patient’s head so that the landmarks may be palpated with the left index finger or thumb. Inferior Alveolar Nerve Block Signs and Symptoms 1. Subjective: Tingling or numbness of the lower lip indicates anesthesia of the mental nerve, a terminal branch of the inferior alveolar nerve. This is a good indication that the IAN is anesthetized, although it is not a reliable indicator of the depth of anesthesia. Soft tissue anesthesia is never a guarantee of pulpal anesthesia. 2. Subjective: Tingling or numbness of the tongue indicates anesthesia of the lingual nerve, a branch of the posterior division of V3. It usually accompanies IANB but may be present without anesthesia of the inferior alveolar nerve. 3. Objective: Use of a freezing spray (e.g., Endo-Ice) or an electric pulp tester (EPT) with no response to maximal output (80/80) on two consecutive tests at least 2 minutes apart serves as a “guarantee” (∼99%) of successful pulpal anesthesia in nonpulpitic teeth. 4. Objective: No pain is felt during dental therapy. Lack of pain when blunt instrument is applied on the buccal gingiva anterior to the mental foramen. Safety Feature: The needle contacts bone preventing over insertion, with its attendant complications. Inferior Alveolar Nerve Block Precautions: 1. Do not deposit local anesthetic if bone is not contacted. The needle tip may be resting within the parotid gland near the facial nerve (cranial nerve VII), and a transient paralysis of the facial nerve is produced if solution is deposited. 2. Avoid pain by not contacting bone too forcefully. Failures of Anesthesia: The most common causes of absent or incomplete IANB follow: 1. Deposition of anesthetic too low (below the mandibular foramen). 2. Deposition of anesthetic too far anteriorly (laterally) on the ramus. 3. Accessory innervation to the mandibular teeth. Inferior Alveolar Nerve Block Complications 1. Hematoma (rare) a. Swelling of tissues on the medial side of the mandibular ramus after the deposition of anesthetic. b. Management: pressure and cold (e.g., ice) to the area for a minimum of 3 to 5 minutes. 2. Trismus a. Muscle soreness or limited movement (1) A slight degree of soreness when opening the mandible is extremely common after IANB (when anesthesia has dissipated). (2) More severe soreness associated with limited mandibular opening is rare. 3. Transient facial paralysis (facial nerve anesthesia) Produced by the deposition of local anesthetic into the body of the parotid gland. Signs and symptoms include an inability to close the lower eyelid and drooping of the upper lip on the affected side.