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The general procedure of a dental nerve block will be described. The specific details are contained within each nerve block described below. Identify the anatomic landmarks required to perform the nerve block. Clean the mucous membrane at the injection site with a gauze square. Apply an antiseptic solution. Apply a topical anesthetic and allow it to work for 2 to 3 minutes. Reidentify the anatomic landmarks. Insert a 25 or 27 gauge needle into the appropriate area to deliver the local anesthetic agent. If the patient experiences paresthesias, do not inject the local anesthetic solution. Paresthesias signify that the tip of the needle is within the nerve bundle. Withdraw the needle 1 to 2 mm and allow the paresthesias to resolve. This usually takes 5 to 20 seconds. Inject the local anesthetic solution. Allow up to 10 minutes for the local anesthetic solution to take effect. Some Dentists prefer to apply pressure to the area immediately next to the site of the anesthetic injection with a cotton-tipped applicator. This aids in distracting the patient from the pain of injection. Other Dentists “jiggle” the mucous membrane to and fro rapidly as they simultaneously introduce the needle.2,3
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Supraperiosteal Infiltration (Field Block)
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This technique is commonly used in dentistry. Excellent anesthesia can be achieved with this technique when it is used to anesthetize a branch of the anterior or middle superior alveolar nerve.3,4 This technique deposits local anesthetic agent against the periosteum of the alveolar ridge adjacent to a tooth (Figure 176-3A). The local anesthetic agent then infiltrates through the periosteum, the cortical plate of the maxilla, and the medullary bone to anesthetize the nerve root as it leaves the apex of the tooth. This technique works best for teeth with associated thin cortical bone. This includes the maxillary incisor, canine, and premolar teeth. The molars of the maxilla in an adult are less likely to be anesthetized with this technique as the cortical bone in which they lie is relatively thick and a poor conduit for the anesthetic. Supraperiosteal infiltration is also a poor technique for anesthesia of mandibular teeth in the adult patient for the same reasons. In children, the cortical bone of the maxillary molars and the mandible is thin and may allow this technique to be effectively utilized to anesthetize a tooth.
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The anterior superior alveolar nerve provides sensory innervation to the ipsilateral medial and lateral incisors, canine, and sometimes the first premolar teeth. The middle superior alveolar nerve provides sensory innervation to the ipsilateral premolars, canine, and first molar teeth.
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Place the patient recumbent in a dental chair with their neck extended 45°. Alternatively, position the patient sitting upright with their back and head firmly set against an examination chair or table.
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Use the nondominant hand to grasp and pull the upper lip outward and upward (Figure 176-3B). Identify the mucobuccal fold above the tooth to be anesthetized.3
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Needle Insertion and Direction
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Clean, prep, and apply a topical anesthetic agent to the mucobuccal fold above the tooth to be anesthetized. Firmly grasp the upper lip. Pull it outward and upward to tighten the tissues and allow a clear identification of the maxillary mucobuccal fold (Figure 176-3B). Insert a 27 gauge needle through the mucobuccal fold over the center of the tooth to be anesthetized (Figure 176-3B). Aim the tip of the needle toward the maxilla. Advance the needle 1.0 to 1.5 cm until it contacts the maxilla (Figure 176-3A). Withdraw the needle 1 mm. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 1 to 2 mL of local anesthetic solution.
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The anesthetic will be deposited in a nonoptimal location if the needle is too deep or too shallow. It may take as long as 10 minutes to achieve anesthesia as the local anesthetic solution diffuses through the cortical bone and to the nerve root. Be careful when using this technique for anesthesia of the incisor or canine teeth because advancing the needle too far may breach the nasal cavity or maxillary sinuses.
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Infraorbital Nerve Block
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The infraorbital nerve is the terminal branch of the maxillary nerve. It exits the maxilla via the infraorbital foramina and supplies sensation to the ipsilateral upper lip, cheek, lateral nose, and lower eyelid. It may be blocked by either an extraoral or intraoral approach.
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Place the patient recumbent in a dental chair with their neck extended 30°. Alternatively, position the patient sitting upright with their head and back against an examination chair or table with their neck extended 30°. Instruct the patient to slightly open their mouth.
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Identify the infraorbital foramen by palpation. It is located below the infraorbital ridge in the midpupillary line (Figure 176-4). The midpupillary line is a line drawn in the sagittal plane (vertical) through the pupil while the patient is staring straight ahead.
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Needle Insertion and Direction (Extraoral Approach)
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Identify the infraorbital foramen as above. Clean and prep the skin over the infraorbital foramen. Instruct the patient to close their eyes. Insert a 25 or 27 gauge needle through the skin overlying the infraorbital foramen (Figure 176-5). Advance the needle to just beneath the subcutaneous tissue. Do not enter the infraorbital canal as this may damage the nerve. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 1 to 2 mL of local anesthetic solution. Massage the area over the infraorbital foramen for a few seconds to ensure optimal infiltration.
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Needle Insertion and Direction (Intraoral Approach)
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Clean, prep, and apply a topical anesthetic agent to the mucosa opposite the first maxillary premolar. Place the nondominant index finger over the infraorbital foramen (Figure 176-6). Retract the upper lip using the nondominant thumb. Identify the mucobuccal fold above the first premolar. Insert a 25 or 27 gauge needle through the mucobuccal fold. Advance the needle toward the nondominant index finger situated over the infraorbital foramen (Figure 176-6B). Stop advancing the needle when the tip is felt beneath the index finger. The estimated depth of penetration of the needle tip is 1.0 to 1.5 cm in an older child or an adult and 0.5 to 1.0 cm in a younger child. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 1 to 2 mL of local anesthetic solution.
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Be careful not to penetrate too deeply when performing the intraoral approach. The infraorbital venous plexus may be disrupted and result in a hematoma. The globe may also be accidentally penetrated. Avoid these complications by positioning the nondominant index finger over the infraorbital foramen and using it to palpate and track the advancing needle tip. The intraoral approach is the preferred technique.
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Nasopalatine Nerve Block
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The nasopalatine nerve provides sensory innervation to the anterior one-third of the hard palate (Figure 176-7A). It exits the maxilla via the incisive foramen in the midline and 0.5 cm posterior to the central incisors.
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Place the patient recumbent in a dental chair with their head extended 45°. Alternatively, place the patient supine with a rolled sheet beneath their shoulder blades to assist in neck extension. Instruct the patient to fully open their mouth.
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The incisive foramen lies in the midline and approximately 5 mm posterior to the central incisors of the maxilla. Overlying the incisive foramen is the incisive papilla, a soft tissue elevation.
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Needle Insertion and Direction
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Clean, prep, and apply a topical anesthetic agent to the mucosa on the anterior one-third of the hard palate. Identify the incisive foramen by first identifying the incisive papilla. Insert a 27 to 30 gauge needle, with the bevel facing the hard palate, from a position immediately lateral to the edge of the incisive papilla (Figure 176-7B). Advance the needle 3 to 4 mm toward the midline or until bone is identified. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 0.25 to 0.35 mL of local anesthetic solution. The area surrounding the injection site will blanch upon deposition of the local anesthetic solution.2,3
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This is a particularly painful injection due to the adherent nature of the mucosa to the underlying hard palate. Topical anesthetics will provide adequate preinjection anesthesia. Some clinicians use a cotton-tipped applicator or a blunt instrument to put pressure on the incisive papilla for 30 seconds prior to and during the injection.3 This seems to defer the attention of the patient and make the injection more bearable. Be careful not to penetrate too deeply with the needle and enter the incisive foramen. Insertion into the incisive foramen will cause severe pain. Injection into the incisive foramen can result in permanent nerve damage.2,3 The mucosa of the hard palate receives its blood supply from the hard palate. Injection of more than 0.4 mL will elevate the mucosa from the hard palate and result in mucosal necrosis. This block may be performed to repair lacerations of the mucosa of the anterior hard palate.
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Greater Palatine Nerve Block
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The greater palatine nerve provides sensory innervation to the ipsilateral posterior two-thirds of the hard palate (Figure 176-7A). It enters the oral cavity via the greater palatine foramen. The greater palatine foramen lies between the second and third maxillary molar and approximately 1 cm onto the hard palate.
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Place the patient recumbent in a dental chair with their head extended 45°. Alternatively, place the patient supine with a rolled sheet beneath their shoulder blades to assist in neck extension. Instruct the patient to fully open their mouth.
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The greater palatine foramen lies 1 cm medial to the gingival junction of the second and third maxillary molar (Figure 176-7C).
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Needle Insertion and Direction
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Clean, prep, and apply a topical anesthetic agent to the hard palate adjacent to the second and third maxillary molars. Insert a 27 to 30 gauge needle 1 cm medial to the junction of the second and third maxillary molars (Figure 176-7C). Ensure that the tip of the needle is held at 90° to the curve of the palate. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 0.25 to 0.35 mL of local anesthetic solution. The area surrounding the injection site will blanch upon deposition of the local anesthetic solution.2,3
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This block may be performed to repair lacerations of the mucosa of the hard palate. The mucosa of the hard palate receives its blood supply from the hard palate. Injection of more than 0.4 mL will elevate the mucosa from the hard palate and result in mucosal necrosis. The position of the lesser palatine foramen is 2 to 4 mm posterior to the greater palatine foramen. The lesser palatine nerve provides sensory innervation to the soft palate and uvula. If anesthetized, as it often is when blocking the greater palatine nerve, the patient may experience a feeling of dysphagia or throat closure. Reassurance is usually adequate to alleviate the patient's anxiety until the anesthesia wears off.
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Posterior Superior Alveolar Nerve Block
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The maxillary nerve exits the skull via the foramen rotundum. It then courses anteriorly into the pterygopalatine fossa and divides into its constituent branches. The posterior superior alveolar nerve provides sensory innervation to the maxillary molar teeth and their associated mucosal tissues.
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Place the patient semirecumbent in a dental chair with their head extended 30°. Alternatively, place the patient sitting upright with their head and back firmly against the examination chair or table and their head extended 30° to 45°. Instruct the patient to fully open their mouth.
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Pull the buccal mucosa laterally and identify the inferior-most posterior portion of the zygoma. It lies posterior, lateral, and superior to the third maxillary molar. The pterygomaxillary fissure lies posterior, medial, and superior to the vestibule between the third maxillary molar and the posterior zygoma. The pterygopalatine fossa can be reached by following the pterygomaxillary fissure superiorly and medially.2,3
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Needle Insertion and Direction
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Clean, prep, and apply a topical anesthetic agent to the recess posterior and lateral to the maxilla. Insert the nondominant index finger between the maxillary molars and the cheek (Figure 176-8A). Palpate the zygomatic process of the maxilla with the index finger. Rotate the index finger 180° so that the pad is against the patient's cheek (Figure 176-8B). Apply outward pressure to move the cheek away from the teeth. Place the needle along the middle of the nail plate of the index finger. Aim the needle and syringe along the index finger (Figure 176-8B). The needle and syringe should be aimed posteriorly, superiorly, and medially (Figure 176-8C). Insert and advance the needle 2.5 cm along the index finger. If the needle contacts bone, withdraw the needle completely and direct it more laterally.2,3 Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 3 mL of local anesthetic solution.
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Bend the needle 30° at the hub to assist in achieving a medial direction of the needle. Do not bend the needle more than 30° as the needle may fracture. It is extremely important to never change the direction of a needle once it is inserted. This is associated with an increased risk of needle breakage requiring an operative procedure to recover the needle segment. Never force the needle. The needle is inappropriately positioned if it is meeting resistance. Abort the procedure, reidentify the landmarks, and reattempt the procedure.2,3 Occasionally, the first molar is only partially anesthetized by this block. Consider supplementation of this block with a supraperiosteal infiltration of the first molar.
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Mental Nerve Block, Intraoral Approach
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The mental nerve is one of the two terminal divisions of the inferior alveolar nerve. It provides sensory innervation to the ipsilateral skin and mucosa of the lower lip and chin. It exits the bony mandible at the mental foramen.
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Place the patient recumbent in a dental chair. Alternatively, place the patient sitting upright or supine with their head against the examination table and in the neutral position. Instruct the patient to slightly open their mouth.
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The mental foramen lies in the same plane as the infraorbital foramen and the midpupillary line (Figure 176-4). The mental foramen is located approximately 1 cm beneath the gum line, between the first and second premolar.
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Needle Insertion and Direction
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Clean, prep, and apply a topical anesthetic agent to the oral mucosa overlying the mental foramen. Grasp the lower lip with the nondominant hand. Pull it outward and downward (Figure 176-9). Insert a 27 gauge needle into the mucobuccal fold between the first and second premolar (Figure 176-9). Advance the needle medially until it contacts the mandible. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 1.5 to 2.0 mL of local anesthetic solution.
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The mental nerve block, as the infraorbital nerve block, has an intraoral and an extraoral approach. The extraoral approach will not be discussed as it is more painful and there is no benefit to its use over the intraoral approach. A description of the extraoral approach to the mental nerve block is found in Chapter 126. A near midline lower lip or chin injury may necessitate bilateral mental nerve blockade due to the midline crossover from each of the mental nerves.2
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The buccal nerve is one of the main branches of the mandibular nerve. It travels down the medial aspect of the ramus of the mandible, anterior to the inferior alveolar neurovascular bundle. It crosses from the medial mandible into the soft tissue of the cheek at the level of the occlusive plane. It supplies the sensory innervation to the mucous membrane of the cheek and vestibule.1 It innervates, to a variable degree, a small patch of skin over the cheek.
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Place the patient recumbent in a dental chair with their head extended 30°. Alternatively, place the patient sitting with their head and back firmly against an examination chair or upright table with their head extended 30° to 45°. Instruct the patient to fully open their mouth.
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Visually identify the third mandibular molar. Palpate the anterior border of the ramus of the mandible. The buccal nerve traverses the anterior border of the ramus of the mandible, posterior and slightly lateral to the third molar at the level of the occlusive plane.
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Needle Insertion and Direction
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Clean, prep, and apply a topical anesthetic agent to the oral mucosa over the anterolateral border of the ramus of the mandible. Place the thumb of the nondominant hand on the inner surface of the cheek. Pull the cheek outward. Insert a 27 gauge needle 1 mm lateral to the anterior border of the ramus of the mandible and at the level of the occlusal plane (Figure 176-10). Advance the needle 3 to 4 mm into the soft tissues. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 2 mL of local anesthetic solution.
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Buccal nerve blocks are used when extensive intraoral manipulation is anticipated, when buccal manipulation or repair is required, or for the incision and drainage of an abscess. It provides additional patient comfort. The block is nearly always performed as an adjunct to an inferior alveolar, maxillary, or posterior superior alveolar nerve block.3
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Inferior Alveolar Nerve Block
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The lingual and inferior alveolar nerves are two of four branches of the mandibular nerve. The nerves initially travel together and inferiorly on the medial side of the mandibular ramus (Figure 176-11A). The lingula is a palpable bony landmark immediately anterior to the mandibular foramen. The inferior alveolar nerve courses posterior to the lingula and enters the mandibular canal via the mandibular foramen. It continues to travel anteriorly within the mandible to provide sensory innervation to the body of the mandible, the mandibular teeth, and the overlying oral mucosa. One of the terminal branches of the inferior alveolar nerve is the mental nerve. The inferior alveolar nerve may be blocked by the classic, open-mouth approach or the closed-mouth approach.
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Place the patient in a dental chair with their head neutral, such that the occlusive surface is parallel to the floor. Alternatively, place the patient sitting upright in an examination chair or on a gurney with their head positioned firmly against the back of the gurney or chair. Instruct the patient to fully open their mouth. Perform the open-mouth approach if the patient can fully open their mouth. Perform the closed-mouth approach if the patient has trismus or cannot fully open their mouth.
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Identify by palpation the anterior border of the ramus of the mandible within the mouth, the coronoid notch within the mouth, and the posterior border of the ramus of the mandible externally (Figure 176-11B). Approximately equidistant from these two points lie the lingual and the inferior alveolar nerves. Palpate the lingula of the ramus of the mandible. It is a bony projection on the medial surface of the ramus of the mandible and 1 cm above the occlusive plane.
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Needle Insertion and Direction (Open-Mouth Approach)
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Clean, prep, and apply a topical anesthetic agent to the inner surface of the ramus of the mandible. Stand opposite the side to be blocked. Place the thumb of the nondominant hand on the anterior border of the ramus of the mandible. Move the thumb posteromedially to identify the lingula. Place the index finger of the nondominant hand against the extraoral border of the mandibular ramus, just above the angle of the mandible. Grasp the ramus between the thumb and the forefinger (Figure 176-11C). Pull the cheek outward using the nondominant thumb as a lever. Place a 27 gauge, 2 inch needle on a 3 mL syringe that contains local anesthetic solution. A 5 mL syringe is too large for this approach. A syringe smaller than 3 mL will not carry enough anesthetic.
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Introduce the needle from the opposite side (Figure 176-11D). Align the tip of the needle toward the lingula with the barrel of the syringe between the contralateral first and second premolars (Figure 176-11D). Hold the syringe parallel to the occlusal plane and 3 to 4 mm above the premolars. Insert the needle into the oral mucosa just superior and posterior to the lingula. Advance the needle until the tip contacts the ramus of the mandible. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 2 mL of local anesthetic solution.
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The above technique is optimal if the operator is right-handed and a right-sided inferior alveolar block is attempted. If the operator is right-handed and attempting a left-sided inferior alveolar nerve block, it is still necessary to stand opposite the side to be anesthetized with the syringe in the dominant hand. Place the nondominant arm over and around the patient's head so that the thumb of the nondominant hand can contact the anterior border of the mandibular ramus and the index finger can grasp the posterior border above the angle of the mandible. The remainder of the technique is the same.
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Needle Insertion and Direction (Closed-Mouth Approach)
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This method can be used when the patient cannot fully open their mouth due to an abscess, edema, mandible fractures, trismus, or if the mandible is wired-closed to the maxilla. This approach deposits the local anesthetic solution superior to the site of the classic, open-mouth approach. The local anesthetic solution will descend, due to gravity, to bathe the inferior alveolar nerve and provide adequate anesthesia.
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Place the nondominant thumb on the inner surface of the cheek. Pull the cheek outward. Place a 27 gauge needle on a 3 mL syringe that contains local anesthetic solution. Place the needle and syringe parallel to the occlusal plane and aligned along the junction of the maxillary molars and their gingiva (Figure 176-11E). Direct the needle just medial to the ramus of the mandible (Figures 176-11E & F). Advance the needle 3 cm through the mucosa. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 2 mL of local anesthetic solution.
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It is crucial that the tip of the needle contacts the mandible in the open-mouth approach. The needle is usually advanced 0.5 to 1 cm before the mandible is encountered. The needle is most likely inappropriately placed and deposition of anesthesia will not produce the desired results if the mandible is not encountered. Remove the needle, reidentify the appropriate anatomic landmarks, and reattempt the procedure if the mandible is not encountered. The buccal, inferior alveolar, and lingual nerves must be blocked on one side to achieve complete anesthesia of the hemimandible. Facial nerve paralysis can occur if the needle is inserted too far posterior and enters the capsule of the parotid gland. This paralysis is usually transient and resolves as the anesthetic wears off.
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The lingual nerve is a branch of the mandibular division of the trigeminal nerve. It travels with the inferior alveolar nerve until the inferior alveolar nerve enters the mandible. The lingual nerve leaves the medial aspect of the mandibular ramus and penetrates the posterior tongue at the level of the occlusive plane, just medial to the third mandibular premolar. It courses anteriorly to provide sensory innervation to the anterior two-thirds of the tongue, the floor of the mouth, and the lingual mucous membrane.1
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Place the patient in a dental chair with their head neutral, such that the occlusive surface is parallel to the floor. Alternatively, place the patient sitting upright in an examination chair or on a gurney with their head firmly against the back of the gurney or chair. Instruct the patient to fully open their mouth.
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Identify the lingual side of the second mandibular molar. The injection site is 1 cm medial to the second mandibular molar.
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Needle Insertion and Direction
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Approach the patient from the contralateral side. Move the tongue upward or toward the contralateral side with a tongue blade. Insert a 27 gauge, 2 inch needle into the mucosa 1 cm medial to the second mandibular premolar (Figure 176-12). Advance the needle posteriorly 1 cm. Aspirate to confirm that the tip of the needle is not within a blood vessel. Inject 1.0 to 1.5 mL of local anesthetic solution.
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The inferior alveolar nerve and the lingual nerve can be, and usually are, blocked simultaneously during an inferior alveolar nerve block. The lingual nerve, however, can be blocked in an isolated fashion. Perform an isolated lingual nerve block only when the initial combined block has failed or for isolated tongue lacerations.1,3 This is an optimal block for tongue laceration repair. However, bilateral lingual nerve blocks may be necessary.