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Dental and Facial Anesthetic Blocks INTRODUCTION Dental and facial anesthesia can be used in the Emergency Department to provide temporary anesthesia for painful dental disorders, and facial injuries as well as to facilitate laceration repair of complex lacerations or incision & drainage of abscesses that may be difficult to directly anesthetize. GOALS OF THE PROCEDURE Provide adequate analgesia for procedures of the mouth or face or to aid with pain control in painful dental disorders. INDICATIONS ! Laceration repair of the forehead, ear, cheek, lip, or chin ! Incision and drainage of dental or facial abscesses ! Pain control for odontalgia GENERAL CONTRAINDICATIONS ! Overlying infection of the injection site ! Allergy to anesthetic ! Patient uncooperation ! Bleeding diathesis or anticoagulation (relative) COMPLICATONS: ! Introduction of infection ! Intravascular injection ! Needle breakage ! Anesthetic toxicity (when exceeding maximum amounts) ! Bleeding ! Allergy to anesthetic ! Pain EQUIPMENT ! PPE (gloves and eye protection) ! Chloroprep or betadine if entering skin ! Sterile 2x gauze ! Local anesthetic (generally 1% lidocaine or bupivicaine) ! Topical anesthetic (cetacaine spray or lollipops) ! Dental syringe ! Needle, generally 25-guage (specific to dental syringe) ANATOMY General considerations Dental anesthesia is generally divided into maxillary (upper teeth) and mandible (lower teeth) approaches. Both the anesthesia of the buccal (outer) and lingual (inner) aspects of the tooth must be considered. Maxillary anesthesia In general, anesthesia for maxillary teeth is achieved with local infiltration of the buccal and lingual aspects of each individual tooth to anesthetize the individual dental nerves. Alternatively, multiple teeth can be anesthetized by blocking the individual nerves that arise from the maxillary nerve (V2), with the most common being the posterior superior alveolar nerve block, nasopalatine nerve block, and anterior palatine nerve block. Mandible anesthesia: Aside from the central incisors, the denser bone in the mandible limits the effectiveness of supraperiostial infiltration. Thus, anesthesia for mandibular teeth is most commonly achieved via the infra-alveolar (IA), long buccal, and mental (incisive) nerve blocks. Infra-alveolar nerve/mental nerve The infra-alveolar nerve (IA) is a branch of the mandibular nerve (off of V3) and travels along the medial aspect of the ramus of the mandible and then enters the mandibular canal before giving off the mental nerve through the mental foramen. IA nerve block provides anesthesia to the ipsilateral lip, teeth, lingual aspect of the gums, and buccal gingival of the anterior teeth, and chin. Patients will also often have ipsilateral tongue numbness from an associated lingual nerve block. Long buccal nerve The long buccal nerve is a branch of the maxillary nerve and courses between the two heads of the lateral pterygoid muscle before coursing under the masseter muscle. It provides sensation to the buccal aspect of the second and third molars. Supraorbital nerve The ophthalmic nerve is a branch of the V1 cranial nerve and exits through the supraorbital notch, which can be found along the superior orbital rim and in line with the pupil. Supraorbital nerve block provides anesthesia to the forehead from the level of the eyebrow and above. Infraorbital nerve The infraorbital nerve is a branch of V2 and exits through the infraorbital foramen. It can be found just inferior to the infraorbital ridge and is in line with the pupil while the patient is looking straight ahead. Infraorbital nerve block provides anesthesia to the middle and superior alveolar nerves, skin of the upper lip, nose, cheek, and lower eyelid. STEPS Supraorbital nerve block Used for anesthesia of the forehead and scalp to the level of the lambdoid suture. 1. Palpate the supraorbital foramen along the superior orbital ridge, in line with the pupil as the patient looks straight ahead. 2. With a finger or gauze roll held just below the orbital rim (to prevent swelling of the eyelid), inject 1-3mL of anesthetic into the area of the foramen. 3. The patient will generally feel parasthesias of the forehead to signify successful placement. If not elicited, inject a small amount of anesthetic in a line along the superior orbital ridge from medial to lateral. 4. Patients may experience a small hematoma or periorbital ecchymosis the following day. MAXILLA ANESTHESIA Supraperiostial infiltration Used for anesthesia of a single tooth. 1. Apply topical anesthetic to the mucosal and/or palatal area to be injected, especially if anterior to the canine as this site is more painful. 2. Orient the needle parallel to the vertical axis of the tooth with the bevel toward the bone. 3. Pull the skin taught and enter at the mucobuccal fold 4. Advance the needle approximately 5mm, aspirate, and inject 0.8-1.0 cc or ½ of the cartridge 5. To anesthetize the lingual surface of a single tooth, orient the needle 45 degrees toward the gingiva, approximately 5-10mm from the center of the tooth and with the bevel aimed toward the palate. 6. Advance the needle until bony contact (3-5mm), aspirate, and inject 0.20.3cc (1/8 cartridge) of anesthetic until the area blanches. Infraorbital nerve block (IO) Ideal for complex lip and facial lacerations as well as anesthesia of the anterior teeth. Can be approached intraorally and transdermally; the intraoral approach will be discussed below. 1. Palpate the infraorbital foramen, which can be found inferior to the pupil as the patient is looking straight ahead. 2. After applying topical anesthetic, orient the needle vertically and enter the mucobuccal fold at the first premolar. 3. Advance the needle toward the infraorbital foramen until bony contact (approximately half of the needle). Retract needle slightly and aspirate. 4. Inject 0.9-1.2cc of anesthetic and massage the area to help manipulate the anesthetic into the foramen. Posterior superior alveolar block (PSA) Used for anesthesia to the second and third molars, and in some patients, the first molar. 1. Apply topical anesthesia to the mucobuccal fold of the second molar, which will be the landmark for injection. 2. Orient the needle with the bevel angled toward the bone, and advance at at 45degree angle medially, superiorly, and posteriorly. 3. Advance the needle approximately 2cm or 2/3 the length of the needle. There should be no resistance or bony contact. 4. Aspirate, and inject one cartridge slowly over one minute. Nasopalatine block Used with supraperiosteal infiltrations or IO block to anesthetize the lingual aspect of the tooth and gums. 1. Identify the incisive papilla and apply local anesthetic to the area. 2. Orient the needle with the bevel toward the palate and advance just lateral the papilla and advance until bony contact. 3. Aspirate and inject ¼ of the cartridge into the area over 30 seconds. 4. The area will blanch, and also there will be a significant amount of resistance since the palate is adherent to the bone at this point. Greater palatine block Provides lingual anesthesia posterior to the canine. 1. With the help of your finger or a q-tip, palpate the greater palatine foramen at the junction of the soft and hard palate and generally medial to the 2nd or 3rd molar. 2. Orient the needle perpendicular to the injection site, which is approximately 2mm anterior to the foramen. 3. Advance until bony contact, aspirate, and inject approximately ¼ of the syringe into the area while keeping pressure on the foramen with the qtip. 4. The tissue will blanch, and resistance is normal. MANDIBLE ANESTHESIA Infra-alveolar (IA) nerve block 1. Apply topical anesthetic to the target area, which is the interior aspect of the mandibular ramus just anterior to the pterygomandibular raphe. 2. Place the thumb of your nondominant hand on the coronoid notch (most concave portion of the mandible) and the index finger just anterior to the ear 3. Orient your syringe with the barrel over the premolars on the OPPOSITE side. 4. Aim toward your index finger, approximately 5-10mm above the occlusal plane of the lower molars. 5. Advance the needle until bone is contacted, which should be approximately 2.5cm or ¾ of the needle length. a. If bone is contacted superficially or not contacted at all, reorient the syringe more laterally and repeat. 6. Withdraw slightly and aspirate. If no blood is aspirated, inject 1.5-2mL of anesthetic (1-2 carpules). a. If blood is aspirated, pull needle back and redirect slightly, then repeat aspiration attempt. 7. Do not use 4% lidocaine with this injection as it can cause permanent parasthesias. (Long) Buccal Nerve Block This block should be done following the IA when attempting to provide anesthesia to the molars to anesthetize the buccal aspect. 1. Identify the target area located distal and buccal to the most distal molar in the arch on the anterior border of the ramus. 2. Orient the bevel of the needle toward the bone and insert parallel to the occlusal plane to approximately 13mm of depth. 3. Aspirate, and if no blood is aspirated, inject approximately 0.2mL of anesthetic over 10 seconds. Mental/incisive nerve block Often used in combination with the IA for anesthesia of the teeth and/or skin anterior to the molars, but can be used alone. 1. Identify the landmarks by palpating for the mental foramen either intraorally or over the chin just inferior to the premolars. 2. Orient the needle vertically, parallel to the second premolar and insert into the mucobuccal fold approximately 5mm. 3. Aspirate, and inject 0.5-1.0cc of anesthetic. 4. Massage over the foramen for approximately 1 minute to help manipulate the anesthetic into the mental foramen. 5. Alternatively, you can enter the mucobuccal fold at the level of the first premolar, angling slightly posterior to reach the mental foramen and inject as above. VIDEO Maxillary injections: https://www.youtube.com/watch?v=GXuF_KUgfGg Mandibular injections: https://www.youtube.com/watch?v=Tkcx32iHxh0 Local infiltration: https://www.youtube.com/watch?v=0kOukYPGVmM Maxillary infiltrations: https://www.youtube.com/watch?v=px1zQh7HJpM Syringe setup: https://www.youtube.com/watch?v=saEdrJyzusw DEEP DIVE ! Further Reading o Roberts & Hedges’ Clinical Procedures in EM. 6th edition. Ch. 30, Pg. 541-553 ! Pearls o Anesthesia of the upper anterior teeth is generally the most painful, so topical anesthesia is recommended prior to injection o Pulling the mucosa taught during injections will help with pain and ease of puncturing the mucosa o Nerve blocks will take longer to become numb than infiltration techniques (approx 3-5 minutes) o If the intraalveolar block fails, you can try a Gow-Gates block (not discussed here but can be found in the “mandibular injections” video