Anatomy of Local Anesthesia – Flashcards
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Compare local infiltration with nerve block local anesthesia.
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Local infiltration is only on terminal nerve endings and is used for soft tissue only; gingival surgery. Nerve block anesthetize close to a nerve trunk
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Compare the effectiveness of maxillary anesthesia with the effectiveness of mandibular anesthesia.
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maxillary anesthesia is more effective because its the bone is thinner in the anterior portion and there is less anatomical variances in it.
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How effective is local infiltration in the maxillary?
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More effective then mandible
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PSA block; Area anesthetized?
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Pulpal anesthesia in the maxillary 1st, 2nd, and 3rd molars Tissue Anesthetized: Maxillary molars (exception of mesiobuccal root of the first molar in some cases): Pulps & periodontal ligaments Overlying buccal gingivae Overlying alveolar bone Maxillary sinus, posterior portion. GP block may also be necessary.
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PSA block; Target area and injection site?
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Posterior superior alveolar (PSA) nerve as it exists the maxilla Site of Injection: In the height of the mucobuccal fold on a 45º angle at the apex of the 2nd maxillary molar distal to the zygomatic process of the maxilla
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PSA block; Symptoms and possible complications?
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Symptoms of anesthesia: none Complications: hematoma Vascular penetration: the pterygoid plexus of veins and/or maxillary a. Harmless anesthesia of branches of the mandibular nerve
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PSA block; How do you avoid complications?
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Aspirate
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MSA block; Area anesthetized?
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Indicated for: Dental procedures on the maxillary premolars and mesiobuccal root of the maxillary 1st molar. GP block may also be necessary.
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MSA block; Target area and injection site?
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Target area: MSA nerve at the apex of the maxillary 2nd premolar The injection site for the MSA block is the tissue at the height of the mucobuccal fold at the apex of the maxillary second premolar.
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MSA block; Symptoms and possible complications?
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Symptoms: Harmless tingling or numbness of the upper lip
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ASA block; Area anesthetized?
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Tissue anesthetized Pulp and periodontal ligaments of the Maxillary incisors Maxillary canine Maxillary premolars* (*) if MSA is not present Other tissue anesthetized Adjacent vestibular gingivae and alveolar mucosa Upper lip - skin and mucous membrane Lateral external nose Lower eyelid - skin/conjunctivae Maxillary sinus - anterior half
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ASA block; Target area and injection site?
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Landmarks: Located in a depression below the infraorbital rim* Medial to the pupil of the eye* - if patient is looking straight Target area: At the apex of the maxillary canine Site of Injection: The injection site is directed to the apex of the maxillary canine - at the height of the mucobuccal fold The injection site for the ASA block is the tissue at the height of the mucobuccal fold at the apex of the maxially canine, just anterior to and parallel with the canine eminence.
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ASA block; Symptoms and possible complications?
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Symptoms: Tingling and numbness of lower eyelid, side of the nose, & upper lip Complications are rare. Hematoma across the lower eyelid that resolves in a few weeks Vascular penetration: hematoma that resolves in a few weeks Intraorbital injection: Temporary blindness and/or double vision
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IO block; Area anesthetized?
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Indicated for: Dental procedures on the maxillary incisors, canine and usually premolar teeth. Nasopalatine block may also be necessary.
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IO block; Target area and injection site?
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Landmarks: Located in a depression below the infraorbital rim* Medial to the pupil of the eye* - if patient is looking straight The target area for the IO block is the ASA and MSA nerves as they ascend to join the infraorbital nerve after the infraorbital nerve enters the infraorbital foramen. The approximate depth of needle penetration for the IO block may vary, but typically is approximately 16 mm. In a patient with a higher or deeper mucobuccal fold or more inferior infraorbital foramen, less tissue penetration will be required than in a patient with a much lower or shallower mucobuccal fold or more superior infraorbital foramen. The injection site for the IO block is the tissue at the height of the mucobuccal fold at the apex of the maxillary first premolar.
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IO block; Symptoms and possible complications?
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Watch your frenums; insert needle more posterior with MSA block to avoid going through. In some cases, adjustment can be made by retracting it more anterior. Make sure to leave at least 5 to 10 mm on each side of frenum
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GP block: Area anesthetized?
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Tissue Anesthetized: Posterior to the maxillary canines Palatal mucosa Lingual gingivae Underlying bone of the palate Posterior portion of the hard palate
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GP block; Target area and injection site?
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Target Area: Greater palatine nerve as it enters the greater palatine foramen Anterior to the greater palatine foramen At the apex of the maxillary 2nd (children) or 3rd molar Site of Injection: Depression by the greater palatine foramen Depression about midway between the median raphe & lingual gingival margin of the molar tooth
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GP block; Discuss the use of pressure anesthesia on the hard tissues of the palate.
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Pressure use creates dull ache that blocks pain from needle
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GP block; Symptoms and possible complications?
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Complications: None. Patient may gag if lesser palatine is anesthetized
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NP block; Area anesthetized?
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Tissue Anesthetized: Palatal mucosa & lingual gingivae of the six anterior maxillary teeth Corresponding lingual plate of alveolar bone Mucoperiosteum of anterior 1/3 of the hard palate
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NP block; Target area and injection site?
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Site of Injection: Lateral to the incisive papilla - never directly because is extremely painful. Incisive foramen is located posterior to and between the central incisor teeth
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NP block; Symptoms and possible complications?
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Symptoms: Numbness in the anterior portion of the palate Complications: Hematoma is rare Avoid enter the incisive canal - it will enter into the nasal cavity.
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AMSA block; Area anesthetized?
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2nd premolar through central incisor.
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AMSA block; Target area and injection site
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Tissues of the hard palate. Injection: Midway between median palatal sutures and max premolars.
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AMSA block; Discuss the use of pressure anesthesia on the hard tissues of the palate.
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Pressure reduces pain
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AMSA block; Symptoms and possible complications?
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Blanching occurs after given injection can cause postoperative ischemia and sloughing. slow injection can stop that.
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Compare the effectiveness of mandibular injections with the effectiveness of maxillary injections.
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less effective because of more density in areas.
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How effective is an infiltration in the mandible?
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The mandible is denser than the maxilla over similar teeth, especially in the area of the mandibular posterior teeth, therefore nerve blocks are preferred to local infiltration in most parts of the mandible.
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IA block; Target area and injection site?
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Target Area for Traditional IA: The inferior alveolar nerve on medial aspect of the ramus prior to its entry into the mandibular foramen Within the pterygomandibular space (infratemporal fossa) Lingual, mental and incisive nerves are also anesthetized. injection site: Identify the coronoid notch (with associated temporalis tendon). laterally and the pterygomandibular raphe & anterior border of the medial pterygoid m medially. Injection site varies. Most frequent recommendation is a little above the occlusal plane, 3/4th of the anteroposterior distance between the above landmarks. Successful technique results in anesthesia of the mandibular teeth on the ipsilateral side to the midline, associated buccal and lingual soft tissue, ipsilateral -lateral aspect of the tongue and lower lip
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IA block; Symptoms and possible complications?
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Symptoms: Numbness or tingling of lower lip Numbness or tingling of the body of the tongue and floor of the mouth Possible complications: Lingual shock Facial paralysis if the facial nerve is mistakenly anesthetized Muscle soreness Hematoma
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IA block; Discuss troubleshooting the IA block depending on the contact of the needle with the bone.
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If bone is contacted early, needle tip is located too far anterior on the ramus. Correction: withdraw needle partially or completely and bring syringe barrel more closely over the mandibular anterior teeth, moves needle tip more posteriorly. If bone is not contacted when inserting even with the usual depth of penetration by the needle, needle tip is located too far posterior on the ramus. Correction: withdraw needle partially or completely and bring syringe barrel more closely over the mandibular molars, moves needle tip more anteriorly. If bone is not contacted, do not deposit the local anesthetic agent. The needle tip may be too posterior and located in the parotid salivary gland where CN VII innervates creating complications.
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IA block; What is the accessory innervation that can prevent a successful IA block?
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Accessory innervation of the mylohyoid.
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Buccal block; Area anesthetized?
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Tissue Anesthetized: Tissue associated with Mandibular molars: Buccal periodontium Associated gingiva Periodontal ligament Alveolar bone Skin & mucosa of the cheek
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Buccal block; Target area and injection site?
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Target: Buccal nerve, also known as long buccal nerve, as it passes over the anterior border of the ramus, and through the buccinator The tissue just distal and buccal to the last molar tooth is the target area for injection
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Buccal block; Symptoms and possible complications?
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Symptoms & Complications: Numbness of Mandibular molars: Buccal periodontium Associated gingiva Periodontal ligament Alveolar bone Rare complications Hematoma are rare
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Mental block; Area anesthetized?
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For dental procedures on the mandibular incisors, canine, and variably first and second premolars
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Mental block; Target area and injection site?
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Target Mental nerve at the mental foramen Injection area: AT the height of the mucobuccal fold over the mental foramen Immediately below the apex of the mandibular second premolar *, or just anterior or posterior to it
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Mental block; Symptoms and possible complications?
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Symptoms and Complications: Numbness of facial gingiva and mucosa of these teeth and lower lip to the midline Harmless. Rare complication. Hematoma is rare
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Incisive block; Area anesthetized?
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The pulp and facial tissue of the mandibular premolars and anterior teeth.
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Incisive block; Target area and injection site?
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Same as the mental block: it is anterior to where the mental nerve enters the mental foramen to merge wit the incisive nerve to form the IA nerve.
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Incisive block; Symptoms and possible complications?
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Same as the symptoms of the mental block with harmless tingling and numbness of the lower lip, except that there is pulpal anesthesia of the involved teeth, and there is an absence of discomfort during dental procedures. As with a mental block, a hematoma rarely occurs. Injection site: anterior to the depression created by the mental foramen at the depth of the mucobuccal fold with the needle in a horizontal manner, the syringe barrel resting on the lower lip.
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Gow-Gates mandibular block; Area anesthetized?
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Nerves anesthetized are the inferior alveolar, mental, incisive, lingual, mylohyoid, and auriculotemporal, as well as the (long) buccal nerves in most cases. Considered a mandibular block because it anesthetizes almost the entire V3.
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Gow-Gates mandibular block; Reasons for use?
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Used in quadrant dentistry in which buccal soft tissue anesthesia from most distal mandibular molar to midline and lingual soft tissues is necessary, and in some cases when a conventional IA block is unsuccessful. Success rate is higher than that of an IA block even taking into account a slightly more complicated procedure. Injection lasts longer that the IA block due to injection area being less vascular, but does require more anesthetic.
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Gow-Gates mandibular block; Target area and injection site?
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The anteromedial border of the neck of the mandibular condyle, just inferior to the insertion of the lateral pterygoid muscle. Injection site: located intraorally on the oral mucosa on the mesial of the mandibular ramus, just distal to the height of the mesiolingual cusp of the maxillary second molar following an imaginary line extraorally from the ipsilateral intertragic notch of the ear to the ipsilateral labial commissure.
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Gow-Gates mandibular block; Symptoms and possible complications?
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Numbness of mandibular teeth to midline, buccal mucoperiosteum and mucous membranes, lingual soft tissue and periosteum, anterior 2/3 of the tongue, the floor of the mouth, and the body of the mandible and inferior ramus, as well as the skin over the zygomatic bone and the posterior buccal and temporal regions. Two disadvantages: numbness of lower lip and temporal region, and longer time necessary for the anesthetic to take effect. The injection is contraindicated in cases with limited ability o open mouth, but trismus is rarely involved.
