Chapter 9 Anatomy of Local Anesthesia

Type of injection that anesthetize a a small area-one or two teeth and associated structures-when the local anesthetic agent is deposited near the terminal nerve endings
Local infiltration

Which is more successful injections, mandibular or maxillary?
Maxillary

Type of injection that anesthetizes a larger area than the local infiltration because the local anesthetic agent is deposited near large nerve trunks
Nerve block

Abnormal sensation from an area such as burning or pricking
Paresthesia

What nerve provides sensory information for the teeth and associated tissue
Fifth cranial or trigeminal nerve

Two types of local anesthetic injections that are commonly used are:
Local infiltration and nerve block

Used to achieve pulpal anesthesia in the maxillary third, second, first molars in patients
Posterior superior alveolar block (PSA)

When dental procedure involves two or more maxillary molars or their associated buccal tissue
PSA

Anesthetizes the buccal periodontist overlying the maxillary third, second, and first molar including the associated gingiva, periodontal ligament, and alveolar bone
PSA

Pulpal
Tooth

Mesiobuccal root of the maxillary first molar is not innervated by the PSA nerve, but by the:
MSA

Target area for the PSA block is the PSA nerve as it enters the:
Maxilla through the posterior superior alveolar foramina on the maxilla’s infra temporal surface.

Injection site for the PSA block is at the:
Height of the mucho buccal fold superior to the apex of the maxillary second molar, distal to the zygomatic process of the maxilla

Angulation of the needle for PSA
upward or superiorly at 45 degree angle to the occlusal plane, inward or medically at 45 degree angle occlusal plane, and backward or posteriorly at a 45 degree angle to the long axis of the maxillary molar

Indicated for dental procedures on the maxillary premolars and mesiobuccal root of the maxillary first molar
Middle superior alveolar block (MSA)

What does the MSA block anesthetize
The pulp of the maxillary first and second premolars and possibly the mesiobuccal root of the maxillary first molar and the associated buccal periodontal tissue including the gingiva, periodontal ligament, alveolar bone

Target area for the MSA block is the MSA nerve:
At the apex of the maxillary second premolar

Injection site for the MSA is:
At the height of the mucobuccal fold at the apex of the maxillary second premolar

Where is the needle inserted for the MSA?
Into the mucobuccal fold until the tip is located superior to the apex of the maxillary second premolar without contacting the maxilla

Commonly used in conjunction with an MSA block instead of using an infraorbital block alone:
Anterior superior alveolar block (ASA block)

What does the ASA block anesthetize:
The pulp of the maxillary canine and incisor teeth, as well as the associated facial periodontal tissue including the gingiva, periodontal ligament, and alveolar bone

Target area for the ASA block is the ASA nerve at the:
Apex of the maxillary canine

Injection site for ASA block:
Height of the mucobuccal fold at the apex of the maxillary canine, just anterior to and parallel with the canine eminence

Where is the needle tip placed for the ASA block?
Superior to the apex of the maxillary canine without contacting the maxilla; approx. at 10 degree angle off an imaginary line drawn parallel to the long axis of the maxillary canine tooth

A useful block that anesthetizes both the MSA and ASA nerves, covering the region for both the MSA and ASA block
Infra orbital block (IO block)

What injection anesthetizes the maxillary premolars, canine, and incisors:
IO block

What injection is indicated when the dental procedures involve more than two maxillary premolars or anterior teeth and the overlying facial periodontium including the gingiva, periodontal ligament, and alveolar bone?
infraorbital block / IO Block

Where is the target area for the IO block?
ASA and MSA nerves; branches of the IO nerve to the lower eyelid, side of the nose, and upper lip are also inadvertently anesthetized

Where is the injection site for the IO block?
height of the mucobuccal fold at the apex of the maxillary first premolar; the approx depth of the needle penetration for the IO block may vary in pts

Where is the needles inserted for the IO block?
into the mucobuccal fold while keeping the finger of the other hand on the infraorbital foramen during the injection to help keep the syringe toward the foramen; the needle is advanced while keeping it parallel with the long axis of the tooth to avoid premature contact with the maxilla

When is the greater palatine or GP block used?
during dental procedures that involve more than two maxillary posterior teeth or palatal soft tissue dital to the maxillary canine

Where in the oral cavity does the GP block anesthetize?
posterior part of the hard palate, anteriorly as far as the maxillary first premolar and medially to the midline as well as the lingual (palatal) gingival tissue in the area

What does the GP block NOT provide?
pulpal anesthesia of the area teeth

What is the target area for the GP block?
anterior to where the GP nerve enters the greater palatine foramen from its location bw the mucoperiosteum and horizontal plate of the palatine bone of the posterior hard palate

Where is the injection site for the GP block?
palatal tissue anterior to the depression created by the greater palatine foramen

Why isn’t infiltration anesthesia of the mandible not as successful as that of the maxilla?
the bone of the mandible is denser than the maxilla over similar teeth, esp in the area of the mandibular posterior teeth

what is preferred over local infiltration for the mandible?
nerve blocks

Useful anesthesia of the bilateral anterior part of the hard palate, from the mesial of the maxillary right first premolar to the mesial of the maxillary left first premolar
Nasopalatine block (NP)

Used when lingual (or palatal) soft tissue anesthesia is required for two or more maxillary anterior teeth
NP block

T/F-NP block does not provide pulpal anesthesia
True

What is the target area for the NP nerve?
Both the right and left NP nerves as they enter the incisive foramen of the maxilla from the mucosa of the anterior hard palate, beneath the incisive papilla

Where is the injection site for NP block?
Lingual (or palatal) tissue lateral to the incisive papilla, which is located at the midline, about 10 mm lingual to the maxillary central incisor teeth

Where is the needle inserted for NP block?
Previously blanched palatal tissue at a 45 degree angle to the palate. The needle is advanced into the tissue until the maxilla is contacted

Useful for soft tissue and pulpal anesthesia of large area covered by the ASA, MSA, GP, NP blocks in the maxillary arch
Anterior middle superior alveolar (AMSA)

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