Higher concentrations of local anesthetics are often used for intraoral injections. 2% lidocaine with 1:100,000 epinephrine is local anesthetic most commonly used by dentists, and this formulation is often available in the ED. If the patient will have to wait more than a few hours for definitive treatment of their dental pain, as is often the case the patient must be referred to dentist or oral surgeon, longer acting agents such 0.5% or 0.75% bupivicaine with 1:100,000 epinephrine will provide longer relief. It has been reported than accidental intravascular injection may occur in 15-20% of intraoral injections (referenced in 6). For this reason, it has been recommended that not more than 4 ml of any local anesthetic agent be injected in the mouth (6).
The interior alveolar and lingual nerves are branches of the trigeminal nerve that run close together within the pterygomandibular space. Distally the inferior alveolar nerve gives rise to the mental nerve, which exits the mental foramen and supplies the skin of the chin and lower lip.
Technique
The landmark for this block is the vertical ridge of the anterior border of the mandibular ramus, which can be identified by palpation with the thumb. In order to avoid accidentally injecting their thumb or being bitten by the patient, the practioner may choose to use a tongue blade to push away the buccal surface of the cheek and expose the target area. The barrel of the syringe should be positioned over the opposite premolar and parallel to the occlusal surface of the lower teeth. The needle is inserted into the oral mucosa just medial to this ridge at a height 1 cm above the occlusal surface of the mandibular third molar. While aspirating, the needle is slowly advanced to a depth of 2 cm and 2-3 ml of agent is injected to block the inferior alveolar nerve. The lingual nerve can be blocked by withdrawing the needle to a depth of 1 cm while aspirating and then injecting another 0.5 ml. If while advancing the needle bone is contacted before the appropriate depth of 2 cm, the needle is likely striking the bony ridge anterior to the sulcus and should be redirected medially.
Maxillary infiltration
Distribution
Maxillary teeth
Anatomy
Dental and gingival branches of alveolar nerve branches supply the individual maxillary teeth.
Technique
Maxillary tooth fractures, periapical and periodontal infections may all be anesthesized through infiltration of the supraperiosteal area of the affected tooth (6). In the case of infections, injecting immediately anterior and posterior to the affected area should be effective. The lip should be pulled away and the needle inserted into the top of the buccal vestibule and directed 3-4 mm towards the root apex of the affected tooth. The needle should be withdrawn slightly of bone is contacted, and 1-2 ml of anesthetic should be infused
