The inferior alveolar nerve block anesthetizes the inferior alveolar nerve and its branches, providing anesthesia to the mandibular teeth, chin, lower lip, and parts of the tongue. A long needle is inserted into the mucosa on the lingual side of the ramus to anesthetize the inferior alveolar nerve as it passes downward. When bone is contacted, local anesthetic is slowly deposited over 60 seconds while aspirating. Successful anesthesia is confirmed through subjective symptoms like lip tingling and objective tests showing no response to pulp stimulation. Complications can include hematoma, trismus, or transient facial paralysis if the facial nerve is contacted.

1. INFERIOR
ALVEOLAR NERVE
BLOCK

2. • Also referred to as - Mandibular nerve block.
• Nerves anesthetized- 1. inferior alveolar, a branch of the posterior division of the mandibular division
of the trigeminal nerve (V3). 2. incisive nerve . 3. mental nerve . 4. lingual (commonly).
• Areas anesthetized – 1. mandibular teeth to the midline , 2. body of the mandible ,inferior portion of
the ramus , 3. buccal mucoperiosteum , mucous membrane anterior to the mental foramen (mental
nerve)., 4. anterior two-thirds of the tongue and floor of the oral cavity (lingual nerve). , 5. lingual soft
tissues and periosteum (lingual nerve).
• Indications – procedures on multiple mandibular teeth in one quadrant , when buccal soft tissue
anesthesia (anterior to the mental foramen ) is necessary , when lingual soft tissue anesthesia is
necessary.
• Contraindications- infection or acute inflammation in the area of injection , patients who are more
likely to bite their lip or tongue, for instance , a very young child or a physically or mentally
handicapped adult or child.
• Advantages- one injection provides a wide area of anesthesia (useful for quadrant dentistry).
• Disadvantages – wide area of anesthesia (not indicated for localized procedures) , rate of inadequate
anesthesia (31% to 81%), intraoral landmarks not consistently reliable, positive aspiration (10% to 15%,
highest of all intraoral injection techniques ), lingual and lower lip anesthesia , discomfiting to many
patients and possibly dangerous (self- inflicted soft tissue trauma ) for certain individuals, partial
anesthesia possible where a bifid inferior alveolar nerve and bifid mandibular canals are present ;
cross-innervation in lower anterior region.

3. • Positive aspiration – 10% to 15%.
• Alternatives – mental nerve block, for buccal soft tissue anesthesia anterior to the first molar , incisive
nerve block , for pulpal and buccal soft tissue anesthesia of teeth anterior to the mental foramen
(usually second premolar to central incisor ), superaperiosteal injection , for pulpal anesthesia of the
central and lateral incisors and sometimes the premolars and molars , Gow-Gates mandibular nerve
block ,Vazirani – Akinosi mandibular neve block , PDL injection for pulpal anesthesia of any mandibular
tooth, IO injection for pulpal and soft tissue anesthesia of any mandibular tooth, but especially molars.
• Technique – 25-gauge long needle is preferred; a 27 gauge long is acceptable.
• Area of insertion – mucous membrane on the medial (lingual) side of the mandibular ramus, at the
intersection of two lines – one horizontal , representing the height of needle insertion , the other
vertical , representing the anteroposterior plane of injection.
• Target area – inferior alveolar nerve as it passes downward toward the mandibular foramen but
before it enters into the foramen.
• Landmarks – a. coronoid notch (greatest concavity on the anterior border of the ramus), b.
pterygomandibular raphe (vertical portion), c. occlusal plane of the mandibular posterior teeth.
• Orientation of the needle bevel – less critical than with other nerve blocks, because the needle
approaches the inferior alveolar nerve at roughly a right angle.
• Procedure- a. for a right IANB, a right-handed administrator should sit at the 8 o’clock position facing
the patient , b. for a left IANB , a right –handed should sit at the 10 o’clock position facing in the same
direction as the patient.

4. • Three parameters must be considered during administration of IANB : 1) the height of the injection ,
(2) the anteroposterior placement of the needle (which helps to locate a precise needle entry point ),
and (3) the depth of penetration (which determines the location of the inferior alveolar nerve).
• Aspirate in 2 planes . If negative, slowly deposit 1.5 mL of anesthetic over a minimum of 60 seconds
.(because of the high incidence of positive aspiration and natural tendency to deposit solution too
rapidly , the sequence of slow injection, reaspiration, slow injection, reaspiration is strongly
recommended.)
• Slowly withdraw the syringe , and when approximately half its length remains within tissues,
approximately half its length remains within tissues, reaspirate . If negative , deposit a portion of the
remaining solution (0.2 mL) to anesthesia the lingual nerve .
• Signs and symptoms – 1. subjective – tingling or numbness of the lower lip indicates anesthesia of the
mental nerve , a terminal branch of the inferior alveolar nerve .This is a good indication that the
inferior alveolar nerve is anesthetized , although it is not a reliable indicator of the depth of anesthesia,
tingling or numbness of the tongue indicates anesthesia of the lingual nerve, a branch of the posterior
division ofV3. it usually accompanies IANB but may be present without anesthesia of the inferior
alveolar nerve .
• Objective – using an electrical pulp tester (EPT) and eliciting no response to maximal output (80/80)
on two consecutive tests at least 2 minutes apart serves as a “guarantee” of successful pulpal
anesthesia in nonpulpitic teeth, no pain is felt during dental therapy.

5. • Safety feature – the needle contacts bone, preventing over – insertion with its attendant
complications.
• Precautions- 1. donot deposit local anesthetic if bone is not contacted , needle tip may be
resting within the parotid gland near the facial nerve (cranial nerveVII), and a transient
blockade (paralysis) of the facial nerve may develop if local anesthetic solution is deposited.
• 2. avoid pain by not contacting bone too forcefully.
• Failures of anesthesia – the most common causes of absent or incomplete IANB – deposition
of anesthetic too low (below the mandibular foramen) , deposition of the anesthetic too far
anteriorly (laterally) on the ramus , accessory innervation to the mandibular teeth, incomplete
anesthesia of the central or lateral incisors.
• Complications – hematoma , trismus , transient facial paralysis (facial nerve anesthesia).