Anatomic Considerations Of Mandibular Anesthesia

Question 1

Whats sensory nerve supply of All mandibular teeth?

Answer 1

🦷 Sensory Nerve Supply of Mandibular Teeth
✅ 1. Inferior Alveolar Nerve (IAN)
Main nerve supplying all mandibular teeth.

Branch of mandibular nerve (V3) — division of trigeminal nerve (CN V).

Enters mandibular foramen → travels in mandibular canal.

It gives off:

🧠 Quick Division (By Region)
🔹 Posterior Teeth (Molars):
Supplied by Inferior alveolar nerve

Buccal gingiva of molars → Long buccal nerve

Lingual gingiva → Lingual nerve

🔹 Anterior Teeth (Incisors, Canines, Premolars):
Supplied by IAN → Incisive branch

Buccal gingiva → Mental nerve

Lingual gingiva → Lingual nerve

Question 2

IAN?

Answer 2

Inferior alveolar:
Provides innervation to the mandibular alveolus, buccal gingiva from premolar teeth anteriorly, and the pulpal tissue of all mandibular teeth on side blocked
Terminal branches
Incisive nerve- remains within inferior alveolar canal from mental foramen to midline
Mental nerve- exits mental foramen and divides into 3 branches to innervate the skin of the chin, lower lip and labial mucosa

Question 3

Lengths Of Short And Long Needles?

Answer 3

Length:
Short- 20mm
Long- 32mm

Question 4

Generally which topical anesthetic agent Used prior to local anesthetic injection to decrease discomfort in non-sedated patients

Answer 4

benzocaine (20%)

Question 5

IAN block and name its different techniques?

Answer 5

Technique involves blocking the inferior alveolar nerve prior to entry into the mandibular lingula on the medial aspect of the mandibular ramus

Multiple techniques can be used for the IAN nerve block
IAN
Akinosi vazirani
Gow-Gates

Question 6

Nerves anesthesized by IANB ?

Answer 6

Nerves Anesthetized
1. Inferior alveolar, a branch of the posterior division of
the mandibular division of the trigeminal nerve (V3)
2. Incisive
3. Mental
4. Lingual (commonly)

Question 7

Areas Anesthesized by IANB?

Answer 7

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) (Pm,Canines and incisors)
4. Anterior two thirds of the tongue and floor of the oral cavity (lingual nerve)
5. Lingual soft tissues and periosteum (lingual nerve)

Question 8

Contraindications of IANB?

Answer 8

Contraindications
Infection or acute inflammation in the area of injection (rare)

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

Question 9

Advantages Of IANB?

Answer 9

Advantages.
One injection provides a wide area of anesthesia (useful for quadrant dentistry).

Atraumatic.

Fewer post-operative complications e.g trismus

Question 10

6 Disadvantages of IANB?

Answer 10

Disadvantages
1.Wide area of anesthesia (not indicated for localized procedures)

2.Rate of inadequate anesthesia (31% to 81%)

3.Intraoral land­marks not consistently reliable

4.Positive aspiration (10% to 15%, highest of all intraoral injection techniques)

5.Lingual and lower lip anesthesia, discom­fiting to ­any patients and possibly dangerous (self-inflicted soft tissue traum­a) for certain individuals

6.Partial anesthesia possible where a bifid inferior alveolar nerve and bifid m­andibular canals are present; cross-innervation in lower anterior region

Question 11

IANB technique?

Answer 11

Technique:
Area of insertion is the mucous membrane on the medial border of the mandibular ramus at the intersection of a horizontal line (height of injection) and vertical line (anteroposterior plane)
↓

Height of injection- 6-10 mm above the occlusal table of the mandibular teeth
↓

Anteroposterior plane- just lateral to the pterygomandibular raphe
↓

Mouth must be open for this technique, best to utilize mouth prop
↓

Depth of injection: 25mm
Approach area of injection from contralateral premolar region
↓

Use the non-dominant hand to retract the buccal soft tissue (thumb in coronoid notch of mandible; index finger on posterior border of extraoral mandible)
⬇
Inject ~0.5-1.0cc of local anesthetic
Continue to inject ~0.5cc on removal from injection site to anesthetize the lingual branch
⬇
Inject remaining anesthetic into coronoid notch region of the mandible in the mucous membrane distal and buccal to most distal molar to perform a long buccal nerve block

Question 12

What should be the depth of penetration in IANB?

Answer 12

20-25mm or 2/3 or 3/4 of total length of long block needle

Question 13

Nerves Anesthesized in GOW GATES block?

Answer 13

1. Inferior alveolar
2. Mental
3. Incisive
4. Lingual
5. Mylohyoid
6. Auriculotemporal
7. Buccal

Question 14

Q: When should a conventional inferior alveolar nerve block be avoided?

Answer 14

A: When it is unsuccessful.

Question 15

Q: Who are patients that might be at risk of biting their lip or tongue during procedures?

Answer 15

A: Young children and physically or mentally handicapped adults

Question 16

Indications Of Gow gates block?

Answer 16

Indications
A. Multiple procedures on mandibular teeth.
B. When buccal soft tissue anesthesia, from the third molar to the midline, is necessary.
C. When lingual soft tissue anesthesia is necessary.
D. When a conventional inferior alveolar nerve block is unsuccessful.

Question 17

Contraindications of Gow Gates? Hint: Same as IANB

Answer 17

Contraindications

Infection or acute inflammation in the area of injection (rare).
Patients who might bite their lip or tongue, such as young children & physically or mentally handicapped adults.
Patients who are unable to open their mouth wide (e.g., trismus).

Question 18

Advantages OF Gow Gates Technique? (Almost same as IANB)

Answer 18

Advantages

Requires only 1 injection; a buccal nerve block is usually unnecessary.
High success rate (>95%), with experience.
Minimum aspiration rate.
Few post-injection complications (e.g., trismus).
Provides successful anesthesia where a bifid inferior alveolar nerve & bifid mandibular canals are present.

Question 19

Disadvantages for gowgates technique?

Answer 19

Lingual & lower lip anesthesia is uncomfortable for many patients & is possibly dangerous for certain individuals.
The time to onset of anesthesia is somewhat longer (5 minutes) than with an IANB (3-5 minutes), primarily because of the size of the nerve trunk being anesthetized & the distance of the nerve trunk from the deposition site (approx. 5-10 mm).

Question 20

Gow Gates Technique?

Answer 20

Start
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v
1. Patient in supine position
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2. Operator positioned to the right & slightly in front
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3. Patient keeps mouth open & remains until injection is complete
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4. Draw an imaginary line from the corner of the mouth to the intertragic notch of the ear
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5. Palpate the anterior border of the ramus & identify the tendon of the temporal muscle
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6. Align the operator visually with the intraoral & extraoral landmarks
- The needle is introduced through the mucosa just medial to the temporal tendon
- Direct it toward the target area on a line extending from the corner of the mouth to the intertragic notch
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7. Advance the needle until the fovea region of the condylar neck is contacted
- Depth of insertion: 25 to 27 mm
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8. Withdraw the needle
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9. Patient keeps mouth open for 20-30 sec
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End

Question 21

Akinosi Closed Mouth Technique?

Answer 21

Useful technique for infected patients with trismus, fractured mandibles, mentally handicapped individuals, children
Provides same areas of anesthesia as the IAN nerve block

Question 22

Nerves Anesthesized Akinosi closed mouth technique are?

Answer 22

1. Inferior alveolar
2. Incisive
3. Mental
4. Lingual
5. Mylohyoid

Question 23

“Anatomical landmarks”
of akinosi block?

Answer 23

a) Occlusal plane of occluding teeth
b) Mucogingival junction of the maxillary molar teeth
c) Anterior border of the ramus

Question 24

“Indications”
Of Akinosi Technique?

Answer 24

Limited mandibular opening
Multiple procedures on mandibular teeth
Inability to visualize landmarks for IANB (e.g., because of large tongue)

Question 25

Contraindications Of Akinosi block?

Answer 25

Infection or acute inflammation in the area of injection (rare) Patients who might bite their lip or their tongue, such as young children & physically or mentally handicapped adults Inability to visualize or gain access to the lingual aspect of the ramus

Question 26

Advantages Of Akinosi Block?

Answer 26

Relatively atraumatic Patient need not be able to open the mouth Fewer postoperative complications (e.g., trismus) Lower aspiration rate (<10%) than with the IANB Provides successful anesthesia where a bifid inferior alveolar nerve & bifid mandibular canals are present

Question 27

Disadvantages? Akinosi Block?

Answer 27

Difficult to visualize the path of the needle & the depth of insertion No bony contact Potentially traumatic if the needle is too close to the periosteum

Question 28

Akinosi block technique?

Answer 28

Patient seated comfortably in dental chair ↓ Operator stands to patient’s right side and slightly in front ↓ Patient is instructed to occlude the teeth ↓ Operator retracts lips to expose maxillary and mandibular teeth (right side) ↓ Syringe aligned parallel to occlusal & sagittal planes ↓ Positioned at mucogingival junction of maxillary molars ↓ Needle (25 gauge long) penetrates mucosa just medial to the ramus ↓ Needle inserted approximately 1½ inches (about 25–27 mm) ↓ Perform negative aspiration ↓ Slowly deposit anesthetic solution

Question 29

Mental nerve?

Answer 29

Mental and incisive nerves are the terminal branches for the inferior alveolar nerve Provides sensory input for the lower lip skin, mucous membrane, pulpal/alveolar tissue for the premolars, canine, and incisors on side blocked

Question 30

Mental nerve block technique?

Answer 30

Technique: Area of injection mucobuccal fold at or anterior to the mental foramen. This lies between the mandibular premolars Message local anesthesia into tissue to manipulate into mental foramen to anesthetize the incisive branch

Question 31

Intraosseous injection?

Answer 31

** Intraosseous Injection:** *(not used for deciduous teeth)* Require the deposition of local anesthetic solution in the porous alveolar bone. By forcing a needle through the cortical plate and into the cancellous alveolar bone or a small, round bur may be used to make an access in the bone for the needle.

Question 32

❌ Why Intraosseous Injection Is Not Recommended in Deciduous Teeth:

Answer 32

🦷 Risk of Damage to Developing Permanent Tooth Buds Primary teeth are located close to the developing permanent teeth. Drilling or penetrating the bone near the apex (to deliver intraosseous injection) can injure or disturb the developing permanent tooth germ, potentially leading to: Malformation Enamel defects Eruption issues