Chapter 14 - Mandibular Injections

Question 1

1. The rate of (+) aspiration in the IANB is the highest of all techniques and approximates …
   a. 2%-5%
   b. 5%-10%
   c.10%-15%
   d15%20%

Answer 1

c.10%-15%

Question 2

2. Alternative to nearly all mandibular LA techniques?
   a. GG
   b. Vazirani-Akinosi
   c. PDL
   d. Infiltrations

Answer 2

c. PDL (although providing only limited areas of anesthesia, it’s an alternative to nearly all other techniques, mandibular and maxillary)

Question 3

3. Which ONE of the following result(s) in pulpal anesthesia?
   a. Buccal NB
   b. Mental NB
   c. A and B
   d. Neither A nor B

Answer 3

d. Neither A nor B

Question 4

4. GGNB - all are essential, except:
   a. Performing one or more aspirations
   b. Meeting bony resistance
   c. Determining the site, height, and depth of penetration as well as the barrel orientation
   d. Having the client remove all ear jewelry before administering

Answer 4

d. Having the client remove all ear jewelry before administering

Question 5

5. Palpating anatomy before all mandibular anesthetic procedures is:
   a. an unnecessary step
   b. helpful in some techniques, useless in others
   c. the least important aspect of assessment
   d. critical to success of these techniques

Answer 5

b. helpful in some techniques, useless in others

(not even possible with Lingual NBs)

Question 6

The correct order (from inferior to superior) of the mandibular techniques listed in relation to the pterygomandibular space?

a. IA, GG, Akinosi
b. IA, Akinosi, GG
c. GG, IA , Akinosi
d. Akinosi, iA, GG

Answer 6

b. IA, Akinosi, GG

Question 7

Q14-1: Describe the field of anesthesia for an inferior alveolar (IA) nerve block.

Answer 7

A14-1:
- structures innervated by IA & typically lingual nerves - mandibular teeth to the midline
- soft tissues of inferior portion of ramus & body of the mandible,
- lower lip
- buccal periosteum of the premolars, canine, & incisors (not molars)
- lingual soft tissues and periosteum
- floor of the mouth, and the anterior two-thirds of the tongue.

Question 8

Q14-2: Explain why the lingual nerve is usually anesthetized when IA nerve blocks are administered.

Answer 8

A14-2: This occurs because the lingual nerve is typically located medial and anterior to the inferior alveolar nerve along the needle pathway.

Sufficient anesthetic solution is often deposited near the site of the lingual nerve (where drops of anesthetic solution have been deposited ahead of the needle) and from the diffusion of solution from the site of IA deposition to achieve lingual nerve anesthesia.

Question 9

Q14-3: Identify 3 key intraoral landmarks for successful IA nerve blocks & purpose of identifying them

Answer 9

A14-3:
1. pterygomandibular raphe
2. coronoid notch on the anterior border of the ramus of the mandible
3. internal oblique ridge on the medial surface of the mandible close to the molars and continuing posteriorly
Purpose of locating these landmarks is to limit areas into which penetrations are made. This allows the tips of needles to end up as close to inferior alveolar nerves as possible, once solution is deposited.

Question 10

Q14-4: Describe the penetration site for the IA nerve block in relation to the three key anatomical landmarks for the IA.

Answer 10

A14-4:
1. slightly lateral to the pterygomandibular raphe
2. at a height 2–3 mm superior to the greatest concavity of the coronoid notch
3. well medial to the internal oblique ridge

Question 11

Q14-5: Where is the deposition site for an IA nerve block?

Answer 11

A14-5: The deposition site is 1 mm lateral to the medial aspect of the ramus and above the mandibular foramen.

Question 12

Q14-6: How many milliliters of local anesthetic solution are deposited for an IA nerve block?

Answer 12

A14-6: A minimum of 1.5 mL of solution (about 3/4 of a cartridge) is deposited.

Question 13

Q14-7: Discuss the most common specific technique-related failures for IA nerve blocks.

Answer 13

A14-7: Depositing solution too far away from the foramen (too shallow, too medial, too posterior, and, especially, too inferior)

• shallow deposition of solution (less than 20–25 mm for a typical adult) decreases the rate of success.
• Deposition medial to soft tissue barriers, such as the sphenomandibular ligament, can block diffusion of solution to the IA nerve.

Question 14

Q14-8: Explain the reason the IA nerve block has a 10% to 15% positive aspiration rate.

Answer 14

A14-8:
- presence of the inferior alveolar artery and veins at the mandibular foramen
- the frequent presence of the maxillary artery in the lower pterygomandibular space
(when present in this location, the maxillary artery has been demonstrated to be located immediately above the level of the mandibular foramen)

Question 15

Q14-9: Define and discuss trismus.

Answer 15

A14-9:
- postinjection muscle soreness or limitation of mandibular movement
- can occur b/c of localized injury to muscle fibers at the site of injection
- risk of increases with the number of penetrations

Question 16

Q14-10: Define and discuss paresthesia.

Answer 16

A14-10: Paresthesia or prolonged anesthesia can occur following nerve blocks and is usually transient.

Studies have suggested many etiologies but have largely failed to identify specific cause-and-effect relationships in nonsurgical procedures.

Question 17

Q14-11: Describe indications for lingual nerve blocks.

Answer 17

A14-11: For pain management during procedures that involve the anterior 2/3s of the tongue and lingual soft tissues of the mandible on one side.

Question 18

Q14-12: Describe the anatomical position of the lingual nerve in relation to the inferior alveolar nerve.

Answer 18

A14-12: The lingual nerve is located in proximity to the inferior alveolar nerve and is usually located medial and anterior to it.

Question 19

Q14-13: Discuss complications related to lingual nerve blocks.

Answer 19

A14-13: The lingual nerve is one of the most frequently injured nerves during dental injections. The symptoms associated with these injuries range from transient “electric shocks” to permanent paresthesias.

Question 20

Q14-14: Describe the field of anesthesia for buccal nerve blocks.

Answer 20

A14-14: The buccal nerve and its terminal branches provide innervation to the soft tissue and periosteum buccal to the mandibular posterior teeth, primarily the molars.

Question 21

Q14-15: Describe the deposition site for the buccal nerve block.

Answer 21

A14-15: The deposition site is at the buccal aspect of the ramus, lateral to the external oblique ridge as the nerve passes over the anterior border of the ramus.

Question 22

Q14-16: What needle is commonly used for the buccal nerve block?

Answer 22

A14-16: 25- or 27-gauge long needles are common following IA injections. When administered alone, a 27-gauge short is recommended, consistent with the shallow depth of penetration and the low rate of positive aspiration (less than 1%).

Question 23

Q14-17: Discuss two factors to consider when a buccal nerve block fails to provide anesthesia.

Answer 23

A14-17: Obtaining adequate retraction and reevaluating the penetration site are critical. If the tissue is not held taut during penetration it can be difficult to achieve full bevel penetration. If retracted tissues are allowed to slump over the penetration site, it may seem that the bevel is inserted when it is not.
If the site of penetration is too medial, the tissue may be too thin and fibrous for adequate penetration. The needle may contact bone on the lateral surface or the retromolar region of the ramus, preventing adequate bevel insertion and causing sharp pain. Locating a more lateral penetration site in more loosely attached mucosa can provide greater success and comfort.

Question 24

Q14-18: When is a mental nerve block indicated?

Answer 24

A14-18: pain management of the buccal soft tissues of the mandible, anterior to the mental foramen.

Question 25

Q14-19: What is the typical depth of insertion for a mental nerve block?

Answer 25

A14-19: The depth of insertion varies with the height of the alveolar process and the angle of tissue retraction but is typically about 4–6 mm.

Question 26

Q14-20: Describe the field of anesthesia of an incisive nerve block.

Answer 26

A14-20:
- both mental & incisive nerve distributions affected
- buccal mucous membrane
- skin of the lower lip and chin
- pulps and facial periodontium of the teeth anterior to the mental foramen to the midline

Question 27

Q14-21: What additional technique step is necessary to assure adequate anesthesia following an incisive nerve block?

Answer 27

A14-21: Gentle pressure is exerted over the bulge of anesthetic solution in the direction of the mental foramen in order to force it through the mental foramen to flood the incisive nerve.

Question 28

Q14-22: Describe the field of anesthesia of a Gow-Gates nerve block.

Answer 28

A14-22: Structures innervated by IA, mental/incisive, lingual, mylohyoid, & auriculotemporal nerves to midline
- Unlike IA nerve blocks, the GG nerve block anesthetizes the buccal nerve 75% of the time.

Question 29

Q14-23: Describe the penetration site for the GG nerve block.

Answer 29

A14-23: Intraorally the penetration site is located in the buccal mucous membrane, directly posterior to the maxillary second molar, at the level of its mesiolingual cusp.

Question 30

Q14-24: Describe the deposition site for the Gow-Gates nerve block in relation to the deposition site for the IA nerve block.

Question 31

Q14-25: Explain why it is important for patients to keep their mouth wide open during and after the Gow-Gates nerve block, and to position the patient upright following the injection.

Answer 31

A14-25:
- anterior orientation of mandible allows condyle to remain fully translated over the articular eminence and provides needle access to the neck of the condyle
- Closure at any time during a Gow-Gates procedure can prevent the needle from reaching the deposition site
- Closure immediately upon completion of the injection and failure to upright the patient can cause diffusion of solution away from the nerve.

Question 32

Q14-26: What is the typical insertion depth for Gow-Gates nerve blocks?

Answer 32

A14-26: The insertion depth is variable, although typically it is about 25 mm. It has been described as being the same to somewhat greater than the penetration depth of IA nerve blocks for the same individual.

Question 33

Q14-27: What is the most reliable way to prevent injury to the temporomandibular joint capsule and the otic ganglion during administration of Gow-Gates nerve blocks?

Answer 33

A14-27: The most reliable way to prevent injury to these structures is to confirm that the needle is at the neck of the condyle by making gentle contact with bone.

Question 34

Q14-28: When is the Vazirani-Akinosi nerve block indicated?

Answer 34

A-14-28: Vazirani-Akinosi (VA) nerve blocks are ideal for pain management of the mandibular teeth in a single quadrant when the ability to open the jaw is limited, because of physiologic, pathologic, or phobic circumstances. This injection is also referred to as the Akinosi or closed-mouth technique.

Question 35

Q14-29: Describe the penetration site for a VA nerve block.

Answer 35

A14-29: The site of penetration is in the soft tissue medial to the ramus, directly adjacent to the maxillary tuberosity at the height of the mucogingival junction of the maxillary molars.

Question 36

Q14-30: Describe the deposition site for a VA nerve block.

Answer 36

A14-30: The deposition site for a VA nerve block is medial to the ramus and well superior to the mandibular foramen to a depth of 25 mm for the average adult. This depth is approximately one-half the anteroposterior dimension of the ramus in the area. The deposition site is between the deposition sites for the IA and GG nerve blocks.