Chapter 12 - Maxillary Injections

Question 1

1. … best describes the needle pathway for an infiltration injection technique?
   a. The needle is parallel to the long axis of the tooth, passing through thin mucosal tissues to superficial fascia containing loose connective tissue, and past small vessels and microvasculature, and nerve endings.
   b. The needle is distal to the long axis of the tooth, passing through thin mucosal tissue of deep fascia of connective tissues, and past small vessels, alveolar bone, and nerve endings.
   c. The needle is parallel to the long axis of the tooth, passing through thin mucosal tissues to superficial tissue tissue, and past small vessels, nerves, and bone.

Answer 1

a. The needle is parallel to the long axis of the tooth, passing through thin mucosal tissues to superficial fascia containing loose connective tissue, and past small vessels and microvasculature, and nerve endings.

Question 2

2. When infiltration injections are unsuccessful, it may be helpful to:
   a. Change the length of the needle and repeat the injection.
   b. Visualize, palpate, check radiographs, and reassess the technique.
   c. Establish contact w/ bone before administering one cartridge of LA.
   d. Repeat the same injection and deposit more LA.

Answer 2

b. Visualize, palpate, check radiographs, and reassess the technique.

Question 3

3. The MSA is absent in ~ 28%-50% of individuals.

a. True
b. False

Answer 3

b. false; MSA is PRESENT in somewhere between 28% - 50% of individuals

Question 4

4. In a typical adult pt, the IO foramen is approximately 8-10 mm below the infraorbital ridge.
   a. True
   b. False

Answer 4

a. True

Question 5

5. …. provides the MOST ACCURATE description of the filed of anesthesia in a PSA injection?
   a. Pulps of max premolars & molars, their facial gingiva, PDL, & alveolar bone on the side injected.
   b. Pulps of max & mand. molars on injected side
   c. Pulps of max teeth to midline, their facial gingiva, PDL, & alveolar bone on injected side
   d. Pulps of max. molars, except sometimes the MB root of the first molar, their facial gingiva, PDL, & alveolar bone on injected side.

Answer 5

d. Pulps of max. molars, except sometimes the MB root of the first molar, their facial gingiva, PDL, & alveolar bone on injected side.

Question 6

6. … is most likely to increase the risk of hematoma following a PSA nerve block?
   a. Needle inserted too deep or too posterior to the deposition site on the posterior surface of the maxilla.
   b. Needle inserted too inferior to posterior suface of maxilla
   c. The porous bony surface of maxilla allows penetration of maxilla-piercing blood vessels
   d. A long needle is inserted, contacting the bony periosteum on the surface of the maxilla.

Answer 6

a. Needle inserted too deep or too posterior to the deposition site on the posterior surface of the maxilla.

(over-insertion can be due to deeper insertion into the pterygopalatine fossa or by location too posteriorly initially)

Question 7

Q12-1: When are infiltration injections indicated?

Answer 7

A12-1: when procedures are confined to one or two teeth or to tissue in a limited area.

Question 8

Q12-2: What structures are affected by maxillary infiltration injections?

Answer 8

A12-2:
- dental plexus of the injected site (the pulps of the teeth and facial areas of the gingiva, periodontal ligament, and alveolus)
- additionally, due to the diffusion of the anesthetic solution, some terminal branches of the facial nerve (VII) are affected. All or a portion of the upper lip, cheek, and lower nose are anesthetized with many maxillary injections.

Question 9

Q12-3: What anatomical feature of the maxilla allows for a high success rate of +anesthesia by infiltration techniques?

Answer 9

A12-3: The facial bone of the maxilla is relatively thin and permeable. Local anesthetic solutions easily diffuse through maxillary bone.

Question 10

Q12-4: Describe the optimum site of penetration for infiltration injections.

Answer 10

A12-4: At the height of the mucobuccal fold nearest the apex of the tooth to be anesthetized.

Question 11

Q12-5: What are the two most common causes of anesthetic failure associated with maxillary infiltration injections?

Answer 11

A12-5:
1. deposition of solution too far from the apex of a tooth
2. inadequate volumes of solution

Question 12

Q12-6: Describe the field of anesthesia for an anterior superior alveolar nerve block.

Answer 12

A12-6:
-pulps of the max. central & lateral incisor & canine
on the injected side
- their facial periodontium
- due to diffusion of LA some terminal branches of the facial nerve are also affected (all or a portion of the upper lip, cheek, & lower nose will be numb)

Question 13

Q12-7: Where is the deposition site for an ASA injection?

Question 14

Q12-8: Discuss the possible anatomical variations related to the middle superior alveolar nerve and the significance to the MSA injection.

Answer 14

A12-8:
- MSA nerve absent in 50% to 72% of individuals
- If MSA nerve is absent, branches of ASA & PSA innervate the 1st & 2nd premolars and the mesiobuccal root of the first molar.

Question 15

Q12-9: What needle is commonly used for an MSA nerve block?

Answer 15

A12-9: A 27-gauge short

Question 16

Q12-10: What is the depth of penetration to the deposition site for an MSA nerve block?

Answer 16

A12-10: based on the location of the apex of the tooth; usually achieved within 5–8 mm.

Question 17

Q12-11: Describe the field of anesthesia for an infraorbital (IO) nerve block.

Answer 17

A12-11: - affects structures innervated by ASA, MSA,& IO nerves.
- pulps of the max. central incisors, canine
- premolars
- their facial periodontium
- the lower eyelid
- lateral aspect of nose
- upper lip
- some pts: MB root of max 1st molar

Question 18

Q12-12: What is the distance from the infraorbital ridge to the infraorbital foramen in a typical adult?

Answer 18

A12-12: In the typical adult, the IO foramen is located approximately 8–10 mm below the IO ridge

Question 19

Q12-13: What volume of anesthetic solution is deposited for an infraorbital (IO) nerve block?

Answer 19

A12-13: Deposit a minimum of 0.9 mL

Question 20

Q12-14: Explain the importance of applying 1 to 2 minutes of finger pressure over the deposition site following an IO nerve block?

Answer 20

A12-14: Applying finger pressure over the deposition site for 1–2 minutes enhances diffusion of the anesthetic solution into the infraorbital canal.

Question 21

Q12-15: What is the indication for a posterior superior alveolar (PSA) nerve block?

Answer 21

A12-15: for pain management of multiple molar teeth in one quadrant.

Question 22

Q12-16: What vascular structures are located in the infratemporal fossa?

Answer 22

A12-16: The maxillary artery, its branches, and the pterygoid plexus of veins.

Question 23

Q12-17: What is the penetration site for a PSA nerve block?

Answer 23

A12-17:
- At the height of the mucobuccal fold
- posterior to the zygomatic process of the maxilla
- generally superior to the DB root of max 2nd molar

Question 24

Q12-18: What needle is commonly used for PSA nerve blocks?

Answer 24

A12-18: A 27-gauge short needle

Question 25

Q12-19: Describe the angle of the needle insertion for PSA nerve blocks.

Answer 25

A12-19:
- upward (45-degrees to occlusal plane of max. teeth)
- inward behind the maxillary tuberosity (45 degrees to midsagittal plane)
- then must be advanced backward behind the posterior aspect of the maxilla ( swing barrel down and out from occlusal & midsagittal planes)

Question 26

Q12-20: What is the optimum depth of insertion for a PSA injection?

Answer 26

A12-20:
The optimum depth of insertion is 16 mm (5 mm from the hub of a 21 mm short needle);

however, clinicians should allow for anatomical variances contributing to the depth of insertion which can range from 10–16 mm.

Question 27

Q12-21: Explain why the PSA nerve block has the second highest risk of hematoma compared to other injections.

Answer 27

A12-21: Because of proximity of its deposition site to the pterygoid plexus of veins and associated maxillary arteries

2ND HIGHEST if considering tuberosity approach to the maxillary or second division nerve block