Chapter 09 - LA Delivery Devices

Question 1

1. Which ONE of the following statements is CORRECT?
   a. The standard aspirating syringe is designed to provide negative pressure on aspiration, unlike the self-aspirating syringe.
   b. The standard aspirating syringe is designed to provide positive pressure on aspiration, unlike the self-aspirating syringe.
   c. Neither the standard nor the self-aspirating syringes provide negative pressure on aspiration.
   d. The standard aspirating syringe is designed to provide negative pressure on aspiration similar to the self-aspirating syringe.

Answer 1

d. Negative pressure is developed in BOTH syringes although the mechanism for creating the negative pressure is different for each type.

Question 2

2. Which ONE of the following is CORRECT when addressing OSHA requirements for medical device safety in dentistry?
   a. Two hands are allowed as long as one hand only secures the needle cap.
   b. Contaminated needles may be bent as long as the bend is accomplished with cotton pliers or a hemostat.
   c. Two hands are never allowed to recap needles even when one hand is holding a hemostat or locking pliers to secure the protective caps.
   d. Uncontaminated needles may be bent.

Answer 2

d. According to OHSA, uncontaminated needles may be bent; contaminated may not.
Recapping - two hands are never allowed unless one hand is holding a hemostat/cotton pliers to hold the cap.

Question 3

3. In comparing a 25-gauge needle with a 30-gauge needle, the 25-gauge needle:
4. Has better aspiration .
5. Breaks more easily.
6. Is less comfortable than the 30-gauge.
7. Has a smaller diameter.
8. Can be used in highly vascular areas.

a. 2,4,5
b. 2,4
c. 1,3,5
d. 1,5

Answer 3

d. 25-gauge
- has larger lumen => greater ease of aspiration
- is beneficial in highly vascular areas
- does not hurt more accord. to studies than a thinner, 30-g needle
- less risk of breaking compared to thinner, 30-gauge

Question 4

4. Long needles are approx. ____ long.
   a. ~ 12 to 22 mm
   b. ~32 to 36 mm
   c. ~ 40 to 42 mm

Answer 4

b. Long needles average ~ 32mm with some noted to be as long as 40mm
[Bassett frequently equates 32mm with 1.5 inches, which is not correct, 32mm =1.26”; 1.5” = 38.1 mm]

Question 5

5. When a stopper is extruded, what has likely caused the problem?
   a. Cartridge overfilled during manufacturing.
   b. Freezing during shipping/handling
   c. Overheating caused pressure
   d. Oxidation of sodium bisulfate has created gas

Answer 5

b. Freezing causes expansion of the solution

Question 6

6. During an infiltration injection you give the patient three stopper-widths of LA. How much solution have you injected?
   a. 0.2 mL
   b. 0.9 mL
   c.1.8 mL
   d. 0.6 mL

Answer 6

d. 0.6 mL (1 stopper = 0.2mL)

Question 7

7. What substance is used as the preservative for epinephrine in local anesthetic cartridges?
   a. Sodium bisulfite
   b. Sodium hypochlorite
   c. Methylparaben
   d. Nitrogen

Answer 7

a. Sodium bisulfite

(Methylparaben obsolete b/c high incidence of allergies).

Question 7

7. What substance is used as the preservative for epinephrine in local anesthetic cartridges?
   a. Sodium bisulfite
   b. Sodium hypochlorite
   c. Methylparaben
   d. Nitrogen

Answer 7

a. Sodium bisulfite

(Methylparaben obsolete b/c high incidence of allergies).

Question 8

Q9-1: List the nine basic armamentarium items for dental local anesthetic injections.

Answer 8

A9-1: The basic armamentarium items for dental local anesthetic injections include:
1. mouth mirror (may also include a cheek retractor)
2. devices for safe needle recapping and disposal
3. syringe devices
4. cotton pliers or hemostat
5. gauze squares for drying tissues and enhancing retraction
6. cotton swabs for application of topical anesthetic agents and predetermination of penetration sites and angles
7. needles of appropriate gauge and length
8. cartridges of drugs
9. topical anesthetic agents

Question 9

Q9-2: What is the most common syringe design in dentistry?

Answer 9

A9-2: sterilizable, breech-loading, cartridge-type, aspirating syringe

Question 10

Q9-3: Identify the components of the syringe in the figure below (disassembled)

Answer 10

A9-3:
A. thumb ring
B. finger grip
C. spring
D. guide bearing
E. piston
F. harpoon
G. syringe barrel
H. needle adaptor

Question 11

Q9-4: What is the advantage of the large side opening on the syringe barrel?

Answer 11

A9-4: The large side opening, or window, on the syringe barrel provides for direct visibility of cartridges throughout injections.

Question 12

Q9-5: What is a disadvantage of a standard size, round thumb ring?

Answer 12

A9-5:
- problems aspirating for clinicians with small hands
- variety of thumb ring designs is available
- oval designs require shorter distances to engage the inside of the thumb ring for aspiration.
- other syringes additionally have smaller-sized thumb rings

Question 13

Q9-6: What is the purpose of the harpoon on the piston?

Answer 13

A9-6:
= the part of the piston inside the barrel that penetrates the stopper
=> allows for retraction of stoppers to create slight negative pressure inside cartridges during aspiration tests
! very sharp; can cause injury if mishandled

Question 14

Q9-7: How are needles identified?

Answer 14

A9-7: by length and diameter (= gauge)

Question 15

Q9-8: Identify the components of the needle in the figure below (disassembled)

Answer 15

A9-8:
A. needle shaft
B. bevel
C. cartridge penetrating end
D. syringe adaptor
E. hub
F. needle cap

Question 16

Q9-9: Which needle has a larger diameter, a 30 gauge or a 25 gauge?

Answer 16

A9-9: Smaller needle gauges are identified by larger numbers, and conversely, larger needle gauges by smaller numbers; therefore, a 25-gauge needle has a larger diameter.

Question 17

Q9-10: Why is a needle designed with a bevel?

Answer 17

A9-10:
= diagonal cut that makes the point of a needle
- to facilitate atraumatic penetration through mucosal and cutaneous tissues

Question 18

Q9-11: What needle lengths are used in dentistry?

Answer 18

A9-11:
Although needle lengths vary slightly among manufacturers, typical lengths are:
long needles ~32 mm (1½ inches),
short needles ~25 mm (1 inch), and
extra-short needles ~12 mm (1/2 inch)

Question 19

Q9-12: Which gauges are most frequently used in dentistry?

Answer 19

A9-12: Needles used in dentistry are typically 25, 27, or 30 gauge.

Question 20

Q9-13: List factors that clinicians use to determine the selection of needles for local anesthetic injections.

Answer 20

A9-13:
- needle deflection
- ease and accuracy of aspiration
- perceived patient comfort.

Question 21

Q9-14: What is the OSHA standard for the prevention of needlestick injuries?

Answer 21

A9-14: According to OSHA, “Recapping or needle removal must be accomplished through the use of a mechanical device or a one-handed technique.” Therefore, clinicians are prohibited from managing needles with two-handed manual recapping techniques.

Question 22

Q9-15: What is the volume of anesthetic solution contained in a cartridge in the U.S.?

Answer 22

A9-15: Cartridges used in the United States contain 1.8 mL of solution.

Question 23

Q9-16: Identify the components of the cartridge in the figure below.

Answer 23

A9-16:
A. cylindrical glass tube
B. stopper
C. aluminum cap
D. diaphragm

Question 24

Q9-17: What are the typical contents of anesthetic cartridges?

Answer 24

A9-17:
- distilled water (the diluent, which is the majority of the solution),
- local anesthetic drug
- vasoconstrictor drug (if present),
- sulfite preservative (when vasoconstrictor present)
- sodium chloride (for isotonic tissue compatibility)

Question 25

Q9-18: What is the volume of solution delivered when two stopper widths are expelled?

Answer 25

A9-18: 0.4 mL

Question 26

Q9-19: What information is listed on the mylar label of the cartridge?

Answer 26

A9-19: Each label lists which local anesthetic and vasoconstrictor drug are contained in the cartridge. Both trade and generic drug names are provided, along with drug concentrations and dilutions of vasoconstrictor, the manufacturer, an expiration date, a local anesthetic drug color code band, and the lot number and bar code.

Question 27

Q9-20: Which anesthetic drug is contained in a cartridge labeled with a black band?

Answer 27

A9-20: Cartridges of 4% prilocaine plain have a 3 mm wide black band.

Question 28

Q9-21: What are the reasons cartridges may have large air bubbles?

Answer 28

A9-21: Large bubbles can result when solutions have been frozen or contaminated.

Question 29

Q9-22: List cartridge integrity expectations prior to administering.

Answer 29

A9-22:
- clear solution
- no large air bubbles,
- no damaged or tarnished caps,
- no leaking stoppers
- lapsed expiration dates

Question 30

Q9-23: Describe storage recommendations for local anesthetic cartridges.

Answer 30

A9-23:
- in cool, dry areas
- at temps recommended in product inserts
- solutions containing vasoconstrictors should be stored in the dark
- never in alcohol or other disinfectant solutions which can leak into them, contaminating the solutions.
- if stored in approved warming devices, it is important to be aware that long-term storage at temperatures higher than typical room temperatures may degrade the contents. Cartridges stored in these devices should be used as soon as possible.

Question 31

Q9-24: What is the typical shelf-life of local anesthetic solutions with and without vasoconstrictors?

Answer 31

A9-24:
- without vasoconstrictors ~24 months
- with vasoconstrictors ~ 18 months

Question 32

Q9-25: List the 10 basic steps for loading a syringe.

Answer 32

A9-25:
1. Select appropriate syringe, needle, and cartridges.
2. Remove the syringe from the sterile pack.
3. Insert the cartridge into the barrel.
4. Engage the harpoon securely into the stopper.
5. Attach the needle to the syringe.
6. Gently pierce the cartridge diaphragm with the penetrating end of the needle shaft.
7. Establish a needle recapping technique.
8. Confirm bevel orientation (when desired).
9. Orient the syringe for viewing of the large window when it is picked up for injection.
10. Retrieve the syringe and proceed with the injection.

Question 33

Q9-26: What is a correct method of engaging the harpoon and confirming it is seated securely in the stopper?

Answer 33

A9-26: To engage the harpoon securely into the stopper, hold the syringe in the “ready for injection” position. Press on the thumb ring until the harpoon is fully seated into the stopper. To confirm seating of the harpoon, gently turn the thumb ring; the cartridge should turn freely in the barrel.

Question 34

Q9-27: List the basic steps for disassembling syringes.

Answer 34

A9-27:
1. Withdraw the syringe from the oral cavity.
2. Move the syringe to the recapping area.
3. Use an appropriate one-handed Work Practice and Engineering Control to cap the needle.
4. Secure the cap to the needle hub.
5. Remove the needle from the syringe and place it in an appropriate sharps container.
6. Remove the cartridge from the barrel and dispose in an appropriate sharps container.
7. Rinse the syringe and process for sterilization.

Question 35

Q9-28: What is the appropriate response if a needlestick or other puncture injury occurs?

Answer 35

A9-28:
- Terminate all anesthetic procedures and treatment
- Wash injured tissues immediately & thoroughly with soap and water
- Notify the facility exposure manager while appropriate first aid is initiated
- Per CDC: postexposure management should include documentation in both the patient record and the exposed individual’s health record

Question 36

Q9-29: Discuss the types of syringes and the advantage of using specialized devices for PDL techniques.

Answer 36

A9-29:
- 2 primary designs: “pistol grip” and “pen type”
- both reduce hand pressures (via mechanical advantage)
- most noticeable feature: closed barrel
- if cartridge fracture within these syringes, there is no danger of glass falling into the mouth

Question 37

Q9-30: What are computer-controlled local anesthetic delivery devices?

Answer 37

A9-30:
= preprogrammed, electronic delivery systems for the administration of anesthetic injections.
- have variable-staged, controlled rates of delivery

Question 38

Q9-31: How do jet injection devices deliver anesthetic solutions?

Answer 38

A9-31:
- use narrow bursts of air, or “jets,” to penetrate mucosa (delivering LA solutions)
- powered by a spring mechanism which provides the pressure that forces the anesthetic out of the syringe into the tissues