Armamentarium

Question 1

 Aspirating:

Answer 1

 with harpoon, it engages thick silicone rubber stopper at the tail end of the cartridge
 Negative pressure will cause blood (if there) to be visible in the cartridge

Question 2

label

Answer 2

Question 3

Caring for Your Instruments
washing?
lubrication?
harpoon?
piston and harpoon replacement?

Answer 3

Wash the syringe after each use
Dismantle and lubricate every 5 autoclavings
Clean Harpoon with brush after use
Replace piston and harpoon on regular basi

Question 4

needle anatomy
factors of the shaft?
greater bevel=?

Answer 4

 Bevel, shaft, the hub, and cartridge penetrating end
 Shaft has two important factors
• Diameter (gauge)
• Length (from tip to the hub)
 Greater angle the bevel, greater the degree of deflection

Question 5

needle gauge

Answer 5

 Diameter of the lumen of the needle
 Smaller the gauge #, Greater the diameter
• Example 25-gauge has greater internal than 30-gauge internal diameter

Question 6

are smaller needles less painful?

Answer 6

 This assumption is unwarrnated !!!
 Hamburg (1972) demonstrated that patient is unable to differentiate among 23-, 25-, 27-, and 30-gauge needle.
 Bottom line
 Patients feel the same regardless of gauges of needle

Question 7

Advantage of Larger Gauge Needle
defelction?
accuracy?
breaks?
aspiration?
pt comfort?

Answer 7

Less deflection, as needle advances through tissues
Greater accuracy in injection
Less chance of needle breakage
Easier aspiration
No perceptual difference in patient comfort

Question 8

when should larger gauge needles be used

Answer 8

Larger-gauge needles should be used when there is a
greater risk of positive aspiration

Question 9

colors of gauges

Answer 9

 Red: 25- gauge
 Yellow: 27- gauge
 Blue: 30- gauge

Question 10

Deflection of needle

Answer 10

Deflection
 Deflection of needle will differ according to gauges
 Deflection becomes important when needle must penetrate a greater thickness of tissue

Question 11

Conventional Dental Needle

Answer 11

 Needle tip is at the lower edge of the needle shaft, deflection

Question 12

Nondeflecting Needle

Answer 12

 The tip of needle is at the center of the shaft
 But over years of use, dentists become accustomed to deflecting needle

Question 13

needle length
weakest portion?
should entire needle ever be completely injected?

Answer 13

 Long and short
 Average short needle is 20mm
 Average long needle is 32mm
 Weakest portion of the needle is at the hub
 Needles should not be inserted into tissues to their hub unless it is absolutely necessary for the success of the injection

Question 14

Handling of Needle
Never used on?
Change after?
Must cover?
Pay attention to?
Proper disposal?
 Recapping?

Answer 14

Never used on more than one patient
Change after 3 or more tissue penetration
Must cover in protective sheath when not
use
Pay attention to the position of uncovered
needle tip
Proper disposal is necessary
 Recapping using “Scoop” technique

Question 15

 Pain on insertion due to

Answer 15

dull needle

Question 16

Breakage of needle

Answer 16

 Do not bent needle if to be inserted into >5mm soft tissue depth
• Most commonly “bent needle” procedures are
 Inferior alveolar nerve block
 Posterior superior alveolar nerve block
 Intrapulpal injection
 PDL injection and Intraosseous injection

Question 17

changing needle direction in tissue?

Answer 17

Don’t change direction of a needle when its embedded in tissue

Question 18

Pain on withdraw may caused by?

Answer 18

Pain on withdraw may caused by “fishhook” barb on the tip

Question 19

cartridge overview
holds what V?
reffered to as?
some made of?

Answer 19

 The glass cylinder can hold 2ml of solution
 U.S. dental cartridge contains 1.8ml of local anesthetic solution
 Dental cartridge is commonly referred as “carpule”
 Some cartridge are made of plastic cylinder instead of glass
 Plastic cylinder isn’t able withstand extended force and will leak

Question 20

label

Answer 20

Question 21

Cartridge Contents
 Calculation of mg of drug in the cartridge

Answer 21

Local anesthetic drug is the main player !!
 Calculation of mg of drug in the cartridge
• Example: 2% lidocaine in a cartridge (1.8ml)
2% = 20mg/ml and we have 1.8ml so
20 mg/ml X 1.8 ml = 36 mg
this means we have 36mg of lidocaine in a cartridge
• How about 3% Mepivacaine in a cartridge
3% = 30mg/ml and we have 1.8ml so

Question 22

possible add in for cartridges

Answer 22

May have Vasopressor
 Sodium bisulfite (antioxident)
 Sodium bisulfite oxidize to Sodium bisulfate
NaCl
 make solution isotonic with tissue
Distilled water

Question 23

how can cartridge be cleaned?

Answer 23

no soaking, use of a moistened wipe with 91% ispropyl or 70% ethyl

Question 24

Care and Handling of cartridges

Answer 24

 No manufacturer claim of sterility about exterior surface of the cartridge
 Bacterial culture tested fail to produce any growth
 Cannot withstand extreme temperature
 No autoclaving especially plastic cartridge
 When heated, vasopressors are destroyed
 Store in room temperature in a dark place
 Study showed no benefit of using cartridge warmer
 Do NOT soak cartridge in alcohol or “cold sterilizing solution”
 Semipermeable diaphragm permits diffusion of these solution
 Read the drug package insert

Question 25

Problems with cartridges
bubble?
extruded stopper?
how to fix?

Answer 25

 Bubble in the cartridge- Small bubble 1-2 mm are usually nitrogen gasand Large bubble with extruded stopper
 Extruded Stopper- >2mm bubble due to frozen cartridge or If no bubble, may caused by diffusion of other agent through diaphragm

• Wescott demonstrated measurable alcohol in cartridge after only one day of immersion in alcohol solution

Question 26

Corroded Cap

Answer 26

 If immersed in disinfecting solution
 Only sterilization needed are
• 91% isopropyl alcohol
• 70 % ethyl alcohol

Question 27

Burning on injection due to

Answer 27

 pH, alcohol, heat, expiration date..

Question 28

cartridge use on more than one?
stored at what temp?
warm before use?
expiration date?
check for?

Answer 28

 Dental cartridges must never be used on more than one patient
 Cartridges should be stored at room temperature
 It is not necessary to warm cartridges before use
 Cartridges should not be used beyond their expiration date
 Cartridges should be checked carefully for cracks, chips and integrity of the stopper and
cap before use

Question 29

 Topical antiseptics before injection optional)

Answer 29

 Betadine
 Chlorhexidine

Question 30

 Topical anesthetic prior to injection

Answer 30

 Placed directed with applicator for 1 min
• Stern and Giddon demostrated topical to mucous membrane for 2-3 mins leads to profound soft-tissue analgesia
 Benzocaine > Lidocaine topical (reduced overdose potential)
 Off label use of EMLA but its biter
 Unmetered spray is not recommended

Question 31

Preparing of the Armamentarium steps

Answer 31

retract piston
insert cartidge
Engage the harpoon in plunger with GENTLE finger pressure
Plastic hubbed needle is screwed onto the syringe
Scoop the needle cap
unload and retract the piston

Question 32

Costly Mistake with post injection

Answer 32

When discarding needle, make sure metal needle adaptor is not discarded

Question 33

Most common psychogenic reactions

Answer 33

 Vasodepressor syncope
 Hyperventilation

Question 34

Medical History Questionnaire
Update every?
allergies?
bleeding?
avoid techniques that?
HF?

Answer 34

Update every 6 months
Allergy
-True, documented, and reproducible allergy to amide is virtually nil
-Epinephrine allergy most likely due to exaggerated physiological response
Bleeding problems (Coagulopathies)
 Avoid techniques with ↑ chance of + aspiration
-Use supraperiosteal, PDL, Intraosseous
Heart Failure
-CHF with disability (ASA III or ASA IV) may demonstrate ↓ liver perfusion ↑ t ½ amide
local anesthesia

Question 35

 ASA IV cardiovascular risk pt is not a candidate for?

Answer 35

 ASA IV cardiovascular risk pt is not a candidate for vasopressors or elective dental care
-Recent (< 6 months) or repeated MI increases risk during dental care or local injection

Question 36

 Judicious use of vasopressors in L.A. is __________ in stable angina

Answer 36

 Judicious use of vasopressors in L.A. is not contraindicated in stable angina
(Unstable angina = ASA IV)

Question 37

 AIDS, Hepatitis A,B, Jaundice… increase half time of?

Answer 37

 AIDS, Hepatitis A,B, Jaundice… ↑ t ½ amide

Question 38

Seizure
 Causes?
 Stress Reduction?

Answer 38

 Causes
• Stress / Anxiety
• Hypoglycemia
• Hyperventilation
 Stress Reduction protocol is needed

Question 39

Pregnancy and injections

Answer 39

 Relative contraindicated especially at 1st trimester
 Consultation with OB-GYN is needed

Question 40

TCAs and LA
type on contraindication?

Answer 40

Tricyclic Antidepressant (TCAs)
- Enhance cardiovascular action to exogenously administered vasopressors
• 5 -10 X increase with levonordefrin and Nore-epi
• 2 X increase with epinephrine
–What’s the big deal ?!=Hypertensive crisis =death

Question 41

Drug-Drug Interactions
Cimetidine?
 H2 receptor blocker?
 Cimetidine + ASAIII CHF = ?
what sort of contrainidcation?

Answer 41

Cimetidine ↑ t ½ of circulating local anesthesia
 H2 receptor blocker compete with lidocaine for hepatic oxidative enzyme
 Cimetidine + ASAIII CHF = relative contraindication for amide local anesthesia

Question 42

other relative contraindications of LA?

Answer 42

Malignant Hyperthermia and Methemoglobinemia (to Prilocaine)

Question 43

cocaine drug to drug interaction
contraindication type?

Answer 43

 Cocaine stimulate nore-epi release and inhibit reuptake
 Tachycardia / hypertension = ↑ myocardio O2 requirement = Cardiac ischemia = MI
72 hrs is needed for Cocaine clearance
Dental correlation:
 Epinephrine-impregnated gingival retraction cord is absolutely contraindicated in the cocaine abuser
 Postpone dental treatment, if suspected cocaine usage within 24 hours

Question 44

reuse needles?

Answer 44

no

Question 45

covered with sheath when not in use?

Answer 45

yes

Question 46

how to recap needle

Answer 46

one handed scoop

Question 47

should needles be bent in cases where if it difficult to access for a block

Answer 47

no

Question 48

what bacteriostatic agent was removed from cartridges?

Answer 48

methylparaben

Question 49

bevel angle importance

Answer 49

greater angle means more deflection

Question 50

bevel bone relation

Answer 50

towards bone, prevent periosteum from being punctured