Theory V - TEST #1

what 2 ions needed for nerve conduction

potassium +

sodium +

the nerve is ? in resting state

polarized

resting state is also called

resting potential

resting state occurs when there's a balance between

positive sodium ion on OUTSIDE

potassium ions on INSIDE

during depolarization the nerve membrane becomes

more permeable to sodium ion

inside of nerve is now +

after depolarization, the permeability of membrane to sodium

decreases as sodium pump actively transports sodium OUT of nerve cell

potassium diffuse and pumped INSIDE of cell

rapid sequence of changes is called

action potential

stimulus is

pain

when the resting potential of nerve membrane is disrupted by stimulus what occurs

depolarization

where is the impulse transmitted when depolarization occurs

along the nerve fiber by ion changes during depolarization

ion changes produce

local currents that flow along from depolarization of nerve to adjacent resting area

commonly accepted primary action of LA agents

reducing nerve membrane permeability to sodium ions

action potential never occurs when

sodium ions remain on outside of the nerve

impulse that arrives at blocked nerve is

unable to transmit to brain

not able to interpreted as pain/discomfort

LA agents

esters

amides

esters are

topical anesthetics

(benzocaine)

esters completely/incompletely in ?

completely hydrolyzed in BLOOD

esters excreted in

urine in SMALL amounts

amides are

biotransformation in liver

liver function of patient influences rate of biotransformation

amides are excreted in

urine

LA exertion in

kidneys (primary)

T/F : blood decreases as LA is injected

F

increased blood flow to injection site as LA agents dilate blood vessels

is there increased bleeding at the injection site?

YES due to increased blood flow to area

vasodilation is

relaxation of blood vessel wall

vasodilation results in

increased blood flow to injection site

What are vasoconstrictors?

pharmacologic agents that cause blood vessels to constrict

vasoconstrictors are identical or similar to ??

adrenalin (produced during sympathetic NS stimulation)

vasoconstrictors are referred to as

sympathomimetic

OR

adrenergic agents

does vasoconstrictors decrease or increase blood into injection site

DECREASE

does vasoconstrictors slow or fasten the LA absorption into blood stream

SLOW

do vasoconstrictors increase or decrease duration of LA action

INCREASES duration

do vasoconstrictors increase or decrease LA effectiveness

INCREASE

vasoconstrictors leads to

lower LA amounts in blood

epinephrine (vasoconstrictor) overdose can result from

CNS stimulation

vasoconstrictors concentrations often expressed as

RATIO

1 : 100,000

epinephrine available as

synthetic

epinephrine obtained from

adrenal medulla of ANIMALS

levonordefin (vasoconstrictor) concentration

greater than 1 : 20,000

vasoconstrictors contraindications

unstable angina

recent MI

recent coronary artery bypass

untreated / uncontrolled hypertension

untreated / uncontrolled congestive HF

determining appropriate LA to use

duration of action / half life

length of time LA is needed

need for pain control after

client health status

current medications

LA allergy

MRD is

max recommended dose

must consider ?? regarding MRDs

age

physical status

weight

pharmacokinetics is

study of action of drugs within body

pharmacokinetics process

absorption

distribution

metabolism

excretion

LA syringes types

reusable

disposable

problems a LA syringe can have

bent harpoon

disengagement of harpoon from rubber stopper

aspirating diffuculty

parts of reusable LA syringe

problems with the LA needle

pain on insertion

pain on withdrawal

needle stick exposure of clinician

needle break

bevel of LA needle is

the very tip

shaft of LA needle is

the middle part

hub of LA needle is

syringe adaptor is

attach the needle to the syringe

cartridge penetration end is

where the cartridge is penetrated

gauge is

diameter of lumen of needle

most common gauges

25

27

30

larger gauge advantages

ridged

stable

less deflection

less breakage

T/F the lower the gauge number is the smaller the diameter

FALSE

the HIGHER the gauge number is the smaller the diameter is

cartridge problems

bubble in cart

extruded stopper

corroded cap

rust on aluminum cap

leakage

burning

broken

armamentarium for LA procedure

syringes

needle

gauge

cartridge

additional armamentarium for LA procedure

gauze

topical anesthetic

applicator sticks

haemostat / cotton pliers

parts of cartridge

rubber diaphragm is

bottom of cart

what is the best clinician ergonomics for LA injection

PALM UP

= better control

topical anesthesia provides

temporary numbing on nerve endings on oral mucosa

topical anesthesia supplied as

ointments

liquids

sprays

patches

supraperiosteal are also called

field block

supraperiosteal incorrectly referred to as

infiltration

supraperiosteal injections involve

depositing anaesthetic near APEX OF SINGLE TOOTH

supraperiosteal injection are

not as successful

supraperiosteal injections are more effective on

mand anteror teeth

supraperiosteal injections commonly done on

max

inferior alveolar nerve block abbreviation

IA

IA needle gauge + length

25-27 gauge

IA operator position

8:00-9:00

IA penetration site

middle of pterygonmandibular triangle

6-10 mm above mand occlusal plane

IA landmarks

anterior board of ramus

coronoid notch

mand foramen

pterygomandibular rapie

IA penetration depth

20-25 mm

two thirds - 3 quarters of needle

IA amount of anesthetic deposited

0.9 - 1.8 ml

1/2 - 1 cartlidge

IA length of time to deposit the LA

60 - 90 seconds

IA anesthesia recommended on

mand teeth

facial soft tissue anterior to mand 1st molar

T/F : IA is an uncommon injection

FALSE

common

IA failure rate

20-25

due to technique

IA anesthetizes nerves ;

inferior alveolair

incisive

mental

lingual

IA complications

LINGUAL SHOCK

lingual shock symptom

momentary

unavoidable

T/F : depositing small amounts of solution will prevent lingual shock

FALSE

target area for IA

above mand foramen

pytergomandibular space mimics

tear drop

how to locate pytergomandibular space

place thumbs / index finger on greatest depression of anterior border of ramus

pterygomandibular located

6-10 mm above occlusal plane

T/F bilateral IA should be done

FALSE

should be avoided (it causes anesthesia of entire tongue)

IA trouble shooting

no bone contact (tip too posterior)

buccal nerve block abbreviation

B

B needle gauge + length

25-27 gauge

B injection operator position

8:00-9:00

B injection penetration site

buccal vestibule

distal + buccal to most distal molar at height of occlusal plane

B injection landmarks

mandibular molars

buccal vestibule

mucobuccal fold

B injection penetration depth

1-4 mm

often only BEVEL is inserted

B injection amount of anesthetic deposited is

0.3 - 0.45

1/8th - 1/4th of cart

B injection length of time to deposit

10-20 sec