Test 1 Flashcards
Where are topical anaesthetics applied?
To the mucous membranes to anaesthetize the terminal nerve endings
Why must topical be placed on dry tissue for maximum effectiveness?
Wetness causes runoff and/or dilutes the product
Why is the concentration of anaesthetic in topical high?
Concentration is higher for topical because it has to diffuse through the tissues
Sprays that deliver a constant stream of topical can be dangerous because
They amount cannot be controlled and it may go beyond the area intended
What are the generic names of the ester topicals?
Benzocaine
Cetacaine
What are the generic names of amide topicals?
Lidocaine ointment
Lidocaine patch
What is Oraqix?
A needle-free subgingival anaesthetic (amide) topical liquid that turns to gel at body temperature and is made of 2.5% lidocaine and prilocaine
Indications for topical anaesthetics
Probing
Periodontal dressing removal
Suture removal
Rubber dam
Scaling/root planing
Prior to injections
What are the contraindications for topical anaesthetics?
Open sores/lesions
Potential for toxicity
History of allergies or sensitivities
Is Benzocaine 20% an ester or amide?
Ester
What supplies are needed for topical placement?
Cotton tip applicator
Gauze
Topical anaesthetic
Basic exam kit
How long to leave topical on tissue?
1-2 minutes
What is a drug that prevents the generation and conduction of nerve impulses?
Local anaesthetic
True or False: local anaesthetics are vasodilators
True
What does a vasodilator do?
Dilates the blood vessels
Mechanism of action of local anaesthetics
Reducing nerve membrane permeability to sodium ions because sodium ions remain on the outside of the nerve cell an action potential never occurs. Impulse that arrives at blocked nerve segment is unable to be transmitted to the brain
What types of LA are used in dentistry?
Esters and amides
Why are amides more commonly used in dentistry?
Less likely to have an allergic reaction to amides
What are the indications for LA use?
Scaling and root planing
Deep pocket debridement
Tooth/root sensitivity
Furcations
Surgery
RCT/restorative work
What is the absolute contraindication for LA?
Client allergy - LA allergy, sulpha drug allergy, bisulfites allergy
What is a relative contraindication?
Only use after weighing the risk/benefits, or there’s no other choice
What are the relative contraindications for LA use?
Cardiovascular disease
Asthma
Uncontrolled hyperthyroidism
Under active thyroid
Pregnancy
Liver dysfunction
Kidney disease
What should be done in regards to LA for clients with diabetes?
Limit epi as it opposes the effect of insulin
Does LA generally have few interactions with other prescribed drugs?
Yes
How much LA should be administered?
Smallest dose that is clinically effective
How are the effects of LA as a vasodilator countered?
By the addition of vasoconstrictors (epi)
What does the addition of vasoconstrictors do for LA?
Decreases blood flow to the area by constricting the blood vessels
Provides haemostats is
Increases duration of LAs effects
Reduces risk of toxicity
What are the adverse effects of LA?
Needle breakage
Hematoma (swelling, bruising)
Transient facial nerve paralysis
Parathesis (prolonged anaesthia)
Trimus (muscle spam causing lock-jaw)
Edema (accumulation of fluid beneath the skin)
Tissue sloughing
Red, burning, pain
What causes needle breakage?
Poor technique or client movement
What causes hematoma post LA injection?
Puncturing of a blood vessel due to over-insertion
What causes transient facial nerve paralysis post LA injection?
Local into the parotid gland
What causes trismus post LA injection?
Irritation to the nerve sheath after injection due to repeated injections, too large a dose, or contaminated solution
What causes edema post LA injection?
Trauma during injection, infection, or contaminated LA or needle
What causes tissue sloughing when using anaesthetic?
Prolonged use of topical
What causes pain during LA injection?
Careless technique, dull need, rapid deposit of LA
What causes burning pain during injection?
Contaminated LA, heated cartridges, expired LA, rapid deposit of LA
What causes systemic complications of LA?
High plasma concentrations of LA drugs
What is a local anaesthetic overdose?
High blood levels of a drug in various organs and tissues
What may result in a local overdose?
Predisposing client factors and drug factors
What are some of the causes of LA overdose?
Injection into a blood vessel
Too much LA injected
Injected too quickly
Slow metabolism of the LA
How to prevent LA overdose?
Aspiration
Minimal doses
Use of vasoconstrictors
Review of health status
Signs and symptoms of mild LA overdose
Disorientation
Nervousness
Flushed skin colour
Apprehension
Twitching, tremors, shivering
Dizziness
Visual/auditory disturbances
Headache
Tinnitus
How to manage a mild LA overdose?
Terminate procedure
Reassure client
Place client in comfortable position
Administer oxygen
Provide CPR if necessary
Monitor vitals
Summon EMS if needed
Allow patient to recover before discharge
Signs of severe LA overdose
Muscle twitching
Convulsions
How to manage LA overdose?
Terminate procedure
Supine position, legs elevated
Call 911
Provide CPR if needed
Administer oxygen
Monitor vitals
Administer an anticonvulsant
Transport patient to hospital after stabilized
When is an epi dose more likely?
If they have a CVS condition or disease
What are the symptoms of an epi overdose?
Tension
Anxiety
Apprehension
Nervousness
Tremors
Increased heart rate
Increased blood pressure
Throbbing headache
Hyperventilation
What are the predisposing factors to LA overdose?
Age - organs may not be fully developed in younger people or diminished in older people
Body weight
Genetics
Disease
Gender
Pregnancy
What are the drugs predisposing factors to an LA overdose?
Potent or weak vasodilator
Drug dose
Route of administration
Rate of injection
Vascularity of injection site
Presence of other vasoconstrictors
Other medications
A comprehensive health assessment will prevent about ___% of potentially life threatening emergencies
90%
The most common overdose reaction of LA with epi is due to
Too large a dose given
The onset of symptoms is gradual but _______ is more common with amides.
May be severe
What is the most intense reaction to LA with epi from?
A rapid intravascular injection
What reduces the systemic toxicity by slowing its absorption of the LA into the CVS?
Vasoconstrictors
How long does the adverse effects of an epi overdose usually last?
5-10 minutes
What are the local signs of an allergic reaction to LA?
Erythema
Urticaria
Puritis
Angioedema
What are the systemic signs of an allergic reaction to LA?
Bronchospasm
Wheezing
Cyanosis
Tachycardia
Laryngeal edema
What is a similar drug to Oraqix but not used for dentistry?
Emla - used for epidural
What happens with Oraqix the longer it is left on?
The deeper the penetration
What does eutectic mean?
Melts or solidifies at a certain temperature
What are the active ingredients in Oraqix?
Lidocaine 2.5%
Prilocaine 2.5%
Does Oraqix anaesthetize the pulp as well?
No
What to check for prior to assembling Oraqix?
If bubble moves back and forth if it doesn’t, but it in cool water or fridge
What is in an Oraqix cartridge?
Lido/prilo
Poloxamers 188 and 407
HCl for pH adjustment
Purified water
pH 7.5-8
How to apply Oraqix?
Apply by tracing it along the margin and waiting 30 seconds
How long does the anaesthetic from Oraqix last?
Approximately 20 minutes
What is maximum application of Oraqix?
5 cartridges per person
How quickly does Oraqix begin working once applied?
30 seconds
How to choose the right LA for your client?
Consider the vasoactivity
Pain control based on length of procedure
Need for post treatment pain control
Client’s health assessment
Allergies
Hemostasis
Why would presence of an infection and the vascularity of an area decrease the duration of LA?
pH changes in the area
What are the amide local anaesthetics?
Arcticane
Bupivacaine
Lidocaine
Mepivacaine
Prilocaine
How much solution in an LA cartridge?
1.8mL
What is the duration of lidocaine 2%?
180-300 minutes
Where is lidocaine 2% metabolized?
In the liver
What LA to choose when antioxidants are contraindicated or CVS conditions?
Mepivacaine 3%
Where is prilocaine metabolized?
In the lungs and some in the liver
Where is articaine 4% metabolized?
90-95% in the plasma
10% in the lungs
What LA would you use for client with liver disease?
Articaine