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CDCA Review: Local Anesthesia Test With
Complete Solutions
What local anesthetic is metabolized by pseudocholinesterase? - correct answer- Esters Where are ester local anesthetics hydrolyzed? - correct answer- In the blood plasma by the enzyme pseudocholinesterase Which antiseptic should not be used? - correct answer- Liquid Alcohol Before using a cartridge you should:
- wipe it with disinfectant
- soak it in alcohol
- autoclave it and or sterilize it? - correct answer- None of the above What part of the syringe indicates that it is an aspirating syringe? - correct answer- Harpoon What is a possible cause of pain on removal of the needle? - correct answer- Needle barb from impaling bone If there is no organic basis for pain - correct answer- Psychogenic pain How does a self aspirating syringe work - correct answer- When you let off pressure from injecting it self-aspirates (negative pressure built into the syringe) When do you aspirate? - correct answer- Immediately before you inject local anesthetic
What is the action of vasodepressors in local anesthetic? - correct answer- increases depth and duration of anesthetic, decreases absorption of local anesthetic and vasopressor Maximum Doses of Epinephrine - correct answer- Normal healthy patient - .2 mg Cardiac patient - .04 mg How much epinephrine is in a cartridge of 1:50,000 epinephrine? - correct answer- .036 mg How much epinephrine is in a cartridge of 1:100,000 epinephrine? - correct answer- .018 mg How much epinephrine is in a cartridge of 1:200,000 epinephrine? - correct answer- .009 mg What causes a hematoma? - correct answer- Effusion of blood into extravascular spaces and can result from nicking a blood vessel, artery or vein. Common in pterygoid plexus of veins with a PSA injection. Treatment of Hematoma - correct answer- Apply pressure for at least 2 minutes, Ice the area immediately, and then use warm moist towels 4-6 hours after to area, rinse with salt water In which injection is a hematoma most likely to occur? - correct answer- PSA What is the volume of local anesthetic in a cartridge? - correct answer- 1.8 mL or 1. mL How do you determine gauge and lumen size of a needle? - correct answer- Smaller the number, larger the lumen 30 = small 27 = intermediate 25 = large Which needle gauge has the smallest lumen? - correct answer- 30 gauge What sensation is lost first? - correct answer- Pain What function does sodium chloride provide in local anesthetic solution? - correct answer- Makes the solution isotonic with tissue What antioxidant prevents biodegradation of vasoconstrictors? - correct answer- Sodium (Meta) Bisulfite
What is the most common thing that causes pain on injection? - correct answer- Injecting too fast A sensation of burning on injection is caused by what? - correct answer- Injecting too fast or injecting a local anesthetic containing a vasoconstrictor (lower pH) Injection site for palatal infiltration of maxillary teeth? - correct answer- 5-10 mm from the free gingival margin of the teeth (vicinity of the root apex) If you need hemostasis only, what type of injection should you administer? - correct answer- Infiltration What is the difference between a nerve block and an infiltration? - correct answer- Nerve block = local anesthetic injected in close proximity to a nerve trunk Infiltration = flooding the area you want to anesthetize with local anesthetic What topical anesthetic is not absorbed well systemically? - correct answer- Benzocaine What occurs during depolarization? - correct answer- Sodium passes into the axoplasm and potassium is pumped out (reverse polarity) What do myelinated nerves do? - correct answer- Transmits electrical impulses faster What is the effect of epinephrine in a local anesthetic cartridge when injected into a patient taking non-specific beta blockers (propranolol) to control hypertension? - correct answer- Increase systolic blood pressure Which of the following is a landmark for the IANB? - correct answer- Coronoid notch Is laryngeal edema life threatening? - correct answer- Yes Where is the pterygomandibular raphe located? - correct answer- Hamulus and pterygomandibular triangle Which of the following injections would numb the lower lip? - correct answer- Mental nerve block What is the depth of needle penetration for the IANB? - correct answer- 20-25 mm, 2/ of length of a long needle (make sure of bone contact before injecting)
How should the bevel of the needle be oriented when injecting? - correct answer- Toward the bone What causes facial nerve (CN VII) paralysis? - correct answer- The introduction of local anesthetic into the parotid capsule located at the posterior border of the mandibular ramus Patient reports pain on opening the next day after an injection. What is the patient experiencing? - correct answer- Trismus = prolonged tetanic spasm of the jaw muscles by which the normal opening of the mouth is restricted (lock jaw). What causes trismus? - correct answer- 1) Trauma to the blood vessels and muscles in the infratemporal fossa
- Injection of alcohol or sterilizing solution contaminated local anesthetic causing irritation to the tissues
- Hemorrhage
- Large volumes of anesthetic solution deposited in one area
- Infection How do you manage trismus? - correct answer- Prescribe therapy, warm saline rinses, analgesics and muscle relaxants to manage the initial phase of muscle spasm Is the maxillary division of the trigeminal nerve (V-2) sensory, motor or both? - correct answer- Sensory only Is the mandibular division of the trigeminal nerve (V-3) sensory, motor or both? - correct answer- Both sensory and motor Which of the following is not anesthetized by the PSA nerve block? - correct answer- MB root of the maxillary 1st molar Numbness in the anterior portion of the tongue indicates that which nerve has been anesthetized? - correct answer- Lingual nerve (IANB injection) Where is the primary site of biotransformation of amides? - correct answer- Liver What causes allergic reactions in ester local anesthetics? - correct answer- A metabolite of the biotransformation process: PABA (Para Amino Benzoic Acid) What would you use to manage an immediate severe allergic reaction? - correct answer- Epinephrine What would you use to manage a delayed allergic reaction? - correct answer- Benadryl
A central incisor has a periodontal defect on the lingual root surface, what injection would you use? - correct answer- Nasopalatine (NP) nerve block You are scaling the lingual of #13, where would you give the injection for palatal infiltration?
- Mucobuccal fold
- Mucogingival junction
- free gingival margin
- apex of tooth #13 - correct answer- Palatal injection adjacent to the apex of tooth
What Injection would numb the lower lip? - correct answer- Mental nerve block The rapid influx of sodium ions into the interior of the nerve cell causes depolarization of the nerve membrane from its resting level to its _________________. - correct answer- Firing Threshold The firing threshold is the magnitude of the decrease in negative transmembrane potential necessary to initiate an _______________. - correct answer- Action potential Why should injection needles not be inserted to their hub? - correct answer- The hub is the most rigid/weakest part of the needle When is a long (32 mm) needle preferred for injections? - correct answer- For all injections where a significant thickness of soft tissue must be penetrated (IANB) Generic = Lidocaine - correct answer- Brand name = Xylocaine Generic = Mepivacaine - correct answer- Brand name = Carbocaine Generic = Prilocaine - correct answer- Brand name = Citanest (Citanest Forte = 1:200,000 epi) Generic = Articaine - correct answer- Brand name = Septocaine Generic = Bupivacaine - correct answer- Brand name = Marcaine What is the most common reason for a lesion on the lower lip a day after injection? - correct answer- Recurrent aphthous stomatitis, herpes simplex Needles and cartridges are disposed in a ____. - correct answer- Sharps container (answer may be needles only)
How does infiltration work? - correct answer- Small terminal nerve endings are flooded with local anesthetic How does a nerve block work? - correct answer- Local anesthetic is deposited near a main nerve trunk Palatal injections only ______. - correct answer- Anesthetize soft tissue (not pulpal tissue) Where is topical anesthetic least effective? - correct answer- Keratinized tissue on hard palate What nerve was anesthetized if the cornea of the eye is numb? - correct answer- 1st branch of the Trigeminal Nerve (V-1) (specifically the ciliary nerves) What causes a dry cornea? - correct answer- IANB injection not contacting bone and going into parotid gland - anesthesia to the facial nerve What is the benefit of slow deposition of local anesthetic? - correct answer- Less painful, less complications Expiration dates of local anesthetic - correct answer- Plain anesthetics = 36 months Anesthetics with vasoconstrictor = 18 months (Sodium bisulfite) Which local anesthetic should not be used on a patient with an allergy to sulfa drugs? - correct answer- Articaine (Septocaine) (not true, but if they ask this question, this should be your answer; this misconception was based on the fact that the thiophene ring in the articaine molecule contains a sulfur atom) 100 pound female patient- what is the MRD limit of cartridges of 2% lidocaine for this patient? - correct answer- 17 X 2% = 34 mg per cartridge 100 lbs. X 2.0 mg/lb. = 200 mg maximum dose 200 mg/ 34 mg = 5.9 cartridges If a patient has an allergy to red wine, what local anesthetic should be used? - correct answer- Local anesthetic without epinephrine (plain) Articaine (Septocaine) What is the volume of LA anesthetic solution in 2 cartridges of Lidocaine? - correct answer- 3.6 ml (or 3.4 ml) (1.8 ml or 1.7 ml per cartridge)
What local anesthetic is metabolized by pseudocholinesterase? - correct answer- Esters Where are ester local anesthetics hydrolyzed? - correct answer- In the blood plasma by the enzyme pseudocholinesterase Which antiseptic should not be used? - correct answer- Liquid Alcohol Before using a cartridge you should:
- wipe it with disinfectant
- soak it in alcohol
- autoclave it and or sterilize it? - correct answer- None of the above What part of the syringe indicates that it is an aspirating syringe? - correct answer- Harpoon
What is a possible cause of pain on removal of the needle? - correct answer- Needle barb from impaling bone If there is no organic basis for pain - correct answer- Psychogenic pain How does a self aspirating syringe work - correct answer- When you let off pressure from injecting it self-aspirates (negative pressure built into the syringe) When do you aspirate? - correct answer- Immediately before you inject local anesthetic What is the action of vasodepressors in local anesthetic? - correct answer- increases depth and duration of anesthetic, decreases absorption of local anesthetic and vasopressor Maximum Doses of Epinephrine - correct answer- Normal healthy patient - .2 mg Cardiac patient - .04 mg How much epinephrine is in a cartridge of 1:50,000 epinephrine? - correct answer- .036 mg How much epinephrine is in a cartridge of 1:100,000 epinephrine? - correct answer- .018 mg How much epinephrine is in a cartridge of 1:200,000 epinephrine? - correct answer- .009 mg What causes a hematoma? - correct answer- Effusion of blood into extravascular spaces and can result from nicking a blood vessel, artery or vein. Common in pterygoid plexus of veins with a PSA injection. Treatment of Hematoma - correct answer- Apply pressure for at least 2 minutes, Ice the area immediately, and then use warm moist towels 4-6 hours after to area, rinse with salt water
When does a patient receive an electrical shock sensation during and injection? - correct answer- When needle contacts the nerve sheath Why does infiltration work better in the maxilla? - correct answer- Less bone density (thinner cortical plate of bone) Which local anesthetic is not an amide? - correct answer- Procaine (Novacain) How long can you safely leave a Dentipatch (EMLA) on tissue? - correct answer- 15 minutes Most commonly used plain local anesthetic? - correct answer- 3% Mepivacaine Plain What gauge needle can be used for infiltration injections? - correct answer- 27 or 30 gauge Which local anesthetic is an ester? - correct answer- Procaine (Novacain) Why would you use caution with an amide if a patient has liver (cirrhosis) disease? - correct answer- Amides metabolized in the liver After infraorbital injection why does the patient's cheek turn white? - correct answer- Blanching or vasoconstriction of blood vessels in the area Why does anesthesia fail to work near an infected tooth? - correct answer- Infection causes a lower pH in the tissue (less free base local anesthetic molecules available to penetrate the nerve membrane)
If a patient has an allergic reaction to an amide, what could you use to inject the patient? - correct answer- Ester local anesthetic If a patient is allergic to both amides and esters, what could you use to inject the patient? - correct answer- Diphenhydramine (Benadryl) What nerve innervates the soft palate? - correct answer- Lesser palatine If the pharynx (throat) is numb, what nerve was anesthetized? - correct answer- Glossopharyngeal (Cranial Nerve IX) What is the most common thing that causes pain on injection? - correct answer- Injecting too fast A sensation of burning on injection is caused by what? - correct answer- Injecting too fast or injecting a local anesthetic containing a vasoconstrictor (lower pH) Injection site for palatal infiltration of maxillary teeth? - correct answer- 5-10 mm from the free gingival margin of the teeth (vicinity of the root apex) If you need hemostasis only, what type of injection should you administer? - correct answer- Infiltration What is the difference between a nerve block and an infiltration? - correct answer- Nerve block = local anesthetic injected in close proximity to a nerve trunk Infiltration = flooding the area you want to anesthetize with local anesthetic What topical anesthetic is not absorbed well systemically? - correct answer- Benzocaine
Patient reports pain on opening the next day after an injection. What is the patient experiencing? - correct answer- Trismus = prolonged tetanic spasm of the jaw muscles by which the normal opening of the mouth is restricted (lock jaw). What causes trismus? - correct answer- 1) Trauma to the blood vessels and muscles in the infratemporal fossa
- Injection of alcohol or sterilizing solution contaminated local anesthetic causing irritation to the tissues
- Hemorrhage
- Large volumes of anesthetic solution deposited in one area
- Infection How do you manage trismus? - correct answer- Prescribe therapy, warm saline rinses, analgesics and muscle relaxants to manage the initial phase of muscle spasm Is the maxillary division of the trigeminal nerve (V-2) sensory, motor or both? - correct answer- Sensory only Is the mandibular division of the trigeminal nerve (V-3) sensory, motor or both? - correct answer- Both sensory and motor Which of the following is not anesthetized by the PSA nerve block? - correct answer- MB root of the maxillary 1st molar Numbness in the anterior portion of the tongue indicates that which nerve has been anesthetized? - correct answer- Lingual nerve (IANB injection) Where is the primary site of biotransformation of amides? - correct answer- Liver
What causes allergic reactions in ester local anesthetics? - correct answer- A metabolite of the biotransformation process: PABA (Para Amino Benzoic Acid) What would you use to manage an immediate severe allergic reaction? - correct answer- Epinephrine What would you use to manage a delayed allergic reaction? - correct answer- Benadryl Allergic reaction management for a patient who immediately starts gasping for air and BP drops below 90/60mmHg - correct answer- Administer epinephrine V-2 exits the cranium through? - correct answer- Foramen Rotundum V-3 exits the cranium through? - correct answer- Foramen Ovale The mental nerve exits the mandible through? - correct answer- Mental foramen The _______ nerve remains in the mandibular canal and forms a nerve plexus that innervates the pulpal tissues of the 1st premolar, canine, lateral incisor and central incisor via its dental branches. - correct answer- Incisive What is the injection site for the Anterior Superior Alveolar (ASA) injection? - correct answer- Mucobuccal fold mesial to the canine eminence What is the injection site for the Middle Superior Alveolar (MSA) injection? - correct answer- Mucobuccal fold above the maxillary second premolar
- Mucobuccal fold
- Mucogingival junction
- free gingival margin
- apex of tooth #13 - correct answer- Palatal injection adjacent to the apex of tooth # What Injection would numb the lower lip? - correct answer- Mental nerve block The rapid influx of sodium ions into the interior of the nerve cell causes depolarization of the nerve membrane from its resting level to its _________________. - correct answer- Firing Threshold The firing threshold is the magnitude of the decrease in negative transmembrane potential necessary to initiate an _______________. - correct answer- Action potential Why should injection needles not be inserted to their hub? - correct answer- The hub is the most rigid/weakest part of the needle When is a long (32 mm) needle preferred for injections? - correct answer- For all injections where a significant thickness of soft tissue must be penetrated (IANB) Generic = Lidocaine - correct answer- Brand name = Xylocaine Generic = Mepivacaine - correct answer- Brand name = Carbocaine Generic = Prilocaine - correct answer- Brand name = Citanest (Citanest Forte = 1:200,000 epi)
Generic = Articaine - correct answer- Brand name = Septocaine Generic = Bupivacaine - correct answer- Brand name = Marcaine What is the most common reason for a lesion on the lower lip a day after injection? - correct answer- Recurrent aphthous stomatitis, herpes simplex Needles and cartridges are disposed in a ____. - correct answer- Sharps container (answer may be needles only) How does infiltration work? - correct answer- Small terminal nerve endings are flooded with local anesthetic How does a nerve block work? - correct answer- Local anesthetic is deposited near a main nerve trunk Palatal injections only ______. - correct answer- Anesthetize soft tissue (not pulpal tissue) Where is topical anesthetic least effective? - correct answer- Keratinized tissue on hard palate What nerve was anesthetized if the cornea of the eye is numb? - correct answer- 1st branch of the Trigeminal Nerve (V-1) (specifically the ciliary nerves) What causes a dry cornea? - correct answer- IANB injection not contacting bone and going into parotid gland - anesthesia to the facial nerve
