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327 Cards in this Set

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What is local anesthesia?
Anesthetic applied to a specific local area that eliminates sensation and pain without loss of consciousness
What type of molecule is cocaine?
An ester
Who developed the inferior dental nerve block techniques for dentistry?
William Stewart Halsted and Richard John Hall in 1884
What drug is commonly known as Novocaine?
Procaine an ester type drug
What was the first amide used in local anesthesia?
Lidocaine which was marketed as Xylocaine. This is a mainstay of local anesthesia in dentistry today
What type of drug is Lidocaine/Xylocaine?
Amide
What are the properties of ester type anesthetics?
Short acting (ok for dentistry in the early 1900’s) Increased incidence of allergy, very slow onset 10-15 min
What are the characteristics of Amide type anesthetics?
Longer duration, short onset 3-5 min, less allergy
Why was epinephrine added to procaine and who did this?
Braun (called the father of local anesthesia) was the person who added it to increase the duration of its effects.
What does the inflammatory soup released by damaged cells do?
Depolarizes nociceptors and stimulates the generation of AP’s
What short peptide is cleaved by proteolytic enzyme from plasma protein that is released into damaged tissue?
Bradykinin which makes free nerve endings more sensitive to noxious stimuli
What does release of substance P cause?
More bradykinin formantion and activation of mast cells and platelets
What substances can diffuse between nerve cells and sensitize them?
Histamine and 5HT
What substances are involved in sensitizing pain response?
PGE2 from COX activity on arachidonic acid, Bradykinin, Histamine and serotonin from mast cells, and substance P from nociceptors, also TRP channels
How is pain sensed in dentin?
Nociceptor nerve endings project along odontoblast processes into dentinal tubules. Tooth damage causes hydrostatic pressure changes that stimulate nociceptor endings
What does local anesthetics block?
Neurotransmission along nociceptor axons
What are the two types of pain fibers?
Type A-delta fibers – fast pain, myelinated
What is a stimulus that is not strong enough to reach threshold called?
A graded receptor potential
What happens in an action potential?
Rapid activation of voltage-gated Na+ channels followed by slower activation of voltage-gated K+ channels
Under resting conditions are the K+ channels or the Na+ channels open?
The K+channels are open the Na+ channels remain closed
What is equilibrium voltage?
The point at which a significant charge accumulation along the membrane opposes further diffusion across the membrane
How many ions actually move across the membrane during an AP?
Very few the membrane is very effective in separating charges so few ions are required
What does a voltage gated channel consist of?
4 clusters of 6 transmembrane domains
How do K+ channels and Na+ channels differ?
K+ channels are made 4 individual polybeptides and Na+ the 4 parts of the cluster are part of a large single polypeptide.
What channels do local anesthetic block?
Voltage-gated channels
How does local anesthetic act on the nerve membrane?
Must be lipophilic to cross nerve membrane. Blocks Na+ channels from the axoplasmic (inside) side. Once in axoplasm anesthetic becomes protonated to enter Na+ channels
What determines the resistance in the axon?
The diameter. Larger = less resistance = faster conduction
What type of axons usually carry acute pain signals?
Myelinated axons
What are the two factors involved in the action of LA?
Diffusion of the drug and binding at receptor site
What must the charge be on the LA to diffuse across the membrane?
Uncharged (neutral)
Why is most LA positive once it gets into the cytoplasm?
The lower pH protonates the anesthetic which acts to keep it inside the cell for a longer period of time
What type of molecule is procaine?
Procaine was the first synthesized ester
What class of molecules is standard practice for LA today?
Amides such as lidocaine
What are 2 disadvantages of esters?
High allergy rate, slow onset
What is special about amides?
Only type available in US as injectable, less allergy, faster onset of action
Which LA lacks an amino terminus?
Benzocaine
A larger pka translates into what for LA?
More anesthetic remains in the charged form, LA is less permeable across the axon membrane so it takes longer to take effect (the lower the pKa the faster the drug onset)
Are anesthetics vasoconstrictors or vasodilators?
Vasodilators. Vasodilation leads to increased blood flow to region which = rapid removal of anesthetic molecules from injection site
In the specific receptor theory Benzocaine is under which classification?
Class C - agents act by a receptor-independent physico-chemical mechanism
What is class D in the specific receptor theory?
Most useful LA agents – agents act by combination of receptor and receptor-independent mechanisms
At physiological pH what is the ratio of charged to neutral LA?
3:1
In inflamed tissue how much more charged LA is there than neutral LA?
10X more charged = LA takes longer to begin working
What does epinephrine in LA do?
Constricts blood flow in capillaries via a1 receptors to make more effective for longer as it is not so quickly flushed from the area.
Why does the injection sting?
Because the epinephrine is stabilized at a pH of 3 and this is what hurts.
Why does acupuncture and other “distraction” techniques work?
Due to the gate theory where secondary neurons actually inhibit pain neurons.
What are some desirable properties for a local anesthetic?
Should not irritate tissue to which it is applied, shouldn’t cause any permanent alteration of nerves structure, should have low systemic toxicity, Should be effective injected or applied locally to mucous membranes and onset time should be short, adequate duration, allergy free, stable in solution, and sterile or able to be sterilized by heat.
What prevents retrograde movement of nerve impulses?
The inexcitable refractory period.
What is the membrane expansion theory?
It is a theorized way of how the anesthetic works and states that anesthetic molecules diffuse to hydrophobic regions of membranes and expand the critical regions of the membrane.
What is the specific receptor theory?
The most favored today that says that local anesthetic works by binding specific receptors on the sodium channels. 4 different sites seem to exist where drugs can alter nerve conduction.
With respect to the specific receptor theory, which class is where most anesthetics take action?
Class D
From which side does LA work?
It blocks the channels from the axoplasmic side.
How does anesthetic gain access in myelinated nerves?
They work at the nodes of Ranvier which have abundant Na channels. At least 3 nodes are necessary to be able to stop the AP.
What role does Ca play in signal propagation?
They are thought to play a regulatory role by increasing the Na permeability of the nerve membrane.
What is the proposed mechanism for LA?
Displacement of Ca ions from Na channels that pemits binding of LA to this site which blocks Na channel and decreases Na conductance a depression in the rate of depolarization and a failure to achieve threshold potential and a lack of signal propagation.
What are the basic components to most LA’s?
they are tertiary amines, amphipathic, an ester or amide intermediate chain and a hydrophilic part (Benzo) to make it injectible.
What are some properties for LA’s?
Linkage defines properties, prepared as basic compounds, Pka 7.5-10, they are weak bases and combine with acids to form salts (soluble in H2O.
What effect does low extracellular pH have on the LA?
Low pH = more cations = less anesthetic in neutral form that is able to diffuse into the axon to have its effects.
What is the most important quality of a given LA?
Its ability to diffuse, best lipid solubility = best clinical effectiveness
Which are the common LA’s we use here in clinic?
From lowest pKa to highest….Benzocaine(topical), Mepivacaine, Lidocaine, Prilocaine, Articaine, and Bupivacaine (long duration)
What factor of LA is affected by the pKa?
The onset. Lower pKa = faster onset
What factor of LA is affected by Lipid solubility?
Anesthetic potency. More soluble = more potent
How does Protein Binding affect LA’s?
Duration. Increased binding = longer duration
How does non-nervous tissue diffusibility affect LA’s?
Increased diffusibility = decreased onset time.
How does vasodilation activity affect LA’s?
Potency and duration, greater vasodilation= less potency and shorter duration.
Where do fibers near the surface of the nerve tend to innervate?
More proximal regions this is why it takes more time for the incisor to become numb vs the molars in an IA injection. The proximal regions are also the 1st region to return to normal.
What is the order for sensory loss of pain, cold, warmth, touch, deep pressure, and motor?
Just in that order…and recovery is the reverse of this.
How is Local Anesthesia different from most other drugs?
They don’t need to attain a therapeutic level in the blood stream before exerting their effects in fact once in the blood stream they are quickly metabolized and cease the desired effect.
What is one characteristic of all LA’s except cocaine that is not ideal?
They are vasodilators and increase vascularity at the injection site that speeds up their own uptake into blood system and eventual metabolism. This shortens the duration of the LA and increases the risk for toxicity.
How would you organize the following according to the rate at which they are absorbed into the blood stream?
Intravenous, Intramuscular, Subcutaneous, and Intramuscular?
Why is oral not an effective route for LA?
Due to poor absorption in the GI where 72% of the LA is inactive.
How can LA by IV injection be a good and bad thing?
Good because it can be used to manage ventricular disrhythmias but it can lead to toxic blood levels.
How is the rate of removal of LA from the blood measured?
In half lives. In 6 half lives 98.5% has been reduced.
What two important structures do LA’s cross?
The blood brain barrier and the placenta into fetal circulation.
Once in the blood stream, where does the LA go?
It is distributed to all areas with the muscles being the largest site due to mass.
What is the half life of Lidocaine?
1.6 hrs.
Why is LA metabolism important?
Because toxicity is determined by the rate of absorption into the blood vs. the rate of metabolism. This process if different for esters and amides.
How are esters metabolized?
Hydrolyzed by pseudocholinesterase (1 in 2800 have atypical PSChE which is a contraindication for Ester LA’s) with PABA as the major metabolite
What is PABA?
Paraminobenzoic acid, a major metabolite of ester type LA’s and THE PRIMARY ALLERGY AGENT for patients.
Where are most amides metabolized?
In the liver. Lidocaine, Mepivacaine, and Bupivacaine are exclusively in the liver where prilocaine is primarily in the liver and some in the lung and Articane is metabolized by plasma cholinesterases and in the liver.
What determines in great part the metabolism rates for amide LA’s?
Liver function and perfusion.
How do hepatic diseases affect the half life of LA’s?
They increase blood levels and cause a longer half life and increased toxicity risk.
What is the primary excretory organ for anesthetic and its metabolites?
The kidney. A small % of a given dose is excreted unchanged more in amides than in esters.
What happens in the case of renal impairment?
Elevated blood levels, risk of toxicity, and relative contraindication for dialysis, glomerulonephitis, or pyelonephitis patients.
What are some systemic effects of LA on the CNS?
Cross the blood brain barrier, depressive effect, High toxic levels can cause tonic-clonic seizures, and at lower concentrations it can have anticonvulsant effects.
What are some possible systematic effects of LA on the CV system?
Direct action on myocardium and peripheral vasculature with myocardial depression leading to decreased excitability, conduction rate, and force of contraction. Peripheral dilation will increase blood flow to increase absorption, decrease duration, and increase bleeding in the area.
What can happen to local tissues due to LA’s?
Skeletal muscle can be damaged due to irritants, but it is reversible and regenerates in two weeks.
What effect will LA’s have on the respiratory system?
At non overdose levels it has a relaxant effect but at overdose levels respiratory arrest is possible, but no effect is seen until near toxic levels.
Why are vasoconstrictors used in LA’s?
Counter act the vasodilator effects of LA and help control tissure perfusion.
How do vasoconstrictors help with LA’s?
slow absorption into CV system and reduce the risk of toxicity, they increase duration of action and decrease bleeding at the site.
What are the vasoconstrictor agents used in LA’s?
Catecholamines. Natural is Epi, and synthetic is levonordefrin.
What are the three types of vasoconstrictors?
Direct-acting on adrenergic receptors, Indirect acting, and mixed acting.
What type of vasoconstrictors are Epi and Levonordefrin?
They are direct acting.
What do the Alpha and Beta adrenergic receptors do?
Alpha-do smooth muscle contraction and Beta do smooth muscle relaxation and cardiac stimulation.
Which type of vasoconstrictor has the greatest effects on all types of adrenergic receptors?
Epinephrine, then NEpi then Levonordefrin.
What is the most common dilution for vasoconstrictors for dentistry?
1: 100,000 or 17 micrograms per cartridge of anesthetic.
What happens to the amount of epi in the plasma after 1 cart of lidocaine with epi?
It is doubled.
What effects does epi have on CV?
Increases BP, Cardiac output, Stroke volume, HR, Strength of contraction,and O2 consumption, and hemostasis
What effects can epi have on CNS and Respiratory system?
It is a bronchiole dilator, but only stimulates CNS in excessive doses.
Where is Epi inactivated?
In the liver by catechol-o-methyltransferase and monoamine oxidase.
What can be some side effects of Epi and overdose?
Fear, Anxiety, tension, restlessness, headache, and palpitation with cardiac dysrhythmias with increase amounts.
How does a patient with CV disease differ with respect to LA?
You would give them about 1/5 the amount of a healthy patient.
What is the goal when it comes to dose of Epi?
The least concentrated solution that produces the desired effect.
What is Levordefrin?
It is neo-corbefrin, a synthetic vasoconstrictor that is 1/6 as effective as Epi, but has the same actions.
How long do short-duration drugs provide anesthesia?
30 min of pulpal or deep anesthesia. Intermediate duration drugs provide 60 min and long duration drugs for longer than 90 min.
What factors affect duration of action for LA?
Individual response, accuracy in deposition, status of the tissues at the site of drug deposition, anatomical variation, type of ingection administered
What are the types of individual responses to duration?
Normal responders = 68% anesthesia for 60 min. hyper responders =15% pupal anesthesia beyond 60 min. Hypo responders = 15% pulpal anesthesia less than 60 min.
What is accuracy of administration?
Deposition of anesthetic close to the nerve providing greater depth and duration of anesthesia very significant in nerve blocks not as significant in infiltration .
How does status of tissues affect duration?
Inflammation, infection, or pain will decrease depth and anticipated duration. Increased vascularity leads to more rapid absorption
What anatomical variations affect duration?
Bone thickness, height of mandibular foramen, width of ramus, zygoma location near 1st molar, flaring of palatal root of max molars
How does the type of injection affect duration?
Nerve block provides more duration that infiltration. Smaller volumes = decreased duration however larger volumes do not increase duration
How is maximum doses of anesthetics measured?
In mg/kg or mg/lb
What is the authors recommended dose for each drug?
Articaine 3.2, Bupivacaine .6, Lidocain with or with out epi 2.0, Mepivacaine with or without epi 2.0, Prilocaine with or without epi 2.7. the authors MRD differs from the manufacturuer in that the manufacturer recommends lido with epi 3.0 and Mepivacaine with or without epi 3.0
What is the max dose for each anesthetic regardless of weight?
Articaine 500mg, Bupivacaine 90mg, Lidocaine 300mg, Mepivacaine 300 mg, Prilocaine 400mg. the manufactures are different from the author in that lidocaine with epi 500mg and Mepivicaine with or without epi 400mg
How do you calculate milligrams per cartridge?
Percent solution = mg per milliliter x volume of cartridge = mg per cartridge (ex. 0.5% = 5mg/ml x 1.8ml = 9mg)
How should you count a partially used cartridge?
Round to the nearest ½ cartridge
When usuing multiple anesthetics how do you determine the max dose?
Total dose of both local anesthetics should not exceed the lower of the two calculated doses, or 200 mg (ex a patient has receive 144mg of prilocaine so he can still receive 56mg of lidocaine. 56 mg/36mg per cartridge = 1.5 cartidges of lido 2% can be given.
How much vasoconstrictor may be given to a normal healthy patent ASA I vs. a patient with significant cardio disease ASA III or IV?
ASA I 1:100000 11 cartridges. ASA III or IV 2 cartridges
What is the max dose of vasoconstrictor?
For ASA I it is 0.2mg per appointment and for ASAIII or IV 0.04mg per appointment
What are the selection factors for anesthetic?
Contraindication against vasoconstrictor or anesthetics agent, efficacy of the anesthetic agent, safety of the anesthetic agent, estimated duration of anesthesia, need for hemostasis or not, simplicity and ease of use
What is the first choice anesthetic?
2% Lidocaine 1:100000
What anesthetic is used when short anesthesia is wanted?
4% prilocaine
What should Articaine not be used for?
IA nerve blocks
What anesthetic is used for long pain control?
.5% Bupivacaine
Why is Articaine controversial?
There may be an increased risk of paresthesia/anesthesia for nerve blocks . Malameds conclusion: articaine is a well-tolerated, safe and effective LA for use in clinical dentistry
At what rate does Articaine bind plasma protein?
95% more than other LA’s
What solutions is there a warning for?
4% solutions (Articaine and Prilocaine) used for nerve blocks in the mandible. some neurotoxicity is a risk factor
What is the schools policy on Articaine?
No Articaine for IA nerve blocks
What does the breech loading metallic, cartridge type syringe allow for?
Purposeful aspiration
What are possible problems with the syringe?
Bent harpoon- can cause cartridge breakage. Disengagement of the harpoon from plunger during aspiration – harpoon is dull. Surface deposits – interfere with syringe function and appearance
What is the needle design?
One piece with attachment for hub. Parts of needle are bevel, shaft, hub, syringe adaptor and cartridge-penetration end
What does gauge refer to?
Diameter of the lumen of the needle – the smaller the number the greater the diameter of the lumen. 30 gauge blue, 27=yellow 25=red
How is deflection a factor with gauge?
Larger gauge needles tend to have more deflection through tissue. Injections such as IA, Gow-Gates, ASA are very prone to deflective forces
What are standard needle lengths?
Long 32mm, and short 20mm
What are the benefits of choosing a small gauge needle?
Less deflection, greater accuracy, less risk of needle breakage, easier aspiration, no perceptual difference in patient comfort
What are a few recommendations with needles?
Use a single needle for only 3 or 4 insertions in a single patient. Never use on more than one patient. Don’t bury the needle, don’t change directions while in the tissue, never force against resistance, keep capped, discard and destroy so they cannot be used by unauthorized persons
What does a red band on a cartridge of anesthetic mean?
That its lidocaine with epi
What are possible cartridge problems?
Bubble in the cartridge, extruded stopper, burning on injection (prolonged sensation can be for disinfectant diffusion into the cartridge), sticky stopper, and broken cartridge
What should always be recorded regarding anesthesia?
1. Drug used/vasoconstrictor used 2. Dose in mg of the solutions 3. Needles used 4. Patient’s reaction (ex tolerated procedure well)
Why can’t everyone get local anesthetic?
LA and vasoconstrictors have systemic effect, Biotransformation occurs in primarily in the liver, % of LA is excreted unchanged, LA’s are not absolutely innocuous drugs, and Administration is not entirely benign
How often should the medical history be updated?
Taken at initial visit and routinely updated at least every six months.
What would cause the medical history to need to be tailored to pt’s needs?
Medical problems, age, intelligence, lifestyle, complexity of planned procedure, anticipated anesthetic methods
What is included in biographic data?
Name, age, gender, occupation, marital status
How is the chief complaint to be recorded?
In the pt’s own wording
What is included in the medical history?
Past major injuries and illnesses, recent minor illnesses, current medications, drug allergies, health-related habits and addiction, date of most recent physician visit
What should be the focus of a social and family medical history?
Relevant inherited diseases
What should guide the review of systems?
Pertinent answers obtained from the history
What do we include in the physical examination?
Review of head, neck and maxillofacial region and vital signs
What are notable CV conditions?
Post MI – no tx within 6 mos of MI, after 6 months ok if no other cardiac concerns. Angina – stable ASA III unstable ASA IV don’t use vasoconstrictor
What is the protocol for stage 1 hypertension?
140-159/90-99, most procedures ok. 1) medical consult before extensive restorative, surgery or before using>.04mg epi (2 cartridges) 2) take and record a pre-and post-surgical BP 3) take and record a pre-and post- procedural BP if more than .o4 mg epi is used
What is the protocol for stage 2 hypertension?
160-169/100-109, some minor procedures okay if approved by faculty 1) medical consult before non-emergency surgery, extensive restorative, SRP 2) do not use >.04mg epi 3) take and record pre- and post-procedural BP reading
What is the protocol for BP 170-179/ 100-109?
Only diagnostic procedures ok. Emergency treatment can only be done in the emergency clinic under supervision of ACLS certified faculty 1) accept pt for comp care only with written consent for the pt’s physician 2) do not use >.04 epi 3) pre and post BP reaking
What is the protocol for stage 3 hypertension?
>180/>110 stop exam, no treatment, refer for medical consult immediately
What alterations are made for pt with hyperthyroid conditions?
If you even treat no vasoconstrictor
Which LA should not be used for pt with methemoglobinemia?
Prilocaine
Which type of LA has a contra indication for pt with atypical plasma cholinesterase?
Esters
Which LA should be used if needed for a pregnant pt?
lidocaine is a B category (caution advised)
What are the 6 vital signs?
Blood pressure, Heart rate, Respiratory rate, Temperature, Height, and Weight
What is normal heart rate?
60-110 bpm, note if regular rate and rhythm
What is normal respiratory rate?
12/min don’t let the pt know you are measuring
Why take temp?
to determine potential systemic infection
Why take height?
To determine BMI
Why take weight?
To determine BMI and dosage of meds
What questions can you ask to make determination of risk?
Is the pt capable, both physiologically and psychologically, to tolerating stresses of tx?
What is the stress reduction protol?
1) sedation: night before and morning of appt. 2) sedation: intraoperative. 3) effective pain control. 4) Morning appointment. 5) time factor: don’t exceed tolerance. 6) hot, humid weather 7) postoperative prescriptions, prn. 8) postoperative phone call: ASA III, IV, postparenteral sedation, general anesthesia, and prolonged or traumatic procedure
What interaction does vasoconstrictor and nonselective B-blockers have?
Serious inc BP reflex bradycardia
What interactions do vasoconstrictor and TCA’a have?
Potentiates effect of levo. 5-10 fold and epi 2 fold ( don’t use levo minimize epi…3 cart)
What interactions can cocaine and/or meth cause?
Major concern is tachycardia, HTN, inc CO and inc oxygen demand, can lead to myo ischemia, MI cardiac arrest. Postpone dental procedures shen cocaine use is confirmed or suspected within last 24 hr
What precaustion should be taken with adrenergic neuronal blocker?
Use minimal dose
Are MAOI’s a concern when using LA?
They once were considered a problem but no longer just use prudence with LA
What is a Local infiltration?
A procedure involving small terminal nerve endings in the area of the dental treatment which are flooded with LA. (treatment is made into the same area LA was deposited)
What is a field block?
This is what is commonly referred to as an infiltration. LA is deposited near the larger terminal nerve branches to anesthetize area. Treatment is made away form site of injection
What is a nerve block?
Local anesthetic is deposited close to main nerve trunk
Where to the main branches of CN V exit the brain case?
V1- sup. Orbital fissure, V2- F. Rotundum, V-3 F. ovale
What is carried in V2 and from what areas?
Sensory no motor. Services the skin of the mid potionof face, lower eyelid, side of nose, upper lip. Mucous membranes of the nasopharynx, maxillary sinus, soft palate, tonsil and hard palate. Maxillary teeth and Periodontal tissues
What are the characteristics of the PSA nerve?
Usually has two branches. One external to the bone and one internal.
What does the external branch of the PSA nerve do?
Continues downward on the posterior surface of the maxilla providing sensory innervations to buccal gingival in max molar region
What does the internal branch of the PSA nerve do?
Enters into the maxilla travels down t he posterior/posterolateral wall fo the max sinus providing sensory to the mucous membrane of the sinus. Provides sensory to the alveoli, periodontal ligaments and pulpal tissues of maxillary 3rd, 2nd and most of 1st molars
In 28% of pts what portion of the molars isn’t covered by the PSA nerve?
The mesiobuccal root of the first molar is MSA or ASA if no MSA
What are the MSA and ASA nerves branches of?
The infraorbital nerve
What makes up the superior dental plexus?
PSA, MSA and ASA nerves
What does the MSA nerve provide sensory for?
Maxillary premolars and perhaps the MB root of 1st molar, the periodontal tissues, buccal soft tissue and the bone in premolar region
What % of people have an MSA nerve branch?
Traditionally 30%-54% most recent data – 72%
When the MSA is absent what nerves cover the area?
PSA or ASA usually ASA
What area’s does the ASA provide innervations for?
Pulpal innervations to central and lateral incisors and canine, sensory innervations to Periodontal tissues, buccal bone, and mucous membranes of these teeth
What are some characteristics of the greater palatine nerve?
Descends through the pterygopalatine canal. Once in the oral cavity the nerve runs forward between the mucoperiosteum and osseous hard palate. Some sensory to parts of the soft palate.
What are the indications for using a PSA injection?
Need for pulpal anesthesia to max 3rd, 2nd and 1st molars (except MB root of 1st molar) and the buccal soft tissue of the same area
Why would a PSA injection be contraindicated?
The pt is at a high risk of hemorrhage (hemophiliac)
What are the advantages and disadvantages of PSA injection?
Advantages: relatively atraumatic, multiple teeth anesthetized w/ single injection. Disadvantages: risk of hematoma, no bony landmarks, 2nd injection often needed for 1st molar
What could has a hematoma with a PSA injection?
Needle puncture of the vasculature (posterior superior artery or vein or pterygoid plexus
What are the indications for using the MSA injection?
Pulpal anesthesia of Max premolars and MB root of max 1st molar. Buccal soft tissue adjacent to these teeth
When would a MSA injection be contraindicated and what are the complications?
During acute infection/ inflammation. Minimal complications
What are the Advantages and disadvantages of the MSA injection?
Advantage: minimizes # of injections and amount of LA for multiple teeth. Disadvantages: MSA nerve present in only about 72% of population
What are the indications for using an ASA injection?
Pulap and esthesia of maxillary incisors and canines as well as premolars and MB root of 1st molar in those lacking an MSA nerve. Also the buccal soft tissue in the area
What are the contraindications and complications of the ASA injection?
Contraindicated if only one or two teeth need anesthesia. Complications: intravascular penetration to infraorbital vessels, orbital injection
What are the advantages and disadvantages of the ASA injection?
Advantages: minimizes # of injections and amount of LA for multiple teeth. Disadvantages: technique sensitive (anatomic land marks are difficult to distinguish) operator discomfort with injection near pt’s eye
What are the indications for using a field block?
Pulpal anesthesia to one or two teeth, minimal soft tissue anesthesia needed
What are the contraindications and complications of field blocks?
Contraindication: acute infection/ inflammation. Complications: penetration of floor on nose and blood vessels is possible
For which teeth can field blocks be used?
Any Maxillary tooth and mandibular incisors ( max 1st molar can be difficult)
What are the indications for a greater palatine nerve block?
Need for palatal soft-tissue anesthesia on more than two teeth. When needed for pain control during periodontal or oral surgical procedures involving palatal soft and hard tissues.
What are the contraindications for greater palatine block?
Inflammation or infection at the injection site, and smaller areas of therapy (one or two teeth)
What are the advantages and disadvantages of the greater palatine nerve block?
Advantages: minimizes needle penetrations, volume of solution, and pt discomfort. Disadvantages: Ho hemostasis except in immediate area of injection. Potentially traumatic.
What are the indications for a nasopalatine nerve block?
Need for palatal soft-tissue anesthesia for more than two teeth, and pain control during periodontal or oral surgical procedures involving palatal soft and hard tissues.
When is nasopalatine nerve block contraindicated?
Inflammation or infection at the injection site, smaller area of therapy (one or two theeth)
What are the advantages and disadvantages of the nasopalatine nerve block?
Advantages: minimizes needle penetrations, volume of LA, and pt discomfort. Disadvantages: no hemostasis except in the immediate area of injection, potentially the most traumatic intraoral injection
What are the characteristics of V3?
It is the largest branch of the trigeminal nerve that has a sensory and a motor root that exit the foramen ovale separately with the motor root medial to the sensory root the two roots merge outside skull and then separate into a small anterior and large posterior division.
What sensory does V3 supply?
Temporal region, auricular, external auditory canal, cheek, lower lip, lower face, anterior 2/3 of tongue and mucous membranes, Mandibular teeth and periodontal tissues, bone of mandible, TMJ, and parotid gland.
Where does the facial nerve lie with respect to the IA nerve?
The IA nerve is medial and anterior to the facial nerve and the facial nerve travels through the parotid gland.
Where is an IA injection indicated?
Where you need pupal anesthesia of all mandibular teeth to the midline and the lingual soft tissues, ant 2/3 of the tongue, and the buccal soft tissue ant. To the mental foramen.
What are the disadvantages of the IA?
Technical difficulty, variability of anatomic landmarks, variability of innervations of lower first molars, and a relatively high rate of failure (15-20%)
What are the possible complications of the IA?
Intravascular injection into the IA vessels (10-15%) or injection into the parotid capsule resulting in facial nerve paralysis.
What is the major advantage of the IA?
You anesthetize the entire lower arch with one injection.
What can be used as a landmark for the IA?
Pterygomandibular Raphe
Why would you do a long buccal injection?
To anesthetize the buccal soft tissues near the molars, especially if using a rubber dam clamp on a posterior tooth.
What might happen If an IA is too far anterior?
You might anesthetize the lingual nerve instead of the IA, hence anesthesia of the tongue is not a good indicator of IA success.
What if an IA is given too far posteriorly?
You could miss the lingual and IA and enter into the parotid capsule and cause facial paralysis.
What if the IA doesn’t contact bone?
It might be too far medial and miss all the nerves. Some say always contact bone in an IA.
What is the path of the long buccal nerve?
It passes between the heads of the lateral pterygoid to reach the external surface of that muscle then it follows the temporal muscle and emerges under the ant border of the masseter muscle and then at the level of the occlusal plane of the mandibular 3rd molar or second molar and then it crosses in front of the ramus and enters the cheek via the buccinators muscle.
What does the long buccal innervate?
Skin of the cheek and then some fibers pass through the retromolar triangle to innervate the buccal gingival of the mandibular molars and the mucobuccal fold in that area.
Does the long buccal nerve innervate the buccinators or the lower lip?
No. But some doctors wait until the lower lip is numb to administer the long buccal. They should however just administer the long buccal immediately following the IA.
What are the indications for the long buccal nerve?
Buccal soft tissues in mandibular molar region w/out pulpal anesthesia.
What are the two terminal branches of the IA?
The incisive and the mental. The incisive stays in the canal and the mental exits canal via the mental foramen.
What does the mental nerve innervate?
It divides into 3 branches that innervate the skin of the chin and the skin and mucous membrane of the lower lip.
What does the incisive nerve innervate?
The pulpal tissues of the mandibular 1st premolar, canine, and incisors via the dental branches.
When is a mental block indicated?
When you need the buccal soft tissues anesthetized for a biopsy or suturing.
What is the possible disadvantage of a mental block?
A Hematoma.
What is the best way to localize the mental foramen?
Use an xray and locate it with respect to the nearest tooth.
How are the mental and the incisive nerve blocks different in their administration?
With the incisive you use your finger to push the anesthetic into the mental foramen, but otherwise they are the same.
What are the indications for an incisive nerve block?
For dental procedures that require pulpal anesthesia anterior to the mental foramen, where the IA is not indicated. It is preferable to bilateral IA’s
What are the advantages for an incisive nerve block?
You get pulpal anesthesia w/out lingual anesthesia, can be used instead of bilateral IA’s, and they have a high success rate.
What are the disadvantages of incisive nerve blocks?
Lingual tissue must be injected separately if lingual anesthesia is desired. You might get partial anesthesia near the midline as there is some overlap with other side and you would need to do some infiltration.
What area does the Gow Gates injection target?
It provides sensory anesthesia to the entire distribution of V3: the IA, lingual, mylohyoid, mental, incisive, auriculotemporal and the buccal.
When would you use a Gow-Gates injection?
In the event of an unsuccessful IA.
What are the indications for the Gow-Gates?
All of the same indications of as the IA and Long Buccal combined.
What are the advantages of the Gow Gates?
One injection for an entire quadrant, High success rate, minimal aspiration rate, few post injection issues, can be successful in the case of bifid IA canals.
What are the disadvantages of the Gow Gates?
Longer onset 5 mins vs. 3-5 for an IA, experience is needed, lingual and lower lip anesthesia is uncomfortable for patients.
What are some possible complications with the Gow Gates?
Hematoma, Trismus, and temporary paralysis of CN III, IV, and VI
What is the Vazirani-Akinosi Injection?
A closed mouth technique that can be used for patient with limited opening.
What nerves are anesthetized with the Vazirani-Akinosi injection?
IA, Incisive, Mental, Lingual, Mylohyoid.
What are the indication for Vazirani-Akinosi?
Limited opening, Multiple procedures, no visible landmarks for an IA.
What are the complication possibilities for the Vazirani-Akinosi Injection?
Hematoma, Trismus, and transient facial nerve paralysis.
Which mandibular injection is considered to be the backbone of dentistry?
The IA.
What volume of anesthetic is recommended for the IA and Buccal injections?
1.5 ml for the IA and .3 ml for the buccal.
What are the 12 possible complication with LA?
Needle breakage, Paresthesia, Facial nerve paralysis, Trismus, Soft-tissue injury, Hematoma, Pain on injection, Infection, Edema, Sloughing of tissues, and postathesthetic intraoral lesions.
Which needle is usually involved in breakages?
30ga shorts, many bent before insertion or inserted to hub.
What can you do to prevent needle breaks?
Don’t bend needle, use smaller gauges, don’t insert to hub and don’t redirect once inside the tissues.
What should you do in case of a needle break?
Grab with hemostat if visible or else contact OMS, stay calm, and document everything, have patient stay still.
What is parasthesia?
Persistent anesthesia, or altered sensation beyond the expected duration.
What can cause parasthesia?
4 % solutions, hemorrhage around nerve sheath, trauma to nerve sheath, and any trauma (injections, implants, third molars)
How do you manage parasthesia?
Personally, reassure likely temporary, appoint and examine patient and chart findings, Inform that it might last 2 months, OMS referral, and change anesthetic and limit anesthetic in that area.
What should you do in the case of facial nerve paralysis?
Reassure it is transient, remove contact lenses, record in chart, and forego tx for the day.
What is trismus?
Restricted jaw movements due to intramuscular injection, hemorrhage, infection, usually an IA or PSA
What do you do for Trismus?
Heat therapy, NSAIDs, warm salt rinse, Benzodiasepines, Movements, consider infection, and contact OMS if longer than 7 days.
What causes a hematoma?
Nicking a vessel during injection, usually during a PSA or IA.
What can a hematoma lead to?
Trismus, pain, and a dead zone prone to infection.
What should you do for a hematoma?
Direct pressure to medial ramus for IA or at mucobuccal fold for PSA, no heat for 4-6 hours. May need antibiotics…especially if diabetic.
How can you mitigate pain on injection?
Use sharp needles, topical, psychosedations, inject slowly.
Can you get an infection from an injection?
Yes, It is rare now, but usually comes from contaminated need as it rests on the glove or penetrates a dirty diaphragm.
What causes sloughing of the tissues?
Prolonged irritation or ischemia of gingival tissues, epithelial desquamation, or strerile abscess (secondary to ischemia due to vasoconstrictor), Usually hard palate.
What are some common post anesthetic intraoral lesions?
Aphthous ulcers, Herpes simplex,
What are some systemic complication with LA?
Adverse drug reactions, Toxic reactions, allergic reactions, drug related reactions and phychogenic reactions.
How common are systemic complication with LA?
2.5 % show complications
What are the most common systemic complications?
Dizziness, tachycardia, agitation, nausea, and tremor. Very rare were serious complications like seizures and bronchospasms.
What is the most common type of adverse reactions for LA?
Anxiety induced issues like syncope and hyperventilation.
What does drug toxicity depend on?
Systemic absorption. The faster gets in the blood stream, the greater potential for toxicity.
What reactions are common to both the LA toxicity and the vasoconstrictor toxicity?
Headache, Anxiety, Diaphoresis, and tachypnea.
Are people ever allergic to Epi?
No. as this is naturally produced in their bodies, but they are probably allergic to the preservative for the Epi which is sodium bisulfate.
What is type one allergy?
Anaphylactic via IgE (insects or hay fever)
What is type two allergy?
Cytotoxic via IgG and IgM (transfusion reactions, autoimmune hemolysis)
What is type three allergy?
Immume complex via IgG (Lupus)
What is type four allergy?
Cell mediated or tuberculin type (contact dermatitis, graft rejection)
What should you do in the case of anaphylaxis?
It is life threatening, use Epi pen as soon as possible, life support, Oxygen, Airway management.
What should you do in the case of vasovagal syncope?
Put patient in supine postion and restore the flow patterns to the brain. (Trendelenburg position) It can be fatal if blood flow is not restored. Maintain airways, verbal stimulation, monitor vitals, smelling salts.
Why might Articaine be contraindicated?
It used to be contraindicated due to sulfa allergies, but recent studies show otherwise.
What are 3 supplemental injection techniques?
PDL injections, intraosseaous injections, and intrapulpal injections.
What are the possible complication for a PDL injections?
Mild pain, Edema and bite sensitivity, ischemia to interseptal tissues and pulp and enamel hypoplasia to developing tooth bud if used on primary teeth.
Where is the intraosseos injection administered?
Directly into the bone between two teeth
What are the possible complications of an intraosseous injecdtion?
Quick systemic uptake, vasoconstrictors can cause palpitations, perforation into tooth roots.
What is the intrapulpal injection?
Injection directly into exposed pulp of tooth to aid in pulp extraction.
What is the goal of endodontics?
Attempt to save a tooth with an otherwise hopeless prognosis by extirpating the infected pulpal tissue.
How might endo problems affect LA?
Decreased tissue pH or you might find that some mand molars get innervations from the n. to the mylohyoid.
What are some major concerns with LA and pediatric dentistry?
Local anesthetic overdose, accidental trauma (cheek biting).
What are some anatomical differences in kids vs. adults?
Cortical bone is less dense and the ramus is shorter so the mandibular foramen is at the occlusal plane. You don’t need PSA for kids just infiltrations on maxillary and infiltration will work most of the time for mandibulars as well.
How deep do you go in an IA on a child?
15mm vs. 25 for an adult.
What is the major consideration with LA in perio patients?
Unhealthy tissues bleed so you need hemostatis via vasoconstrictors.
What are the LA considerations for OMS?
Lots of pain control needed in broad areas, hemostasis always needed, easy to overdose so Volume is the issue. Regional blocks used.
What does OraVerse do?
It accelerates the rate of redistribution of LA from submucosa into CV system…it reverses the effects of vasoconstrictors.
What are the legal considerations for LA?
Consent.
What are some LA products that can be used for SRP?
Lidocaine and Prilocaine gels delivered into sulcus of the facial aspect.
What emergency poses the greatest risk to pts and concern the dentist the most?
Immediate or anaphylactic reactions
What can cause anaphylactic reactions?
Most frequently result from drug administration or reaction to an allergen in impression material or other materials used in the oral cavity
What are the signs and symptoms of anaphylaxis/allergy?
Urticaria (itching, flushing, hives), rash, rhinitis, bronchospasm, laryngeal edema, weak pulse – syncope, loss of consciousness, cardiac arrest
Hat is the treatment for anaphylaxis/allergy?
BLS, Epi (.3 to.5ml of 1:100000 IM, repeat if no response), Oxygen, Diphenhydramine (50mg IM), Corticosteroid, CPR, Airway management (intubation or cricothyrotomy
What is the most common cause of LA toxicity?
Rapid intravascular injection
How quickly do reactions to LA occur?
Quickly 30-60 sec or slowly 1hr after injection
What signs do LA toxicity and vasoconstrictor toxicity have in common?
Headache, anxiety, Diaphoresis, tachypnea
How should anesthesia reactions be treated?
BLS, airway/breathing/circulation, give O2, for severe reaction pt should be transported to the ER ASAP
How should a ACLS trained doc treat anesthesia reactions?
Start IV fluid, support Blood pressure with vasopressors, treat arrhythmias, treat allergic reaction with diphenhydramine and/or Epi, titrate diazepam to effect if there is persistent seizure activity, transport pt to the ER ASAP
What is hypoglycemia?
A life threatening condition that is more critical than hyperglycemia in an emergency situation that must be treated rapidly
How is hypoglycemia treated?
Administration of glucose even if definitive diagnosis is not made, glucose given in hyperglycemic crisis will not significantly affect the pt (hypo or hyper give glucose)
What are the signs and symptoms of hypoglycemia?
hunger, nausea, cool moist skin, shallow respirations, Irritation, Confusion, and Bizarre behavior
What should you to in the event that a pt has a hypoglycemic emergency?
Terminate procedure and administer glucose (oral or IV - 5% D5W), perform BLS, transport to hospital
What is syncope?
Transitory and sudden loss of consciousness following a period of cerebral ischemia
Is syncope life threatening?
No usually benign however if the flow patterns to the brain are not restored life threatening cardiovascular and pulomonary effects can occur
What are predisposing factors that can lead to syncope?
Fright, pain, emotional stress, anxiety, hunger, sudden postural changes and exhaustion
What is the most common emergency in the dental office?
Syncope 90% of emergencies
What are early signs of syncope?
Loss of color/ pallor, perspiration, nausea, increased heart rate, feeling of warmth
What are late signs of syncope?
Yawning, dilated pupils, cold extremities, hypotension, dizziness, loss of consciousness
How do you treat syncope?
Put pt in the trendelenburg position, maintain open airway, verbal/physical stimulation, 02, ammonia inhalant (optional), and monitor vital signs
What is angina pectoris?
Chest pain caused by temporary myocardial ischemia without damage to the heart muscle
What is the ischemia that causes angina pectoris caused by?
Narrowed coronary arteries the inhibit proper blood supply to the myocardium so O2 demands are not being met in times of stress
What causes narrowing of the arteries?
Atherosclerotic vessel disease, coronary artery vasospasm or a combination of both entities
What are the signs of angina pectoris?
Chest pain brought on by myocardial stress (left center or center of chest in location) chest fullness, burning, tightness, pain can radiate to neck left arm jaw back shoulder and epigastrium, weakness dyspnea, nausea, diaphoresis, pain can last up to 20 min. if prolonged pt should be evaluated
What is the treatment for angina pectoris?
Avoid situations that cause it, stop procedure and allow pt to rest, monitor vital signs repeatedly, place pt in semireclined position, provide O2, administer aspirin 650 mg, administer sublingual nitroglycerin (.4mg) every 5 minutes for three doses – if symptoms are not relieved assume MI
When does an MI occur?
When ischemia is prolonged and myocardium is irreversibly damaged
What are the signs of MI?
chest pain (crushing, radiating to neck, jaw arm and back, substernal), hypertension or sypotension, indigestion, diaphoresis, shortness of breath, tachycardia or bradycardia, dysrhythmisa, and loss of or alteration in consciousness
How should you treat a MI?
do everything you would for angina and if the pt doesn’t respond assume MI and notify EMS,prepare for transport and transport pt to hospital ASAP
What are the three major causes of stroke?
Arterial thrombosis, embolism, hemorrhage of the vasculature
What are the signs and symptoms of stroke?
Headache, confusion, vertigo, nausea/ vomiting, change in mental status, alteration in consciousness, alteration in vision, alteration in speech, extremity weakness, facial weakness, hypertension
How do you treat a stroke?
Pt in supine position with head slightly elevated, assess and monitor vitals, initiate BLS as indicated, give O2 if needed, transport pt to nearest hospital
What is sudden cardiac arrest?
Condition in which heart stops abruptly, usually caused by ventricular fibrillation. Not the same as a heart attack. Has no warnings and is unpredictable results in death if not treated immediately
What is the difference between heart attack and sudden cardiac arrest?
Heart attack is when blood flow is blocked causing damage and victim usually remains conscious SCA the victim always loses consciousness and is caused by abnormality in heart’s electrical system
What is the ideal treatment for SCA?
Early CPR Early defibrillation
Why is early defibrillation so important?
Chances of success decrease 7-10% each minute
What is the Epi dosage for each age group?
Adults .5ml, teenagers .4ml, kids .3ml, babies .2ml
What are the advantages and disadvantages of epipens?
Advantages – quick (given in thigh through cloths) and safe dosage. Disadvantages – only one dose, quick expiration, price
Where are crash carts and AEDs located in clinic?
In emergency and between teams 2 and 3, and 1 and 4
Who decides when to activate the emergency medical system?
The responding faculty member