Test 2 Flashcards
What do vasoconstrictors oppose in local anesthetics?
Oppose rapid uptake
Specific protein receptor theory
The binding of local anesthetic molecules to structural proteins known as specific protein receptor sites. Temporarily transform nerve membranes to nonexcitability.
2 primary routes of delivery
Topical
Submucosal injection
Topical route of delivery
Effective on mucosa due to ease of penetration through mucosal barriers
Submucosal injections route of delivery
Allows for direct placement of drug close to nerves
Desirable properties of local anesthetics (3)
Biocompatibility, safety and efficacy, and pKa and pH.
Biocompatibility
Nonirritable, nontoxic to tissues, nonallergenic, biotransformable, completely reversible, no systemic effects
Safety and efficacy
Effective in tissues and mucous membranes, rapid onsets and no residual effects, therapeutic durations, adequate potency, sterilizable, patient remains conscious.
pKa and pH
Relevance of pKa (the dissociation constant) and pH. When pKa=pH, there is an equal distribution of cations and unchanged base molecules in solution
Clinical application of pKa
Local anesthetics have pKa range from 7.7-8.1. Determine onset of local anesthetics
Primary benefit of local anesthetic
Suppression of pain sensations without significant central nervous system depression. Allows for the majority of dental procedures to be performed under local anesthesia without exposing patients to the risks of general anesthesia
Biotransformation
Metabolism of local anesthetic drugs, reduces or eliminates their toxicity. Breaks down the drug into its components called metabolites. Process occurs primarily through one of two pathways, the liver or in the blood.
Liver pathway
Hepatic p450 isoenzyme system
Metabolism in the blood is by what?
Pseudocholinesterase
What is an enzyme responsible for
Breaking down esters
Biotransformation of amides
Amides are bupivscaine, lidocaie, and mepivacaine.
In the liver by hepatic p450 isoenzymic system. In addition to the liver, prilocaine is biotransformed in the kidneys and lungs with very little excreted unchanged
Biotransformation of esters
Esters include benzo cane, procaine, tetracaine. Biotransformed in the blood by pseudochlorinesterase
Elimination half-life
The rate at which a drug is removed from the system execution. The time necessary to metabolize and secrete 50% of a drug. Shorter half-life drugs may be readministered sooner with less risk of overdose. Consideration should be made with nursing mothers. Articaine has the shortest half-life of all amides
Shortest to longest half-life of amides
Articaine equals .75 hours. Prilocaine equals 1.6 hours. Lidocaine equals 1.6 hours. Mepivacaine equals 1.9 hours Bupivicaine equals 3.5 hours
Nasopalatine landmark
Incisive foramen
Risks for nasopalatine
Minimal risk. Post op pain injection. Hematoma rarely. Postop edema
Indication for nasopalatine
Palatal soft and osseous tissue in the anterior third of the palate: canine to canine
Landmarks for palatal anterior superior alveolar
Nasal Palantine canal in the incisive papilla
Risks for the palatal anterior superior alveolar
Risk is minimal. Postop pain injection site. Hematoma rarely. Post op edema. Risk of necrosis with use of epi-
Indications for palatal anterior superior Alveolar nerve
Pain management of the maxillary anterior sextons in is especially useful in cosmetic procedures that involve smile lines
Landmarks for the anterior middle superior alveolar nerve block
Between the premolars. Junction between the vertical Alveolar process and horizontal palatal process
Risks for the anterior middle superior alveolar
Risk is minimal. Some patients experience a burning at site of injection. Postop pain at injection site. Hematoma rarely. Postop edema. Risk of the necrosis increases with the use of epi-
Indication of anesthesia for the anterior middle superior alveolar
Pain management of the incisors, canine, and premolars on the anesthetized side as well as palatal tissue from the midline through the molars in the buccal periodontium of the pulpally affected teeth
Landmarks for a greater palatine
Greater palatine formation is found palatal to the apices of the second and third maxillary molars
Risks for greater Palantine
Post procedural heretic lesions are more common in palatal injections. Caution with epi to prevent palatal necrosis. Hematoma rarely. Post op edema
Indications for greater Palatine
Pain management of the palatal soft in osseous tissues distal to the canine in one quadrant
Landmarks for that inferior alveolar
Pterygomandibular raphae. Coronoid not on the anterior border of the Ramis of the mandible. Internal oblique Ridge on the medial surface of the molars and continuing posteriorly.
Risks for the inferior alveolar
Trismus: post injection soreness or limitation. Paresthesia: nerve injury/prolong anesthesia. Post operative soft tissue injury – biting of lip, cheek or tongue
What injection has the highest failure rates in dentistry
Inferior alveolar. This is due to anatomical variations, need for deeper penetration, depositing too far from foramen and accessory innervation from other nerves
What are alternative injections for the inferior alveolar
Gow gates, vazirani-akinosi, intraosseous injections including periodontal ligament.
Landmarks for lingual nerve block
Same as inferior alveolar- Pterygomandibular Rafe, coronoid not on the anterior border of the ramus of the mandible, internal oblique ridge of the medial surface of the mandible
Risks for the lingual nerve block
Lingual nerve is one of the most frequent injured nerves during dental injections. Symptoms range from transient “electric shock” to permanent paresthesia
Alternative injections for lingual nerve block
GG nerve block. Multiple infiltrations
Landmarks for buccal nerve block
Buccal fold just distal and buccal to the most posterior roller for which soft tissue anesthesia is required.
Risks for buckle nerve block
Rare: bleeding and hematoma
Alternative injections for buckle nerve block
Rarely needed. Multiple infiltrations
Key landmarks for mental/incisive nerve block
Depth of mucobuccal fold superior to mental foramen. Or just anterior to the mental foramen. Berries with location of the mental foramen: locate the foramen prior to penetration and use radiographs or your finger
Risks for mental/incisive nerve block
Bleeding, hematoma, postoperative discomfort
Alternative injections for mental/incisive nerve block
Multiple infiltrations
Landmarks for incisive nerve block
Same as mental nerve block: depth of mucobuccal fold superior to foramen. Or just anterior to the mental foramen
Risks for incisive nerve block
Bleeding, hematoma, postoperative discomfort
Alternative injections for incisive nerve block
Multiple infiltrations
Risks for Gow gates
Injection into temporomandibular joint or optic ganglion. Temporary paralysis of cranial nerves – three, four, and five. Hematoma
This is a true mandibular block
PDL indications
Used when other injections have failed. When widespread anesthesia is contra indicated. For patients with bleeding disorders in highly vascular areas.
PDL technique
Enter the Saugus then penetrate the junctional epithelium. Advanced within the PDL to a point of resistance. Look for blanching in the attached gingiva of the tooth. Can bend the needle in the middle to gain access to the area you want to numb
Intra septal injection
Provides anesthesia to the periodontium lingual to a tooth. Inject through the soft tissue until the bone is contacted
Intra pulpal
Used when the pulp is inflamed. Non-intraosseous. Penetrate directly into vital pulpal tissues
Administration related factors
Device related factors. Needle bevel considerations- orientation recommendations. Needle deflection consideration- gauge of needle. Quality of cartridge contents – damage to solutions during shipping and handling. Clinical judgment – adequate volumes of solution
Volume considerations for troubleshooting in adequate anesthesia
Volume must be adequate to flood targeted neural membranes. This must be according: anatomy, individual responses – previous history of responses to anesthetic, Length of anticipated treatment
Physiological barriers for troubleshooting in adequate anesthesia
Phobias of needles, fear of insufficient anesthesia, hating the feeling of being numb
Physical barriers for troubleshooting in adequate anesthesia
Bony prominences, shallow vestibules, die lacerations, small foramens
Chemical barriers for troubleshooting inadequate anesthesia
Inflammation, infection, vascular injury
Tachyphylaxis
Refers to the failure of subsequent administrations of local anesthetic – in the same appointment – to prolong the duration, extent, and intensity of the anesthetic effect. Causes can be tissue edema, localized hemorrhaging, decreases in tissue pH, clot formation
Accessory (expected) innervations
Typical, and expected, deviations
Aberrant (unexpected) innervations
Unexpected variations, highly unusual. Majority of abarrant innervation failures can be addressed with PDL injections
Atypical innervation for posterior superior Alveolar block
PSA injection may require greater Palatine block or a PDL as a supplement
Atypical innervation for middle Superior alveolar block
MSA nerves are missing in a significant percentage of the population. Clinicians can infiltrate as needed
Atypical innervation for anterior superior alveolar block
Crossing novation from the contralateral side ASA nerve. Phone in the anterior maxilla is unusually dense. The vestibule has little vertical height. Maxilla has an exaggerated curvature over the roots of the teeth
Atypical innervation for palatal innervations of maxillary central incisors
May need supplemental injections with nasal Palantine nerve or a PDL injection
Atypical innervation for inferior alveolar nerve block
IA Nerve block has a relatively high incidence of in adequate anesthesia. Can pause assessor he innervation from: mylohyoid nerves – incidence of 60% –, buckle nerves, lingual nerve, contralateral incisive and mental nerves, sensory fibers traveling with motor fibers, bifid IA nerves, branches from the cervical plexus – to the anterior teeth –
Atypical innervation of intravascular injection
Intravascular injections take solution away from the target site and distributed throughout the body
Atypical innervation for inflammation
Performing nerve blocks away from the side of information can help. Local anesthetic drugs are package primarily in cationic form; as they diffuse through healthy tissue with pH values near 7.4
Local complications
Occur more frequently then systemic complications. These include: postoperative soreness, prolong anesthesia, soreness at area of injection, syncope, pain from self injury, mild inflammation following muscle penetrations
Systemic complications
(Toxicity) occur less frequently but are generally more serious. These include: overdose – peripheral nerve blocks; associated with the highs incident of systemic toxicity-, allergy, idiosyncratic response.
Hematoma
Form when a blood vessel get snipped during injections and blood leaks into the surrounding tissue. Development can be rapid and dramatic. Most common site is the PSA – close proximity to the pterygoid Plexes –. Avoid by aspirating, keeping needle straight, minimizing needle penetrations, avoiding moving needle around in the tissue. Discontinue treatment, apply pressure and ice. Tell patient to avoid aspirin, advised patient of what to expect
What does trismus include
Motor disturbance of the trigeminal nerve. Most frequently occurs in the medial pterygoid muscle, followed by the lateral pterygoid and the temporalis. Causes include: tetanus (lock jaw), tumors, bony ankyloses, foreign bodies, fracture, fascial space infections, in large coronoid processes, hemorrhage and muscle trauma following injection, drama to need a movement,
Prevention of trismus
Minimize the number of needle penetrations, change needles frequently, I sure needle contamination does not occur. THIS IS MOST IMPORTANT TO MINIMIZE CONTACT WITH A STERILE NEEDLE
Management of trismus
Apply hot, moist towels for 20 minutes every five hours – five minutes on, 10 minutes off –, use analgesics as needed, Open/close mouth gradually/repeatedly, monitor for signs of infection, if signs/symptoms worsen, contact oral surgeon or position
Causes a needle fracture
Use proper gauge and link needles to avoid broken needles
Causes include: unexpected movements, too small of lumen, bending needles at the hub, inserting needle too far, faulty needles, excessive force and repositioning, excessive numbers of penetrations with the same needle
Management a needle fracture
Have sterile hemostat/forceps nearby, do not allow patient to close mouth, if needle is visible, remove with hemostat, if needle isn’t visible: inform patient, IMMEDIATELY referred to oral surgeon, keep detailed records – location, size, patient communication log –
Self injury
Inform patient and/or caregivers of risk of self injury following anesthesia
Injuries include: tongue, lips, cheek biting. Burning of mouth via food/drinks.
Management of self injury
Palliative therapy; such as over-the-counter preparations for protection of oral sores and pain relief
OraVerse
Agent that can help reverse- of soft tissue – anesthesia
Where does paresthesia most frequently occur
In the lingual nerve
Paresthesia
And altered sensation and/or persistent partial or complete numbness. Has the potential to affect taste if the chorda tympani is involved.
Hyperesthesia
Increased sensitivity to stimuli following nerve injury
Dysesrhesia
Sensation of pain from non-noxious stimuli that may follow local anesthetic procedures
Ageusia
Absolute loss of ability to perceive sweet, sour, bitter or solid substances due to chorda tympani injury
Hypogeusia
Relative loss
Possible causes a paresthesia
Direct trauma from surgery or needle, drug-induced=neurotoxicity, detergent effects of drugs, pressure from localized Adema, hire a local anesthetic drug concentrations, that’s vascoconstrictor and their preservatives
Prevention of Paresthesia
Slow disposition, reduce volumes for 4% drugs by 50%, for articaine, use high block techniques, in pallet, limit volume to
Paresthesia response/management
Speak with the patient personally, reassure the patient, schedule to evaluate the patient as soon as possible, document the conversation, determine and record the extent in degree, diagram field of altered sensation,
Allergy
A major difference between overdose and allergy is that allergies are not dose-dependent. Can be local or systemic reactions, systemic allergy reactions can be life-threatening, can be an allergy to and amide or the sulfite preservative in the vasoconstrictor.
Localized allergy reactions
Most frequent after topical anesthesia contact, usually limited to, respond well to antihistamines, majority of contact allergies due to the metabolic byproduct of esters
How to respond to allergy
Rapid recognition and response. Removal of remaining traces of topical drugs
Prevention of allergy
Avoid: medications that have induced allergy in the past, same – glass topicals that produced hypersensitivities, consult with previous providers whenever patient reports past allergic experiences, referred for allergy testing to confirm reports, document in the chart
Management of delayed reactions to allergies
Schedule ASAP to evaluate post operative allergic lesion/reactions, recommend over-the-counter Benadryl or prescribe diphenhydramine as appropriate
Systemic allergic reaction
Less frequent than local, yet far more serious. May occur due to: local anesthetic drugs themselves, sulfite preservatives with vasoconstrictors, even after, to the byproduct of hydrolysis
Symptoms of systemic reactions
Skin reactions, G.I./GU reactions, respiratory, CVS,
Management of systemic reactions
Administer oxygen, administer epinephrine: adult .3 mg intramuscularly or subcutaneously, child .15 mg. administer diphenhydramine: adult 50 mg intramuscularly or subcutaneously, child 25 mg
Fear
An emotional response to immediate threat or danger; that’s that something bad might happen; heart rate increases, sweating, hyperventilation, nausea; shaking, pacing, rapid speech
Anxiety
An emotional response to a threat or danger that is not immediately present or is unclear; can occur hours or days before the appointment
Phobia
Persistent, irrational fear of a specific object or situation that results in a compelling desire to either avoid the situation or two endured with dread; phobias interfere with the person’s ability to function; interfere with oral health, resulting in pain
Behavioral overt signs for phobia
Pacing the waiting room, visiting, ringing hands, gripping the arms of chairs
Physiological signs of phobias
Perspiration, changes in respiration, shallow breathing, increased heart rate, increased blood pressure
Three concepts to consider when treating fearful patients
- The patient clinician relationship. 2. The patient sense of control over a potentially threatening environment. 3. The patient’s ability to cope with a stressful situation
Informational control
Emphasis on the sensations that the patient will experience, the steps involved, and time expected for treatment
Behavioral control
Allows patients to take actions to lesson, shortening, or terminate stressful situations; example: raise left-hand during procedure
Cognitive control
Mental maneuvers through which patients can lessen their Feafel, negative thoughts in their reactions to these thoughts; distraction strategies of listening to music or watching TV
pKa
Dissociation constant
