ORAL SURGERY Flashcards
Which of the following is false?
A) LA enters the cell in dissosciated form
B) Higher pkA decreases onset time
C) Duration of LA most depending on protein binding
D) The potency of LA dependent on lipid solubility
B) Higher pkA decreases dissosciation = Slower onset
Explain the duration of action, dose and contraindications/side effects for:
- Lignocaine
- Articaine
- Prilocaine
Lignocaine: 2% 1:80,000 adrenaline
- Dose: 7mg/kg with adrenaline or 4mg/kg without
- Duration of action: Half life approx 1.5hrs
- Side effects: Minimal, careful in renally impaired patients
Articaine: 4% 1:100,000 adrenaline
- Dose: 7mg/kg with adrenaline or 4mg/kg without
- Duration of action: Half life approx 1.5hrs
- Side effects: Contrainidcated for pregnant or breastfeeding women
Prilocaine: 3% felypressin
- Dose: 9mg/kg with felypressin or 4mg/kg without
- Duration of action: Half life approx 1.5hrs
- Side effects: Methaemoglobinaemia (highest risk out of all LA)
Which of the following is most correct regarding amide metabolism and excretion?
A) Amides are primarily metabolised in plasma by cholinesterase and excreted in kidney
B) Prilocaine is the exception and is metabolised by tissue and plasma cholinesterase
C) Amides are primarily metabolised in liver and excreted by kidneys
D) Articaine is additionally metabolised in lungs
C)
Explain the components and onset of action of xylocaine cream and EMLA
Xylocaine - 5% lignocaine, onset rapid 3-5mins, does NOT work on intact skin, mucosa only
EMLA - 2.5% lignocaine and 2.5% prilocaine, onset slow 1hr, DOES work on intact skin
Which of the following is false?
A) Treatment should be refused for patient with coronary artery disease
B) Adrenaline may be used as a bronchodilator for asthmatic patient
C) Prilocaine is the choice of LA for patients taking TCA and SNRI
D) Plain LA should be used for patients with hyperthyroidism
A)
You are preparing an extraction of 36 for a patient. Which of the following is most appropriate for LA delivery?
A) Buccal infiltration of 36
B) IAN block for Q3
C) IAN block for Q3 and long buccal nerve block
B) IAN block for Q3 and lingual infiltration of 36
C)
What are the causes of trismus and how can this be minimised?
Causes of trismus:
• Trauma to muscles or blood vessels by needle (ie. Multiple injections)
• Haemorrhage: large volumes of blood slowly resorbed to produce tissue irritation
• Needle tract infection
• LA tainted with alcohol/chlordhexidine
• Excessive volumes of LA deposited into restricted area
Prevention: • Use sharp needles • Aseptic technique • Avoid repeat injections in same area • Use minimum effective volumes of LA
Which of the following is incorrect regarding management of complications with LA?
A) Inadvertent LA spread - reassure patient situation is transient and keep cornea lubricated if facial nerve anaesthesia has occurred
B) Slow onset of anaesthesia - Increase concentration of LA deposited
C) Trismus - Apply heat therapy, warm saline rinse and NSAIDS, review patient
D) Haematoma - Apply firm pressure and icepacks, avoid heat for several hours
B) Increasing volume deposited is recommended rather than increasing concentration (if otherwise injected correctly)
Why might pain or burning occur at injection site?
- Blunt needle
- Injection into inflamed tissues
- > 25G needle (especially for palate)
- Injecting too quickly
- Injecting under too much pressure
- Cold LA solution
- Expired LA (long shelf life → acidified)
You are extracting tooth 42. Which forceps should be used? A) No. 2 B) No. 19 C) No. 74 D) No. 107
C)
You are extracting tooth 15. Which forceps should be used? A) No. 95 B) No. 76 C) No. 29 D) No. 74
B)
What is the three criteria that defines MRONJ?
- Current or previous treatment with anti-resorptive or anti-angiogenic agents
- Exposed bone or bone that can be probed through an intra-oral or extra-oral fistula(e) in the maxillofacial region that has persisted for more than eight weeks
- No history of radiation therapy to the jaws or obvious metastatic disease to the jaws
List 3 factors that place a patient at high risk of MRONJ?
o Previous diagnosis of MRONJ
o Treated with antiresorptive/antiangiogenic drugs for management of cancer
o Currently or previously taking a bisphosphonate for > 5 years
o Concurrent treatment with systemic glucocorticoid
You are extracting tooth 33 on a patient. The patient has advised you that they are on an anticoagulant. Which of the following is correct management?
A) If the patient is on warfarin, this should be stopped prior to the appointment.
B) NSAIDs are choice of analgesic for patients on antiplatelets.
C) Dabigatran morning dose should be delayed.
D) Patient can continue to take their rivaroxaban dose.
D)
A) Acceptable INR = 4 for simple surgery
B) NSAIDS can increase risk of bleeding in patients on antiplatelets
C) Simple surgery dose not require any changes to NOAC medication
Explain the four stages of healing.
- Haemostasis
Vasoconstriction in the first 10mins
Platelet aggregation, degranulation and fibrin formation - Inflammation → 10mins – 3 days (Peak ~ 2 days)
Cytokines
Capillary vasodilation – redness, swelling and pain
WBC infiltration
Neutrophil infiltration
Monocyte infiltration and differentiation to macrophage
Lymphocyte infiltration
3. Proliferation → Up to 3 weeks Re-epithelisation Angiogenesis Proliferation of granulation tissue Collagen synthesis ECM formation
- Remodelling/Maturation → 3 weeks – 2 years
Collagen remodelling = Physical contraction of wound
Vascular maturation and regression
Scar tissue formation
What are the four principles of wound management?
- Remove debris
- Reduce bone and sharp edges
- Achieve haemostasis
- Reposition and stabilise tissues
Which of the following is false in management of medical emergency?
A) Vasovagal syncope - Place patient in a supine position
B) Asthma attack - Administer 2-4 puffs of bronchodilator and administer oxygen/adrenaline if possible
C) Hypoglycaemia - Provide a long-acting glucose, check BGL after 5 minutes and provide fast-acting glucose
D) Epileptic seizure - Remove danger source, allow patient have seizure and call 000
C) Provide fast acting and then long acting glucose source
Which of the following is correct
A. The intermediate chain of the LA molecule differentiates the anaesthetic as either an amide or ester
B. Local anaesthetics in natural form are acidic
C. pKa of LA determines its potency
D. The aromatic ring of the LA molecule is hydrophilic
A is correct
B - they are naturally weak bases, they require acidification via HCl to form salts - which are stable and hydrophilic
C. pKa determines the onset of action, lipid solubility determines potency
D. The aromatic ring is lipophilic
Explain why local anaesthetic is not as effective in inflamed tissue on a chemical level
Inflamed tissue has a lower pH than normal tissue and so the LA exists more in a cationic form –> the cationic form is less able to permeate the cellular membranes and take effect
Which component of anaesthetic is the only associated cause of allergic reactions
The antioxidant sodium metabisulfite, a stabiliser preventing oxidation of adrenaline. This may cause a reaction in patients who have sulfite allergies. Uncommon.
LA and/or adrenaline alone do not cause allergic reactions
You are going to extract a 11, you will be placing infilrations to anaesthetise the area.
Which nerves are you aiming to anaesthetise
Anterior Superior Alveolar nerve (from CNV2) and the Nasopalatine nerve (from CNV1)
At what BP level should you refuse tx, and at what level do you rest the patient for 5 mins and then re-take BP?
refuse tx - 180/110
rest & review 160/100
Which of the following is incorrect?
A. If 5 cartridges of vasoconstrictor-cointaining LA is given to a patient on B-blockers, there could be a dangerous increase in BP
B. People with recent bypass or MI <60 days should postpone elective tx
C. A patient with a BGL level of 10 should be referred to their GP
D. A patient with well-managed hyperthyroidism can have the normal concentration of vasocontrictors
C. BGL 15+ should be reffered to a GP.
You have an 4 year old child who needs anaesthetic. The child weighs 17kg, and has NIL medical conditions or medications.
Which anaesthetic do you choose and what is the upper limit
2% Lignocaine w/ 1:80,000 adrenaline
(Articaine is not safe to use in children <4yrs)
Lignocaine max dose 7mg/kg
17kg –> 119mg
2% lignocaine = 20mg/ml
119mg/20mg/ml = 5.95ml
Dental cartridges are 2.2ml –> Max dose is 2.7 cartridges
If you have given an IANB, where is the potential of inadvertant spread and which additional structures could this anaesthetise
Infratermporal Fossa –> auriculotemporal nerve and long buccal nerve
Parotid Gland –> facial nerve
Which of the following is correct
A. A Couplands elevator is a curved elevator used in a wedging/turning motion
B. A Cryer is a curved elevator with a left and right version, designed for maxillary 3rd molars
C. Warwick-James elevators are straight elevators that can generate a lot of force
D. Root picks are not known for having the tips break
B
A. Couplands are straight elevators
C. Warwick-James can be straight or curved but they are delicate instruments, only used in a turning action –> not for great force or wedging actions
D. Tips can break off the root pick –> care must be taken in their use
You are a right handed dentist about to extract a tooth from Q4, where should you be standing
Standing behind the patient
Q1, 2 & 3, you should be in front of the patient
What are the three stages in the technique of tooth removal
Primary/Apical Drive –> wedging effect to break PDL and lift tooth in its socket
Secondary Movement –> slow directed rotation (anteriors) and bucco-lingual (posteriors) movements with apical force to loosen the tooth
Tertiary Movement –> final delivery
Define the following;
Healing by;
- primary intention
- secondary intention
- tertiary intention
Primary - epithelial cells of two wound edges make direct contact e.g. sutured wound, to reduce granulation tissue and therefore scar tissue
Secondary - migrating cells make a connection after a period of time, through granulation tissue or not. Increased chances of scarring
Teritary - wound left open on purpose
List 4 local measures of haemostasis
Pressure Clot stabilising agents - e.g. gelatemp, gelfoam, spongostan Sutures Adrenaline Bone Wax - used as a last resort Tranexamic Acid
What are the symptoms of an oro-antral fistula
- fluid in nose when drinking
- food in nose
- fluid travelling down into mouth
- foul taste
- air bubbles from a hole/depression in soft tissue when performing the valsalva moanoeuvre (patient holds nose and gently breathes out)
What are 4 risk factors of alveolar osteitis
Mandible
Female
Smoker
Hx of alveolar osteitis
Which of the following is the correct management protocol for an angina/MI incident
A. follow DRSABC, administer oxygen, administer 400mcg glyceryl trinitrate
B. follow DRSABC, Check BP, administer oxygen, administer 300mcg adrenaline
C. follow DRSABC, administer oxygen, administer 300-550mg aspirin, IF symptoms persist administer 400mcg glyceryl trinitrate sublingually
D. follow DRSABC and continue CPR until ambulance arrives
C
A. should administer aspirin prior to trinitrate
B. checking BP is unecessary, adrenaline is given in anaphylaxis not CV emergencies
D. this is the protocol for a stroke
How would you treat a dry socket (alveolar osteitis)?
- Saline irrigation to remove food particles
- Mechanical removal of necrotic debris/bone
- Mechanical debridement of socket to stimulate bleeding
- Potentially placing antiseptic dressing in the socket (alvogyl) - suture if placing dressing
- Review patient in 48-72hrs
