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