Long Qs Flashcards
Describe the positioning and structure of nociceptors and explain how nociceptors (chemical) are activated in response to an injury.
- Nociceptors are found in the periphery as simple free nerve endings. They are peripheral nerve fibre branches which terminate as naked, unmyelinated endings in the dermis. They are there to sense any damage or change in the external environment.
- When the skin is damaged there is inflammation which triggers the release of prostaglandins, bradykinin and histamine that sensitize peripheral nociceptors and induce hyperalgesia.
Types of nociceptors:
- Mechanical – Respond to strong pressure (work due to stretch activated ion channels).
- Thermal – Respond to burning heat/extreme cold (tells you when temp. is too hot when you get burning sensations from putting your hand over a burning kettle for example). We have separate receptors to let us know it normal temperature; these are to alert us of extreme (damaging) temperatures. They also work due to a hydrogen channel system.
- Chemical – Respond to histamine or other chemicals as listed above
Describe the route of nociceptors from the teeth.
- The primary efferent travels caudally in the spino trigeminal tract
- to the brain stem
- they synapse with second order neurons (sensory in pars caudalis).
- Axons then ascend contralaterally to the thalamus
- in the trigeminothalamic tract
- project into the cortex via the VENTRAL POSTERIOMEDIAL NUCLEUS of thalamus
- This is C and A delta fibres from the tooth pulp
Briefly describe the processes of classical and operant conditioning.
- Classical conditioning- A reflex (salivation at presentation of food) is associated with a stimulus (ringing a bell). After several presentations, the stimulus becomes associated with the reflex (sound of bell becomes associated with salivation).
- Operant conditioning- The learner (rat) operates on the environment (presses a lever) to produce a reward (food). Eventually the operation becomes associated with the reward and the rat will continue to press the lever even without food appearing.
Explain how responses can be conditioned to certain stimuli and how dental anxiety can develop from this.
Stimulus-response:
o Emphasises responses that are observable and measurable
o Learning as the foundations of human behaviour
A reflex (e.g. salivation at presentation of food) is associated with a stimulus (ringing a bell)
After several presentations, the stimulus becomes associated with the reflex (salivation on ringing of bell)
Unconditioned stimulus > Response Conditioning stimulus > No response Pairing of US and CS > Conditioned response Eventually CS > Conditioned response e.g. US – bad experience > Response – anxiety CS – dental visit > No response Pairing of US and CS > CR - Anxiety CS – dental visit > CR – Anxiety
List and describe the medical conditions to consider when administering local anaesthetic to a patient.
Special attention to patients with:
- Epilepsy
- Impaired respiratory function
- Impaired cardiac conduction
- Impaired hepatic function or severe renal dysfunction
- Contains sodium metabisulphite – may cause allergic reaction (rare)
Most common side effects:
- Vascular disorders: Hypotension, hypertension
- Gastrointestinal disorders: Nausea, vomiting
- Nervous system disorders: paraesthesia, dizziness
- Cardiac disorders: bradycardia
o Β blockers may interact with lidocaine to cause cardiac depression.
o Β blockers may interact with adrenaline to cause severe hypertension.
(But we still use lidocaine with adrenaline for patients taking them)
List what you record in patients’ notes after administering a local anaesthetic injection.
- Consent gained
- Topical applied (name)
- Type of injection
- Type of needle
- Name of anaesthetic
- Size of cartridge
- Batch number
- Expiry date
- Site of injection
- How much anaesthetic used
- How many cartridges
- Successful or not
- No adverse reactions
- Post-operative advice
List the anatomical landmarks for identification along with the tissues that will be anaesthetised when administering an inferior alveolar nerve block.
Landmarks:
- Coronoid notch
- Pterygomandibular raphe
- External oblique ridge
- Internal oblique ridge
- Retromolar triangle
- Occlusal plane of mandibular molars
Tissues:
- The body of the mandible and the lower portion of the ramus
- All mandibular teeth
- The floor of the mouth
- The anterior two thirds of the tongue
- Gingivae on the lingual surface of the mandible
- Gingivae on the labial surface of the mandible
- Mucosa and skin of the lower lip and chin
Describe the procedure of administering an inferior alveolar nerve block.
- Gain consent
- Apply topical anaesthetic
- Target area: inferior alveolar nerve, near mandibular foramen
- Area of insertion: medial ramus, mid-coronoid notch
Level with occlusal plane (1cm above)
¾ posterior from coronoid notch to pterygomandibular raphe - Insertion, injecting as you go to anaesthetise tissues and potential to numb the lingual on insertion
- Advance to bone (20-25mm)
- Bony contact
- Retract and aspirate, inject solution
- Remove needle, double click, dispose in sharps bin
- Patient to get numb lip (feels fat), false indication of numbness as patient may indicate numbing of tongue (lingual nerve).
- For successful, probe the soft tissues and give comparison on other side, shouldn’t feel sharpness of probe etc.
Outline the management techniques of anxiety control available for patients.
For basic marks:
- Reassurance
- Behavioural techniques
- Acupuncture
- Hypnosis
- Conscious Sedation
- General Anaesthesia
For extended marking, evidence of explanation of answers such as:
- Negotiated stop sign
- Research clearly shows that patient’s anxiety levels are significantly reduced if they know that they can pause treatment. The dental professional, who is providing your treatment, will ask you to raise your hand if you want to pause treatment.
Tell-show-do
- The dental professional will tell you about the procedure, show you what instruments they will use and then carry out the procedure.
Behaviour shaping and positive reinforcement
- Behaviour shaping is defined as a series of steps towards the ideal behaviour. By rewarding good behaviour we hope to teach children to behave in such a manner that allows adequate dental treatment to take place.
This can be achieved by giving stickers to children at the end of a successful appointment, facial expressions, approval by pat on the shoulder or other reinforcing touch and words.. - Within dentistry, fears are usually related to a specific procedure such as use of local anaesthetic (a needle). The desensitization technique hopes to overcome this fear by exposing the patient, gradually to each stage of the procedure. First, the patient is taught to relax, and in this state exposed to each stage of the procedure. This can mean that 2 visits may be spent on this before active treatment can commence.
Describe the advantages and disadvantages of Intravenous (IV) Sedation.
Advantages:
- Non-irritant
- Wide safety margin
- Titratable effects
- Rapid induction
- Reversible
Disadvantages:
- Respiratory depression
- No analgesia
- Amnesia
- Post-operative supervision
- Monitoring equipment
For sedation there is some specialised equipment needed such as life vital monitoring, sedation monitoring equipment and emergency equipment as well as proformas.
