OFS- special aspect of orofacial pain

Question 1

What is allodynia and give an example of allodynia

Answer 1

pain due to stimulus that does not normally provoke pain eg trigeminal neuralgia

Question 2

Factors affecting perception of pain

Answer 2

intensity, emotion, past experience, other concomitant sensory experience, race, placebo

Question 3

Characteristic of fast pain

Answer 3

sharp pain, well localised, short duration, thermal and mechanical nociceptos, A-d fibers

Question 4

Characteristic of slow pain

Answer 4

aching burning pain, poorly localised, long duration, polymodal nociceptors, C fibers

Question 5

Where does double pain arise from

Answer 5

2 different fiber conducting at diff velocity

Question 6

How does tissue damage cause stimulation of nociceptors

Answer 6

tissue damage will cause release of chemical 
to sensitise (prostaglandin- damaged cells, substance P-primary afferent) and activate (potassium-damaged cells. bradykinin-damaged vessel, serotonin damaged endothelial and platelet, histamin-mast cells) nociceptors

Question 7

How is peripheral sensitisation occur

Answer 7

Antidromic activation cause neuron to release substance P

Question 8

Describe the pain caused by hot pulps

Answer 8

antidromic activation cause release of SP and calcitonin gene related peptide.
SP cause plasma extravasation and mast cell degranulation and activate nociceptors . CGRP cause dilation of blood vessel and odema formation which cause release of bradykinin activating nociceptors

Question 9

Process of central sensitization

Answer 9

tissue/peripheral nerve injury increases C fiber input–> increase in summation of slow synaptic potential–> alteration in second messengers–> activates protein kinase –> increase excitability and synaptic efficacy causing central sensitisation

Question 10

How to prevent central sensitisation in dentistry ans why do we want to prevent central sensitisation

Answer 10

preventing CS will reduce post-op pain

Administer LA after GA for third molar exo to prevent CS

Question 11

Differences between Allodynia vs Hyperalgesia

Answer 11

Allo: CS
Hyper:CS+PS

Question 12

key effects of substance p in dental pulp

Answer 12

vasodilatory, histamine release, increase blood flow, increased vascular permeability, increase bp,

Question 13

conditions or procedure that will increase substance p release

Answer 13

caries, pulpitis, granuloma, cavity prep, orthodontics, tooth beaching

Question 14

2 types of 2nd order neuron and their effects

Answer 14

nociceptive and Wide dynamic range

Question 15

3 nucleus of trigeminal sensory neuron

Answer 15

mesencephalic, chief and spinal

Question 16

3 part of spinal nucleus of CNV

Answer 16

sub nucleus oralis, interpolaris and caudalis

Question 17

describe the trigeminal pain pathway

Answer 17

1st order neuron enters at the level of pon, then descend to the medulla and synapses with 2nd order…….

Question 18

5 theories of pain

Answer 18

specific, intensity, pattern, gate control, neuromatrix

Question 19

What is the gate control theory and what are the 4 component

Answer 19

interaction between nociceptive and non-nociceptive input at the the spinal cord level in the form of a gating mechanism
4 component
large fibers (non-nociceptive, touch)
small fibers (nociceptive)
subsatantia gelotinosa (spinal gating system)
T- cells (transmission cells sending pain signals to the brain)

Question 20

How does the gate control theory work

Answer 20

small fiber activation will inhibit inhibitory cells from inhibiting transmission of pain
Large fiber does opposite hence inhibiting pain transmission

Question 21

What is the neuromatrix theory

Answer 21

The neuromatrix theory of pain states that the perception of painful stimuli does not result from the brain’s passive registration of tissue trauma, but from its active generation of subjective experiences through a network of neurons known as the neuromatrix.

Question 22

What is referred pain

Answer 22

Pain from internal organ is felt as pain in a more superficial region, cz nociceptor fibers from viscera and cutaneous structure converge on the same pain pathway

Question 23

What are 5 categories of special aspects of pain in the orofacial region

Answer 23

Referred pain, TMD, Headache, Neuralgia, Phantom pain

Question 24

Common causes of TMD

Answer 24

Structural or mechanical displacement, functional or neuromuscular and psychological

Question 25

common causes of headache

Answer 25

stress and anxiety (excessive contraction of the scalp muscle affecting regional blood flow causing changes in the cerebral blood flow)

Question 26

Common causes of neuralgias

Answer 26

peripheral changes, compression of trigeminal sensory root, degenarative changes in myelinated fibers in the ganglion

Question 27

What are the 3 theories of dentinal sensitivity

Answer 27

Neural- afferent fibers present in the dentinal tubules (not true)
Transduction- odontoblast and nerve fibers has a synaptic relationship (not truw)
Hydrodynamic theory- fluid movement through the dentinal tubules distort the local pulp environment causing pain

Question 28

Factors affecting susceptibility of nerve fibers to LA

Answer 28

Size (smaller first), Myelination (myelin first)

Rate of firing(fast firing first)