diagnostic testing Flashcards
what are the ideal properties of pulp test
Chambers 1982
- simple to conduct
- objective
- non invasive and non injurious
- accurate
- inexpensive
- reproducible
- standardised
limitations of pulp sensibility testing
- it tests responsiveness of sensory neurons to stimulus and this is subjective
- poor correlation between sensibility testing and histopathology
- tests are inference
- qualitative
- does not measure degree of health/ disease of pulp
- does not provide info about vascular supply to pulp (true indicator of pulp vitality)
but if we want quantitative evaluation of pulp status, it requires histological exam which is not practical
what are the 2 types of pulpal nerves and features of them
A delta fibres
- myelinated
- fast conducting so will give sharp short pain
- responds to hydrodynamic stimuli applied to dentine eg drilling
C fibres
- unmyelinated
- slow conducting so its a slow dull aching pain
- responds to stimuli from pulp
- high threshold, located in core of pulp
- activated mostly under pathological conditions eg intense thermal and mechanical stimulation
what is the hydrodynamic mechanism of dentine sensitivity
thermal stimulation will result in volume change and hence the rapid movement of fluid in dentinal tubules via capillary action
heat: expansion of fluid -> inward flow of fluid towards pulp
cold: contraction of fluid -> outward flow of fluid away from pulp
then pulp tissues distort at pulp dentine border, which are densely innervated
activate sensory nerve terminal in underlying pulp
-outward excites more than inward flow
what are the different methods for heat test and what kind of response points to what kind of diagnosis?
need to RDI first!
methods
- bathe tooth in hot water or syringe hot water onto tooth
- apply hot GP to buccal surface
- use dry prophy cup to create frictional heat
- if not can just give patient hot water to drink
if response is immediate and intense -> pulpitis
- if not normal response is delayed (2-4s) because activate C fibres
but heat test got high false +ve rate and hence results are less reliable than cold test & EPT
what are some reasons for false positives and false negatives for EPT
false +ve:
- contact metallic surface of restorations
- partial pulp necrosis (for multi rooted teeth)
- anxious patient
- ineffective isolation
false -ve:
- immature apex
- recent trauma
- sclerosed canals
- drugs that increase pain threshold
limitations of EPT
- contraindicated in patients with cardiac pacemaker
- does not distinguish between reversible and irreversible pulpitis
- does not work if probe is not placed on natural tooth structure
why does pulpitic pain often progress to a dull ache
because the progression of pulpitis is from A fibres to C fibres and C fibres maintain capability to conduct nerve impulses longer than A fibers
so change from short sharp pain to dull, aching throbbing pain that is poorly localised
A fibres will decrease in activity with progression of pulpal inflammation and hypoxia (like slowly die) whereas C fibres continue to maintain activity even during hypoxia
defn of normal pulp
a clinical diagnostic category in which the pulp is symptom free and normally responsive to pulp testing
defn of reversible pulpitis
a clinical diagnosis based on subjective and objective findings indicating that the inflammation should resolve and pulp return to normal
defn of symptomatic irreversible pulpitis and asymptomatic irreversible pulpitis
irreversible pulpitis = based on subjective and objective findings indicating that the vital inflamed pulp is incapable of healing
additional descriptor for symptomatic = lingering thermal pain, spontaneous pain, referred pain
for asymptomatic = no clinical symptoms except for the fact that inflammation is produced by caries, caries excavation and trauma
defn of pulp necrosis
a clinical diagnostic category indicating death of dental pulp
pulp usually not responsive to pulp testing
defn of previously treated tooth
clinical diagnostic category indicating that the tooth has been endodontically treated and the canals are obturated with various filling materials other than intracanal medicaments (must not be intracanal medicament!)
defn of normal apical tissues
- normal periradicular tissues that are not sensitive to percussion or palpation
- lamina dura surrounding root is intact and PDL is unfirom
defn of symptomatic apical periodontitis
- inflammation producing clinical symptoms including a painful response to biting and/ or percussion or palpation.
defn of asymptomatic apical periodontitis
inflammation and destruction of apical periodontium that is of pulpal origin, appears as an apical radiolucent area and does not produce clinical symptoms
defn of acute apical abscess
an inflammatory reaction to pulpal infection and necrosis characterised by rapid onset, spontaneous pain, tenderness of tooth to pressure, pus formation and swelling of associated tissues
defn of chronic apical abscess
an inflammatory reacton to pulpal infection and necrosis characterised by gradual onset, little/no discomfort and the intermittent discharge of pus through an associated sinus tract
defn of condensing osteitis
diffuse radiopaque lesion representing a localised bony reaction to a low grade inflammatory stimulus, usually seen at apex of tooth
how does internal resorption occur and what is the clinical presentation
when there is inflammation in the pulp, the pulp transforms into highly vascularised granulation tissue with osteoclastic activity and resorbs dentinal walls of root canals
it is usually asymptomatic, responds within normal limits
may present with pink spot on crown
what happens during EPT
- ionic shift of dentinal fluid in tubules
- local depolarisation of A delta fibres (mainly at pulp dentine junction) & generation of AP
- stimulate A delta fibres via excitation of nerves to elicit a response
what happens during cold test
cold causes contraction of dentinal fluid liquid in dentinal tubules
rapid outflow of fluid causes distortion of tissue in pulp denitne junction
activate A delta fibres at pulp dentine junction to give short sharp pain
