Care of the pulp Flashcards
What cells are found in the pulp
odontoblasts
What nerves are found in the pulp
- alpha fibres (myelinated)
- C fibres (unmyelinated)
Are blood vessels found in the pulp?
yes
how can you tell that the pulp is vital
if it responds to stimuli
can the pulp regenerate
yes
what is the relationship with dentine?
close relationship, procedures in dentine = treatment of both pulp and dentine
what are the functions of the pulp
nutrition
sensory
- temp
- pressure
- pain
protective
- tertiary dentine formation (odontoblasts)
- reparative healing
formative
- secondary dentine
how can you injure the pulp
- caries
- cavity preparation (heat generation, type of bur used)
- restorations (restorative materials/ microleakage/ etch)
- dehydration of dentine (air, water)
- trauma
- cutting odontoblast processes
- toothwear
- periodontal pathology
- orthodontic treatment
- radiation therapy
is it better to have more or less remaining dentine thickness
more (less damage to pulp)
how can the restoration material cause injury to the pulp
- toxicity
- water absorption
- heat of reaction
- poor marginal adaption/ seal
- cementation of restoration
Why is it that ‘the deeper the cavity, the greater the dentine premeability’?
dentine tubules increase in number(? - see structure of tooth tutorial) and diameter as they approach the pulp
what things can penetrate the pulp via the dentine tubules
bacterial substances polysaccharides antibodies immune complexes complement proteins tissue destruction products
what nerve fibres contribute to dental pain
Alpha and C
What kind of pain do Alpha fibres contribute to
sharp pain
What kind of pain do C fibres contribute to
dull/aching pain
increased pulpal blood flow
increased pulpal pressure
Are alpha fibres myelinated or unmyelinated
myelinated
Are C fibres myelinated or unmyelinated
unmyelinated
how do you test the alpha fibres are responding (vitality)
Electric pulp test (EPT)
why is it important to determine/diagnose pulpal health
because diagnosis drives treatment plan
what are the 2 types of classification of diagnosis
pulpal diagnosis
periapical diagnosis
What are the different pulpal diagnosis’s
Healthy pulp Reversible pulpitis Irreversible pulpitis - symptomatic - asymptomatic Necrotic pulp Previously treated Previously initiated therapy
What are the different periapical diagnosies
Normal Periapical periodontitis - Symptomatic - Asymptomatic Acute apical abscess Chronic apical abscess Condensing osteitis
What indicates a healthy pulp
vital
- free of inflammation
why might a healthy pulp be removed
if endodontic treatment is indicated for:
- elective or prosthetic purposes
- traumatic pulp exposure (ideally treat within 24 hours, but if not RCT required)
Describe the pulp in reversible pulpitis
vital but inflamed pulp
can reverse to health if adequate vital pulp therapy performed
how can you diagnose reversible pulpitis
regular response to sensitivity tests (many dianostic mistakes made)
what characterises reversible pulpitis
- pain to cold, lasts a short time
- hydodynamic expression - microleakage (A fibres)
- no change in pulp blood flow
what characterises irreversible pulpitis
- vital pulp
- spontaneous pain, intermittent, sleep disturbance
- negative to cold, pain to hot e.g. tea/ coffee (C fibres)
- increase in pulpal blood flow
what characterises necrotic pulp
non-vital pulp
partial or total necrosis
what are the treatment options for necrotic pulp
mature teeth (closed apices):
- RCT
- extraction
immature teeth with open apices
- pulpotomy
- pulpectomy then full RCT
- extraction
what are the treatment options for irreversible pulpitis
(investigations suggest pulpal inflammation can not heal)
treatment options:
- pulpectomy required then RCT
- extraction (unrestorable tooth, patient preference)
What characterises normal periapical tissues
Not sensitive to percussion or palpation
Radiographically:
1. lamina dura intact
2. PDL space uniform
What characterises symptomatic periapical periodontitis
inflammation of the apical periodontium
Pain:
- biting
- percussion and/or
- palpation
May have periapical radiolucency
Severe pain to percussion and/or palpation highly indicative of degenerating pulp
-RCT required
What characterises asymptomatic periapical periodontitis
Inflammation and destruction of the apical periodontium (of pulpal origin)
appears as an apical radiolucency
no present clinical symptoms
- no pain on percussion
- no pain on palpation
What characterises an acute apical abscess
- inflammatory reaction to pulpal infection and necrosis
- rapid onset
- spontaneous pain
- extreme tenderness to pressure
- pus formation
- swelling
- may be no radiographic signs of destruction
- malaise
- fever
- lymphadenopathy
What characterises a chronic apical abscess
- inflammatory reaction to pulpal infection and necrosis
- gradual onset
- little or no discomfort
- intermittent discharge of pus through sinus tract
- peripapical/periradicular radiolucency
can be identified by:
- carefully placing GP cone into sinus tract
- take radiograph
What characterises condensing osteitisis
diffuse radiopaque lesion
- represents localised bony reaction to a low-grade inflammatory stimulus
- usually seen at apex of tooth
what are signs of a non-vital tooth
Discolouration
- yellow
- grey
- pink
sinus
gross caries
large restoration
radiographic evidence
- periapical radiolucency
- periradicular radiolucency
What causes a tooth to turn yellow
obliteration of dentine tubules
What causes a tooth to turn grey
blood products in dentine tubules
What causes a tooth to turn pink
cervical resorption
What is the primary function of a sensibility test
to differentiate “vital” from “non-vital”
how do you get around the fact that sensibility tests are very subjective
compare the patient’s response with a contralateral tooth then re-examine same tooth
What are the different sensibility tests
- Electric pulp tests (EPTs)
- Thermal tests
- cold tests
- heat tests - Test drilling
What substance is used in the cold sensibility tests
- frozen sticks of CO2 or ice
- cotten pellet/ roll sprayed with
ethyl chloride, difluorodichloromethane or endo-ice
What substance is used in the hot sensibility tests
hot gutta percha (GP)
What are the problems with sensibility tests
- these tests stimulate nerve fibres (don’t assume that nerve fibres in pulp correlates to vital blood supply)
- these tests do not indicate state of blood supply
- tooth vitality is related to blood supply, not nerve stimulation (laser doppler needed to assess blood flow)
What fibres are stimulated using an EPT
A delta fibres (?)
unmyelinated C fibres may or may not respond
What is the procedure for the EPT
Teeth thoroughly dried
- Prevents current transfer to adjacent teeth
Isolate tooth/teeth
Conducting medium (toothpaste/ fluoride gel) required - Tip of EPT probe
EPT probe placed on incisal edge or cusp tip adjacent to pulp horn
- Most sensory nerves found here
Patient completes circuit by holding handle of EPT
Current slowly increased
- Occurs automatically
- Pt. indicates when a tingling/ heat sensation is felt (Can pull probe away from tooth)
What does a positive response from the EPT indicate
- Vital pulp tissue in coronal aspect of pulp chamber
- No indication of reversibility of inflammation (healing)
- No correlation between pain threshold and pulp condition (measurement of electric voltage/ score is not accurate)
What does a negative response from the EPT indicate
- Reliable indicator for pulpectomy procedure in 97.7% cases
- EPT of young pulps (teeth with open apices) or recently traumatised teeth
(unreliable)
How does thermal testing work
believed to work by hydrodynamic forces
- fluid movement in dentinal tubules (due to thermal stimulus)
- activates pulp’s sensory nerve receptor units in pulp
What is a negative response to cold test indicate
highly indicative of pulpal necrosis
what is the procedure for cold test
teeth carefully dried and isolated
place cole object close to pulp horn
either frozen stick or cotton pellet/ roll sprayed with e.g. ethyl chloride
Why do you have to be super cautious with heat tests
too much heat may cause irreversible pulpitis
what pain happens with heat tests
Initial stimulation of A-delta fibres
(Sharp pain)
Continued stimulation results in C-fibre activation
(Dull radiating pain)
What is the procedure for heat tests
Vaseline on tooth
Apply hot gutta percha/ green stick to tooth
what is a negative heat test indicative of
necrotic pulp
Not possible to ascertain degrees of reversibility of inflamed symptomatic pulp
When is test drilling used
Used when full coverage restorations present
what is the procedure for test drilling
No local anaesthetic given
Cut into tooth
what does a negative response to test drilling indicate
- Patient reports severe pain or no pain felt when cutting dentine
- Sensitivity-like response to dentine preparation – tooth is vital
What is an alternative to test drilling
Isolation crowned tooth with rubber dam
(No LA)
Spray cold water and air
Assess patient response
what are the different clinical factors which affect tooth vitality
- carious pulp exposure
- age
- periodontal disease
- previous pulpal insult/ trauma
how does carious pulp exposure impact treatment
Pulp exposed to caries and bacteria
Vital treatment of carious exposures less than 50% successful
Therefore RCT required
However – not in all cases
• E.g. Immature teeth with incomplete root development – Consider removal of necrotic parts of pulp only (Pulpotomy)
How does increasing age affect the pulp
Continued dentine formation
Reduced pulp size and volume
Increased:
Fibrous components
Calcification
Decreased:
Cellular components
Number of blood vessels and nerves
Overall:
Pulp less likely to reverse an inflammatory response
How does periodontal disease affect the pulp
Moderate to severe periodontal disease
Result: “prematurely aged” pulp
Pulp in periodontally involved tooth
less resistant to inflammation than healthy pulp (not universally accepted)
how does a previous pulp insult affect pulp
Caries, caries removal and restorative procedures
- Tubule occlusion (Reparative dentine formation,
Pulpal fibrosis)
“Premature aging” of pulp
(Less likely to heal than healthy pulp)
how do you maintain pulp vitality
prevention of pulpal damage
treatment of pulpal damage
How can you prevent pulpal damage
Know tooth anatomy
- Size, location and proximity of pulp
- Pre-assessment (Radiographs)
Avoid drilling into pulp
- Stop if close to pulp
- Caries can be left over pulpal floor in some cases
(Placement of well-sealed restoration)
Cavity close to pulp
- Use of cavity sealers
- Indirect pulp cap
Cavity into pulp (exposure)
- Direct pulp cap
How can cavity sealers help prevent pulpal damage
Protect pulp from:
- bacteria and their products
- toxic effects during setting phase of restorative material
Whole exposed pulpal dentine must be covered
Material must:
- adhere to dentine rather than restorative material
be thin
(Otherwise – reduces strength of restorative material)
- Not dissolve in biological liquids
Types - Varnishes (Material dissolved in organic solvent e.g. ether) - Liners - Base materials
How can a cavity base/liner help prevent pulpal damage
Thicker sealant
- Thermal protection
(Thermal effects arising through restorative material)
Examples:
- Zinc phosphate
- Zinc oxide eugenol
- Calcium hydroxide
e. g. Dycal - Resin modified glass ionomers (RMGI)
e. g. Vitrebond
What are the advantages and disadvantages of calcium hydroxide
Advantages
Bacteriocidal/ bacteriostatic
- High pH – Stimulates fibroblasts
(Reparative dentine formation (healing))
- Stimulates recalcification of demineralised dentine
(by stimulating pulpal cells)
- Neutralises low pH from acidic restorative materials
BUT: - Cytotoxic (Can kill pulp cells) - Weak cement - Very soluble if not protected
How do dentine bonding agents help protect the pulp
Dentine primers with/ without adhesives are both tolerated by the pulp
Marked reduction in microleakage demonstrated by dentine bonding agents
However
Use is VERY “technique sensitive”
What is a summary of treatment options for pulpal damage
Which liner and when?
Dependent upon the RDT
Treatment of pulpal damage
Indirect pulp cap
Or stepwise excavation or seal caries in
Direct pulp cap
Partial pulpal removal – Pulpotomy
Full pulpal removal – Pulpectomy
Progress to RCT
