Care of the pulp Flashcards
What is the pulp?
- Tissue that lies in the middle of the tooth
Is the pulp a vital tissue?
- Yes because it has a blood supply
What cells are present in the pulp?
- Odontoblasts
What nerves are present in the pulp? (2)
- Alpha fibres (myelinated)
- C-fibres (unmyelinated)
What characteristics does pulp have since it is a vital tissue? (2)
- Responds to stimuli
- Has regenerative potential
What is the nerve plexus of Raschkow?
- Sensory nerve fibres that originate from superior and inferior alveolar nerves innervate the odontoblast layer of the pulp cavity
- These nerves enter the tooth through the apical foramen as myelinated nerve bundles
- They branch to form subodontoblastic nerve plexus of Raschkow
What are the functions of the pulp? (4)
- Nutrition
- Sensory
- Protective
- Formative
What are the sensory functions of the pulp? (3)
Can sense:
- Temperature
- Pressure
- Pain
What is the protective function of the pulp?
- Tertiary dentine formation (odontoblasts) - reparative healing
What is the formative function of the pulp?
- Secondary dentine
What is the correlation between clinical symptomatology and pulpal histopathology?
- Poor correlation between what’s going on histopathologically and what the patient is feeling (symptoms)
What different things do we need to know the pulps reaction to? (4)
- Caries
- Operative manipulations
- Trauma
- Periodontal disease
Etc.
What are things that can cause injuries to the pulp? (14)
- Caries
- Cavity preparation
- Restorations (materials: microleakage, etch)
- Trauma
- Tooth wear
- Periodontal pathology
- Orthodontic treatment (forces applied to the tooth)
- Radiation therapy
- Cavity/crown preparation (heat generation, type of bur)
- Dehydration of dentine (air, water)
- Cutting odontoblast processes
- Direct injury to the pulp
- Remaining dentine thickness
- Restoration material
For what reasons can the type of restoration material cause damage to the pulp? (5)
- Toxicity
- Water absorption
- Heat of reaction
- Poor marginal adaptation/seal
- Cementation of restoration
What do dentinal tubules do as they approach the pulp?
- They increase in diameter
Therefore: the deeper the cavity, the greater the dentine permeability - Dentine tubules DO NOT increase in number as they approach the pulp
What is dentine permeable to? (6)
- Bacterial substances
- Polysaccharides
- Antibodies
- Immune complexes
- Complement proteins
- Tissue destruction products
What is key towards initiating and maintaining pulpal and periradicular pathology?
- Micro-organisms
Pain will typically fall into 2 categories. What are the 2 categories and what type of fibre stimulates them?
- Sharp pain = alpha
- Dull/aching pain = C fibres
What are the characteristics of alpha fibres? (3)
- Myelinated
- Sharp pain
- Stimulated by electric pulp testing
What are the characteristics of C fibres? (4)
- Non-myelinated
On stimulation:
- Dull/aching pain
- Increased pulpal blood flow
- Increased pulpal pressure
Why is there increased pulpal pressure when c fibres are stimlated?
- When C fibres are stimulated you get increased blood flow into the tooth which increases the pressure in the tooth - as it has no where to expand
What are the different possible pulpal diagnoses? (6)
- Healthy pulp
- Reversible pulpitis
- Irreversible pulpitis (symptomatic/asymptomatic)
- Necrotic pulp
- Previously treated
- Previously initiated therapy
What is the pulpal diagnosis ‘previously treated’?
- A clinical diagnostic category indicating that the tooth has been endodontically treated and the canals are obturated with various filling materials, other than intracanal medicaments
What is the pulpal diagnosis ‘previously initiated therapy’?
- A clinical diagnostic category indicating that the tooth has been previously treated by partial endodontic therapy e.g. pulpotomy/pulpectomy
What is the pulpal diagnosis ‘healthy pulp’?
- Vital: free of inflammation
- symptom free and normally responsive to vitality testing
In what cases would healthy pulp be removed?
Removed if endodontic treatment indicated for:
- Elective or prosthetic purposes
- Traumatic pulp exposure: ideally treat exposure within 24 hours but if not RCT is required
- In very severe wear cases: as a result of this the pulp has managed to place lots of tertiary dentine - pulp is vital but need to get rid of it so you can place a crown
What is the pulpal diagnosis ‘reversible pulpitis’?
- Vital
- Inflamed pulp
- Investigations suggest it can reverse to health if adequate vital pulp therapy performed
- Many diagnostic mistakes made
- Regular response to sensibility tests
What kind of response do you get from sensibility tests with reversible pulpitis?
- Regular response to sensibility tests
What is the pulpal diagnosis ‘irreversible pulpitis’ (symptomatic or asymptomatic)?
- Vital
- Inflamed
- Investigations suggest pulpal inflammation can not heal
- Symptomatic = patient in pain
- Asymptomatic = no pain felt by patient
What are the treatment options for irreversible pulpitis? (2)
- Pulpectomy required then RCT
- Extraction (unrestorable tooth or patient preference)
What does the difference between reversible and irreversible pulpitis depend on?
- Difference depends on clinical symptoms seen
What is occurring in reversible pulpitis? (3)
- Pain to cold, lasts a short time
- Hydrodynamic expression - microleakage (A-fibres)
- No change in pulp blood flow
What is occurring in irreversible pulpitis? (3)
- Spontaneous pain, intermittent, sleep disturbance
- Negative to cold, pain to hot (C-fibres)
- Increase in pulpal blood flow
What is the pulpal diagnosis ‘necrotic pulp’?
- Non-vital pulp
- Partial or total necrosis
What are the treatment options for necrotic pulp in mature teeth (closed apices)? (2)
- Root canal treatment
2. Extraction
What are the treatment options for necrotic pulp in immature teeth (with open apices)? (3)
- Pulpotomy
- Pulpectomy then full RCT
- Extraction
What is a pulpotomy?
- Remove some of the pulp (the necrotic pulp) then seal over the vital pulp
What is a pulpectomy?
- Removal of the entire structure of a tooth, including the pulp tissue in the roots
What is the periapical diagnosis ‘normal periapical tissues’?
- Not sensitive to percussion or palpation
- Radiographically: lamina dura intact, PDL space uniform
Radiographically what does it look like if periapical tissues are normal? (2)
- Lamina dura intact
- PDL space uniform
What does it look like radiographically if there is damage to the lamina dura?
- If start to see a blurring effect where you can’t clearly see the outline of a tooth on a radiograph then the lamina dura is damaged
What is the periapical diagnosis ‘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
When would you get pain if the tooth had symptomatic periapical periodontitis? (3)
- Biting
- Percussion and/or
- Palpation
What might we see radiographically if a patient has symptomatic periapical periodontitis?
- Might have a periapical radiolucency
What is severe pain to percussion and/or palpation highly indicative of?
- Highly indicative of a degenerating pulp
What is the periapical diagnosis ‘asymptomatic periapical periodontitis’?
- Inflammation and destruction of the apical periodontium (of pulpal origin)
- Appears as an apical radiolucency
- Patient complains of no problems
- No present clinical symptoms: no pain on percussion or palpation
What will appear radiographically if a patient has asymptomatic periapical periodontitis?
- Appears as an apical radiolucency
What is an acute apical abscess?
- Inflammatory reaction to pulpal infection and necrosis
What are common signs and symptoms of an acute apical abscess? (9)
- Rapid onset
- Spontaneous pain
- Extreme tenderness to pressure
- Pus formation
- Swelling
- May be no radiographic signs of destruction
- Malaise
- Fever
- Lymphadenopathy (disease affecting lymph nodes)
How would we treat an acute apical abscess?
- Try to drain abscess
- Make an incision on abscess and get puss out
- Open up tooth to remove infected pulp
- Place dressing
- Then get patient back to do RCT or extraction
What is the periapical diagnosis ‘chronic apical abscess’?
- Inflammatory reaction to pulpal infection and necrosis
- Gradual onset
- Little or no discomfort
- Intermittent discharge of pus through sinus tract
Do we see periapical/periradicular radiolucency’s radiographically when a patient has a chronic apical abscess?
- Yes
How can the suspect tooth of a chronic apical abscess be identified?
- Carefully place GP cone into sinus tract
- Take radiograph
What is condensing osteitis?
Diffuse radiopaque lesion:
- Represents localised bony reaction to a low-grade inflammatory stimulus
- Usually seen at the apex of the tooth in which there has been a long standing pulpal infection
What are signs of a non-vital tooth? (5)
- Discoloration (yellow, grey, pink)
- Sinus
- Gross caries
- Large restoration
- Radiographic evidence (periapical radiolucency, periradicular radiolucency)
What is the primary function of sensibility testing?
- Primary function is to differentiate ‘vital’ from ‘non-vital’ pulp
Patients responses to sensibility testing are very subjective, how can we overcome this?
- Compare patient’s response with a contralateral tooth then re-examine the same tooth
Give examples of sensibility tests? (3)
- Electric pulp tests
- Thermal tests (cold tests: ethyl chloride, Heat tests: hot GP)
- Test drilling
What are the problems with sensibility tests? (6)
- These tests stimulate nerve fibres (don’t assume that nerve fibres in pulp correlates to vital blood supply)
- These tests do not indicate the state of the blood supply
- Tooth vitality is related to blood supply, not nerve stimulation (laser doppler needed to assess blood flow)
- A bit subjective for different patients
- Difficulties in testing multi-rooted teeth
- Periradicular inflammation occurs before pulp totally necrotic so tooth might respond to tests but the tooth is in the stages of dying off
How do electric pulp tests work?
- Electric current used to stimulate sensory nerves at the pulp-dentine junction
- Passes current through tooth and sees if patient can feel any electric stimuli
What nerve respond to electric pulp tests?
- A-delta and A-alpha fibres stimulated
- Unmyelinated C-fibred may or may not respond
What is the procedure for using the electric pulp tester? (6)
- Teeth thoroughly dried (prevents current transfer to adjacent teeth)
- Isolate tooth
- Conducting medium (tooth/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 and patient indicates when a tingling/heat sensation is felt - can pull probe away from tooth)
What does a positive response from an electric pulp test indicate/have no indication of? (3)
- Vital pulp tissue in coronal aspect of pulp chamber
- No indication of reversibility of inflammation (healing)
- No correlation between pain threshold and pulp condition
Is a negative response from an electric pulp tester a reliable indicator for pulpectomy procedures?
Yes, in 97.7% of cases
Is a negative response from an electric pulp tester a reliable indicator for young pulps (teeth with open apices) or recently traumatised teeth?
- Unreliable
How are thermal tests believed to work?
- Believed to work by hydrodynamic forces:
- Fluid movement in dentinal tubules (due to thermal stimulus)
What are the 2 types of thermal tests?
- Cold tests
- Heat tests
Give 2 examples of cold tests?
- Frozen sticks of carbon dioxide or ice (not reliable)
- Cotton pellet/roll sprayed with:
- ethyl chloride (not reliable)
- diflurodichloromethane
- endo-ice
What is the procedure for cold tests? (2)
- Teeth carefully dried and isolated
- Place cold object close to pulp horn
What is a negative response from a cold test highly indicative of?
- Highly indicative of pulpal necrosis
Why do we need to be careful when carrying out heat tests?
- Too much heat can cause irreversible pulpitis
What kind of pain can heat tests stimulate in the pulp?
- 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? (2)
- Vaseline on tooth
- Apply hot GP/green stick to tooth
What is a negative response to heat tests indicative of?
- Indicative of necrotic pulp
- Not possible to ascertain degrees of reversibility of inflamed symptomatic pulp
When is test drilling used as a sensibility test?
- Used when a full coverage restoration is present (renders other forms of testing impossible)
What is the procedure for test drilling? (2)
- No LA given
- Cut into tooth
How can we diagnose teeth by using test drilling as a sensibility test? (2)
- Patient reports severe pain or no pain felt when cutting dentine
- Sensitivity-like response to dentine preparation - tooth is vital
What can be used as an alternative to test drilling as a sensibility test? (one thing - 4)
- Isolate crowned tooth with rubber dam
- No LA
- Spray cold water and air
- Assess patient response
What clinical factors can influence susceptibility to pulpal disease? (4)
- Carious pulp exposure
- Age
- Periodontal disease
- Previous pulpal insult/trauma
How can we try to avoid carious pulp exposures?
- Want to remove caries from the wall of the cavity first then into the centre, as if you accidently drill into the pulp and still have caries, you are exposing the pulp to caries (infection)
In a carious pulp exposure what is the pulp exposed to? (2)
- Caries and bacteria
Vital treatment on carious pulp exposures is less than 50% successful. Therefore what is required? (2)
- RCT required
- However, not in all cases e.g. immature teeth with incomplete root development - consider removal of necrotic parts of the pulp only (pulpotomy)
Why is age a clinical factor which can influence the susceptibility of the pulp to carious exposure? (4)
Continued dentine formation:
- Reduced pulp size and volume
Increased:
- Fibrous components
- Calcification
Decreased:
- Cellular components
- Number of BV’s and nerves
Overall:
- Pulp less likely to reverse an inflammatory response
What does moderate to severe periodontal disease result in, in relation to the pulp?
- Results in prematurely aged pulp
What is pulp in periodontally involved teeth less resistant to than healthy pulp?
- Less resistant to inflammation
Caries, caries removal and restorative procedures results in tubule occlusion, what causes this? (2)
- Reparative dentine formation
- Pulpal fibrosis
Does premature aging pulp heal the same as healthy pulp?
- No, it is less likely to heal than healthy pulp
How are we able to maintain pulp vitality? (2)
- Prevention of pulpal damage
- Treatment of pulpal damage
How can we as dentists prevent pulpal damage? (4)
- Know tooth anatomy
- Avoid drilling into pulp
- Care of cavities close to pulp
- Appropriate treatment of cavities into the pulp (exposure)
How can knowing tooth anatomy prevent pulpal damage? (2)
- Size, location and proximity of pulp
- Pre-assessment (radiographs)
How can avoiding drilling into the pulp prevent pulpal damage? (2)
- Stop if close to the pulp
- Caries can be left over pulpal floor in some cases (placement of well sealed restoration)
How can we prevent pulpal damage with a cavity close to the pulp? (2)
- Use of cavity sealers
- Indirect pulp cap
How can we prevent pulpal damage with a cavity into the pulp (exposure)? (1)
- Direct pulp cap
What is a direct pulp cap?
- Cap placed onto pulp that has been exposed
What is an indirect pulp cap?
- When there is still a bit of dentine present over the pulp a cap is put onto the dentine on top of the pulp
What do cavity sealers protect the pulp from? (2)
- Bacteria and their products
- Toxic effects during setting phase of restorative materials
How much of the pulp needs covered when you are using a cavity sealer?
- Whole exposed pulpal dentine must be covered
- IF you have exposed the pulp you need to make sure you fully cover it, not partially cover it
What are the requirements of a cavity sealer? (3)
- Adhere to dentine rather than restorative material
- Be thin (otherwise reduces strength of restorative material)
- Not dissolve in biological liquids
Why, is we use a cavity sealer do we want the material to bond to dentine and not the restorative material?
- As if we have to remove the restorative material at any point we don’t want to rip off the cap
What are the different types of cavity sealer? (3)
- Varnishes (material dissolved in organic solvent)
- Liners
- Base materials
When using cavity sealers we rarely use varnishes and more often use liners and base materials. Why is this?
- Because bases and liners usually have more thermal protection, they are also thicker
What are examples of cavity base/liners? (4)
- Zinc phosphate
- Zinc oxide eugenol
- Calcium hydroxide (Dycal)
- Resin modified glass ionomer (Vitrebond)
Calcium hydroxide is bacteriostatic/bactericidal. What properties does it have that allows it to be like this? (3)
- High pH - stimulates fibroblasts (reparative dentine formation)
- Stimulates recalcification of demineralised dentine (by stimulating pulpal cells)
- Neutralises low pH from acidic restorative materials
What are the negative properties of Calcium Hydroxide? (3)
- Cytotoxic (can kill pulp cells)
- Weak cement
- Very soluble if not protected
What is there a marked reduction in when using dentine bonding agents?
- Marked reduction in microleakage
What is a negative about dentine bonding agents?
- Use is VERY technique sensitive
What are the treatment options for a tooth with pulpal damage? (6)
- Indirect pulp cap
- Direct pulp cap
- Stepwise excavation
- Seal in caries
- Pulpotomy
- Pulpectomy
