Pulp Flashcards
(158 cards)
1
Q
What is secondary dentine?
A
Laid down throughout life - physiological
has regular structure
pulp gets smaller
2
Q
What is tertiary dentine?
A
reactionary: laid down in
response to an insult to the
pulp.
• Structure varies
3
Q
What is a true pulp stone?
A
Composed of dentine
4
Q
What is a false pulp stone?
A
Amorphous calcifications
5
Q
What happens to pulp stones with age?
A
Increase in number and size with age
6
Q
Name denegerative pulp pathology?
A
Fibrosis
Calcifications
Internal resorption
(May be age changes or ‘idiopathic’)
7
Q
Name inflammatory pulp pathology?
A
Pulpitis
8
Q
What is pulpitis?
A
inflammation of the pulp
• most common aetiology: dental caries
9
Q
What are the defence reactions of dentine to pulpitis?
A
- dentine sclerosis
* reactionary dentine formation
10
Q
What are the causes of pulpitis?
A
bacterial infection
Dental caries secondary to crack/fracture, lateral root canals, canals in furcation, invaginated odontome
bavteraemia
Trauma • Physical • Direct blow • Heat • Dessication • Chemical - Filling materials/liners • Mechanical - Cavity preparation
secondary to attrition, abrasion, erosion
11
Q
What are the clinical features of pulpitis?
A
often poorly localised pain
• may radiate to adjacent jaw, neck, face
• continuous or intermittent
- Reversible
- Symptomatic irreversible
- Asymptomatic irreversible
12
Q
What is the pattern of pulpitis?
A
Starts as a localised lesion directly related to
proximity of caries e.g. pulp horn
• Inflammation will spread throughout the pulp if
caries untreated
• Rate of progression & character of pulpitis will
vary between teeth and individuals
13
Q
How does tertiary dentine protect the pulp against an irritant?
A
• forms in response to caries • increase the distance of the pulp from the irritant • this reduces and may halt pulpitis
14
Q
What is the response to late dentine caries?
A
Acute inflammation • vasodilation • inflammatory exudate • accumulation of neutrophils • death of odontoblasts
15
Q
What does hypoxia in pulp tissue lead to?
A
local tissue necrosis • release of inflammatory mediators • further inflammation and neutrophil accumulation • formation of pus: a pulp abscess
16
Q
What does untreated pulpitis lead to?
A
Pulp necrosis
periapical pathology
17
Q
How may chronic hyperplastic pulpitis - pulp polyp form?
A
open carious cavity with pulp exposure - usually first permanent molars
18
Q
What is a pulp polyp?
A
Granulation tissue in the pulp chamber
• Surface ulcerated and covered by fibrin and
neutrophils
• may become covered by epithelium
• source of epithelium uncertain: either saliva or
gingival crevice
• Clinically appears red and bleeds easily (less
so if epithelialized); often painless
19
Q
How can the pulp heal?
A
Use of calcium hydroxide may stimulate dentine
formation
• Need contact with pulp for it to be effective
• Clinically need to decide whether to ‘pulp cap’
or to extirpate the pulp following exposure
20
Q
When does reactionary dentine form?
A
Low grade irritant to pulp
Laid down in relatively normal structure
21
Q
When is reparative dentine formed?
A
Highly carious fast moving lesion moving to pulp
Irregular structure of dentine forms
22
Q
What type of pulpitis may result from a tooth fracture?
A
Open acute pulpitis
23
Q
What type of pulpitis may result from trauma to the tooth?
A
Closed acute pulpitis
24
Q
What type of pulpitis is largely related to dental caries?
A
Chronic pulpitis - open and closed
25
What type of pulpitis is the most common?
Closed chronic pulpitis - caries related
26
What is an invaginate odontome?
Developmental abnormality of tooth - crown of tooth folds in on itself, produces a pocket seen in cingulum of tooth seen on palate - allows bacteria into pulp and produce pulpitis
27
What is bacteraemia?
Transient bacteria in the circulation e.g. from dental work
28
What is desiccation?
Drying out the pulp with 3 in 1
29
How may a pulp abscess be isolated?
Localised to pulp horn
| Surrounded by granulation tissue to keep inflammation and infection in
30
Who is chronic hyperplastic pulpitis usually seen in?
Age 10 through to teenagers
31
How may idiopathic internal resorption occur?
Differentiation of odontoclasts in pulp which resorp tooth from inside out - seen clinically as pink spot
32
what gives rise to pulpal inflammation?
Bacteria and their by products
33
What is needed to diagnose pulp and periapical disease?
Patient complaint History of complaint Clinical examination
Special investigations Pulp tests Periapical tests Additional tests Radiography
34
What are the classifications of pulp and periapical disease?
```
Normal pulp
Reversible pulpitis
Symptomatic irreversible pulpitis
Asymptomatic irreversible pulpitis
Pulp necrosis
```
35
What would you include in a pain history?
Location – specific to tooth or generalised?
– Initiating or relieving factors eg hot/cold, biting, sweet stimuli, bending forwards?
– Character – dull, sharp, throbbing, shooting (trigeminal neuralga)?
– Duration – short or long lasting?
– Severity – causing sleep loss, pain scale (1-10)?
–Spread/radiation – to adjacent structures, referred pain?
36
How may occlusion tests reveal a pulpal problem?
teeth with an acute apical abscess may become raised occlusally due to the build up of pressure resulting in extreme tenderness on biting and high occlusal contacts
37
What do isolated deep pockets indicate?
Highly indicative of vertical root fracture
38
What causes yellow/cream discolouration of the tooth?
- Due to deposition of tertiary dentine resulting in thicker dentine tissue and reduced light transmission
- Tooth may be vital or non-vital
39
What causes grey/black discolouration?
Due to pulpal blood products staining dentine
| • Tooth will generally be non-vital
40
What is sensibility testing?
* Tests the ability to respond to a stimulus
| * Assessment of the pulp’s nerve supply
41
What is vitality testing?
Tests whether the pulp is vital i.e. has a functioning blood supply
42
What sensibility tests can you do?
- cold
- heat
- electric pulp testing
43
What vitality tests can you do?
- pulse-oximetry
| - laser doppler flowmetry
44
What sort of fibres respond to sharp dental pain?
A-delta fibres
45
What sort of fibres respond to achy dull pain?
unmyelinated C fibres - pulpal inflammation
46
How would you do an ethyl chloride test?
– Spay the ethyl chloride onto a cotton wool pellet and wait a few seconds for ice crystals to form
– Ideally isolate the tooth in question
– Test an adjacent tooth, buccal and palatal surfaces
– Wait at least 30 seconds
– Test the tooth in question buccal and palatal surfaces
– If no response, wait one minute, then test again
47
What is the only sensation that can be felt from a tooth?
Pain (sensory nerves are only nociceptors)
48
How would you carry out the electric pulp test?
– Explain the procedure to the patient!
– Ideally isolate the tooth in question
– Use toothpaste to form a good contact with the tooth
– Test an adjacent tooth, buccal surface
– Wait at least 30 seconds
– Test the tooth in question buccal surface
– If no response, wait one minute, then test again
49
What factors affect the reliability of sensibility testing?
- Varying thickness of enamel/dentine
• Restorations, notably Crowns
• Teeth with Open Apices
• Patient response factors
50
What does sensitivity mean in terms of reliability of sensibility tests?
Sensitivity (true positive) measures the proportion of actual positives which are correctly identified as such (e.g. the percentage of teeth with an intact nerve supply which are correctly identified as having an intact nerve supply
51
What does specificity mean in terms of reliability of sensibility tests?
Specificity (true negative) measures the proportion of negatives which are correctly identified as such (e.g. the percentage of teeth without an intact nerve supply which are correctly identified as not having an intact nerve supply
52
How is pulse-oximetry carried out?
– Passes wavelengths of light to a photo sensor to detect pulsing arterial blood
– Equipment is expensive
– Not proven to be as reliable as current, cheap methods of sensibility testing
53
How is laser doppler flowmetry carried out?
– Light is transmitted through the pulp – If a blood flow is present the light will be scattered, which is detected by a sensor
– Equipment is expensive
– Not proven to be as reliable as current, cheap methods of sensibility testing
54
What are the types of periapical tests?
- Percussion (not true vitality test) - is it painful?
– Palpation (not true vitality test) - palpate over the apices to check apical inflammation and pus production
– Tooth slooth
55
What is a tooth sloth?
- pyramidal plastic with an indent where the cusp sits
- Allows pressure testing of individual cusps
• Pain on biting is usually an indication of periapical inflammation
• Pain on release of pressure is usually an indication of a crack
56
What tests exist for cracks in the teeth?
```
Tooth sloth
Tongue spatula (broken in half)
```
57
What additional pulp tests exist?
-Transillumination (Direct light though the tooth to detect pathology, especially cracks and fractures which cannot be seen under the dental light - however lots of teeth have natural cracks)
• Selective anaesthesia
• Test cavity
58
Why would you use selective anaesthesia?
When patient can't isolate where the pain is coming from, can numb tooth which you think is causing pain
59
When would you test cavity?
As a last resort
fairly certain tooth has been found
- begin access cavity prep without local
- if they feel sensation then tooth is vital
60
When would you take an x ray?
After you have arrived at the provisional diagnosis
61
What are periapicals used to detect/confirm?
* apical pathology
* periodontal bone loss
* Root fractures etc
62
What are the diagnostic warning signs?
- Pulp chamber constriction
| - pulp stones (possibility indicate previous trauma, occlusal parafunction)
63
What can aid diagnosis if a sinus is present?
- insert a gutta percha point into the sinus tract
| • The gp point will appear on the radiograph and ‘point’ to the source of the infection
64
What are the classifications of pulpal diagnoses?
```
- Normal pulp
– Reversible pulpitis
– Symptomatic irreversible pulpitis
– Asymptomatic irreversible pulpitis
– Pulp necrosis
```
65
What are the signs and symptoms of reversible pulpitis?
- History of pain to cold or sweet stimuli
Pain lasts a few seconds following removal of the stimulus
• Poor pain localisation
• Usually relieved by analgesics
• Pain is not spontaneous and does not keep the patient awake
• Tooth will usually respond in an exaggerated fashion to pulpal sensibility testing
• No clinical signs of periapical pathology, however the tooth may be tender to pressure
• No periapical radiographic changes, but there may be signs of caries, lking restorations etc
66
What are the consequences of inflammation in the pulp?
- Painful pulpitis (but not always)
- Pulp tissue breakdown (pulpal necrosis)
- Root canal infection leading to apical periodontitis/abscess
67
What is the result of inflammation in the pulp?
reduced blood flow leading to:
| Ischemia. Cellular acidosis. Degeneration of the metabolically active odontoblasts.
68
What anatomical features are unique to the dental pulp?
Unyielding walls
Constricted blood source
Tooth surrounded by bone
69
Why are the anatomical features of the pulp unfavourable when it comes to inflammation?
Unyielding Walls - Limits pulp swelling
Constricted Blood Source
• Limits blood supply - Subject to “strangulation” by pulp swelling
Tooth Surrounded by Bone - Bone infection invariably results
70
What do dendritic cells do in the pulp?
Alert the immune system
71
Where do A-delta and C fibres run?
A-delta fibres extend into the tubules
C-fibres run in the deeper pulpal tissues
72
What is reactionary dentine?
Response by primary odontoblasts to mild stimuli such as;
- Initial pre-cavitated stage of enamel caries -Slow progressing caries
- Shallow tooth preparation
dentine remains mainly normal structurally, OB are vital, dentinal tubules present
73
What is reparative dentine?
- The insult or injury destroys the primary odontontoblasts --- Secondary odontoblasts organise themselves and secrete new dentine
- How well this new layer organises itself and the nature of the stimulus will dictate the rate of formation of new dentine
- less sensitive to thermal, osmotic and evaporative stimuli, more porous and impregnated with soft tissue which is prone to infection, reduced or no tubular fluid (because it is laid down faster)
74
What are the causes of damage to the pulp?
* Microbial
* Mechanical
* Thermal
* Chemical
* Pathologies
75
How can bacteria gain access to the pulp space?
- CARIES
- Cavity prep
- Microleakage around restorations
- Cracks Trauma = Periodontal defects
76
What methods can be used to reduce microbial contamination during operative procedures?
* Rubber dam
| * Antimicrobial agents - use chlorhexidine soaked onto a cotton wool pledget following cavity preparation
77
What types of mechanical attacks can affect the pulp?
External trauma
Dental Treatment :
Tooth surface loss
78
How can dental treatment affect the pulp?
- instrumentation trauma
- thermal build up-heat kills tissue
- dessication
- pulpal exposure
- chemical attack
79
What pathologies can cause resorption in the pulp?
- Orthodontic forces
- Trauma
- Bleaching
- Tumours
- Unknown aetiology
80
What is vitality?
having an intact blood supply - usually means innervation is also intact but not always the case
81
What are the characteristics of an ideal pulp tester?
- Must be effective on both anterior and posterior teeth (single/multi-rooted)
- Must be effective if the tooth is carious or if it has been restored
- Must be effective when secondary dentine has been deposited
- Must be effective in unusual circumstances (re-implanted, transplanted teeth)
82
What are the tests for innervation (more common on clinic)?
Electrical stimuli
| Thermal stimuli - cold (ethyl chloride) or hot (gutta percha)
83
What are the tests for blood flow (vitality)?
u.v. light photography
oximetery/photplethysmography
laser-Doppler flowmetry
84
What are the prinipals of conventional pulp testing?
Patient indicates a response
Tests whole of the pain pathway not just the pulp
Sensation should be uncomfortable but not painful at detection threshold
Confirm by questioning that it's the pulp being stimulated, not the gingiva or periodontal ligament (PDL more buzzing feel)
85
What makes pulp testing difficult?
- The pulp is in an enclosed chamber making access difficult
- The pulp chamber is practically opaque (n.b. dentinal tubules are opaque)
- Electrical resistance (impedance) varies widely
- Pulp size diminishes due to secondary dentine
86
How does an electrical pulp tester achieve good electrical contact with the pulp?
Avoid gingival margin and restorations as electricity would spread here
use toothpaste - acts as a conductor (has lots of ions in it that conducts)
- electroconductive rubber
- indifferent electrode in hand or via handle and operator
teeth isolated - no saliva, dentures etc
87
How do electrical pulp testers work?
Directly activates pulpal nerve fibres (bypass receptors) by depolarising the nerve fibres due to the electricity from the box - AP's generated
electrical current flowing into nerve cell causes depolarisation but most pulp testers generate voltage pulses not current pulses, therefore electrical resistance (impedence) of the tooth is important
88
What law links voltage, current and resistance?
Ohm' low
current = voltage/resistance
This explains why the voltage can be converted into current for an electrical pulp tester
89
What is a common way of getting a false negative from an electrical pulp tester?
Tooth with a lot of resistance - old age - calcified
technology insufficient to generate enough current to excite nerves due to high resistance
90
What is the difference in outcomes with most commercial pulp testers and constant current devices?
Commerical - often cause false positives because of stimulus spread to gingival margin and periodontal ligament
constant current - few false positives but more false negatives
91
Where are pulpal nerve fibres excited?
Where current density is the highest
92
What is the relationship between electrical threshold and pulp status?
No relationship - increasing electricity doesn't mean pulp will feel more or be more or less healthy, just need a response (70% of the time correct)
93
How do Laser-Doppler flow meters work to test blood flow?
Optical fibre directs infra-red light to the tissue
Light is scattered by moving red blood cells inside the vessels and undergoes a 4kHz change in frequency (doppler shift)
This light mixes with light scattered by stationary objects = beating
More cells = greater intensity of beating
Second fibre collects light which is analysed by a photodetector to produce estimate of blood flow
94
What are the problems with laser- doppler methods?
Signal is not in absolute units rather it is a product of number of cells scattering the light and their velocity
Signal is only linear if the volume fraction of red cells in tissues is less than 1%
Humans - considerable gingival and periodontal contamination of the blood flow signal (up to 80% of the signal)
- cost £10K upwards
95
How do bacteria gain access to the pulp space?
```
Caries
Cavity preparation
Micro-leakage around restorations
Cracks
Trauma
Dessication
Periodontal defects
```
96
What prevents release of bacterial toxins from the root canal space along the dentinal tubules and out into the PDL?
Cementum
97
What is the 1st and 2nd line of defence in the tooth?
1st - pulp
| 2nd - peri-apex (tissue fluids, inflammatory exudate, immune cells)
98
What does the pre-operative radiograph for an RCT show?
shape of canal
number of roots and canals
presence of any PA lesion
presence of any previous root treatment
any other pathology
visibility of pulp chamber and canal space
restorability of tooth (clinical assessment)
99
What is the ultimate aim of RCT?
Prevent or cure apical periodontitis by eliminating the source of infection
100
What are the objectives of RCT?
Complete removal of the irreversibly damaged or necrosed dental pulp (mechanical prep)
Dissolution and debridement of inflamed and infected tissue from the pulp space by thorough cleansing. disinfection and shaping (chemical prep)
create an optimal shape to allow a well-compacted root canal filling to be placed (obturation)
101
Why are the antimicrobial irrigants (sodium hypochlorite) used?
Flush out remnants of pulp tissue and debris created during mechanical prep
to dissolve residual pulpal tissue
to kill bacteria and remove bacterial biofilm
to clean the parts that are inaccessible e.g. lateral canals to instrumentation
to facilitate insrumentation and prevent root canal blockages by acting as a lubricant
to remove the smear layer
102
Why is access in a straight line?
It reduces stress on instruments to reduce the chance of instrument fracture
It reduces the chance of procedural errors
It simplifies treatment by providing a clear path of insertion for the instruments
103
Why is the coronal two thirds prepared first?
Removal of the bulk of infected pulp tissue and dentine
Reduced risk of pushing infected debris apically or through to the peri-radicular tissues
Elimination of interferences in the coronal third, thus minimizing the risk of blockages apically
Early introduction of irrigants into the apical portion of the canal
Easier negotiation to working length
Improved tactile feedback apically
104
What happens without a glide path to the canal?
Ledge formation
Transportation
Zip formation
Perforation
105
Why does the working length need to be determined?
To enable the root canal to be prepared as close to the apical constriction as possible (0.5mm-1mm short of apical foramen)
106
What helps to determine the working length?
Root morphology
Radiographic interpretation of canal anatomy - apex
Radiographic working length interpretation
107
What can over instrumentation lead to?
Damage to the root apex and periapical tissues
Extrusion of debris which may contain micro-organisms, elements of necrotic pulp, and infected dentine chips
The presence of excess root filling material in the PA tissue which may act as foreign matter
108
What is the method of determining the working length?
Measure the pre-operative radiograph - estimated working length
Tactile feedback of the apical constriction - choose file large enough to feel the constriction
Diagnostic or Working Length radiograph
Electronic Apex Locator (EAL)
Paper point - if blood/fluid on it, then gone beyond paper point
109
What can you use to help you locate the apex?
Careful study of high quality radiographs (digital)
Magnification of radiographs, changing the contrast and light
Keeping apical anatomy foremost in your mind
Use tactile sense to locate apical constriction
Observe blood/fluids on instrument tip or anywhere on a paper point
Use and understand your apex locator
110
What is apical transportation?
An apical transportation of the root canal represents iatrogenically moving the physiologic terminus to a new location on the external root surface. ... A canal that has been apically transported predisposes to obturation overextension where gutta percha moves beyond the foramen and into the periapical tissues.
111
Why does the apex need to be prepared?
Needs to be enlarged to create adequate space for irrigants and filling material
112
Why is the apex tapered?
Optimal shape for effective irrigation and root canal filling
113
What is the minimum size the MAF has to be?
#25 file at minimum or at least 2 file sizes above the file size which first fitted snuggly at working length
114
Where is step-back prep used?
Prepares the apical 1/3 by creating a series of steps
achieved by shortening the length of the file and reducing the length by 1mm and continued until met up with the coronal 2/3 prep
115
What is apical gauging?
After step back is finished and apical prep done, insert MAF - should feel light resistance and snugness at working length
if the file moves apically at all, then a larger size is needed, move up 1 file size and repeat apical gauging procedure
if MAF size is increased, then step back process is done again.
116
What are the properties of an ideal irrigant?
```
Antimicrobial
Cheap
Able to dissolve pulp tissue
Able to remove the smear layer
Easy to use
Long shelf-life
Compatible with dentine
Tissue-friendly
Substantive (remain in the root-canal for a sustained period)
Non-corrosive for dental instruments
Non-toxic
```
117
What is the smear layer?
An amorphous film of organic and inorganic material generated from instruments contacting the root canal walls
It ‘plugs’ the dentinal tubules
Delays the penetration and effects of antimicrobials
118
What is the action of irrigants?
Removal of debris
Lubrication of instruments
Antisepsis
Decomposition and removal of blood and tissues
119
What type of irrigants can be used?
Medical-grade Sodium Hypochlorite (NaOCl, 1% (Kill time: 90 minutes-5.25% Kill time 90 seconds)
Ethylendiaminetetraacetic acid (EDTA, 17%)
Chlorhexidinegluconate (2%)
Iodine compounds (Allergic reaction)
120
What does sodium hypochlorite not remove?
The smear layer
121
Which irrigant can remove the smear layer?
EDTA - must be used in conjuction with NaOCl after
122
What are the benefits of removing the smear layer?
It harbours the bacteria and may also act as nutriment for microbes
May act as a barrier to irrigant and medicament penetration
May influence the quality of the bond obtainable with root canal sealers
If disintegrates after completion of RCT, will affect the seal of root canal filling material
123
Which irrigant should not be used in conjuction with NaCOl and why?
Chlorhexidine - formation of a cytotoxic precipitate known as parachlorianiline (PCA) which occludes the dentinal tubules.
124
What is used to dry the canals?
Paper points
125
What type of intervisit medication is used?
Non-setting calcium hydroxide
| Odontopaste
126
How does calcium hydroxide act?
Damages bacterial cytoplasmic membranes
Denatures proteins
Damages DNA
Inactivates bacterial enzymes
Bacterial replication is associated with loss of genes and lethal mutations
Hydroxyl ions to induce lipid peroxidation
This results in the destruction of phospholipids and the breakdown of lipopolysaccharides!
127
What anti-bacterial substances are in odontopaste?
5% Clindamycin (antibiotic)
1% Triamcinolone (corticosteroid)
+ (calcium hydroxide in a zinc ocide paste)
128
How do you place the inter-visit medication?
Master K-file/straight probe for coronal 2/3
small k file - reaches apex to paint all walls
Large paper point
Lentulo spiral fillers
129
What do you place on top of the inter-visit medication?
Endo sponge
GIC/IRM/Kalzinol (ZOE)
130
How is the calcium hydroxide removed?
Flush out the calcium hydroxide with an irrigation syringe and sodium hypochlorite and break it up with a K file
use an ultrasonic scaler (or air scaler) with water ‘on’
131
Why might some RCT's need more than one visit?
Infected or necrotic teeth
acutely symptomatic teeth
inadequate time
if canal cannot be dried
132
What are the ideal properties of a root canal filling material?
```
Radiopaque
Inert
Bio-compatible
Safe
Long shelf life/long working time
Easily introduced into the canal
Easily removed
Prevent leakage
Adapt to irregular shape of the root canals
Dimensionally stable on setting
Compatible with other materials
Inexpensive
Bactericidal
Insoluble in tissue fluids
```
133
What is the purpose of the root canal sealer?
Take up voids around the filler
Fill accessory and lateral canals
Fill the space between GP points
Lubricate and help the GP points to move
134
What are the properties of an ideal root canal sealer?
```
Biocompatible
Non-toxic
Safe
Inexpensive
Long shelf life / adequate working time
Easy to handle
Radiopaque
Dimensionally stable on setting
Insoluble in tissue fluids
Not stain the tooth
Easy to remove
```
135
What types of root canal sealer exist?
ZOE based: e.g. Tubliseal
Calcium Hydroxide based: e.g. Sealapex
Resin based: e.g. AH Plus
136
What are the types of obturation techniques?
Cold Lateral Condensation
Thermoplastic Condensation:
Warm Lateral Condensation
Warm Vertical Condensation
137
Describe cold lateral condensation
Select a master point
Fit it in the canal
Mark the GP at working length or grip it securely in endodontic locking tweezers
Apply sealer to the master point
Paste the canal walls with the sealer
Seat the point into the canal at full working length
While the spreader is in place, take an accessory point in the tweezers and dip it into the sealer
Do not leave the points or the GP in the sealer, may soften, making insertion difficult
Repeat the sequence using gradually larger spreaders and GP points until the canal is filled
Remove excess gutta-percha from the canal orifice with a heated instrument, and firmly compact the remaining GP to seal the coronal access of the tooth.
Cut back all GP to the entrance of the root canal orifice, leaving a clean pulp chamber
138
Why may there be discoloration of the clinical crown?
Endodontic materials can stain
By-products of pulp tissue breakdown
Subsequent coronal leakage
Staining from filling materials in the access cavity/pulp chamber
139
What are the stage of mechanical prep?
```
Tooth Isolation (RD)
Access to the pulp chamber
Straight-line access
Location of canal orifices
Opening of the coronal two thirds (Coronal flare)
Working length determination
Prepare the ‘glide path’
Shape the canal to working length (Apical preparation)
Clean and disinfect the canal
```
140
What type of syringe if used for irrigation?
side-vented syringe
141
What is the apical delta?
The branching pattern of small accessory canals and minor foramina seen at the tip or apex of some tooth roots.
142
How may you get misreadings with an electronic apex locator?
Lateral canals
Saturated canals
Restorations
File is too small
bone loss - loss of PDL
143
Why is the radicular space obturated as well?
eliminates leakage
reduces coronal leakage and bacteria contamination
seals the apex from the periapical tissue fluids
entombs the remaining irritants in the canal
144
Where should the length of the obturation extend to apically?
To the apical constriction
145
What is used to spread and pack the accessory points into the canal?
Hand spreader/finger spreader (better)
146
How do you pick the size of the finger spreaders?
It is based on the width of the canal
| Spreader should reach within 1-2mm of working length each time
147
What is the aim of an inter-visit dressing?
To ensure and maintain a bacteriostatic/cidal environment in the root-canal between RCT appointments
148
What are the objectives of an inter-visit dressing?
Prevent bacterial proliferation and reduce bacterial count
Prevent ingress of contaminants from oral cavity that may provide nutrients for existing bacteria
provide an effective seal between appointements that's easily removed
149
What is the % of bacteria that can still be isolated from canals after disinfection?
50%
150
What is the pH of calcium hydroxide?
>12
151
What can you put on top of the calcium hydroxide dressing as an extra barrier?
Cavit or Coltosol
152
Why is cotton wool no longer used int he access cavity?
Catches the bur and ruins it
has no anti-microbial properties
fibres get trapped in cavity margin and wicks bacteria and contaminants from the oral environment
153
Why is GIC used as the final step of the inter visit dressing to restore cavity?
Provides effective durable seal but easy to remove as well
Chemically set GIC provides reliable and predictable bond to enamel and dentine
fluoride releasing
154
What is the order of the inter-visit dressing?
Ca(OH2) - sponge - cavit/coltosol - GIC/IRM/ZOE
in anterior teeth with less space - cavit or sponge
155
Why may odontopaste be used in the canals sometimes inter visit?
Used as a paste into the root canal to help calm
down a very acute situation.
Not to be left a long period of time
Ledermix can also be used
156
Ledermix (similar to odontopaste) - what are the components?
Antibiotic - demeclocycline calcium
• Corticosteroid - triamcinolone acetonide.
• sodium sulphite anhydrous
157
What does DFU stand for?
Direction for Use
158
What are the post operative instructions for a root canal treatment?
Expect discomfort from either residual pulpal or periapical inflammation!
• 2-3 days common
• Inflammation peaks at 5-7 days and lasts 10-12
• Analgesics
• Anti-inflammatory drugs NSAID’s e.g. Ibuprofen
• Advise against codeine
• Adjust occlusion
