Endodontology Flashcards
(88 cards)
1
Q
What is it?
A
Understanding the form, function, health of, injuries to and sciences of disease of the pulp. The prevention and treatment of diseases to the pulp and periradicular region.
2
Q
What is pulp dentine?
A
Specialised tissue showing primative response to stimuli - recognises pain or not.
3
Q
What are the functions of the pulp?
A
Development of the tooth (endomesenchyme)
Sensation (pain)
Nutrition (blood supply)
Defence (partially effective)
4
Q
What is the response to irritation?
A
Inflammation (increased blood flow in enclosed space = pain) Secondary dentine Arterio-venous shunts Recovery Death
5
Q
What are causes of injury to the pulp?
A
Caries Dentistry (iatrogenic damage) Scaling Trauma Loss of tooth substance through tooth wear Periodontal diseases
6
Q
What are the bacterial species’ involved in the root canal system?
A
Mixed aerobes and anaerobes
Killed by proteolytic substances which attack proteins
7
Q
What are periradicular tissues and their response to infection?
A
Surrounding alveolar bone, cementum and periodontal ligament, protective response to infection.
8
Q
Why may LA not work?
A
Hyperaemic pulp - acute pulpal inflammation/hyperexcitability of nerve fibres (C fibres) means LA is unable to block the conduction of these impulses.
Increased vascularity may remove LA more rapidly and pH of products may be more acidic
Infection
Patient factors - anxiety
9
Q
What are additional anaesthesia techniques?
A
Intraligamentary
Intrapulpal
Intraosseous
10
Q
Why is rubber dam mandatory?
A
Protection of airway Protection of irrigants Prevention of contamination Improved access and visualisation Patient comfort
11
Q
What is used to seal a rubber dam and secure it?
A
Rubber wedgit and oraseal around the tooth once rubber dam placed.
12
Q
What must be ensured regarding condition of tooth before treatment?
A
Crown restorable
Caries and defective restorations removed
Sound coronal restoration
13
Q
Why do we take periapical radiographs?
A
- Number of canals
- Number of roots
- Morphology of canals
- Extent of current restoration
- Presence of caries
- Presence of canal sclerosis/pulp stones/previous RCT/fractured instruments
14
Q
What is the aim of access?
A
Remove roof of pulpal chamber No damage to pulpal floor Straight line access Conservative Retentive for temporary restoration
15
Q
What do you need to find canals?
A
Good light, loupes, magnification, explorer
16
Q
How can safe ended burs be used around the floor of the pulp chamber?
A
They have no cutting flutes or diamond at the tip so can be used safely around floor.
17
Q
What can ultrasonic instruments do?
A
Carefully remove infected dentine around canal orifices and prep the canals.
18
Q
What is chemomechanical preparation?
A
Mechanical cleaning and shaping with files and chemical disinfection.
19
Q
Which part is prepared first?
A
Coronal part, removes heavily infected tissue and prevents bacteria being carried apically.
Straight part prepared with - gates glidden burs and files and the remainder 2/3 with files, irrigation used throughout.
20
Q
What do gates glidden burs do?
A
Don't cut at the tip Will stay within the canal Steel Break easily Designed to break at shank Sized according to number of bands
21
Q
What do we use in the apical 1/3
A
K - files
Stainless steel
Sized according to diameter at tip
10 = 0.1mm
22
Q
What are qualities of a intra-canal medicament?
A
Antibacterial, aids periapical healing, therapeutic, anti-inflammatory, long lasting, non-irritant, easy to remove and cheap.
23
Q
When do we use intra canal medicaments?
A
Persistent infection, unable to dry prepared canal, incomplete apex, incomplete prep, insufficient time for obturation.
24
Q
What properties of CaOH mean it is an intracanal medicament?
A
Antibacterial Aids repair Apexification Dissolves debris Easy to remove
25
What is the aim of temporisation?
Seal tooth, restore function, prevent over eruption, restore aesthetics
26
What is the aim of obturation?
3D seal of canal preventing microorganisms entering and reinfecting. Use GP cones and finger spreaders to condense.
27
Different types of sealers
Zinc oxide eugenol - fills in voids
CaOH - antibacterial
Glass ionomer - radiopaque
28
How does disease start in the pulp-dentine complex?
```
Ongoing carious insult
Trauma
Periodontal problems
TSL
Dental procedures
```
Caries - pulpal disease - periapical disease - extends into dentine - pulp inflammation and laydown of tertiary dentine.
Fluid movement in dentinal tubules causes pain
Pulp starts to calcify and move away, removing caries will maintain vitality if not inflammation becomes irreversible.
29
What is pulpal necrosis?
No blood supply in the root canals, last nerve cells to die are the c fibres - severe pain of irreversible pulpitis.
30
What is a biofilm?
Aggregation of micro-organisms growing on solid substrate, complex community interactions, extracellular matrix of polymeric substances.
31
What bacteria are in the apical region?
Low oxygen, facultative anaerobes, lower bacterial counts but less accessible to treatment
32
What bacteria are in the coronal region?
High oxygen, more carbohydrate and nutrients, higher counts and more accessible to treatment
33
What is periapical disease?
Biofilm forms within root canal and matures
| Disease is inflammatory immune system reacting to presence of microbes and their products apically.
34
What are the zones of fish?
Infected
Contaminated
Irritated
Stimulated
35
What is an apical granuloma?
Consists of granulomatous tissue with inflitrate cells, fibroblasts and well developed fibrous capsule, no live bacterial content.
Epithelium may grow into entrance of root canal forming plug like seal at apical foramen.
36
What do aB fibres do?
Touch and pressure, low threshold and fast
| Myelinated
37
What do a (delta) fibres do?
Hot cold sensitivity, low threshold and fast
| Myelinated
38
What do c fibres do?
High threshold, slow dull pain associated with pulpal inflammation
Unmyelinated and smaller than a fibres
39
What are the problems with diagnosis?
Cant see the tissues you are diagnosing
Relying on reported symptoms
Poor correlation between symptoms and histology
40
What do you look for extra-orally?
Swellings, assymetry
| Discharging sinus - one of those teeth could be non vital place GP point and radiograph§
41
What do you look for intra-orally?
Examine dentition - palpate and percuss suspected teeth
Vitality test
Is there caries how extensive if so
Does the pulp look calcified
Do the root canals look curved or sclerosed?
42
What gives a 3D view of tooth?
Cone beam computerised tomography - increased dose
43
Can you have pulpitis and apical periodontitis in multi rooted teeth?
Yes
44
Diagnoses
Dentine hypersensitivity
Reversible or irreversible pulpitis
Acute apical periodontitis - TTP, no lesion radiographically
Chronic apical periodontitis - no symptoms, lesion present
Chronic periapical periodontitis with suppurative sinus
Periapical abscess - localised swelling
Chronic apical periodontitis with acute exacerbation
45
Differential diagnosis
Sinus pain - have they had a cold recently?
TMJ pain
Headache disorders
Systemic - cardiac, neoplastic
Neuralgia - trigger spots
Neuritic - shingles post herpetic neuralgia
Psychoactive drugs
46
How to tell the difference between odontogenic and non odontogenic pain?
Odontogenic pain is relieved by LA, unilateral, thermal change, biting, sweet produces pain with percussion
47
What is the purpose of RCT?
To maintain asepsis of the root canal system or disinfect it entirely. Chemomechanical preparation of the root canal, obturate and restore.
48
What are difficulties in root canal treatment?
Curved root canals - procedural errors and don't conform to same shape as canals
Complexity of system
Difficulties in getting irrigants through the system
49
What is essential before undertaking?
Correct diagnosis and treatment plan
Pre-operative assessment is key
Good radiograph essential
50
How to assess radiograph?
Are the roots curved and where?
How many canals are there?
Is the canal obvious or sclerosed?
Is the apex damaged or open?
51
If the tooth is restorable before RCT what do we do?
Build it up to facilitate RCT and prevent fracture
52
What is the access strategy?
Estimate distance to the roof of the pulp chamber and floor, use bur on wet film or measuring tool on digital. Line up for largest part of pulp chamber go through the rood then move to safe ended bur (endo Z) remove all of the pulp chamber roof until you see all the floor.
Go through with long tapered diamond through cingulu into dentine change angle of the bur in line with long axis of the tooth.
53
What do you need for access?
Good isolation, good magnification, good pre-op assessment and knowledge of anatomy
54
What to do in access
Remove restoration to see restorability
Build tooth back up to create four walls
Aim for largest canal (distal lower molar, palatal upper molar)
Breakthrough roof of chamber
Remove roof of chamber with safe ended bur
Ensure you can see chamber floor
Remember how many canals you're looking for
55
How do we prep the canals?
Crown down - start in coronal part of the tooth, start coronal flare, flare middle part then apical 1/3
56
If you do not coronal flare what do you risk?
File fracture, placing debris in apex of the tooth
57
What is the stepdown technique?
Files manipulated in a filing motion step winding motion of balanced force.
Anti curvature - file away from danger areas (furcations)
58
What are the different types of files?
```
Stainless steel/nickel titanium
K type (K-file, K-flex, K-flexo)
H type - hedstrom
```
59
What are K files made up of?
Stainless steel
Twisting blank wire
Variations depending on shape of wire
60
What are hedstrom files?
Aggressive cutting flutes
| Can only be used in hand filing motion
61
For every 1mm back with a 2% taper how much does diameter increase by?
0.2mm
62
What are gates glidden burs?
Has a long shank to enter deeply into tooth and give visibility
Number of bands indicate size (2,3,4 most common)
Use a brushing motion cutting on the outstroke
63
When do we determine working length?
Once coronal flare is completed
| We want to prepare to apical constriction
64
What do we use to determine working length?
Electronic apex locator
| Diagnostic radiograph
65
How do we determine working length on a radiograph?
Paralleling technique with endoray holder, take radiograph with file in.
Estimate from pre-op radiograph use EAL get zero reading and subtract 0.5mm/1mm from this working length.
Take size 10 to 15 to length work until loose and irrigate between and then next file.
If next file doesn't go easily to within 2mm of working length go back to previous file and work looser.
Work until master apical file reached (25/30) step back to blend with coronal flare.
66
Why do we irrigate?
To remove debris to prevent canal blockage, tissue dissolution (chemical), biofilm removal (physical) and antimicrobial (chemical)
67
What different irrigants are there?
```
LA, water saline - no effect beyond physical flushing
Iodine
EDTA
Chlorhexidine
Sodium hypochlorite
```
68
What are ideal properties of irrigants?
Cheap, safe, non toxic, antibacterial, dissolve tissue, no deleterious effect on dentine, good flow
69
What are the properties of sodium hypochlorite?
Dissolves organic tissue, antibacterial, cheap, good flow properties
70
Problems of sodium hypochlorite
Toxic, painful and leads to tissue necrosis if extruded under pressure, damages clothing, can damage dentine by removing collagen.
71
What are the properties of chlorhexidine?
Antibacterial at 2%, released from dentine over periods
72
Problems of chlorhexidine?
Does not dissolve tissue, cannot be mixed with NaOCl - makes carcinogenic mixture that blocks root canals.
73
What are the properties of EDTA?
Chelating agent, has no antibacterial effect, dissolves inorganic material - removes debris well can help break down biofilm.
74
Problems with EDTA?
Does not dissolve organic tissue and neutralises NaOCl so use separately.
75
What do we irrigate with usually?
NaOCl inbetween files once canals prepared
76
What is MDI?
Where we pump irrigant then pump GP point and repeat to make irrigant flow more readily to apical portion
77
Why obturate?
Mitigate potential for re-infection and substrate leakage
78
How does bacteria get back into root canals?
Defective coronal restorations
Open dentinal tubules
Accessory canals exposed by periodontal pocketing
Apical leakage
79
What are the aims of obturation?
Fill entire pulp space, provide barrier to reinfection from microbiota, provide barrier to potential nutrient supply from periapical tissues.
80
when do we obturate?
Ensure canal is prepared and irrigated
Canal must be dry - no blood/pus
Patient symptom free, sinuses resolved
81
What do we use if it is not possible to obturate?
Dress canals with CaOH - high pH, antimicrobial or odontopaste if there is pulp remnants you cannot remove - anti inflammatory.
82
What do we use in obturation?
Gutta percha with sealer - bioceramic cements
83
What are rolled GP points made up of?
75% ZnO, 20% GP (B phase) 5% wax
84
What does sealer do?
Fills in defects in root filling material, flows into lateral and accessory anatomy bonds root filling to core material.
85
Properties of sealer
Antimicrobial, non-toxic, easy to mix, long working time, insoluble, radio-opaque good flow properties
86
What different types of sealers are there?
```
Eugenol based (tubliseal, kerr's, roth's, grossman's)
Resin based (AH)
Bioceramic - most commonly used (endosequence, MTA - fillaplex)
```
87
What is the techniques of obturation?
```
Cold lateral compaction - most common
Warm lateral - hot GP increased flowability, more difficult to control
Carrier based
Paste
Cement
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88
What is the cold lateral compaction technique?
Try in finger spreader - choose largest that will go within 2mm of working length
Choose GP point that is same size of master apical file, try ensuring it goes to working length and fits snuggly
Dry canals with paper points and coat with thin film of sealer using GP point.
Place into canal alongside finger spreader aiming to get within 2-3mm of working length, apply lateral and apical pressure for 15 seconds twist and withdraw
Fill resulting space with accessory GP point matched to spreader size, coated in sealer
Work quickly due to space lost by elastic recoil
Repeat, when two accessory cones are in take radiograph to make sure you are at the right length, try and fit more points in until you can't.
Use heated plugger to remove excess GP and pack down GP in coronal 1/3 do not leave GP in pulp chamber.
