Endo Flashcards
0
Q
What are the four principle to endo ?
A
- Respect the integrity of the pulp and the periodontal tissues by avoiding mechanics, and chemical trauma
- Protect vital pulp
- Provide RCT tho eliminate any source of infection
- Follow up
1
Q
What is endo?
A
Branch of dentistry that deals with the aetiology diagnosis prevention and management of diseases of the dental pulp and their sequelae
2
Q
What are the stages to endo?
A
Diagnosis Access Canal prep Canal medicaments Obturation Follow up
3
Q
What type of bacteria cause endo lesions?
A
Aerobic and anaerobic but becomes more anaerobic with time and more gram negative
4
Q
What type of relationship exist between the bacteria?
A
Symbiotic
5
Q
Name the bacteria involved in endo?
A
Streptococci
Prevotella oralis
Porphyromonas
6
Q
How do Bactria gain access to the root?
A
Deep carious lesion
Anchoresis
Perio
Trauma
7
Q
What is the mantra for endo?
A
Cleans
Shape
Obturate
8
Q
What is the aim of endo?
A
Provide a 3D hermitic apical and coronal seal
9
Q
What lesion may we see adjacent to the tooth to indicate pulp deAth?
A
Sinus
10
Q
What must we take before beginning endo?
A
Medical dental and social history
Full pain diagnosis
X-ray
11
Q
What must you look at on the pre op X-ray?
A
- Large restoration or caries, previous pulp cap,
- pupal reaction, narrow canals, chamber, internal resorption
Pulp chamber: position of roof and floor and how much reparative dentine
Root canals: number of roots and canals, how much calcification, pulp,stones? And canal curvature
Any previous root filling, Periapical radiolucency
12
Q
What is the apical war zone?
A
PMN
Macrophages
B and T cells
Plasma cells
13
Q
What are the inflam mediators involved?
A
CLN
Complement
Lysozymes
Neuropeptides
14
Q
What is the perical lesions caused by?
A
PLC
Prostaglandins
Leukotrienes
Cytokines
15
Q
What must you assess with regards to the tooth that you are going to Do RCT on?
A
Look: Colour Caries Presence of sinus Erythema over apex
Touch:
Mobility
TTP
Tender to palpation
Invasive :
Vitality
Local perio
Radiograph to show pulp morphology
16
Q
What is the first stage of endo once the assememt has been done? And what can you use for this?
A
Access
High speed burs for initial access and them slow speed eg tapered fissure/endo Z/Blunt ended/ or round burs
17
Q
What is special about some of the ways the access burs are made?
A
They have long shanks and some have blunt ends (non cutting tip)
18
Q
What is the diagnosis for the pulp following investigations?
A
Healthy
Reversible pulpitis
Irreversible pulpitis
Necrotic pulp
19
Q
What are the requirements of the pre op radiograph?
A
Treatment tooth centrally located with at least 3-4mm peri Radicular tissue available and taken with film holder to minimise distortion
Second film taken at 15/20 degrees horizontal parallax
20
Q
What is the purpose of the access cavity?
A
Removes the entire roof of pulp
Allows debridement
Allows access to the canals with straight line
Allows placement of temporary cement between visits
Conserved tooth structure but still achieve goal s
21
Q
What shape should the access cavity be?
A
Non undercut
22
Q
What is the shape of the access cavity determined by?
A
Position and number of pulp horns
23
Q
How manu pulp horns does an incisor have?
A
3
24
How many pulp norms does a canine have?
2
25
How Many pulp horns does a premolar have?
2
| Ovoid
26
What shale is the access cavity for molars?
Triangular
27
What size magnification does an operating microscope use?
X16
28
What size magnification do loupes provide?
X2 to 4.5
29
What can be used to locate canals?
```
Knowledge of anatomy
Information from radiographs
Magnification technqiue
Trans illumination with white light
Canal probe
Fine endo instruments eg 6,8
Dyes
Ultrasonic
```
30
What access problems may you come across?
Crown in situ so loss of directional sense
| Obstruction within canal eg pulp stones, post crown, fractured instrument
31
How do you acces?
1. Check depth from reference point to roof of pulp chamber
2. Use tapered fissure bur to create outline in dentine
3. Continue in depth until pulp chamber reached
4. Apply rubber dam
5. Remove roof of pulp using slow speed long shank bur Refine the cavity and cut on the out stroke to flare access
6. Clear debris from chamber with excavators
7. Irrigate with sodium hypochlorite
8. Locate orifices if canal and check straight line access
32
What is the advantage of rubber dam?
Protects oro pharynx
Protects soft tissue From caustic material
Retracts soft tissue and tongue and improved access
Maintains clean dry and aseptic working environment
33
What is the next stage following access?
Measure the working length
34
How can working lengths be measured?
Tables of average length
Apex locator
Radiographs
35
What is the average length for the maxillary incisors and premolars from average value tables? What is the disadvantage of this?
```
Central: 23.70
Lateral: 22.10
Canine: 27.30
Four: 22.30
Five: 22.30
```
Dis: makes huge assumptions
36
How does an apex locator work?
Measure electrical resistance between an instrument in a root and an electrode attached to the oral mucosa
It passes a direct current through the tissue
37
What is the average value of the resistance at the apical tissus?
6.5kohms
38
How acurste are apec locates?
90%
39
What are the problems with apex locators?
Dentine debris can deflect from accuracy
Avoid use on wide canals and open apices
Remove excess fluid
Wet canals: absolutely ALmmachines only from pus, exudate, hyochlorote
Heavily restored teeth: all machines
Poor contact of lip electrode
40
What is the radiographic working length?
Measurement from fixed reference point kncisallt or occlusals to the radiographic Apex of the root minus 1mm
41
What is the working length?
Distance from a fixed reference point on the crown of a tooth to the terminus near the radiographic apex
42
What is the terminus?
Point where tooth naturally constricts where secondary cementum invaginates
43
Once you have got your working length what must you check?
Canal patency
44
How can we open the orifice of the canal?
Hedstrom
Gates glidden
SX protaper fils
45
How are Hedstrom files made?
They are machines from a round blank by cutting a spiral groove along the shank. This creates a sharp cutting blade to produce a file with an aggressive cutting action
46
What are the dis of Hedstrom?
Creates a lot of debris
| Inflexible
47
How do you use gates gliddens?
Cut in out stoke
| Start with largest one and work way down
48
What type of cutting tip do GG's have?
Non cutting tip
49
How are GG's manufactured?
So they fracture at the neck
50
What sizes of GG's are there?
0.5 to1.5mm
51
How can you calculate the diameter of the GG?
In hundredths of mm
| 20(GG + 1) + 10
52
What is the process to orifice enlargement?
1. Size 10k file passed to apical constriction 1mm from apex using watch winding to check canal patency
2. Largest Hedstrom that passes 3mm into orifice is used with a rasping action cicrumfrentially around canal periphery and cut on out stroke
3. Use progressively smaller hedstroms but DO NOT NEGOTIATE CURVE
53
What is the purpose of orifice enlargement?
Removes heavily infected material
Improves access to apical third
Improved irrigation
Reduces the effective curvature
54
How are the standards of some endo instruments monitored ?
ISO: international standards applied to endo files
55
What does ISO relate to?
Standardised sizing relating to diameter 1mm from tip of instrument and colour coded handles
Standard working length of 16mm
Standard taper of 2%
56
What length are the files made in?
21
25
31
57
How do you use K files?
1. Small watch winding action at apex to create apical stop
2. Two sizes larger then the first file that binds and this is you MAF
3. Step back with progressively smaller files
4. Recapitulate with MAF
58
When would the step back technqiue be used?
Large canals
| Mostly anterior teeth
59
What instrumention techniques are thre?
Stepbac,
Modified Stepbac,
Crown down
60
How does the step back work?
Instrumentation of the canal starts at the terminus and works backwards to the coronal aspect
61
How does the modified step back work?
Coronal aspect is opened up first before creating terminal stop and flare backwards to first flare
62
How does the crown down technique work?
Instrumentation begins at the most coronal aspect towards the terminus
63
What are the filing techniques?
```
Balanced force
Reaming
Anti curvature
Watch winding
Longitindal circumferential
```
64
How do you instrument a curved canal with SS and NiTi files?
SS: watch winding and balanced force
NiTi: hand filing with balanced force and rotary filing
65
Outline the stages of modified step back
Access
Patency checked with 10k
EWL and CWL
Orifice enlargement using Hedstrom/GG
Create apical stop at CWL (MAF is 2 sizes up from first file that binds)
Watch winding with size 10 and 15 and blacked force with 20 above
Irrigate and recapitulate
Step back (second flare) 1mm shorter each time
66
What filing techniques can be used to create apical stop?
Balanced force and anti curvature
67
What are the advantages of the balanced force technique?
Superior shaping
File remains centrally within the canal
Less debris is pushed apically
68
What are the diasadvantes of the balanced force technique?
Needs copious irrigation and flute cleaning
69
What are the two phases to balanced force?
Power phase: engagement, this is when the place the file in canal until binds, advanced file by a clockwise rotation of 60 degrees
Control phase : cutting phase: apply apical pressure rotate file 120 degrees anticlockwise
70
What size k file do you use balanced force?
20+
71
What errors can arise in canal preparation?
```
Incomplete debridement
Lateral perforation
Apical perforation
Blocked canals
Ledging
Apical zipping
Elbow formation
```
72
How do apical zips arise?
Wrong rotation of the instrument
73
How do elbows form?
Inappropriate precurving
74
When is longitudinal circumferential filing used?
Large irregular shaped canals at the step back stage
75
What is the advantage of anti curvature filing?
Advantage: avoids strip perforation on inner curve or curved canal, uses a 3:1 filing ratio and need pre curved k files
76
Which is the disadvantage of anti curvature ?
Copious irrigation and recapitulate and careful of elbows
77
What are the ideal properties of root canal irritants?
```
Non irritant
Bactericidal
Dissolve organic material
Remove in organic material,
No staining to dentine
Libricates instruments
```
78
What irrigants do we use in RCT?
Sterile saline
LA
Sodium hypochlorite
CHX
79
What percentage of sodium hyochlorote do we use?
0.5-5%
80
What are the advantages of sodium hypochlorite?
Antibacterial
Dissolves organic debris
Non irrigant to vital tissues
81
Which chelating agents do we use?
EDTA 15/17%
82
What is the effect of EDTA?
Breaks down inorganic debris
Lubrcates
Gets rid of smear layer when used with sodium hypochlorite
Effervescence with sodium hypochlorite
83
How does the crown down technique work?
We of
84
How does the crown down technqiue workB
Removes heavily infected material from the coronal pulp chamber and improves irrigation and reduced the effective curvature of the canals
Coronal and mid sections of the canal are opened first and then they only engage a small section of the canal
85
When are protaper files used ?
Small canals curved canals
86
What is the order for protaper files?
```
SX: Orange
S1: purple
S2: white
F1: yellow ISO 20
F2: red ISO 25
F3: blue ISO 30
```
87
What is the cutting length of protwpers?
14mm
88
What is the maximum flute diameter for protwpers?
1.2mm
89
What are the advantages of protaoers?
Progressive taper design that improves flexibility and cutting efficiency
Fewer file changes needed
Engages smaller area of dentine this reduces torsional loads,mile fatigue, and potential for separation
Convex triangular surface which reduces contact between the file and the dentine
Greater cutting efficiency since balanced pitch and helical angles
Elasticity and shape memory
Progressive taper of 2-19%
90
T/F NiTi have two crystallographic phases?
T
Autensitic and martensitic
The phase change is stress induced
91
Which out of autensitic and martensitic is the daughter?
Martensitic
92
How much flexible is NiTI than SS files?
3-5
93
T/F there is decreased ledging and transportation with NiTi?
T
94
What is the sequence to protaper files?
1. SX file clockwise and engage dentine until snug
2. Disengage by rotating counterclockwise 45-90 with apical pressure e
3. Rotate handle clockwise whilst simultaneously withdrawing to ensure removal of dentine
3. Resstablish patency with size 10
5. CWL and increase apical stop to size 15 and then 20 to create Glyde pathway
6. S1
7. S2
8. Finishers
95
Which medicaments can be placed in the canal?
Chemical: beechwood creosol
Antibiotic/steroid
CaOH paste
96
Which antibiotic steroid paste formula is there?
1g Leadermix
30mg Demethylchlortetracycline (bacteriostatic)
10mg Triamcinalone acetonide
97
When should you use leadermix?
Actuatly inflamed vital pulp where Anlagesia for extirpation cannot be obtained
Insufficient time to embark on endo following pulpal exposure
98
What is usually the medicatment of choice?
CaOH
BP powder with 1:8 barium sulphate
Paste: hypocal and reogen
Life: catalyst paste only
99
What are the features of CaOH that make it ideal?
Hydroxide ion: pH12.5 which is bactericidal to wide group of organisms, effective solvent of organic debris, promotes hard tissue genesis, neutralises acids in areas of resorption, OH combines with lactic acid and stops action of dentinoclasts
Calcium ion needed to activate calcium dependant ATP reaction for hard tissue genesis from Krebs cycle
100
How do you place CaOH?
Spiral root filler
Hand file
Injection syringe
101
What are rh used ofnCaOH?
```
Pulp cap
Internist medicatment
Treatment of large Periapical lesions
Root resorption
Apexificatjon
Root fracture and perforation
```
102
What are the common temp dressings?
Cotton wool and GIC or ZnO eugenol
103
What should the master GP relate to?
Master file
104
How can the master cone be too long?
Incorrectly calculated working length
| GP too small and pushed through apex
105
How can the master GP be too short?
Incorrect working length
Filing debris has blocked terminus
Selected Master GP that is too long
106
What is the purpose of obturation?
To prevent microorganism from entering or re infecting the root canal
Prevent tissue fluids from percolating back into the root canal system and providing a culture medium for any residual bacteria
107
Obturation aims to provide?
A 3d coronal and hermetic seal to prevent microleakage
108
What is the smear layer?
Made from organic and inorganic debris and extends into tubules for 1-2 to 40 mincrons
May contain microorganism and creates an avenue for leakage microorganism
Acts as a substrate for microbial proliferation
109
How can you remove the smear layer?
17% EDTA with sodium hyochlorote
| 10-55% citric acid then sodium hypochlorite
110
Which materials we're used for canal obturation?
Paste
Silver points
Cements
Amalgam
111
Which material are used now?
MTA
| GP
112
What is the problem with silver points?
Single cone and relies heavily on sealer
113
What is GP made from ?
Transpolyisoprene
GP: 19-22%
ZnO: 59-75
Waxes, colouring agents and metal salts: 3%
114
What is the length of SX file?
19mm
115
What is the length of S1-F5?
21,25,31 mm
