Access And Advances Flashcards
What is the first stage of endo treatment? And what does this entail?
- Access
2. Consider pulpal anatomy and need to remove the pulpal roof but do not damage pulpal floor. Identify canal orifices
What are the factors which would indicate if a tooth can be root treated?
General factors to consider: adequate access, poor OH, general health, attitude of patient
Local factors: PROVE + signs of resorption, unsusl anatomy
What must you ensure with regards to the access cavity?
It is divergent
It allows straight line access
What is the purpose of straight line access?
Allows for good instrumentation and irrigation
What is the problems with using radiographs to obtain information from?
Heavily restored dentition: restorations may mask anatomical information
What shoud the access cavity reflect?
The shape of the pulp chamber
When shoud the rubber dam be put on?
Once the access cavity is made
What percentage of upper second molars have two mesio buccal root canals?
65%
Where should you look for the second MB canals?
Need to look for a fissure which often extends from the main MB canal to the P canal
T/F C shaped canals may split part way down the canal?
T
They may also be continuous
Which burrs can be used to access the root canal?
Blunt tips,
Long shanks and
very small round head burs
What can be used to identify the canal orifice?
- Ultrasonic
- Magnification
- DG16 probe
What is the purpose of orifice engagement?
Aids straight line access to apical third
Removes heavily infected material
Reduces the effective curvature
Improved irrigation
What instruments can be used to enlarge the orifice?
Hedstrom
Gates glidden
Rotatary orifice shaper
How can you enlarge the orifice using the crown down approach?
- Hedstrom file first if size 3 GG cannot pass into canal
- Select the largest GG burr that will pass freely into canal
- Cut on out stroke
- Use progressive smaller gates glidden in the straight portion of the canal only
What are the aims of canal prep?
Clean / remove bacteria and organic debris
and shape : produce an ideal shape to receive obturating material
What solutions can be used to clean irrigate and librciate the canals?
- Sodium hypochlorite
2: LA - CHX 2% and new R4 20% which can be used as an antibac dressing
- Cheating agent eg EDTA
- Potassium iodide
What percentage solution is sodium hypochlorite used in?
0.5-5%
What are the properties of sodium hypochlorite?
- Antibac
- Dissolve organic debris
- Non irritant to vital tissue at low concentrations
What are the features of CHX as a Cana irrigant?
- Acts as a lubricant as the hibisscrub formula
- Low toxicity
- Broad spectrum
- Substantive
Which lubricating pastes can we use?
Canal plus, Glude
What are libricating pastes?
They are a group of material that improve the cutting effeciency of the file
What does Glyde contain?
10% urea peroxide
15% EDTA
Water soluble base
What is the purpose of Glyde?
- Lubrication which increases cutting efficiency of k files by 200% and Hedstrom files by 30%
- Acts as a chelating agent and removes the smear layer
Which chelating agents can we use?
EDTA 17% removed rhe smear layer
Citric acid solution
Which size irrigating needles do we use?
27 gauge side delivery needle which avoids extrusion through the apex
What are the areas for advances in canal preparation?
- File design
- Hand preparation technique
- Mechanised prep technique
What are the development in file designs?
- NiTi files
- Increased taper files
- Greater taper files
- Slow rotary files
- Bud shaped cutting file used in light speed
- Orifice enlarging files with greater taper design
What is the advantage of NiTi files?
They have improved flexibility and they only engage in the area of dentine that needs removing
Elastic behaviour
Use in slow rotation
Reduced straightening of curved canals
BUT sudden fracture and cost
What are the tapers of the increased taper files?
0.4 and 0.6
What are the tapers of the greater taper files?
;06, .08, .10, .12
How does the traditional step back technique work?
- Apical region prepared to MAF of ISO 25/30
- Canal flared towards coronal aspect by placing successively larger files 1mm short of previous instrument
- Recapitulate between all files
What are the problems encountered with step back technique?
- Diffcult to maintain CWL in curved canals
- Iriigation limited by narrowness of coronal orifice
- Debris forced apically
What have been the advances and modification to step back?
Hand filing
- Modified step back
- Anticurvatjre filing
- Crown down
- Balanced force
Mechanised
- Light speed
- Endo sonics
- Slow rotary: profile , hero , quantec, GT rotary, protaper
During the modified step back what happens first?
Canal patency is checked first using a size 10k with a watch winding technique to the apex
The orifice is then enlarged and this is where the coronal part of the curve is opened away from the Furcal wall and this the effective curvature is reduced
What is another name for anti curvature filing?
Abou rass
What is the main aim behind the AC filing?
Filing is directed away from the inner curvature of the canal and avoids strip peroration
When is AC filing mainly used?
In very curved canals
What filing ratio is used in AC filing?
3:1
Outer wall : inner wall
What is the disadvantage of AC filing?
Need copious irrigation and recapitulation
What must be done to the files for AC?
Bend them around a mirror handle of around the special instrument
What filing action is used with AC?
Push pull
DO NOT ROTATE
How are the tips of modern files shaped?
They are blunted to prevent them from gouging into dentine
