cleaning and shaping the root canal

Question 1

RCT

Answer 1

prevent and intercept pulpal and pariradicular pathosis
2) preserve natural dentition when affect by pathosis
3) 95% for irreversible pulpitis
- 85% success for necrotic

Question 2

aim of RCT

Answer 2

1) clean, shape, disinfect
2) obturate
3) healing
4) primary goals are remove soft and hard tissue, create space for delivery irrigants, obturation material
5) preserve integrity of radicular structures

Question 3

mechanical objectives of cleaning and shaping

Answer 3

1) continuously tapering cone
2) prep in multiple plane creating a flow concept
3) prep should be wide coronally and narrow apically
4) apical foramen should remain in its original position
5) apical opening should be kept as small as is practical

Question 4

ideally

Answer 4

1) root canal should include complete and centered incorporation of the original canals into the prepared shape
- with current techniques, this goal is unlikely to be met
2) to retain as much cervical and radicular dentin as possible so not to weaken the root

Question 5

prep shape

Answer 5

1) removal of infected pulp and dentin
2) create prep shape and antimicrobial efficacy through the removal of pulp and dentin and creation of space for delivery of irrigants

Question 6

continuous taper that encompasses the original shape and curvature of a given root canal

Answer 6

1) final prep size and taper is debatable

Question 7

alloys in RCT

Answer 7

1) stainless steel
- stiff and inexpensive
1) nickel titanium

Question 8

isolation

Answer 8

1) single tooth isolation

Question 9

tip design

Answer 9

1) guide the file through the canal
2) cutting, non cutting, partially cutting
3) mishaps
- transport the canal if the tip is capable of enlarging the canal (cutting) and it remains too long in one position
4) break the file if a non cutting tip is forced into a canal smaller than the tip

Question 10

blade

Answer 10

1) the cutting edges of the file that deflects and chips from the wall of the canal
2) effectiveness depends on its angle of incidence

Question 11

flute

Answer 11

1) groove inbetween the blads

Question 12

helical angle

Answer 12

1) angle that the cutting edge males with the long axis of the file

Question 13

pitch length

Answer 13

1) distance between a point on the leading edge and the corresponding point on the adjacent leading edge

Question 14

taper

Answer 14

1) amount the file diameter increases each mm along its working surface from the tip towards the file handle
2) can have constant or variable taper

Question 15

ISO norms

Answer 15

1) taper .02 the increment in diameter is 0.02mm x each mm of length
2) all the colors except pink, gray, purple repeat every 6

Question 16

K type

Answer 16

1) k- files
- made by twisting a stainless steel wire with a square cross section
- increase the resistance to torsion and make the file useful in the negotiation of the canals
5) f-flexofiles
- triangular cross section, rounded end

Question 17

hedstrom

Answer 17

1) conical steel or niti wire with round section
2) it is ground into this shape

Question 18

barbed broach

Answer 18

1) machined from a conival blank filament of SS creating numerous hooks
2) have an elevated capacity of breaking

Question 19

filing

Answer 19

1) push pull movement 2-3 mm distance
2) can use circumferential filing
3) watch winding

Question 20

ni-ti rotary file features

Answer 20

1) ability to alter their type of atomic bonding which causes a significant changes in the mechanical properties of the properties and crystallographic arrangement of the allow
- temperature and stress
2) super elasticity and memory shape

Question 21

ESR CM vs WAVEONE

Answer 21

1) ESR CM is size #30 and less invasive, can be autoclaved
2) safety tip

Question 22

where to end the apical prep

Answer 22

1) apical limit
- distance from the major diameter (apical foramen to the CDJ 0.72m)
2) optimal end point is the apical constriction
- this in theory, would create the smallest wound
3) make a stable flat reference point
- in close proximity to straight line path of instrument

Question 23

how to determine working length

Answer 23

1) radiograph
2) apex locator
3) paper point
- used to confirm at the end of the appt

Question 24

radiograph

Answer 24

1) parallelling technique

Question 25

inaccuracy of radiographic WL

Answer 25

1) some clinicians have advocated the use of the electronic WL in lieu of the placement of a file in the canal and a radiograph
2) should be in the green, and you can decide if you want to be 0.5 mm shorter
- repeat the measurement 3 times

Question 26

apical patency

Answer 26

1) refers to passage of a small hand file to the apical foramen to prevent the blockage of the foramen due to debris

Question 27

glide path

Answer 27

1) smooth radicular tunnel from canal orifice to phsyiologic terminus
2) mechanical or manual