cleaning and shaping II

Question 1

biomechanical

Answer 1

1) use of instruments with irrigants

Question 2

chemomechanical

Answer 2

1) chemicals with instruments

Question 3

purpose of instrumentation

Answer 3

1) remove debris
2) shape canal
3) permits irrigant penetration
4) prepare for obturation

Question 4

tapering funnel

Answer 4

1) tapering funnel from apex to access cavity
2) cross-section should be narrow at every point apically
3) foramen in original spot, small as practical
4) looks like a tornado

Question 5

working length

Answer 5

1) defined as length between coronal reference

Question 6

recapitulation

Answer 6

1) small K file or master apical file to remove debris

Question 7

patency

Answer 7

1) a size #8 k fil to go slightly through the foramen without binding or enlarging
2) removes the vapor lock so irrigant reaches apex

Question 8

working length and patency

Answer 8

1) working length is 0.5mm shorter

Question 9

anticurvature filing

Answer 9

1) danger zone near the furcation area
2) straighten as we use them, which can cause strip perforation

Question 10

balances force technique

Answer 10

1) K files with rounded batt tips
2) counterclockwise and clockwise

Question 11

what is taper

Answer 11

1) diameter increase per millimeter

Question 12

step back technique

Answer 12

1) you can create taper by backing off each 1 mm and increase 0.5mm diameter in size file

Question 13

pre-flaring crown doqn

Answer 13

1) less risk of extrusion
2) less risk of flare up
3) earlier penetration of irrigant
4) less change in working length
5) greater tactile sensation
6) apex locators are more accurate
7) less risk of breaking a file

Question 14

where to find apical constriction

Answer 14

1) 0.5 mm from the major diameter (apical foramen)
2) portal of exit is frequently not at the apex

Question 15

determine working length

Answer 15

1) apex locator and tells you where you are touching PDL
2) file in the root and take radiograph
3) paper point to check for tissue fluid after all the tissue has been removed

Question 16

apical preparation size

Answer 16

1) root canal systems were enlarged 2,3,4,5,6 sizes bigger than initial instrument
2) at least 3 sizes bigger promotes healing
3) minimum of 25.06 or 30.04
(diameter at apex and taper)
- for irrigant to reach the apex

Question 17

why use irrigants

Answer 17

1)35% of the canal is untouched by the instruments
2) impossible to remove bacteria from apex and ramifications
3) tissue and bacteria exist in isthmus between canals

Question 17

effect of taper

Answer 17

1) bigger taper increases the irrigation

Question 17

effect of size

Answer 17

1) bigger size increases irrigant

Question 18

ideal irrigant

Answer 18

1) antibacterials
2) remove smear layer and inactivate LPS
3) dissolve tissues

Question 19

no irrigant

Answer 19

1) possess all good qualities
2) sodium hypochlorite is irritating, cannot remove all smear later, not induce cell mediated response

Question 20

how does NaOCl work

Answer 20

1) saponification
- break down fatty acid
2) acid base reaction
3) chlorination
- break down AA, inhibit enzymes. damage cell membranes, denatures proteins, damage DNA

Question 21

maximize efficacy

Answer 21

1) multisonics that allow irrgant to work its way down to canals

Question 22

danger of sodium hypochlorite

Answer 22

1) if it goes outside the tooth into periodontal tissues
2) pain, swelling, major bleeding through the canal
3) bend the needle short, and side vented, measure the needle, keep syringe moving

Question 23

EDTA

Answer 23

1) chelator
2) removes the smear layer right before obturation
3) aids in canal instrumentation (negotiating blocked canals)
4) used in regenerative procedures to release GF from dentin

Question 24

chlorohexidine

Answer 24

1) DO NOT USE
2) doesn’t dissolve tissue
3) causes precipitation

Question 25

do not use compressed air or water

Answer 25

1) if it is not sterile or do not contain disinfecting properties

Question 26

calcium hydroxide

Answer 26

1) basic between 11-12 pH
2) dissolves tissues
3) inactivates LPS and cytokines
4) bacterial free in 7 days

Question 27

necessary radiographs

Answer 27

1) pre-op
2) working length
3) cone fit
4) mid obturation
5) post op

Question 29

proper sequence

Answer 29

1) subjective
2) we use brassler, NiTi rotary instruments = faster and preps are more centered
3) coronal flaring should be accomplished with the brassler to 1/3 WL
3) use apex locator and advance file to red area, then retract until bery last green
4) take WL radiograph

Question 30

cleansing and shaping

Answer 30

1) glide path must be established
- accomplished with hand files to a loose size #15
2) #25 then to #30 blue
3) canals should be flooded with sodium hypochlorite but glyde should not be used with rotary instruments because it increases torque

Question 31

mishaps

Answer 31

1)inspect files
2) do not reuse files
3) torsional failure or cyclic fatigue

Question 32

common complications

Answer 32

1) not enough irrigation
2) not maintaining patency
3) using instruments that are too big
4) using instruments out of sequence
5) packing dentin debris
6) never use a rotary instrument without creating a guide path to size #15 first

Question 33

pitfalls

Answer 33

1) transportation
2) ledge
3) apical zip
4) perforation

Question 34

golden rules

Answer 34

1) always have NaOCl in canal when shaping
2) use files in order
3) maintain patency

Question 35

rotary instrumentation

Answer 35

1) determine working length
2) coronal flaring
3) glide path to 15
4) irrigate and confirm patency with #8
5) 30.04 to working length
6) apical gauging