Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

3BDS ENDODONTICS > 2 - Accessing the Root Canal System: Incisors, Canines, Premolars > Flashcards

2 - Accessing the Root Canal System: Incisors, Canines, Premolars Flashcards

1
Q

a correctly sized and sited access cavity is one of the most important factors in allowing what?

A
  1. enabling efficient and effective root canal preparation and obturation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q 
good access cavity design: 
what does it allow?
what does it help avoid?
what does it provide?
why should we conserve as much tooth structure as possible?
A
  • allows
    1. removal of roof of pulp chamber and pulp horns
    2. direct vision of pulpal floor and canal orifices
    3. straight line access into canals
  • helps avoid damage to pulpal floor or perforation
  • provides retention for placement of a temporary restoration between visits
  • overzealous access cavities-> may render tooth unrestorable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

use of rubber dam to cut access cavity while inexperienced: why is it better to cut without?

A
  • cutting with rubber dam may risk losing orientation and perforating the tooth - especially if tooth is crowned, tilted, rotated or if pulp chamber calcified
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

with incisors - where is the most common perforation?

A

towards the labial surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

access cavity preparation - friction grip burs:
what is used to cut initial preparation?
what is used to cut through metal?

A
  • round or fissure diamond burs

- tungsten carbide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

access cavity preparation - latch grip round burs:

normal and long shanked burs are used for?

A

used to lift the roof of the pulp chamber and remove overhanging dentine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

access cavity preparation - safe ended burs: what is good about it?

A

non-cutting tip - avoids damaging the floor of the pulp chamber

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

5 general requirements for successful endodontics?

A
  • diagnosis and tx planning
  • knowledge of tooth anatomy and canal morphology
  • effective cleaning and shaping to the correct length
  • obturation
  • coronal seal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

cleaning and shaping the root canal system:

what does cleaning hope to achieve?

A
  • removal of organic pulp debris, microorganisms and toxins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

cleaning and shaping the root canal system:

what does shaping hope to achieve?

A

controlled removal of dentine to produce a tapering shape that can be disinfected and sealed throughout its length with a root canal filling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

biological objectives of root canal treatment?

A
  • confine instrumentation to the root canal
  • prevent extrusion of necrotic debris
  • remove all tissue debris and substrate for bacterial regrowth
  • create sufficient space for irrigation and intra-canal medication
  • complete cleaning and shaping in one visit if possible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

design objectives of root canal treatment?

A
  • to create a continuously tapering funnel shape
  • maintain apical foramen in original position
  • keep apical opening as small as possible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the use of a “front-surface” mirror?

A

it is an endodontic mirror that will not give a double image and it is used for all endodontic procedures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the aseptic technique? what is it used for?

A
  • aseptic technique: do not use instruments from RCT kit until tooth has been isolated by rubber dam
  • it helps to exclude contamination with organisms that have greater resistance to treatment than members of the root canal’s microbia e.g. facultative anaerobes & yeasts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

instrumentation:

what does it NOT do?

A

instrumentation DOES NOT:

  • eradicate endodontic infection
  • lead to healing of lesion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

instrumentation:

what are the aims of it?

A
  • mechanically removes pulp tissue, microorganisms and infected dentine
  • creates space for effective irrigation and disinfection
  • creates space for placement of a root canal filling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

instrument fracture: what may it affect?

what might happen if you try to remove excess tissue in order to retrieve the instrument?

A
  • it may impede disinfection of the root beyond the instrument
  • may cause reduced root strength or root perforation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

factors contributing to root fracture?

A
  • operator: lack of proficiency
  • instrumentation technique
  • instrument design
  • use of torque controlled motors
  • instrument size and radius of curvature
  • surface condition
  • rotation rate
19
Q

flexural stress (fatigue): how does it form and propagate?

A
  • microcracks form on surface of the metal

- these cracks propagate with loading, until instrument fails

20
Q

torsional stress:

  • also known as?
  • how does it occur?
  • when does the instrument fail?
A
  • shear failure
  • occurs when the tip or other part of the instrument binds to the canal wall, whereas the handpiece keeps rotating the instrument
  • file fails when the shear strength is exceeded
21
Q

rotary NiTi files:

  • most use speeds of?
  • each file requires?
  • how are they different from hand ss files?
  • used with what sort of motions?
A
  • 250-300rpm
  • a specific torque setting
  • files have a higher taper then hand ss files
  • pecking motion, brushing motion or painting motion
22
Q

what does torque refer to?

A

it describes the forces that act in a rotational manner

23
Q

low torque control motors:

  • torque values are set at which level?
  • why do motors have precise values?
  • values are low or high for which type of instruments?
A
  • torque value is set at less than the value of torque at deformation, and at separation of the rotary instruments
  • so that the limit of elasticity is not exceeded
  • low for smaller, less tapered instruments. high for larger, more tapered instruments
24
Q

ProTaper Next:
design features?
what effect does its movement have?

A
  • bilateral symmetrical rectangular cross section with an offset from the central axis of rotation
  • asymmetrical rotary motion that travels along the file
  • swaggering effect
25
Q

ProTaper Next:
file contacts canal wall at how many points in any given cross section?
how is this useful? what is it good for?

A
  • file contacts canal wall at 2 points in any cross section
  • minimizes engagement between file and dentine
  • improved safety and cutting efficiency, less stress on the file and more efficient debris removal
26
Q

ProTaper Next:

reduced engagement between instrument and dentine contributes to?

A
  • a reduction in taper lock, screw in effect, and less stress on the file
27
Q

ProTaper Next:
removes debris in what direction?
this allows for? which leads to?

A
  • removes debris in coronal direction
  • this allows for more space around the flutes, meaning that cutting efficiency is increased, as the blades stay in contact with the surrounding dentine walls
28
Q

endodontic microbes:

different species dominate at different stages: this depends on?

A
  • availability of nutrition
  • oxygen level
  • local pH
29
Q

endodontic microbes in primary cases?

A
  • nutrients: proteins and glycoproteins
    degradation of pulpal tissue and exudate
  • black pigmented bacteria (prevotella, porphyromonas)
  • fusobacterium nucleatum
  • veillonella parvula
  • eubacterium
  • enterococci 5%
30
Q

endodontic microbes in root filled teeth?

A
  • enterococci 29-77%
  • streptococci
  • lactobacilli
  • actinomyces
  • candida
  • eubacterium alactolyticus
  • propionibacterium propionicum
  • dialister pneumosintes
31
Q

limitations of instrumentation:

in oval shaped canals, only how much of the walls can be contacted by instruments?

A

40%

32
Q

root canal irrigants - ideal requirements?

A
  • eliminate or minimise microorganisms
  • inactivate endotoxin
  • dissolve necrotic pulp tissue remnants
  • lubricate the root canal instruments
  • remove the smear layer and biofilm
  • be systemically non-toxic
  • be non-caustic to periodontal tissues
33
Q

irrigants: examples?

A
  • sodium hypochloride
  • citric acid
  • ethyldiaminetetraacetic acid EDTA
  • 2% chlorhexidine
34
Q

sodium hypochloride:

  • what kind of antimicrobial effect? what can it eliminate? antimicrobial properties rely on?
  • capable of dissolving ___?
  • how much concentration?
A
  • broad spectrum antimicrobial effect
  • bacteria, fungi, spores, viruses
  • rely on free chlorine
  • can dissolve necrotic tissues
  • 1 to 5.25%
35
Q

sodium hypochloride:
how much concentration should be used?
at what volume?
for how long?

A
  • not more than 1% wt/vol
  • 20mls per canal
  • rotary preparation techniques are quick however sufficient time should still be allocated to irrigation
36
Q

sodium hypochloride disadvantages?

A
  • unpleasant taste
  • high toxicity
  • inability to remove smear layer when used alone
37
Q

complications during irrigation? how to avoid?

A
  • damage to clothing: use plastic bibs and ensure needle correctly attached to syringe
  • damage to eye: always wear safety glasses, eye should be washed with large amount of tap water/saline and patient referred to opthalmologist
38
Q

injection of sodium hypochloride beyond apex: happens when?

A
  • wide apical foramina
  • apical constriction destroyed during root canal prep or by inflammatory resorption
  • extreme pressure during irrigation
  • binding of irrigation needle tip
39
Q

symptoms of injecting NaOCl beyond apex?

A
  • extreme pain, burning sensation
  • haematoma and ecchymosis
  • swelling
  • profuse haemorrhage from the root canal
  • 2nd infection and tissue necrosis
  • parasthesia
40
Q

treatment of injecting NaOCl beyond apex - should focus on?

A
  • minimising swelling
  • controlling pain
  • preventing secondary infection
  • reviewing the patient until symptoms resolved
41
Q

treatment of injecting NaOCl beyond apex - examples of methods?

A
  • analgesics
  • external compression with cold packs, replaced with warm compresses for a few days
  • antibiotics may be needed to prevent secondary infection
  • refer to OS if pt requires surgical intervention
42
Q 
smear layer:
how is it produced?
contains what? 
what does it do?
what can it prevent?
A
  • cleaning and shaping the root canal can produce a layer that covers the instrumented walls
  • inorganic and organic substances e.g. microorganisms, necrotic materials
  • protects microbes in the dentinal tubules from the effects of disinfectants
  • prevents complete adaptation of obturation materials to the root canal surfaces
43
Q

chelating agents: 17% ethylenediaminetetraacetic acid EDTA: smear layer particles are soluble in?
they react with what in dentine to form what?
works with what to dissolve organic components?

A
  • soluble in acids
  • EDTA reacts with calcium (inorganic) ions in dentine, forms soluble calcium chelates
  • works with sodium hypochloride, which dissolves the organic components
44
Q

organic acids - 10% citric acid
works with?
can leave behind what?
how does it compare to EDTA?

A
  • works with NaOCl
  • precipitation crystals
  • not as effective

3BDS ENDODONTICS (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions