Root Canal Flashcards

1
Q

Steps to a root canal:

A

1) Access prep
2) Cleaning and shaping
3) Filling/obturation

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2
Q

cause of primary vs secondary endodontic infection

A

Primary- bacteroides (gram negative obligate anaerobe)

Secondary- Enterococcis faecalis

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3
Q

most important step of RCT for technique

A

access

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4
Q

shape of access for incisors

A

triangular or ovoid on lingual surface

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5
Q

shape of access for canines

A

ovoid

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6
Q

shape of access for premolars

A

ovoid (narrow)

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7
Q

shape of access for maxillary molars

A

4 canals (2 in MB root) –> blunted triangle/rhomboidal

3 canals –> triangular

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8
Q

shape of access for mandibular molars

A

4 canals (2 canals/root) –> rectangular

3 canals (more common, 2 canals in D root) –> trapezoidal

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9
Q

Which premolar is the most common to have two roots and two canals?

A

maxillary 1st premolar

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10
Q

How far is WL from the apex?

A

0-2 mm

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11
Q

What is this method of cleaning and shaping?
Shape the coronal third –> apical third –> middle third (small to big) usually using hand instruments
Shaping the coronal third allows access for a file to reach the apical third, at which the operator can then shape from apical to coronal

A

Step-back

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12
Q

What is this method of cleaning and shaping?
Coronal –> apical direction usually using rotary instruments (use progressively smaller files as you reach more apical, change files when you feel resistance)

A

Crown-down

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13
Q

refers to filling and sealing the cleaned and shaped canal system

A

obturation

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14
Q

2 obturation materials

A

gutta percha filler + ZOE sealant

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15
Q

Name the obturation technique: Using a finger spreader for placement of multiple gutta percha cones to WL until spreader can no longer penetrate the coronal part of the canal

A

cold lateral

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16
Q

Name the obturation technique: seating gutta percha cone to WL and using a heated plugger instrument to compress the gutta percha

A

warm vertical

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17
Q

instruments with a 0.04mm or 0.06 mm taper, uses an electric handpiece that rotates according to RPM

A

NiTi rotary instruments

18
Q

taper of SS hand files

A

0.02mm

19
Q

ISO color coding for SS hand files from small –> large

A

pink, grey, purple, white, yellow, red, blue, green, black

20
Q

SS hand files that are twisted-square in cross section, rotate clockwise –> counterclockwise

A

K-files (Kerr)

21
Q

SS hand files that have spiral grooves, aggressive, cuts in retraction

A

H-files (Hedstrom)

22
Q

drill used to open 1/3 of canal for straight line access

A

Gates-Glidden drill

23
Q

hand file with a twisted-triangle cross section, rotated clockwise

A

reamer

24
Q

hand file used to remove entangled and difficult to remove substances

A

barded broaches

25
Q

formula for file diameter

A

D0 + (# mm from tip) (taper)

26
Q

irrigant that dissolves tissue (organic matter) and is antibacterial

A

sodium hypochlorite (NaOCl)

27
Q

irrigant that dissolves inorganic material (smear layer) and lubricates

A

EDTA

28
Q

irrigant used in re-treatment to dissolve gutta percha

A

choloform

29
Q

when a pathway is created and allows communication between the root canal and periodontium

A

perforation

30
Q

Signs of perforation:

A
  • sudden pain
  • immediate hemorrhage
31
Q

tx for a perforation

A

internal repair with MTA

32
Q

Possible perforation locations:

A

Furcal- through pulp floor
Coronal- through the crown
Strip- from too much coronal flaring
Root- through root surface

33
Q

common location for strip perfs to occur

A

mandibular molars, distal surface of the mesial root (mesial side of mandibular molars has thicker dentin, so always favor this side)

34
Q

For a root perforation, there is a better prognosis the more _______ the perforation is.

A

apical

35
Q

an irregularity created by the operator on the root canal wall, occurs when the original pathway of canal is lost during instrumentation

A

ledges

36
Q

Ledges often occur in ________ and ________ diameter canals.

A

longer / smaller diameter

37
Q

Files naturally tend to straighten out in curved canals, hence _______ files are less likely to create ledges due to their flexibility.

A

NiTi

38
Q

bypassing the ledge by using a smaller instrument/file

A

renegotiation

39
Q

when an instrument breaks and remains within the canal

A

instrument separation

40
Q

Reasons why instrument separation might occur:

A
  • inadequate irrigation to allow instrument to move in and out
  • files are too big and get lodged in canal
  • used, weak files and more prone to fracture
  • flexible NiTi files more prone to fracture
41
Q

The _______ the complication/error occurs in the root canal process, the better the prognosis is. Why?

A

later –> more instrumentation and disinfection occurred prior to the fracture = greater proportion of bacteria removed and killed