Lec Access, Cleaning, and Shaping Flashcards

1
Q

Steps to endo:

A

diagnose, pretreat, access, clean and shape, obturate, restore

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2
Q

Access:

A

cavity, opening prepped to gain entrance to the RC system, not a hole

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3
Q

Shape of access hole reflects:

A

Shape of pulp chamber

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4
Q

Why do we need access hole?

A

remove entire pulp, get straight line access to apical 3rd

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5
Q

Access shape of incisors:

A

triangle

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6
Q

Access shape of canines:

A

oval

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7
Q

Access shape of premolars:

A

Oval

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8
Q

Access shape of mandibular molars:

A

trapezoid

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9
Q

Access shape of max molars:

A

triangle

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10
Q

Teeth that have triangle access preps:

A

incisors, max molars

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11
Q

Teeth that have oval access preps:

A

canines, premolars

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12
Q

Teeth that have trapezoid access preps:

A

man molars

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13
Q

Shape of incisors of eldery:

A

oval since pup horns are no longer there

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14
Q

Min size of access cavity:

A

max size of pulp chamber

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15
Q

This can happen if the access cavity is not developed smoothly and slowly through to the orfice of canal:

A

overextension of root wall

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16
Q

Gen principles for access cavity prep:

A

outline form, convenience form, caries removal

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17
Q

Define access form:

A

recommended shape of access cavity based on tooth type (and age of pt), external projection of internal shape

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18
Q

Define convenience form:

A

to facilitate instrument placement wo straining instrument, usually to gain straight-line access

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19
Q

Functions of caries removal:

A

aseptic env, allows assessment for restorability, sound tooth on which to place a provisional

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20
Q

We irrigate with:

A

sodium hypochlorite (NaOCl)

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21
Q

EDA sf:

A

estimated depth of access, from pre-op RG incisal/ occlusal to pulp chamber, how to find pulp chamber

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22
Q

2 steps to acces technique:

A

penetration, funneling

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23
Q

Access bur for ant teeth and most premolars:

A

2 round perp to lingual surface, outline form incisal to cingulum into dentin 2-3mm, redirect to long axis, funnel on out stroke to flare walls, esp incisally

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24
Q

You may not drop into pulp chamber if:

A

chamber is calcified

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25
Bur to flare walls of access cavity:
safe-ended diamond
26
TF? Flare walls of access cavity should converge G-I.
F. diverge
27
Ant teeth have __#__ anatomical triangles:
2: Lingual/ Dentinal, Incisal/Enamel
28
Problem related to anatomical triangles:
they impede straight line access
29
TF? Both anatomical triangles:o anterior teeth are in dentin.
F. 1 in dentin, 1 in enamel
30
To remove Lingual/ Dentinal anatomical triangles:
files, GG
31
To remove Incisal/Enamel anatomical triangles:
during funneling/ flaring access cavity: #2 round or safe-ended diamond
32
Dif bw perforation and gauge:
all the way through tooth, vs. impaled
33
3 laws for access orientation:
centrality, concentricity, CEJ
34
Law of centrality
chamber floor always in center of tooth at CEJ
35
Law of concentricity:
chamber walls share same center as external surface at CEJ
36
Law of CEJ:
most consistent, repeatable landmark for locating position of pulp chamber (PC)
37
Dif bw initial entry for access prep bw ant and pos teeth:
pos: straight down, ant: perp to lingual surface first, then straight down
38
How to place bur based on CEJ level:
tip of bur at mid-facial CEJ, parallel to long axis, keep orientation, access prep on lingual
39
3 types of filing motions:
Filing, Reaming, Watch winding
40
Filing:
dynamic movement, to debride canals, mainly push-pull
41
Reaming:
quarter turn clockwise rotation and pull (true reaming is rotation)
42
Watch winding:
rotating back and forth, 1/4 to 1/2 turn one direction, then the other
43
Only direction you can rotate while at the same time pulling the file out:
clockwise
44
What to do to files before using:
precurve, never touch files, GP or paper points w hands!
45
WL sf:
working length
46
WL:
coronal reference point to point at which prep and obturation should terminate
47
Where to terminate prep:
apical constriction/ minor apical diameter
48
How to determine WL in our course:
we define apical constriction as 0.5mm short of major foramen, WL = actual tooth length - 0.5mm
49
How to determine WL in real world:
apex locator
50
Filing motion to use when initially filing to WL determined by measurement from RG
watch wind: 8, 10, then 15
51
Length to which we initially file:
estimated RG length
52
Why is it most difficult ot move from a 10 file to a 15 file?
50% increase in diameter, use 10 file until it is very loose
53
15 file = ___mm
0.15
54
Reference point:
incisal or coronal point used to measure canal length
55
Ant vs. pos reference points:
incisal edge vs. cusp tip (triangular ridge
56
Level at which to stop stopper:
reference point
57
WL is always measured from here:
reference point, you must always communicate that to faculty
58
Smallest size file that will show up on RG:
15 file
59
Tip of fie must be within __mm of the major foramen:
1mm, as close to as possible
60
What to do if the file in during RG is flush w major foramen:
take file out and measure from stopper to tip of file
61
True RG length:
length of file from reference point to major foramen
62
WL from true RG length:
Ture RG length - 0.5mm
63
Major foramen usually exits here:
side of root
64
Cleaning
removal inorganic debris, organic substrates, related microorganisms
65
Shaping:
making shape to facilitate disinfection, irrigation, and placement of filling
66
TF? We clean to shape.
F. vice versa
67
Objectives of cleaning and shaping:
remove infected hard and soft tissue, make room for irrigation, make continuous, tapering, conical form
68
Do files do a lot of cleaning?
no, shaping
69
Mechanical instruments used:
hand files, rotary files, gates Glidden (shapes, little cleaning)
70
Chemicals used in irrigation:
Sodium Hypochlorite, chlorhexidine, EDTA ethylenediaminetetraacetic acid
71
Irrigant we use in clinic:
EDTA
72
How to clean the canal:
irrigation
73
Files instrumenting the canal leave over ___% of the walls untouched.
35%, irrigation essential
74
2 major technique concepts:
Step-Back, Crown-Down
75
Step-Back method:
smaller, more flexible files in apical 3rd, files sequentially larger than MAF at incremental lengths of 0.5 to 1mm short of WL
76
Taper in canal is created in this direction w the Step-Back technique:
apex to coronal
77
Crown-Down technique:
early flaring w rotary, incremental removal from orifice to apical foramen, larger to smaller files
78
Basic hand file technique at UB:
establish RG length, access, negotiate canal, establish patency, establish WL, instrument to WL to size 25 initially, flare coronal 1/2 w Gates 2,3,4 step-back), Step-back 1mm from size 25-60, establish a master apical file (MAF), step back again from MAF to 60, irrigating and checking patency all the times
79
MAF:
largest file used to full working length of the completely prepped root canal
80
To establish MAF:
at least a size 25, next set 30 to your WL and watch wind down wo forcing, if 30 reaches WL try 35, etc., when too large to reach WL, last file THAT REACHED WL is the MAF
81
Patency:
8 or 10 file placed slightly beyond major foramen, ensures WL is not lost & apical portion is not packed w debris
82
GG #2:
size 70 file
83
GG #3:
size 90 file
84
GG #4:
size 120 file
85
How to use GG files:
step-back (1-2mm) cutting on outstroke only and never beyond 1/2 of canal length (true WL, right? check)
86
Recapitulation:
Repeating steps to prevent debris build up in canal, sequential reentry and reuse of each previous instrument
87
Why do we step back twice if the numbers don't match up?
To keep the taper consistent (does this assume that we always leave some debris in canal or on the walls during the 1st step back? check)
88
Method for WL and initial prep:
get 10 to major foramen, 15 to WL, back to 10 to MF, up to 20 to WL, 10 to MF, 25 to WL, 10 to MF
89
GG flaring technique:
2 to 1/2 canal length, 10 file to MF, 3 to 1mm short of 1/2 canal length, 10 file to MF, 3 to 2mm short of 1/2 canal length, 10 file to MF
90
Step-back technique:
25 to WL, 30 to 1mm short of WL, 10 to MF, 35 to 2mm short of WL, 10 again, 40 file 1mm short of last, 10 file, 45 GG 1mm short of previous, 10 file again, 50, 55, 60 (no 10's bw? check)
91
MAF:
25 then 30 both to WL, 10 to MF, 35 to WL, 10 to MF, 40 to 1mm short of WL, 10 to MF, 45 to 2mm short of WL, 10 to MF, 50 to 3mm short of WL, 55 1mm short of 50, 60 1mm short of 55 (check, no 10's bw?)
92
Step-back always starts from which file?
The last one to go all the way to WL