Quiz 1 Flashcards
what are the two ways to move a file?
rotary and linear
what basic file types (hand, endohandle, or handpiece) use rotary movement?
hand and handpiece
what basic file types (hand, endohandle, or handpiece) use linear movement?
hand and endohandle
which filing motion is used for apical filing?
balanced force
which filing motion is good for oval shaped canals?
circumferential filing
list the 5 types of filing motions
- watch winding
- linear filing
- balanced force
- circumferential
- reaming
what is the degree of the flute angle on a K-type file?
40*
what is the degree of the flute angle on a hedstrom file?
60* (most positive rake angle)
what is the degree of the flute angle on a reamer file?
20* (most negative rake angle)
which file is the most efficient hand file and why?
hedstrom because it has the most positive rake angle, meaning it is the most efficient at shaving and cutting
what are the rake angle functions for negative, neutral, and positive rake angles?
- negative - smoothing
- neutral - smoothing, minimal cutting
- positive - cutting and shaving
what are the 3 elements of a file that influence cutting?
- sharpness
- rake angle
- force
file efficiency is reduced after how many strokes?
200
during coronal prep, what is the order that gates glidden drills are used?
4, #3, #2
what are the corresponding numbers and sizes associated with #4, #3, and #2 gates glidden drille?
#4 = 110 = 1.1mm #3 = 90 = 0.9mm #2 = 70 = 0.7mm
what is the ideal taper?
0.05mm
describe the step back technique used to achieve ideal taper
- start with the initial apical file (ex. #25)
- determine working length (ex. 18mm)
- set first three files to working length (#25, #30, and #35 all set to 18mm)
- set each additional file back 1mm (#40=17mm, #45=16mm, #50=15mm, #55=14mm, #60=13mm, etc)
- using the watch winding movement with 4-8 cycles per file, work your way up through the files using passive gentle touch pressure only, returning to the IAF between each successive file. irrigate between each file.
- repeat as necessary
what files have a triangular cross sectional shape?
flex R, large K-reamer, large K-file
what files have a square cross sectional shape?
small K-flex, small K-reamer, small K-file
what files have a diamond cross sectional shape?
large K-flex
what files have a teardrop cross sectional shape?
hedstrom
what files have a double helix cross sectional shape?
unifile, S-file
what do the stripes on a file shank designate?
size and taper
what does file color coding designate?
size, and it may vary according to the manufacturer
what does the file # designate?
diameter at D0
what are barbed broaches made of? what are they used for?
- stainless steel
- remove canal contents
what motions are used for root canal prep?
reaming and filing
do reamers have fewer or greater twists?
fewer twists, meaning they have increased flute spacing
what is the only motion that can be used with hedstrom files and why?
filing motion only (not reaming) because it can stress the file and lead to fracture
what is the shape of a gates glidden?
elliptical
what are gates glidden drills used for?
used to open orifices and straight line access (removes the dentin shelf and does the coronal flare)
T or F:
gates glidden drills have a safe-tip
true
how do peeso reamers differ from gates glidden drills?
- they have longer cutting edges
- parallel instead of elliptical shape
- you can get them with or without the safe-tip
what are peeso reamers used for?
straight line access
gates glidden and peeso reamers should be restricted to what two uses?
orifice opening and coronal flare
what are lentulo spirals used for?
used with a slow-speed handpiece to spin pastes/sealers/cements into canal spaces
what are some ways you can place sealer material?
endo file or spreader, paper point, lentulo spiral, injection, or gutta percha cone
what are the two main obturation methods?
cold lateral condensation and warm vertical compaction
what is the taper on a standard spreader?
0.02
NiTi spreaders are good for what types of canals?
small curved canals
what are two uses for pluggers?
can be heated to transfer heat to gutta percha, or they can be used to compact gutta percha
what is a glick #1?
heated plugger
what is 70% isopropyl alcohol used for?
surface disinfectant
describe cold sterilization
- least desirable
- ~24 hour immersion in gluteraldehyde (or a similar solution)
- cannot verify with biologic indicators
describe steam/chemical autoclave sterilization
- gauze-wrapped
- 20 minutes at 121*C and 15psi
what is one advantage and one disadvantage of pressure sterilization?
- advantage = causes less rusting
- disadvantage = can dull sharp edges
what type of instruments is dry heat sterilization superior for?
sharp edged instruments
what temperature and for how long should you use dry heat sterilization?
160*C for 60 minutes
___ indicates that an object is visibly free of debris, stain, or potential contaminants
clean
___ is an attempt to reduce microbial contamination, but may not necessarily result in an object being sterile
disinfection
a ___ object is completely free of all bacteria, viruses, fungi, or other living organisms
sterile
what are the 5 criteria for canal preparation?
- develop a continuously tapered funnel
- maintain original shape of canal
- maintain apical foramen in its original position
- keep apical foramen as small as possible
- develop glassy smooth walls
what is the PURPOSE of shaping?
to facilitate cleaning and provide space for obturation materials
what is the OBJECTIVE of shaping?
to maintain/develop a continuously tapered funnel from canal orifice to apex
in lateral compaction, the canal should be large enough for the spreader to be placed within how many mm of the working length? what about for warm vertical compaction?
- lateral compaction - within 1-2mm of WL
- warm vertical compaction - within 3-5mm of WL
as dentin is removed from canal walls, does the root become more or less resistant to fracture?
less resistant - in other words, it becomes more prone to fracture
the degree of shaping is determined by what 3 things?
- preoperative root dimensions
- obturation technique
- restorative treatment plan
what are the 3 stages of root canal preparation?
- preflaring (prior to bringing any file to the apical third of the canal)
- instruments reach working length
- stage 3 is introduced in cases where canals are curved; in this case, stage 2 is used to create additional enlargement into the secondary curvature, and working length is reached in stage 3
what are the 6 properties of an ideal irrigant? is there currently any solution that meets all of these requirements? if so, what is it?
- organic tissue solvent
- inorganic tissue solvent
- antimicrobial action
- nontoxic
- low surface tension
- lubricant
there is currently no solution that meets all of these requirements
coordinated use of ___ and ___ is imperative to maximize the antibacterial efficacy of endodontic procedures
mechanical shaping and irrigation
___ is reciprocating, back and forth (clockwise/counterclockwise) rotation of the instrument in an arch and is used to negotiate canals and to work files to place
watch winding
___ is defined as the clockwise cutting rotation of the file
reaming
___ is defined as placing the file into the canal and pressing it laterally while withdrawing it along the path of insertion to scrape (plane) the wall
filing
___ is used for canals that are larger and/or not round, and involves placing the file into the canal and withdrawing in a directional manner sequentially against the mesial, distal, buccal, and lingual walls
circumferential filing
circumferential filing is not very effective beyond the ___ third of a root canal
coronal third
the stepback technique reduces ___ and improves ___
reduces procedural errors and improves debridement
the last file used in the stepback sequence is called the ___
final file
what is the basic difference between the stepback technique and the stepdown technique?
stepback involves going from smaller files to larger files, and stepdown involves starting with larger files and moving towards the apex with smaller files
the ___ method is considered the most effective hand instrumentation technique
balanced force
___ is accomplished by taking a small file to working length to loosen accumulated debris and then flushing it with 1-2ml of irrigant
recapitulation
if the MAF easily extends past the working length, the apical configuration is considered ___
open
if the MAF stops at the working length and a file 1-2 sizes smaller is placed at the same depth and also stops, the apical configuration is called an ___
apical stop
if the MAF stops at the working length and a file 1-2 sizes smaller is placed at the same depth and goes past the corrected working length, the apical configuration is called a ___
seat
