Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
spoon excavators, hatchets, chisel , gingival margin trimmers are?
|
Cutting Instruments
|
|
|
Parts of hand instrument?
|
Handle (shaft)
Shank Blade (nib) |
|
|
Most Handles are? diameter
|
5.5mm
|
|
|
Joins handle to blade?
Classified by number of angles |
Shank
|
|
|
-Angles of the shank are designed so the cutting edge of the blade lies within 2-3 mm of the axis of the handle.
|
Shank balance
resists rotation increases effectiveness of the blade reduces potential damage of tooth/soft tissue |
|
|
Refers to a shank in which two or more angles are required to bring the working end of the instrument to near alignment with the axis of the handle
|
Contra-angled instruments (shank)
|
|
|
Instrument Formulas:
-Primary cutting edge is at right angle to long axis of blade? -Primary cutting edge is not at a right angle to the long axis of the blade, curved instruments |
Three number formula
Four number formula |
|
|
Width of blade in tenths of?
length of blade in? angle of blade to handle in? |
mm
mm centigrade |
|
|
Circle divided in to 360 parts?
divided in to 100 parts? |
Astronomical Circle
Centigrade Circle |
|
|
Non-cutting instruments:
blade is replaced by? |
nib
|
|
|
blade and cutting edge are on a plane w/the long axis of the handle
-cleav/shave enamel in vertical direction and smooth gingival floor in class 2 preaparations -Right/left cutting |
Hatchet (enamel)
|
|
|
Primarily used on Max teeth
blades rotated 45degrees from the plane of the long axis of the handle |
Off-angle Hatchet
|
|
|
Removal of carious dentin
|
Spoon excavators
|
|
|
primarily for cutting/smoothing enamel
-angle <12.5 centigrade of blade to handle |
chisels
|
|
|
Planing preparation walls
-forming line angle -angle >12.5 centigrade of blade handle |
Hoe Excavator
|
|
|
Designed to produce a proper bevel on gingival enamel margins of proximal-occlusal preparations
-beveling axiopulpal line angle -mesial/distal <85/>90 c -angled in two directions r/l |
Gingival margin trimmers
|
|
|
shape amalgam and composite
|
Carver
|
|
|
condense smooth and finish filling margins
-bend cast gold restorations -shape metal matrix bands |
Burnishers
|
|
|
Double/single-ended instrument to carry triturated amalgam to prep.
|
Amalgam carrier
|
|
|
greatest delicacy of touch and stability grip?
|
modified pen grasp
|
|
|
used in patients mouth for increased control
-commonly used in lab |
Palm-thumb grasp
|
|
|
Principles of Sharpening (7)
|
clean
proper bevel angle light pressure use rest or guide remove little amount of metal lightlt hone unbeveled side of blade re-sterilize afterwards |
|
|
types of sharpening stationary stone
|
Microcrystalline quartz (arkansas stone)
Silicon carbide Aluminum Oxide |
|
|
Bur types:
carbide harder than steel -more efficient for intra-coronal preps, removal of restorative materials and tentive features. -more efficient for extra-coronal preps, beveling enamel margins, and enalmeloplasty |
Tungsten Carbide
Diamond |
|
|
Bur Cutting:
1.) used for high/low speed cutting 2.) originally developed for fissure burs to obtain adequate cutting effectiveness at low speeds. used at high speeds, produce unduly rough surfaces. Can be used to remove old restorations |
Fissure
Cross-Cut Fissure |
|
|
bur numbering is based upon ? of bur (ANSI)
|
Size (diameter)
|
|
|
(ISO) bur numbered based upon size and ? of bur
|
shape
|
|
|
Bur cutting surfaces:
side toward the direction of cutting (clockwise) -side away from direction of cutting? |
Rake Face
Clearance Face |
|
|
Angle created by rake face and the radius of the bur
-If rake face is ahead of radius, rake angle is said to be negative |
Bur Rank Angle
|
|
|
Most important design characteristic of bur blade
Increases life expectancy of bur Most effective performance w/ high/low speed ranges |
Negative Rake Angle
|
|
|
Produces more acute angle on edge of blade
Used to cut softer, weaker tooth structure (caries) Will leave irregular surface in sound enamel/dentin -blade chips and dulls rapidly |
Positive Rake Angle
|
