OPERATIVE Instrumentation for Operative Dentistry Procedures Flashcards
what are the two preparation hand instrument categories?
cutting and noncutting
what are the 3 parts of a hand instrument?
- handle, shank, and blade
- for noncutting instruments, the part corresponding to the blade is called the nib, and the end of the nib (working surface) is called the face
operative cutting instrument formulas consist of 3 or 4 numbers separated by dashes. what do the numbers correspond to?
- first number is the width of the blade or cutting edge in tenths of a mm (0.1mm)
- second number of a 4-number code indicates cutting edge angle expressed as a percent of 360 degrees
- third number of a 4-number code (or second number of 3-number code) is blade length in mm
- fourth number (or 3rd number) indicates blade angle
___ instruments are used to cut hard or soft tissues of the mouth
cutting
___ are instruments used for removal of caries and refinement of the internal parts of the preparation
excavators
___ are instruments used primarily for cutting enamel
chisels
what are the four types of excavators?
- ordinary hatchets
- hoes
- angle-formers
- spoons
which type of excavator has the cutting edge of the blade directed in the same plane as that of the long axis of the handle and is bibeveled?
ordinary hatchet
ordinary hatchets are primarily used on ___ for ___
anterior teeth for preparing retentive areas
which type of excavator has the primary cutting edge of the blade perpendicular to the axis of the handle and is used for planing tooth preparation walls and forming line angles?
hoe
which type of excavator is a monangle instrument and has the primary cutting edge at an angle other than 90 degrees to the blade?
- angle-formers
- they are available in pairs (R and L)
what are angle-formers used for?
sharpening line angles and creating retentive features in dentin and can also be used in placing a bevel on enamel margins
angle-formers may be described as a combination of a ___ and a ___
chisel and gingival margin trimmer
which type of excavator has slightly curved blades with cutting edges either circular or clawlike?
spoons
the circular edge of a spoon is called a ___, whereas the clawlike blade is termed ___
discoid, cleoid
spoon shanks may be ___ or ___ to facilitate accessibility
binangled or triple-angled
what are spoon excavators used for?
removing caries
what angle are the blades of chisels?
-straight, slightly curved, or binangle
where is the primary edge oriented in straight chisels? what other chisel is it similar in design to?
- perpendicular to the axis of the handle
- carpenters chisel
what is the name of the design for a chisel with a slightly curved shank and blade?
wedelstaedt design
the force used with all chisels is basically a ___
straight thrust